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LI Fengfeng, LI Yong, LI Lei, WAN Yang, CHEN Jiaheng, LU Yuedong
2025,49(5):1-15 ,DOI: 10.3969/j.issn.1673-5005.2025.05.001
Abstract:
The Cretaceous Mishrif Formation in the southeastern Iraq was deposited in a carbonate ramp environment, characterized by diverse and complex reservoir origins and significant development contradictions. Based on data of 11 coring wells across four oilfields in the southeastern Iraq, the sedimentary characteristics of the carbonate ramp were clarified, reservoir types were classified by integrating pore genesis, composition, physical properties, microstructure, and production performance, and the controlling mechanisms of the carbonate ramp on reservoir development were identified. The results show that the carbonate ramp of the Mishrif Formation is mainly influenced by wave action with weak tidal activity. Facies variation is not pronounced, components are poorly differentiated, reefs are difficult to preserve, and bioclastic shoals are widely developed. Allochems are rare but bioclasts are abundant. Gravity flows are absent, and lithologies are diverse in restricted environments. Reservoirs are classified into four types:vug-dominated, intergranular pore-dominated, isolated pore-dominated, and microporous-dominated. Vug-dominated reservoirs develop in point shoals and are jointly controlled by sedimentation, penecontemporaneous diagenesis, and tectonics. Intergranular pore-dominated reservoirs occur in barrier shoals and tidal channels, mainly controlled by sedimentation. Isolated pore-dominated reservoir form in lagoons and front shoal-basin settings, controlled by diagenesis. Microporous-dominated reservoirs develop in low-energy settings such as lagoons, slope bottoms, and deep-water shelves, with limited diagenetic alteration. Overall, in carbonate ramps, high-energy sedimentation promotes the development of high-quality reservoirs with strong microstructure heterogeneity. Deep-water and restricted environments control the formation of baffles and barriers. A large number of high-porosity but low-permeability reservoirs occur in open and deep-water environments, showing weak lateral heterogeneity, while restricted environments host complex reservoir combinations, with strong spatial heterogeneity due to facies changes.
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WANG Ke, ZHANG Ronghu, LI Ling, WANG Junpeng, HUANG Qingxuan, CAO Hui, WANG Lijuan
2025,49(5):16-30 ,DOI: 10.3969/j.issn.1673-5005.2025.05.002
Abstract:
Natural fractures are key factors in improving the quality of low-porosity reservoirs and enhancing petroleum productivity. Establishing natural fracture development models in analogous outcrops is an effective method to guide the prediction of subface fracture distribution.Using the Kuqa foreland basin as an example, a natural fracture development model of anticlinal structures was established by applying 3D laser scanning technology to identify natural fractures, supplemented by manual measurements and geological data from typical petroleum reservoirs. The evolution process of natural fractures was also analyzed. The results show that natural fractures in anticlinal structures of the Kuqa foreland basin are mainly high-angle, and can be classified into two stages (pre-fold and syn-fold) and five types. Pre-fold fractures are few in number and mostly ineffective, thus making only a limited contribution to petroleum accumulation in the basin. By contrast, syn-fold fractures abundant and highly effective, serving as efficient seepage channels for petroleum migration and forming essential geological conditions for fractured petroleum reservoirs in the Kuqa foreland basin. Although the density of natural fractures in the anticline cores is lower than that in the wings, the fracture aperture, permeability, and petroleum productivity are higher, consistent with exploration results from typical anticlinal petroleum reservoirs. Considering the current limitations of 3D laser scanning, such as the need to improve fracture recognition rates and the difficulty in identifying parameters like fracture aperture and filling coefficient, it remains necessary to develop feasible methods to further optimize and refine the technology.
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LIU Hua, HAN Xiao, PENG Guangrong, LONG Zulie, HOU Maoguo, YANG Xingye, LIU Pei
2025,49(5):31-43 ,DOI: 10.3969/j.issn.1673-5005.2025.05.003
Abstract:
The Huizhou 26 sub-sag is rich in oil and gas resources,but its fluid phases are complex and variable, with unknown origins. Based on crude oil properties, well fluid compositions, and organic geochemical data, this study applies empirical statistical methods and PVT phase diagrams to identify the hydrocarbon phase types in the area. The spatial distribution characteristics and genetic mechanisms of these phases are analyzed. Through a comprehensive examination of the formation stages and processes of different reservoir types , three phase evolution models are proposed:initial oil-phase filling, two-stage oil-phase superposition, and early oil-phase followed by late gas-phase charging. The results provide theoretical guidance for the efficient exploration of deep hydrocarbons. The crude oil from Huizhou 26 sub-sag is characterized by low density, low viscosity, low sulfur content, and high wax content. Three hydrocarbon phase types are identified:black oil, volatile oil, and condensate gas. Among these, black oil is the most widely distributed, while volatile oil and condensate gas occur mainly in the Huizhou 26-6 and 21-8 structural zones. Vertically, the Enping Formation is dominated by volatile oil and condensate gas, whereas black oil, volatile oil, and condensate gas coexist in the Wenchang Formation. Some wells display vertical alternation of oil and gas phases. The spatial variability of oil and gas phases is primarily controlled by the thermal maturity of source rocks and the hydrocarbon charging process. Specifically, the maturity level of hydrocarbons during the main filling stage and the extent of late mixing with high-maturity hydrocarbons are the key controlling factors.
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CHENG Bin, SUN Jie, FU Dawei, MA Dajun, CHEN Lijun, SU Ting, LIU Hua
2025,49(5):44-56 ,DOI: 10.3969/j.issn.1673-5005.2025.05.004
Abstract:
By analyzing the abundance, type and maturity of source rock organic matter, and utilizing rock pyrolysis instruments and Kinetics software, the hydrocarbon generation kinetic parameters of high-quality source rocks in the second section of the Wenchang Formation were obtained. These parameters were then integrated with typical geological heating rates as well as the burial and thermal evolution history of the depressions to clarify hydrocarbon generation characteristics and conversion rates. The results show that significant differences exist in the kinetic parameters and hydrocarbon generation characteristics of the second section of the Wenchang Formation across different sags of the Zhu Ⅲ depression. In Wenchang B sag, the activation energy distribution is relatively narrow (179.91-259.41 kJ/mol), with a lower main activation energy (213.38-217.57 kJ/mol). Hydrocarbon generation begins earlier, reaches its peak sooner, and exhibits a higher maximum generation rate. In contrast, source rocks in Wenchang C sag have a wider activation energy range (188.28-297.06 kJ/mol) and a higher main activation energy (225.94-234.30 kJ/mol), resulting in later initiation and peak of hydrocarbon generation, and a lower maximum generation rate. At present, hydrocarbon conversion rates of the Wenchang B sag source rocks are significantly higher than those of the Wenchang C sag, with rates exceeding 90% in the eastern sub-sag and 30% in the western sub-sag, while those in the Wenchang C sag generally remain below 10%. These differences in current conversion rates are mainly attributed to the combined effects of sag structural evolution and source rock hydrocarbon generation characteristics, which have significant implications for future oil and gas exploration. In particular, the eastern sub-sag of the Wenchang B sag shows substantial potential for mature oil and gas reservoir exploration , while the Wenchang C sag has relatively limited potential.
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FANG Zhengwei, LIU Huimin, TIAN Wen, ZHANG Pengfei, ZHANG Liqiang, GUO Wei, HAO Peng
2025,49(5):57-70 ,DOI: 10.3969/j.issn.1673-5005.2025.05.005
Abstract:
The shale in the steep slope and deep zone of continental faulted basins is characterized by large thickness, multiple lithofacies types, and complex vertical and horizontal variations. At present, the understanding of shale lithofacies distribution in these zones is limited, which restricts shale oil target-area and layer selection as well as exploration deployment. Using thin-section identification, whole-rock mineral X-ray diffraction, total organic carbon analysis, well-log interpretation, and seismic waveform analysis, a systematic study was carried out on the lithofacies characteristics and distribution patterns of shale in the Upper Sub-member of the Fourth Member of Shahejie Formation (E2s4cs) in the Minfeng Sub-sag, located in the steep-slope and deep zones of the Dongying Sag. The results show that four shale lithofacies are most developed in the E2s4cs of the Minfeng Sub-sag:organic-rich laminated carbonate shale, organic-rich laminated carbonate-mixed shale, organic-rich laminated clay-mixed shale, and organic-rich laminated felsic-mixed shale. The thickness center of the Minfeng Sub-sag is dominated by organic-rich laminated felsic-mixed shale, while the low-uplift area on the southern margin mainly develops organic-rich laminated carbonate shale; the transitional zone is dominated by organic-rich laminated carbonate-mixed shale and clay-mixed shale. From the northern source area to the southern margin of the Minfeng Sub-sag, four lithofacies combinations are developed successively, forming an irregular east-west-trending strip distribution in plane view. Vertically, from the bottom to the top of the E2s4cs shale interval, the distribution of felsic-mixed shale gradually expands across the subsidence center and is not influenced by the overall retrogradation of the glutenite body.
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WEI Baojun, XIA Kai, LIU Jian, ZHANG Bicheng, WANG Rongzhen
2025,49(5):71-81 ,DOI: 10.3969/j.issn.1673-5005.2025.05.006
Abstract:
The fractional Fourier transform (FRFT) was combined with a tongue-like curve variable-step adaptive filtering technique based on correlation characteristics to process linear frequency modulation (LFM) signals contaminated by noise. Simulation results demonstrate that most of the noise in LFM signals can be filtered out by first applying the optimal-order FRFT to time-domain signals, followed by the tongue-like curve variable-step adaptive filtering algorithm in the optimal fractional Fourier domain. This procedure allows for effective extraction of the useful signals. Under low signal-to-noise ratio conditions, the adaptive filtering technology outperforms moving average processing and wavelet transform methods, making it more suitable for extracting weak target signals from high-intensity noise and broadening its range of applications. When the transformation order is optimal, the signal error converges to its minimal value rapidly, and the final extreme value reached is the smallest, resulting in the best filtering performance. The larger the frequency modulation slope of the LFM signal, the higher the corresponding optimal order, and the mean square error under the optimal order increases. For multi-component LFM signals with varying intensities, a sequential extraction approach of first extracting strong signals then weak signals can be applied to extract different components step by step. This approach effectively reduces interference from strong components on weak components, thereby optimizing the extraction performance of the weak signals.
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Experiment on multifactorial mechanisms of CO2 injection for enhancing deep coalbed methane recovery
CHEN Zhangxing, LIANG Hao, LI Ying, LIU Zimin, LI Haitao, JIN Zhixiong, LEONHARD Ganzer, LI Ke, LI Hong, QIN Haiyang
2025,49(5):82-92 ,DOI: 10.3969/j.issn.1673-5005.2025.05.007
Abstract:
In this study, the field injection and production process were simulated using an online visual nuclear magnetic resonance (NMR) technique to investigate CO2-enhanced coalbed methane recovery (CO2-ECBM) through physical experiments, and the impacts of pressure, temperature, injection volume, water saturation, and pore characteristics on CH4 desorption and displacement were analyzed. The results indicate that increasing injection pressure from 10 MPa to 20 MPa can reduce CH4 adsorption capacity by 32.6%, demonstrating a significant role of pressure on enhancing the competitive adsorption of CO2. Temperature elevation can linearly decrease CH4 adsorption by 30%, while higher CO2 injection volume can reduce CH4 desorption by 27.6%, conforming to a linear relationship. Additionally, increased water saturation can reduce CO2 displacement efficiency, with a decline in CO2 adsorption capacity as water saturation increases, indicating that occupation of adsorption sites by water molecules inhibits the gas displacement process. Larger pore diameters can enhance CH4 adsorption capacity, and CO2 displacement efficiency can be improved progressively as pore size increases. The experimental results confirm the preferential adsorption of supercritical CO2 in deep coal seams, which is governed by multifactorial coupling mechanisms.
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GAO Yonghai, YU Xin, LI Hao, ZHAO Xinxin, SUN Xiaohui, SUN Baojiang
2025,49(5):93-101 ,DOI: 10.3969/j.issn.1673-5005.2025.05.008
Abstract:
In deep water drilling, there are challenges to work out the temperature and pressure variation patterns in wellbore and it is difficult to determine the gas influx (overflow) and drilling fluid loss positions, especially under the complex coexistence of overflow and loss conditions. In this study, a transient wellbore temperature and pressure model under the coexistence of overflow and circulation loss conditions was established, based on heat transfer analysis and accounting for the impact of variable mass flow in wellbore annulus on temperature and pressure changes. The analysis of the gas influx and circulation loss coexistence was conducted by defining and calculating the temperature and pressure differences along the annulus. The simulation results indicate that the temperature difference is generally greater under the condition of upper gas influx and lower circulation loss positions compared to that with upper circulation loss and lower gas influx, while the pressure difference is generally greater under the condition of upper circulation loss and lower gas influx compared to upper gas influx and lower circulation loss. An abrupt change of annular temperature difference in an open hole section mostly corresponds to a gas influx position, while a transition in annular temperature difference in an open hole section corresponds to a circulation loss position. A larger initial gas invasion pressure difference can result in a greater annular temperature difference at the wellhead. As the initial circulation loss pressure difference increases, the annular temperature difference at the wellhead decreases.
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YANG Hongwei, LIU Kerou, ZHANG Hui, YANG Boyuan, MA Dexin, YANG Zhi, LIU Junbo
2025,49(5):102-109 ,DOI: 10.3969/j.issn.1673-5005.2025.05.009
Abstract:
Electro-hydraulic pulse plasma is considered to be a new and efficient rock breaking technology. However, there is currently a lack of research on its rock breaking effect under the bottom-hole conditions in oil and gas well drilling. In this study, the rock breaking effect of electro-hydraulic pulse plasma under different confining and axial pressures was studied by experiments and stress wave modelling. A calculation model for the distribution of stress waves inside rocks under electro-hydraulic pulse plasma was established, and the distribution characteristics of stress wave peaks in granite rock samples were analyzed for the verification of the model. Coupling with the experimental testing of the ultrasonic parameters with granite, shale, and sandstone rock samples under different confining and axial pressures, the influence of confining and axial pressures on rock breaking effect by the electro-hydraulic pulse plasma was obtained. The results show that compressive, shear, and tensile stresses can occur simultaneously inside the rock sample under the impact of the electro-hydraulic pulse plasma shockwave, and the influence of axial pressure on rock breaking is greater than that of the confining pressure. When the confining pressure and axial pressure increase, the peak stress wave inside the rock also increases, indicating that the electro-hydraulic pulse plasma can also have good effects on rock breaking under real downhole drilling conditions.
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Electro-hydraulic fracturing experiments and numerical analysis of factors affecting crack formation
YU Qing, ZHANG Hui, LIU Kerou, CAI Zhixiang, YANG Ruizhi, MA Dexin, WU Yongchuan, LIU Junbo
2025,49(5):110-118 ,DOI: 10.3969/j.issn.1673-5005.2025.05.010
Abstract:
Electro-hydraulic pulsed discharge is a technology that can generate powerful shock waves in liquids, which can be used to effectively fracture rocks. In this study, indoor experiments were firstly carried out using two pieces of self-made concrete samples subjected to multiple electro-hydraulic shock waves to observe the fracturing effect. Then, using the nonlinear finite element software Ls-dyna, the electro-hydraulic pulsed discharge was considered to be equivalent to cyclic underwater explosion to obtain an indirect simulation of the rock fracturing process caused by the electro-hydraulic shock waves. The effects of discharge distance, charging energy, confining pressure and discharge times on rock fracturing were analyzed, and the order of the influence degree of each factor on crack formation was given by means of orthogonal analysis. The results show that, after 30 times impact loads generated by underwater pulsed discharge, crush zones, annular cracks, corner cracks and lateral cracks appeared on the concrete samples. The annular cracks, corner cracks, and lateral cracks can be mainly caused by reflected tensile waves, circumferential tensile waves, and water wedge effect. Crush zones were mainly caused by the head-on impact of shock waves and water wedge effect. The formation of rock fractures cab be inhibited by increasing the confining pressure, decreasing the charging energy, increasing the discharge distance and decreasing the number of discharges. The order of the inhibition effect to crack formation of the influence factors is confining pressure, charging energy, discharge distance and the number of discharges.
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SONG Yajun, DONG Changyin, LI Jingwei, XUE Dongyu, ZHOU Bo, LI Guolong
2025,49(5):119-126 ,DOI: 10.3969/j.issn.1673-5005.2025.05.011
Abstract:
In this study, simulation experiments were conducted to study the evolution of fluid inflow profiles and the formation mechanism of hotspots in non-homogeneous sand production horizontal wells using a large-scale horizontal well testing equipment. Three non-homogeneous reservoir rock models were constructed by an artificially cementing method. The experimental results show that fluid and sand production can exhibit a synergistic effect, with the difference of sand-out intensity between strongly and weakly consolidated reservoir regions increasing with the fluid production. Eventually, the sand production profile distribution is inverse to the initial compressive strength distribution, resembling the initial rock porosity and permeability distribution. Under the influence of the sand-fluid synergistic production mechanism, local high-rate inflow hotspots may emerge after long production periods. The experiments reveal that a hotspot area can contribute over 80% of the total fluid production. Due to the formation of high-rate inflow hotspots, the inflow coefficient in low consolidation strength/high porosity/high permeability regions can increase from an initial range of 0.2-0.4 to over 0.8. Meanwhile, the permeability distribution of the reservoir can shift from an initial gradual variation along the horizontal well to a highly heterogeneous distribution, with the values of permeability increasing by up to 17.5 times.
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NIU Langyu, CHENG Linsong, WANG Zhikai, JIA Pin, WU Yucheng
2025,49(5):127-136 ,DOI: 10.3969/j.issn.1673-5005.2025.05.012
Abstract:
To accurately study the multiphase production dynamics in shale reservoirs with highly developed beddings, a tri-phase (oil-gas-water) production flow mathematical model considering the interaction between opened beddings and shale matrix was firstly established. A dynamic drainage area (DDA) concept was introduced to solve the model, and the dynamic changes of the length and aperture of opened beddings were accounted. Based on the model, a production dynamic interpretation method was developed in combination with the straight-line analysis (SLA) and automatic history matching (AHM) methods. In a case study, the key flow parameters of a producing well in a typical shale oil block were interpreted using the new method presented in this paper, and the well 's production capacity was predicted. The results indicate that the closure of opened beddings in the length direction mainly affects the size of the matrix controlled by the opened beddings and has a significant impact on the peak production and gas production rate. Meanwhile, the closure in the aperture direction of opened beddings affects the peak production and decline rate of the oil-gas phases. The both closure mechanisms must be considered simultaneously in order to more realistically simulate the post-fracturing production process of shale oil.
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LIN Riyi, LI Chenglin, ZHENG Weibo, WANG Xinwei
2025,49(5):137-145 ,DOI: 10.3969/j.issn.1673-5005.2025.05.013
Abstract:
In order to solve the problem of intermittency in solar photovoltaic power generation, an unsteady state model of the packed bed phase change heat storage tank was established, and the influence of inlet flow rate, inlet temperature and initial temperature on the heat storage process was studied by numerical simulation. The results show that increasing the inlet temperature is the most effective way to improve the heat storage power. When the inlet temperature is 363 K, the heat storage power is increased by 21.2% and 75.2% respectively compared with that of 353 and 343 K. The increase of inlet flow rate does not change the total amount of heat storage, but results in a higher heat storage power and an increase in the thickness of the thermocline. The heat storage power at the inlet flow rate of 0.001 m/s is 20.4% and 64.8% higher than that of 0.0008 and 0.0006 m/s, respectively. The heat storage power at an initial temperature of 290 K is 6.2% and 12.7% higher than that of 295 K and 300 K, respectively, but the initial temperature has few effects on the thickness of the thermocline.
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XU Weiwei, ZHAO Yali, HUO Liming, YU Shiwen, CHEN Kai
2025,49(5):146-155 ,DOI: 10.3969/j.issn.1673-5005.2025.05.014
Abstract:
Suspended droplets in oil experience pronounced polarization and deformation under the influence of an external electric field. Traditional grid-based methods face limitations in capturing the intricate local features of the droplet interface, while gridless particle methods offer advantages with respect to capturing the droplet interface. The present study establishes a coupled model, consisting of smoothed particle hydrodynamics (SPH) and finite volume method (FVM). The nodal electric field force was solved using the FVM and transferred to SPH particles. Thereafter, the SPH method calculates the forces and updates the position information of particle. The coupling of the electric field and flow field enhances the precision of interface capture and numerical simulation. The numerical findings were compared and validated using published experimental data. Based on this, the study examines the aggregation behavior of droplets under a rectangular wave electric field, illustrating the process of droplet aggregation and analyzing the variation of interfacial tension. The results show that two droplets approach each other in an oscillating manner under a rectangular wave electric field, with interfacial tension hindering droplet approach and promoting the fusion process.
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WANG Huan, ZHANG Hongna, ZHANG Yiming, ZHANG Yongmin, WU Xiuhua
2025,49(5):156-164 ,DOI: 10.3969/j.issn.1673-5005.2025.05.015
Abstract:
In nuclear industry, cyclone separator is often used for gas-solid separation in circumstances such as transporting, processing and dust-controlling of uranium compound powders. In this study, the influence of temperature on the separation performance and flow field of a cyclone separator was simulated by using the commercial software Barracuda based on the MP-PIC model. The aim of this study is to test the feasibility of MP-PIC model in predicting the performance of the cyclone separator. The results show that the MP-PIC model can simulate the influence trends of inlet gas velocity and temperature on the performance indicators of the cyclone separator. The predicted performance and flow field parameter variation laws are generally in good agreement with the experimental results. However, the predicted vortex strength is quantitatively weaker than experimental results, and this is mainly reflected in the fact that the pressure drop and gas velocity obtained from the simulation are both to some extent lower than the experimental values. This is related to the large eddy turbulence model and the relatively low grid resolution used in the simulation.
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LI Changyou, REN Jingwen, WANG Yuting, WANG Hanxiang
2025,49(5):165-173 ,DOI: 10.3969/j.issn.1673-5005.2025.05.016
Abstract:
To address the current challenges of corrosion susceptibility, fatigue vulnerability, and excessive outer diameter in fiber-reinforced thermoplastic pipes (RTPs) connection joints, this study designed a novel fusion-reinforced joint based on theoretical modeling. A methodology combining finite element simulations and burst testing is employed to systematically investigate the failure mechanisms of fusion-reinforced joints of RTPs under burst loading conditions. The progressive damage evaluation method based on the VUMAT subroutine was developed by combining the 3D Hashin failure criterion with the maximum stress criterion, and integrating residual stiffness modeling and cohesive zone modeling. Experimental and numerical results demonstrate that the ultimate failure mode is the failure of the adhesive layer and the fusion zone. The damage evolution process progresses through four distinct stages, namely the initial undamaged stage, the adhesive layer damage stage, the matrix damage stage, and the final catastrophic failure stage. The damage of the adhesive layer spreads from both ends of the joint towards the center, with insufficient shear strength of the adhesive interface identified as the primary contributing factor. Matrix damage in the RTPs reinforcement layer initially occurs adjacent to the joint interface and progressively extends to non-joint regions. The matrix damage in the joint area is influenced by the expansion law of the adhesive layer damage.
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LI Shuai, ZHANG Guangqing, XUE Xiaojia
2025,49(5):174-182 ,DOI: 10.3969/j.issn.1673-5005.2025.05.017
Abstract:
Horizontal well multi-stage fracturing is one of the key technologies for the efficient development of unconventional oil and gas reservoirs. However, some well pads are limited by factors such as reservoir distribution and environmental protection, making it impossible to arrange wells conventionally. A new fan-shaped well network layout model was proposed to maximize the utilization of reserves in this type of reservoir. This study derives an analytical solution for the induced stress distribution of multiple wells and fractures in a new fan-shaped well network at any angle. The indoor hydraulic fracturing experiments on the fan-shaped well network were conducted to study the crack propagation law of adjacent horizontal wells in the fan-shaped well network, verify the model 's accuracy, and divide the risk zone of the fan-shaped well network. The results indicate that the change in angle between the horizontal well and the minimum horizontal principal stress affects the initiation and propagation of cracks. As the angle increases, the fracture morphology becomes more complex. The measured deflection angle of the crack is in good agreement with the theoretical calculation of the main direction, and this analytical solution can predict the direction of crack propagation. Due to the variable well spacing feature from the toe to the root of the fan-shaped well network, the new cracks at the root of the horizontal well are subjected to greater stress shadows from the old cracks in adjacent wells. According to the fracture morphology, the fan-shaped well network is divided into low-risk areas (the deviation angle of the horizontal well is less than 45°), medium-risk areas (the deviation angle of the horizontal well is 55 °-65°), and high-risk areas (the deviation angle of the horizontal well is greater than 75°).
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YIN Shixuan, XU Baochang, MENG Zhuoran, CHEN Yiqi, YOU Xiangning
2025,49(5):183-191 ,DOI: 10.3969/j.issn.1673-5005.2025.05.018
Abstract:
Drilling into formations with narrow safety pressure windows may lead to abnormal downhole conditions such as gas kick. Aiming at gas kick early detection in the managed pressure drilling process, an adaptive observer is applied to estimate downhole uncertain parameters and unknown states, and based on this, a gas kick detection method is established. A simplified gas-liquid two-phase flow model is established based on the "dual-shape" bubble representation approach, and is compared with OLGA simulation data to verify the validity of the model. A Luenberger-like adaptive observer is designed and applied to estimate the key parameters and states of downhole gas kick conditions, then a gas kick detection method is constructed by combining the Hotelling 's T2 test statistics. The results indicate that the designed adaptive observer can real-timely estimate the gas volume and accurately track changes of bottom hole pressure and outlet flow rate. Compared with acoustic method, delta flow method and pit volume method, the gas kick detection method can quickly and significantly achieve early detection of different gas kick situations.
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LI Guan, LIU Yudan, LIU Bin, MA Yunxiu, CHEN Lei, LIU Gang
2025,49(5):192-201 ,DOI: 10.3969/j.issn.1673-5005.2025.05.019
Abstract:
Pitting corrosion on the bottom plates of storage tanks is the primary cause of failure, and the three-dimensional morphology of pits is the crucial data for corrosion evaluation. Existing statistical studies on pitting corrosion mainly focus on one-dimensional or two-dimensional parameters, such as depth and aspect ratio, without fully reflecting the three-dimensional morphology of pits. To elucidate the evolution of the three-dimensional morphology of pitting under the oil-water-sludge covering layer on storage tank bottom plates, corrosion tests are conducted using Q235 steel. Surface morphology testing methods and MATLAB software are employed to statistically analyze the morphology and evolution of corrosion pits on the carbon steel surface. A classification method for pit types based on morphology is proposed, and mathematical representations of the three-dimensional morphology of different pit categories are developed. Furthermore, the evolution of pit morphology is characterized using typical parameters from mathematical functions. Corrosion pits are categorized into parabolic, conical, bimodal and flat-bottomed. The results show that during different corrosion stages, the shapes of the pits are mainly parabolic and conical. Parameters representing horizontal dimensions and surface inclination of pits follow a log-normal distribution, with the logarithmic mean (μ) showing an inflection point at 60 days of corrosion. Pit depth parameters follow a Gaussian distribution, with the mean value (μ) exhibiting an exponential increase with corrosion time.
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ZHU Xiping, YANG Xiliang, ZHANG Xin
2025,49(5):202-209 ,DOI: 10.3969/j.issn.1673-5005.2025.05.020
Abstract:
The electromagnetic bearing is a core component of integrated compressor units, and its reliability directly affects the operational stability. To address the challenges of insufficient failure samples, difficulties in reliability assessment and inadequate risk quantification for electromagnetic bearings of the high-power integrated compressor unit, this study proposes a state analysis model for electromagnetic bearings based on failure mode and effects analysis (FMEA) and Bayesian network (BN). By integrating prior knowledge with observed data, the model can effectively handle the incomplete and uncertain information, identifying 21 potential failure modes of electromagnetic bearings and their impacts. Based on the assessment results of severity, occurrence and detectability, the failure modes were ranked by risk, and the high-risk failures such as bearing collapse, frictional wear, power supply faults and bearing corrosion were analyzed. The results show that risk values of auxiliary bearing collapse, friction loss, power failure, bearing corrosion, main control board failure, signal transmission failure, etc. are relatively high. The corresponding optimization and improvement measures proposed based on the characteristics of failure modes can reduce the probability and impact of failures, and lower the research and development costs.
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In-situ polymerized gel electrolyte for constructing interface-stable high-voltage lithium batteries
LI Zhongtao, WANG Yimou, DU Yuting, JIANG Sisi
2025,49(5):210-219 ,DOI: 10.3969/j.issn.1673-5005.2025.05.021
Abstract:
Under high-voltage operation, the solvents and anions in traditional gel polymer electrolytes (GPEs) are prone to irreversible oxidative decomposition, leading to the formation of heterogeneous high-impedance cathode electrolyte interphase (CEI) film and the dissolution of transition metals. Meanwhile, the liquid components in the electrolyte react violently with the lithium metal to form a fragile solid electrolyte interphase (SEI) film. This exacerbates the uneven ion flux, dendrite growth, and accumulation of "dead lithium", significantly increasing the risk of short-circuiting and accelerating capacity fade. Therefore, a composite gel electrolyte was developed through molecular design and interfacial synergistic regulation strategies, using in-situ copolymerization of polyethylene glycol diacrylate (PEGDA) and 2,2,2-trifluoroethyl acrylate (TFEA) as the framework, and succinonitrile (SN) as an additive. The results show that the -CF3 groups in TFEA are preferentially reduced to form a LiF rich SEI layer, which has high ionic selectivity to homogenize the lithium-ion flux, inhibit dendrite formation, and achieve stable cycling of lithium symmetric cells for over 1 300 h. On the cathode side, the high-voltage oxidative decomposition of SN generates highly ionic Li3N, which synergistically constructs a stable CEI layer with the LiF component formed by the oxidative decomposition of TFEA, jointly suppressing the decomposition of solvents/lithium salts and the dissolution of transition metals. The electrochemical stability window of the electrolyte is significantly extended to 4.8 V, and the assembled Li||LiNi0.8Co0.1Mn0.1O2 cell achieves a high capacity retention of 75.23% (at 0.5 C) after 120 cycles at 4.5 V.
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ZENG Xiaojun, JIN Chulong, ZHANG Zuliang, LIU Jingzhou, ZHAO Huiqin
2025,49(5):220-226 ,DOI: 10.3969/j.issn.1673-5005.2025.05.022
Abstract:
A 2D/2D MXene/TiO2-MoS2 heterostructure was fabricated via wet etching. The structure was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). And the electrochemical properties of the heterostructure were investigated as well. It is found that wet-etching yields few layer of 2D MXene nanosheets, which could provide a larger surface area for the growth of ultrathin 2D MoS2 nanosheets. The MoS2 nanosheets tend to grow vertically on the MXene nanosheets, thereby offering a greater surface area and more exposed active sites. Some MXene nanosheets are in-situ derived into TiO2 nanoparticles, forming a rich heterogeneous interface between MXene, TiO2 and MoS2. And these interfaces modulate the electronic structure of the heterostructure, effectively improving its charge transfer efficiency, thereby improving the catalytic activity and stability of the material. The 2D/2D MXene/TiO2-MoS2 heterostructure exhibits remarkable oxygen evolution reaction (OER) performance, with an overpotential of only 376 mV at a current density of 50 mA/cm2. After a 40 h constant voltage stability test, the voltage retention rate reaches 99.2%.
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ZHAO Lianming, HAN Wenxi, YAN Guangkun, PENG Zeyue, DING Tao, REN Hao, XING Wei, ZHAO Guang, BI Weiyu
2025,49(5):227-235 ,DOI: 10.3969/j.issn.1673-5005.2025.05.023
Abstract:
The first-principles density functional theory calculations was used to investigate the performance of dual-atom catalysts (DACs) anchored on a Mo2CO2 MXene substrate (denoted as M1M2/Mo2CO2, where M1=Fe,Co,Ni and M2=Co,Ni,Cu) for the electrocatalytic conversion of methane (CH4) to methanol (CH3OH). The stability of the catalysts was assessed via formation energy and dissolution potential calculations. The catalytic activity and selectivity were probed through reaction free energy analysis. The origin of catalytic activity was elucidated via electronic structure analysis. It is found that the formation energy of M1M2/Mo2CO2 catalyst is from -4.44 eV to -2.62 eV, and the dissolution potential is between 1.03 V and 1.77 V, exhibiting excellent thermodynamic and electrochemical stability. Among them, the activation energy barrier of methane on CoCu/Mo2CO2 is only 0.05 eV, indicating excellent catalytic activity. Within a potential window of 0.74 V to 1.01 V (vs. RHE), this catalyst achieves methanol selectivity exceeding 99%. The catalytic activity shows a positive correlation with the charge ratio (q(M1)/q(M2) of the dual-metal centers. The high activity of CoCu/Mo2CO2 originates from its q(M1)/q(M2) ratio of 0.3, which is close to the theoretical optimum value.
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XU Na, LI Manman, LIU Bin, CHAI Yongming, DONG Bin
2025,49(5):236-245 ,DOI: 10.3969/j.issn.1673-5005.2025.05.024
Abstract:
Through a coordination-driven self-assembly strategy of ultrathin tannic acid (TA) layer and Ru ions, the electronic structure (Ni(OH)2-TA-Ru) rich in 2 nm Ru nanoparticles on the surface of nickel hydroxide was optimized. Electrochemical evaluations, structural characterizations, and density functional theory (DFT) calculations were utilized to assess the hydrogen evolution reaction (HER) activity, long-term operation stability, and electronic structure characteristics of Ru active sites. It is found that Ni(OH)2-TA-Ru only requires 53 and 70 mV overpotentials at 100 mA/cm2 in 1 M KOH and alkaline seawater (1 M KOH + seawater), respectively, which are 51.7% and 36.2% lower than that of Pt/C/NF (109.7 mV). Chronopotentiometric tests are stable for 100 h and 72 h, respectively. The TA ultrathin layer modified Ni (OH)2 support induces the formation of electron-deficient Ru species, downshifting the Ru d-band center by 0.35 eV. This electronic restructuring weakens Ru-H bond strength, accelerates the desorption of hydrogen intermediates (H*), and promotes the Heyrovsky rate-determining step and enhancing alkaline HER kinetics.
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SUN Meng, LIU Hongyan, WANG Xiaokang, XU Mingming, JIANG Beibei, HOU Manman, FAN Weidong, SUN Daofeng
2025,49(5):246-254 ,DOI: 10.3969/j.issn.1673-5005.2025.05.025
Abstract:
Two isostructural copper-based metal-organic frameworks (UPC-55 and UPC-56) were synthesized via a solvothermal reaction using methoxy-functionalized tricarboxylic acid ligands and copper nitrate. Their structures and stability were characterized and tested through single-crystal X-ray diffraction, thermogravimetric analysis, and infrared spectroscopy. It is found that the treatment of methoxy functional groups makes UPC-55 and UPC-56 exhibit selective adsorption of C2H2. Due to differences in functional group positioning, their adsorption separation capabilities vary slightly. At 298 K, the adsorption of C2H2 by UPC-55 and UPC-56 are 31.8 cm3/g and 52.2 cm3/g. The equal proportional C2H2/CO2 separation ratios are 3.508 and 5.345, respectively.
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ZHAO Qingshan, WANG Hui, LIU Yachao, HAN Xuan, NING Hui, WU Mingbo
2025,49(5):255-264 ,DOI: 10.3969/j.issn.1673-5005.2025.05.026
Abstract:
A ternary deep-eutectic solvent (DES) system was constructed using glycerol, urea, and cobalt chloride. And a three-dimensional nanoflower-like nickel foam-supported CoCO3-NiOOH catalyst (CoCO3-NiOOH/NF(D) was fabricated through one-step deep-eutectic solvothermal method. The results show that the foam nickel support in situ reacts with the ternary DES under solvothermal conditions, resulting in a composite of CoCO3 and NiOOH enriched with oxygen vacancy defects. The three-dimensional conductive network effectively promotes interfacial electron transfer and the exposure of active sites. The prepared CoCO3-NiOOH/NF(D) catalyst exhibits excellent electrocatalytic oxygen evolution (OER) performance. The overpotential is only 295 mV at a current density of 20 mA/cm2 and the Tafel slope is 78.1 mV/dec. The performance is much better than the CoCO3-NiOOH/NF(W) catalyst synthesized by the traditional hydrothermal method ( 407 mV, 112.8 mV/dec). Additionally, the CoCO3-NiOOH/NF(D) catalyst also demonstrates excellent cycling stability, maintaining a current density retention rate of 92% after a long-term stability test of 60 h.
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LI Yan, MA Zhe, SHANG Jingyuan, WANG Ting, FENG Xiang, CHEN Xiaobo, YANG Chaohe, CHEN De
2025,49(5):265-272 ,DOI: 10.3969/j.issn.1673-5005.2025.05.027
Abstract:
In order to clarify the structure-activity relationship between the microscopic pore structure of zeolites and the reaction performance of polyethylene, the performance of four zeolites with different pore structures (regular microporous channels and cage structures) in the catalytic cracking reaction of polyethylene were explored. It is found that for SAPO-34, the long chain hydrocarbons produced by the initial thermal cracking are difficult to enter the pores of the zeolite for catalytic cracking, and the products are mainly long chain alkanes/olefins. Thermal cracking intermediates are more likely to be catalytically cracked into light olefins in the pores of ZSM-5 zeolites. The large pores of Beta and USY zeolites provide a certain space for the secondary reactions of low carbon olefins (such as Diels-Alder reaction, cyclization and aromatization), and the final products contain more aromatic hydrocarbons. Compared with Beta zeolite, the unique cage structure of USY limits the contact and further reaction of the reaction intermediates with some active sites to a certain extent, and reduces the yield of aromatics and light olefins.
Volume 49,2025 Issue 5
地质与勘查工程
地质能源开采工程
能源装备与控制工程
先进能源材料
Volume 49,2025 Issue 5
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FENG Cong-jun, SHAN Qi-tong, SHI Wei-cheng, ZHU Sui-wei
2013(1):1-7 ,DOI: 10.3969/j.issn.1673-5005.2013.01.001
Abstract:
The reservoirs heterogeneity and its control on the remaining oil distribution of K1q4 in Fuyu Oilfield were researched on the basis of core analysis, physical property, logging curve and dynamic data. The results show that the reservoir heterogeneity is serious. Three types of interlayer of muddy, calcium, muddy gravel are found in the formation, and there are five vertical connection ways in the interlayer sand body. Plane porosity and pore parameters, heterogeneity coefficient distribution are obviously influenced by sedimentary microfacies and sand body distribution. The parameter value of main part of the river is high, the more it near the river channel, the lower the value of parameter is. Interlayer 's unconnected-distribution makes the reservoir heterogeneity more serious. Because of division of interlayer, the whole sand body is divided into several independent parts and the traditional remaining oil distribution of rhythm sand body changes. At the same time, the lateral distribution of the interlayer controls the range of remaining oil efficiently.
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CAO Ying-chang, YANG Tian, WANG Jian, YUAN Guang-hui, XI Ke-lai, LI Xiao-yan
2013(6):1-9 ,DOI: 10.3969/j.issn.1673-5005.2013.06.001
Abstract:
This study focused on the beach-bar sandstone reservoir in the upper part of the fourth member of Shahejie formation in the southern slope of Dongying sag. Core, thin sections, physical properties and other technical methods were used to analyze the characteristics and genesis of effective reservoirs. The results show that the reservoir pore space includes mainly primary pores with partial secondary and mixed intergranular pores. Favorable sedimentary environment is the foundation of high-quality reservoirs. Different kinds of diagenesis and their intensity affect the quality of reservoir. Hydrocarbon charging and overpressure are the favorable preservation conditions of reservoir properties, and their interactions affect the types of reservoir space, the distribution and combination, and evolutional characteristics of reservoir. The distributions of pore space in effective reservoirs are sectionalized in depth. At 1.0-2.0km, weak diagenesis and well preservation of primary porosity in ordinary pressure form effective reservoirs which contain mainly primary pores. At 2.0-3.1km, dissolution increases reservoir space. Hydrocarbon charging and overpressure save reservoir space and form effective reservoirs which have primary pores, secondary pores and mixed pores. At 3.1-3.6km, hydrocarbon charging and overpressure hold part of primary pores and form effective reservoirs which contain mainly primary pores and a few secondary ones.
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DUAN Wei, HOU Yu-guang, HE Sheng, TU Wei-wei, YIN Shi-yan, QUAN Yong-bin
2013(6):17-23 ,DOI: 10.3969/j.issn.1673-5005.2013.06.003
Abstract:
Combining comprehensive analyses of geological, geophysical and geochemical data and modeling using petroleum system modeling technology, this study tries to restore the evolution processes of organic matter in three sets of Paleozoic shales with no or little drilling data in Petrel subbasin of Bonaparte Basin in Australia. The results show that the entire Permian is the generation peak of Carboniferous shale gas, and the Middle and Late Permian may be the generation peak of oil cracking gas. The shale gas in the Carboniferous Milliigans formation may have been under destruction since the Jurassic, leaving presently limited gas in the shale. The Jurassic is the generation peak of shale gas in the Permian Keyling formation. The shale of Hyland Bay formation in the upper Permian has been at gas generation peak since the Tertiary, and the period since the late Tertiary may be the generation peak of oil cracking gas. Controlled and influenced by regional differential settlement, the source rocks in the middle and north part of Petrel subbasin are deeper with a relatively high degree of organic evolution, while in the east and west part of the basin the rocks are shallower with a relatively low degree of thermal evolution.
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PENG Bo, ZOU Hua-yao, TENG Chang-yu, HAO Fang
2013(6):10-16,23 ,DOI: 10.3969/j.issn.1673-5005.2013.06.002
Abstract:
Based on 545reservoir pressure measurements in 186boreholes and the calculated shale pressure of 65boreholes using equivalent depth method, the evolution and distribution characteristics of overpressure in Damintun depression were studied by using numerical simulation method. The dynamic mechanism of hydrocarbon expulsion from the thick source rock was discussed through the integrated analysis of the evolution, distribution and activity of faulting in the depression. The results show that overpressure is extensively developed in the depression. Compaction disequilibrium resulted from high sedimentary rate and hydrocarbon generation are the main controlling factors for the development and evolution of overpressure. The numerical simulation shows that overpressure increased gradually from the period of Es4and reached maximum at the period of Es1. The development of overpressure is relatively slower in the faulting zone. It is suggested that overpressured fluid is mainly episodically expulsed from geopressured sediments. The dynamic mechanism of overpressure-dominated and tectonic-overpressure controlled episodic petroleum accumulation includes natural hydraulic fracture, mud diapir, faulting dominated and overpressure promoted.
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YU Shun, LIU Guang-di, SUN Ming-liang, SONG Xin-xin, YANG Jiao
2013(6):24-30,35 ,DOI: 10.3969/j.issn.1673-5005.2013.06.004
Abstract:
Targeting at Ordovician carbonate reservoirs and their hydrocarbon enrichment characteristics in Tabei Uplift, this study focuses on the methodology and critical parameter distribution models for petroleum resources assessment in marine carbonate rocks. Petroleum resource of calibrated area in Ordovician carbonate reservoir was calculated, and it is shown that the Ordovician carbonate reservoir in Tabei Uplift can be divided into two types:the buried hill karst and the internal karst. Thin layers of oil and gas overlap vertically, and tend to connect laterally in the horizontal plane to form large areas of distribution. Therefore, the carbonate reservoirs are characterized by wholly oil-bearing and locally enriched oil, and the oil and gas enrichment is mainly controlled by carbonate reservoirs. By statistically analyzing petroleum geology data, critical distribution model parameters in petroleum resources assessment in marine carbonate calibrated areas were obtained. These parameters distribution models include effective thickness coefficients, effective area coefficients, effective volume resource abundance and effective area resource abundance model. Petroleum resource in the buried hill karst calibrated area was calculated based on Monte Carlo simulation using effective volume resource abundance and effective area resource abundance. The results show about 1.47343billion tons of oil and about 276.6billion cubic meters gas deposits, suggesting great exploration potential in marine carbonate rocks in Tarim Basin.
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LI Zhao-min, L Qi-chao, LI Song-yan, LI Bin-fei, SUN Qian
2013(5):100-106 ,DOI: 10.3969/j.issn.1673-5005.2013.05.015
Abstract:
Fracturing treatment is essential for the development of coalbed methane(CBM) fields. In the fracturing of coal seams, high filtration loss, serious formation damage, low flow-back and poor efficiency were the main problems when using conventional water-based fracturing fluids. A nitrogen foam fracturing fluid system with low formation damage was developed based on the geological features of CBM reservoirs. The formula of the foam fluid mainly includes a bactericidal agent, foaming surfactants and clay stabilizers. Filtration loss, dispersion, and microscopic foaming experiments were conducted for testing the capacities of the fluid system as a foaming and fracturing fluid. Experimental results show that the fracturing fluid has a good foaming ability and foam stability, excellent shearing bearing ability, strong sand carrying capacity. The plugging effect of foam can significantly reduce the filtration loss, and nitrogen can improve the flow back ability of the fracturing fluid. The surfactants in the fracturing fluid can also reduce the interfacial tension between coal and water, thus improving the dispersion of coal powders in the fluid. In comparison with conventional fracturing fluids, the nitrogen foam fracturing fluid can cause much less formation damage to the CBM reservoir.
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YAN Zi-feng, WU Xiao-zhong, XING Wei
2013(5):186-189 ,DOI: 10.3969/j.issn.1673-5005.2013.05.027
Abstract:
A self-assembly method was adopted to synthesize graphene oxide aerogel (GOA), which was further reduced by hydrogen at 1100℃ to obtain graphene aerogel (GA). Nitrogen adsorption analysis results show that both aerogels possess high BET surface areas (approximate 870m2·g-1). FT-IR analysis results reveal that the surface of GOA has more oxygen-containing groups than those of GA. Elemental results display that the C/O molar ratios of GOA and GA are 1.7and 69.9, respectively. Electrochemical measurements show that at the current density of 0.2A·g-1, the specific capacitance of GOA with high surface functionalized degree could reach up to 155.8F·g-1, while GA with low surface functionalized degree exhibits a high-rate supercapacitive performance.
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YAO Jun, LIU Pi-yang, WU Ming-lu
2013(5):107-113,119 ,DOI: 10.3969/j.issn.1673-5005.2013.05.016
Abstract:
Based on Green 's function and source functions, the analytical solution of pressure in a horizontal well with multiple hydraulic fractures was obtained by using mirror-injection and superposition theorem. At first, pressure drop was derived in three different conditions:infinite surrounding, prescribed flux and prescribed pressure when the top and bottom of the formation were prescribed. Then, new solutions of the wellbore pressure were described assuming that the wellbore of the horizontal well had infinite flow conductivity. According to Stehfest numerical inversion, the pressure drop was derived considering wellbore storage and skin factor. The pressure plots and pressure derivative curves on different conditions in the fracturing horizontal and the influence of fracturing parameters were analyzed. The results show that there are five flow regimes including fracturing linear flow, fracturing radial flow, formation linear flow, system radial flow and bound influence. For a dual porosity model, cross flow exists which flows from matrix system to the fracture system. In dimensionless form, pressure drops when the fracturing number rises. However, when the pressure wave reaches the boundary, the fracturing number has little effect on the flow. The fracture length influences both the time when the fracturing radial flow appears and the pressure drop before forming linear flow. Under the same production time, the longer the fracture length, the later the fracturing radial flow appears and the less the dimensionless pressure drops. The spacing between two fractures influences the time when the fracturing radial flow ends; when the spacing is smaller, the time for fracturing radial flow lasts shorter. The results are verified in engineering application to prove the feasibility of the models.
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PU Boling, DONG Dazhong, WU Songtao, ER Chuang, HUANG Jinliang, WANG Yuman
2014(4):19-25 ,DOI: 10.3969/j.issn.1673-5005.2014.04.003
Abstract:
To ascertain the contribution of different pores to shale gas reservoir, pore types, size and distribution of Lower Paleozoic marine shale in southern Sichuan Basin were studied using a variety of analytical testing methods. Pore space characteristics and influencing factors were discussed. The results show that Lower Paleozoic shale reservoir space can be divided into three main types, including mineral matrix pores, organic pores and micro-fractures, and can be further subdivided into nine types. Organic pores and interlayer pores between clay minerals are mainly developed in Longmaxi shale. Organic pores, dissolution pores and fractures are mainly developed in Wufeng shale. Organic pores are rarely in Jiulaodong shale, where dissolution pores and fractures are well distributed. Pore types and distributions show differences in Lower Paleozoic shales, which are mainly affected by mineral composition, the abundance of organic matter and diagenetic evolution. Micro-pores are developed in Lower Longmaxi shale, with high specific surface area, providing a bulk of reservoir spaces for shale gas adsorption, which makes it a beneficial shale reservoir.
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SHI Baohong, LI Rongkun, TIAN Wen, JING Xianghui, CAI Zhenghong
2019,43(4):1-10 ,DOI: 10.3969/j.issn.1673-5005.2019.04.001
Abstract:
Based on a large number of well data and core observations, the reservoir difference characteristics and genesis of Chang 91 in the Jiyuan area of Ordos Basin were analyzed using comparative analysis. The results show that the sand bodies of Chang 91 in the east of the study area have the characteristics of small thickness of single layer, poor longitudinal continuity, and medium-low structural maturity.The sand bodies of Chang 91 in the west of the study area are thick, good pore throat connectivity, with good physical characteristics, especially the permeability, and the oil layers are thicker than the eastern ones. The dual superposition effects of sedimentation and diagenesis result in the different reservoir characteristics between the east and the west. In the east, there are mainly two types of sand bodies, namely, underwater distributary channel and estuarine bar at the leading edge of meandering river delta, while braided river delta leading edge underwater distributary channel sands deposited are the main sands in the west. During the diagenetic evolution, the reduced porosity of the reservoir in the west with relatively coarse grain size sandstone and better pore throat structure was lower than that in the east due to compaction. The cementation has a great influence on reservoir physical properties. Early cementation has little influence on reservoir porosity in west, late cementation has a great influence on reservoirs in west, and the reservoirs became dense after late cementation. However, the early cementation has a great influence on the porosity of the eastern reservoir, and the reservoir becomes denser eventually after the early cementation.
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SONG Guangzeng, WANG Hua, SUN Zhipeng, LIU Xiaolong, XU Meng, REN Jinfeng
2014(4):9-18 ,DOI: 10.3969/j.issn.1673-5005.2014.04.002
Abstract:
Based on geological and geophysical data, the Paleogene syndepositional fault and its control on sequence architecture of Lingshui sag were studied by analyzing the combination features and faulting-activity rate of the fault. The results show that three kinds of frameworks, i.e., asymmetric graben, symmetric graben and half-graben, were developed individually in the east, middle, and west of Lingshui sag. Three kinds of structural paleogeomorphologies, i.e., up-dip foot slope break belt, down-dip foot slope break belt and gentle slope-break belt, were developed in response to the changes of faulting-activity, which influenced the sequence-infill patterns. Different sequence-infill patterns distributing within tectono-stratigraphic frameworks have characteristic sequence architectures, which will favorably contribute to exploration of potential reservoirs and subtle oil pools in deepwater area.
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YANG Kaikai, BIAN Weihua, WANG Pujun, FENG Yuhui, LI Zhao, ZHANG Zengbao, LIU Xiaokang
2019,43(4):21-30 ,DOI: 10.3969/j.issn.1673-5005.2019.04.003
Abstract:
In order to identify characteristics, genesis and reservoir significance of vesicle filling, volcanic rocks with amygdules of Carboniferous Batamayineishan Formation were sampled in eastern Junggar Basin. Based on thin section observation, EPMA, geologic thermometer and vesicle filling rate analysis, the amygdules were characterized. The results show that the filling minerals include silica, zeolite, celedonite, chlorite, and saponite. There are two filling models, mono- and multiple component ones. Mono-component amygdules include silica and celedonite ones. 10 types of multiple component amygdules can be recognized, including quartz→zeolite, chlorite→quartz, and quartz→celedonite→saponite. The formation temperature of chlorite at the edge of amygdales is between 84.7 and 123.6 ℃,which indicates a low temperature filling process. The amygdules form from precipitation and crystallization of epigenetic fluid. The quality of volcanic reservoirs becomes worse due to the vesicle filling process. 94.5％ of the primary vesicle space is completely lost. Although vesicle filling has such a negative influence on reservoir quality, residual amygdule inner pores and amygdule shrink pores still have some reservoir capability. In addition, the dissolution pores generated by the fluid which participate in the formation of amygdule can also compensate the reduction of vesicle volume to a certain extent.
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ZHANG Yang, LU Fengming, QIU Longwei, JIANG Jiguo, GUO Zhiqiao, DAI Li
2019,43(4):11-20 ,DOI: 10.3969/j.issn.1673-5005.2019.04.002
Abstract:
Taking the Poyang Lake Ganjiang Delta and Gubei Depression as main study objects, this study focuses on the distribution distance of a lake river dominated delta affected by river and water level fluctuations.Using statistical analysis of typical river dominated deltas satellite photos and fine anatomic of underground work area delta, this paper first used two parameters to express river dominated level, then illustrated the relationship between delta distribution distance and altitude, sediment depth and length, and slope angel of delta front lobe.Lastly, the effects of river dominated level and water level fluctuations on the distribution distance of delta are clarified. The results show that there are two parameters to express river dominated level:the slope in relationship type of delta split level and cumulative quantity of distributary channel, and the delta 's opening angel. The smaller the slope and opening angel, the larger the river dominated level and the delta 's distribution distance. With the extension of the delta, its altitude decreases logarithmically decrease up to the prodelta 's height. The slope angle of delta front first increases and then decreases subsequently. With the increase of sediment depth, the length of every delta lobe linearly increases, and the slope angle increases logarithmically until the suspension angle. Water level fluctuation ΔH and delta distribution change ΔL are mainly controlled by basins slope α and delta front slope β and ΔL=1〖〗tan α-1〖〗tan βΔH.
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XU Chun-ming, LIU Yang, ZHAO Suo-qi, SHI Quan
2013(5):190-195 ,DOI: 10.3969/j.issn.1673-5005.2013.05.028
Abstract:
Molecular composition of petroleum asphaltenes has been a major research challenge for petroleum chemistry community both in upstream and downstream of petroleum industry. Heavy petroleum asphaltenes and their subfractions were characterized by using negative ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS). The composition of heteroatoms in heavy petroleum samples and asphaltenes is rather complex. Class species such as N1, N1O1, N1O1S1, N1O2, N1S1, O2, O2S1, O2S2, O2S3, O3, O3S1, O4are identified with high resolution FT-ICR MS. Oxygen and multi-heteroatom containing species tend to precipitate into asphalenes. Heptane derived asphaltenes have higher molecular condensation degree than pentane derived asphaltenes. Molecular composition of asphaltenes from various crude oil is very different. Asphaltenes derived from Canada vacuum topped bitumen(VTB) have more heteroatom classes and higher molecular condensation degree than that of Sudan heavy oil asphaltenes. Sulfur species are absent from Sudan heavy oil asphaltenes in which oxygen class species show a very high relative abundance. Minimal variations in molecular condensation degree can lead to significant changes in asphaltene solubility in solvents. The research results provide evidence at molecular level that compounds with high molecular condensation degree and/or multi heteroatoms tend to precipitate from solvent with non or weak polarity. The characterization on neutral nitrogen and acidic oxygen compounds reveals the compositional complexity of asphaltenes. Under current conditions only limited amount of asphaltene moieties are revealed in negative ion ESI analysis, however a significant amount of small molecules are highly likely to present in petroleum asphaltenes.
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GAO Jin-sen, WANG Gang, LU Chun-xi, XU Chun-ming
2013(5):181-185 ,DOI: 10.3969/j.issn.1673-5005.2013.05.026
Abstract:
Facing the challenge of heavy oil processing, the chemical engineering details of flow characteristics, heat transfer in fluid catalytic cracking (FCC) riser reactor and the mechanism of cracking reaction, were particularly described, which were based on the fundamental research of turbulent gas-solid two-phase flow and lumped kinetics theories. In order to maximize the light oil yield and obtain clean gasoline, a new idea of "zoning-regulation" was proposed according to the parallel-sequential reaction mechanism and competing-adsorption between different hydrocarbons. Then the reaction performances of feedstocks with different properties were met by their optimal catalytic conditions. In view of the above works, a series of processing or new technologies matched by the novel structures or special equipments were successfully developed.
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LIN Yuanhua, DENG Kuanhai, NING Huazhong, SHI Yunsheng, ZENG Dezhi, LIU Wanying
2021,45(1):117-126 ,DOI: 10.3969/j.issn.1673-5005.2021.01.014
Abstract:
The effects of solubility of acid gases such as H2S and CO2 in liquid medium on the corrosion and environmental fracture (SSC and HIC) of tube and casing in different wells in the same block or in different sections of the same wells were investigated. On the basis of the test device simulating the solubility of CO2 in the environment of oil and gas wells, the CO2 solubility tests under different temperatures, pressures and salinities were carried out. The gray correlation method was used to analyze the sensitivity of CO2 solubility from three aspects of temperature, pressure and salinity, through which the correlation between CO2 solubility and temperature, pressure and salinity were obtained. Based on the experimental data and the improved P-R EOS, the method of combining the fugacity coefficient model and the mixing rule was used to fit and analyze the correlation between the prediction results and the binary interaction parameters in the model, and the binary interaction parameters were obtained to modify and improve the prediction model of CO2 solubility in formation water. Phase equilibrium data of CO2 formation water system under experimental temperature (303.15-363.15 K), pressure (5-30 MPa) and salinity (0-0.7 mol/kg) were calculated. The results show that there is a transition pressure when CO2 solubility changes with pressure (the transition pressure in this experiment is 15 MPa). Under the transition pressure, CO2 solubility increases faster with pressure; the temperature is the main controlling factor of CO2 solubility, followed by pressure and salinity; the CO2 dissolution process is controlled by the mixture of temperature, pressure and salinity, and its solubility change trend mainly depends on the dissolution rate and escape speed of CO2 gas molecules in aqueous solution. The comparison between experimental data and prediction results of CO2 solubility shows that the optimized prediction model is accurate and reliable.
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TANG Xiao-ming, CAO Jing-ji, WEI Zhou-tuo
2013(5):57-64 ,DOI: 10.3969/j.issn.1673-5005.2013.05.008
Abstract:
According to elastic reciprocity theorem, the shear-wave radiation from a borehole dipole source is reciprocal to the reception in the source orientation of the borehole fluid displacement caused by the incidence of plane shear waves upon the borehole. Consequently, the borehole radiation pattern can be utilized to compute the borehole reception directivity. The results show that the radiation away from borehole can be accurately computed using an asymptotic solution in the far-field of the borehole. The use of the reciprocity theorem and the asymptotic solution greatly reduces the computational effort in the reflection survey simulation. The simulation results agree well with those from a 3D finite difference elastic wave simulation. The modeling results also show that the SH-wave component from the dipole source is a dominate component for the dipole shear-wave imaging. Simulation and processing results of cased-hole dipole reflection survey data also demonstrate the feasibility of applying the borehole shear-wave imaging technology in cased boreholes. The results of this work provide a fast and accurate algorithm for simulating the dipole-shear wave reflection survey along a borehole.
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WANG Lin, LI Yuxing, ZHU Jianlu, WANG Yating, SHENG Huanhuan, WANG Wuchang
2014(4):148-153 ,DOI: 10.3969/j.issn.1673-5005.2014.04.022
Abstract:
As the single-core can 't afford the high load of dynamic simulation of the cool down process in LNG cold box, a symmetric multi-core parallel computing method under shared memory was proposed to implement the dynamic simulation of the cool down process in cold box of nitrogen expansion liquefaction process with pre-cooling. In dynamic mathematical models, one-dimensional model is used in the simulation of plate-fin heat exchanger, and compressor, expander and throttle were treated as steady-state operations. In parallel methods, compute units were divided and coupled in the boundary based on the characteristics of parallel machine and liquefaction process. The simulation processes of parallel units were controlled using synchronization barrier, and the data were communicated through explicit function calls. The comparison of simulation results with experimental data shows that the dynamic models and parallel methods were reasonable. The simulation results show that the cooling rate of the working fluid depends mainly on the polytropic efficiency of the expanders. The result of performance test of parallel computation shows that the parallel method accelerates the simulation process 23 times, and the efficiency of computing nodes is 3.83 times the efficiency of the single-core computing.
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WANG Jun, YANG Yong, ZHANG Yang, YANG Baoliang, JIANG Long, QIU Longwei, ZHAO Junying
2017(1):1-10 ,DOI: 10.3969/j.issn.1673-5005.2017.01.001
Abstract:
To study the impact of water level change on the sedimentary characteristics of distributary channel in Poyang Lake delta, this research applied methods of modern sedimentary investigation, mining profile, and grain size analysis to delta plain distributary channels in Ganjiang middle branch delta and Xinjiang delta front. The results suggest that there are two types of sedimentary units in the distributary channels in Ganjiang middle branch delta:lag deposit and point-bar; and three types in the distributary channels of Xinjiang delta front:tadpole-shaped sand ridge, linear low-lying sand, banded channel sand, respectively. When water level rises, sediments mainly deposit onshore back to the source in delta distributary channel; meanwhile, point bar receives sediments and develops water rising wedge-shaped sand. Sediments mainly prograde towards the basin, and delta develops at low water level. When water level declines, point bar develops water falling lateral sand. When water level rises, delta front distributary channel develops tadpole-shaped sand ridge,which is subsequently transformed into banded channel sand by waves on both sides of the river; when water level declines, delta front distributary channel develops banded channel sand. Affected by water level change, sand in the distributary channel shows a heterogeneous distribution in both the plane and vertical profiles, while sand in the delta front distributary channel has typical in plane zoning features.
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CUI Ming-wei, CAO Xue-wen, FENG Zi-yan, ZHANG Jun, MA Yu-peng
2013(6):123-128,134 ,DOI: 10.3969/j.issn.1673-5005.2013.06.020
Abstract:
A method to calculate failure pressure of oil-gas pipeline with localized corrosion defects was established based on stress concentration theory and the numerical simulation data. This method was used to assess the impacts of radius of localized corrosion and localized corrosion depth on oil-gas pipeline failure pressure. The reliability of evaluating the localized corrosion with the non-linear finite element method was also validated. Compared with existing calculation methods, the calculation method introduced has both small error and evenly distributed error in calculating oil-gas pipeline failure pressure, therefore, it meets the requirements of predicting oil-gas pipeline failure pressure with localized corrosion defect.
