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MENG Fanchao, SHI Xiaolan, WANG Wei, ZOU Dehui, QIN Liyuan
2026,50(3):1-15 ,DOI: 10.3969/j.issn.1673-5005.2026.03.001
Abstract:
This study focuses on the Permian volcaniclastic-carbonate hybrid rocks in Jianyang area of Sichuan Basin. Based on thin-section observations, mineral auto-scanning, carbon and oxygen isotope data, fluid inclusion analysis, and in-situ major and trace element measurements, the characteristics and reservoir-forming mechanisms of volcaniclastic-carbonate mixed sedimentary reservoirs were systematically investigated. The results show that the hybrid rocks in Jianyang area can be classified into three subtypes:carbonate-bearing volcaniclastic hybrid rocks, volcaniclastic-rich carbonate hybrid rocks, and volcaniclastic-bearing carbonate hybrid rocks. These rock types exhibit a regular spatial distribution related to their distance from the volcanic eruption center. The volcaniclastic-carbonate hybrid rocks experienced three major stages of diagenesis:volcaniclastic consolidation and cementation, magmatic hydrothermal alteration, and burial diagenesis. The main diagenetic processes include condensation and contraction, hydrothermal fluid filling of vesicles, carbonate mud filling of breccias, compaction, calcite cementation, feldspar cementation, and alkaline fluid dissolution. Albite in the study area is interpreted to be of authigenic origin, while the calcite was mainly precipitated from meteoric water-modified hydrothermal fluids. The formation and evolution of the volcanoclastic-carbonate hybrid reservoirs were jointly influenced by deep hydrothermal fluids, meteoric freshwater, and alkaline fluids. Alkaline dissolution is identified as the key factor controlling the development of high-quality reservoirs. Such reservoirs are mainly distributed in slope zones characterized by strong volcanic activity and intense alkaline dissolution. This study provides important insights into the reservoir-forming mechanisms of volcaniclastic-carbonate hybrid rocks and has significant implications for hydrocarbon exploration and development in carbonate reservoirs associated with volcanic activity.
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GAO Chonglong, DONG Zhiwu, TANG Song, JI Youliang, CHE Guoqiong, LI Shun, LI Xiang, REN Ying, XU Rui, LI Yilun
2026,50(3):16-31 ,DOI: 10.3969/j.issn.1673-5005.2026.03.002
Abstract:
The Xu4 member in the Guang 'an area of the Central Sichuan Basin is a typical tight sandstone gas reservoir characterized by high water saturation, poor reservoir properties, and strong heterogeneity. Complex gas-water relationships and frequent water production from wells present significant challenges for reservoir evaluation and gas-water discrimination. Conventional reservoir parameter evaluation and prediction methods show limited applicability, resulting in difficulties in identifying gas and water layers and constraining gas-water distribution patterns. To address these issues, this study integrates drilling, logging, core, experimental, and production data to establish nonlinear logging interpretation models for lithology, reservoir properties, and gas-bearing characteristics using a machine learning-based BP neural network approach. These models are further applied to characterize gas-water layers and their distribution patterns. The results show that the interpretation results achieve a lithology prediction accuracy of 94.7%, porosity prediction accuracy of 95.6% within an absolute error of ±1.5%, permeability prediction accuracy of 95.5% within half an order of magnitude, and water saturation prediction accuracy of 94.1% within a relative error of ±8%. Regional gas-water identification achieves an overall gas-layer discrimination accuracy of 96%. The gas-water distribution patterns of the high-water-saturation tight sandstone reservoirs in the Xu4 member can be classified into five types, namely isolated, normal, inverted, center-gas-edge-water, and fault-sealed patterns. The most favorable gas-bearing targets are developed in coarse-grained, high-quality reservoir facies belts associated with local structural highs, where buoyancy and reservoir quality jointly enhance gas-water differentiation.
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GAO Jian, YANG Yongzhi, GAO Ming, LI Jinlong, ZHOU Tiyao, Lü Wenfeng, LI Zheng, LI Wei, WANG Hao
2026,50(3):32-43 ,DOI: 10.3969/j.issn.1673-5005.2026.03.003
Abstract:
Field applications of CO2 flooding have demonstrated that CO2 can more readily penetrate small pores than water, thereby activating low-permeability and low-saturation non-oil intervals that are ineffective under water flooding conditions. These newly activated intervals form effective permeable reservoir bodies, referred to in this study as potential layers for CO2 flooding. Taking the CO2 flooding reservoir in Daqingzijing Oilfield, Jilin, as an example, a comprehensive method for the identification and characterization of the potential layers for CO2 flooding is established using displacement experiments, geochemical analyses, well logging data, and production testing results. This proposed workflow consists of four key steps: (1) determining the displacement utilization lower limit through laboratory experiments; (2) identifying sedimentary genesis using geochemical data; (3) calibrating well logs with core data to achieve single-well identification of potential layers, and (4) delineating lateral connectivity boundaries based on microfacies-controlled connectivity patterns. A three-step logging identification method for potential layers is developed, including qualitative discrimination using characteristic logging responses, determination of top and bottom boundaries through overlapping log-curve patterns, and fine-scale identification using a high-precision permeability interpretation model. A three-step progressive fine-constraint well logging identification model is established for CO2-flooding potential layers, and the CO2-flooding connectivity in the study area is quantitatively re-evaluated under the constraints of potential layer depositional development and correlation patterns. The combination relationship between potential layers and oil layers is clarified, and supporting CO2-flooding production and efficiency enhancement technical strategies is formulated, provides certain reference significance for the fine geological study of CO2-flooding reservoirs. The results show that the lower permeability threshold for CO2 flooding potential layers in the study area is 6×10-5 μm2, with permeability values between 6×10-5 μm2 and 1×10-4 μm2. The clay content ranges from 10% to 15%, while carbonate content ranges from 6% to 12%. These potential layers are mainly associated with hydrodynamic transition zones and weakly cemented calcareous bands. Compared with water flooding, the connectivity rate of dominant microfacies under CO2 flooding increases by 18.9 percentage points, with connected thickness increasing by 1.7 m. For non-dominant microfacies, the connectivity rate increases by up to 34.2%, and connected thickness increases by 1.1 m. By introducing a potential layer, two enhancement strategies—reconstructing injection-production well patterns using old wells and optimizing injection-production relationships through layer supplementation—were implemented. These measures resulted in an average CO2 sweep efficiency increment of 12.8% and an average recovery rate increase of 6.9% across five combined patterns in the study area. These findings demonstrate that CO2 flooding potential layers constitute a crucial geological parameter that should be incorporated into both CO2 flooding development plans and dynamic performance analysis.
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WU Yixiong, HU Lin, LI Fang, GUO Shusheng, WU Bohan
2026,50(3):44-56 ,DOI: 10.3969/j.issn.1673-5005.2026.03.004
Abstract:
Due to their unique geological and engineering conditions, deepwater and deep gas reservoirs face dual challenges of low porosity and low permeability, as well as high exploration and development costs. Therefore, obtaining accurate reservoir property information is crucial for improving gas field economic performance and optimizing development strategies. Based on an analysis of diagenetic evolution and the main controlling factors affecting reservoir properties in the study area, this study establishes diagenetic facies classification criteria centered on the proportions of primary and secondary pores, together with their characteristic logging responses. Sensitive logging parameters are optimally selected, and both chart boards and deep learning algorithms are employed to achieve logging-based identification of diagenetic facies. For permeability modeling, a novel variable effective overburden pressure petrophysical modeling method dedicated to deep-water and deep formations is proposed to achieve the accurate conversion of surface experimental permeability to in-situ reservoir permeability. On the basis of reservoir diagenetic facies classification, a comprehensive permeability prediction model is further developed by incorporating multiple parameters including porosity and gamma ray logging data. The results indicate that the proposed method improves the proportion of logging permeability with errors within half an order of magnitude by 23.7% for six wells in the study area. The proposed method significantly improves the accuracy of permeability evaluation in exploration wells and demonstrates strong potential for application in similar complex reservoirs characterized by high effective overburden pressure and well-developed secondary porosity.
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CHEN Shuangling, WANG Xiaojuan, WU Changjiang, ZHANG Xiaoli, LIANG Yilin, LIU Jingdong, YANG Ke, PAN Ke
2026,50(3):57-68 ,DOI: 10.3969/j.issn.1673-5005.2026.03.005
Abstract:
Tight sandstone gas reservoirs located far from source rocks in the Jurassic Shaximiao Formation represent an important target for oil and gas exploration in the Sichuan Basin. The natural gas charging capacity controlled by the fault-sand configuration plays a critical role in governing the scale of gas accumulation and enrichment in the Shaximiao Formation. However, quantitative evaluation of the selective charging capacity of natural gas into different sandstone bodies remains limited. Taking the central Sichuan Basin as an example, this study investigates the characteristics and origins of natural gas reservoirs, as well as the evolution of source-fault-sand configuration relationships, to quantitatively evaluate natural gas charging processes and determine the charging capacity of tight sandstone reservoirs in the Shaximiao Formation. The results indicate that the tight sandstone gas in the Shaximiao Formation of the central Sichuan Basin is mainly sourced from the Xujiahe Formation. Significant differences exist in the gas charging capacities of different fluvial sandstone bodies within the Shaximiao Formation. Among them, the No. 8 sandstone member east of the Longquanshan Fault exhibits the highest charging capacity, followed by the No. 8 sandstone member south of the Jiao① Fault. These sandstone bodies play a decisive role in gas accumulation and enrichment within the Shaximiao Formation. Comprehensive analysis demonstrates that efficient source-fault-sand coupling is the key factor controlling tight sandstone gas accumulation far from source rocks. Specifically, the source-fault configuration controls the scale of gas supply, while the fault-sand configuration determines the effectiveness of gas charging.
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LI Hui, LI Wei, FU Dawei, JIA Haibo, ZHOU Gang, CAO Mingyue, LEI Xin, WANG Jiajun, GUO Puyang
2026,50(3):69-83 ,DOI: 10.3969/j.issn.1673-5005.2026.03.006
Abstract:
To address the challenges of limited drilling data and the difficulty of evaluating exploration potential in low-exploration sags of the Beibu Gulf Basin, this study systematically assesses and compares the potential of such sags through detailed analysis and quantitative/semi-quantitative characterization of structural and depositional features during the hydrocarbon source rock formation period. A systematic evaluation methodology, termed the "tectonic three-rate and sedimentary three-unit" approach, was established using hydrocarbon-rich sags as analogs to assess the distribution patterns and exploration potential of source rocks in low-exploration sags within the Beibu Gulf Basin. The results indicate that during the deposition of the source rocks of the second member of the Liushagang Formation, the Beibu Gulf Basin was primarilly controlled by NE-trending faults, resulting in extensional tectonic styles and the development of single-fault half graben or double-fault graben sag structures. The rate of fault activity, horizontal extension rate, and basement subsidence rate jointly controlled the structural framework and sedimentary infill of the sags. Significant differences are observed among the sags in terms of parent rock type and uplift rate, sediment dispersal systems and the locations of "grit chambers"during sediment transport, the scale of semi-deep to deep lacustrine environments, paleowater depth, paleo-oxidation conditions, and source- to-sink ratios during source rock deposition. Based on the comprehensive evaluation, two highly prospective subsags, the eastern subsag of the Haizhong sag and the eastern subsag of the Maichen sag, are identified as favorable exploration targets.
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YUAN Yi, ZHANG Liwen, XU Shiqi, WEI Xiuli, ZHENG Ronghua, WANG Pan, LIU Yan, YUE Jiaheng, XUE Kai, LIANG Wenjun
2026,50(3):84-93 ,DOI: 10.3969/j.issn.1673-5005.2026.03.007
Abstract:
The JM3 well area in the Jiergalangtu sag is a key target for low-rank coalbed methane (CBM) exploration in the Erlian Basin. However, unclear enrichment patterns and controlling factors have restricted further development planning in this area. Based on drilling cores, logging and coring data, and geochemical analyses, this study systematically investigates the favorable geological conditions and principal controlling factors governing low-rank CBM enrichment in the Saihantala Formation, and establishes a comprehensive evaluation system for favorable exploration targets. An innovative "structure-seal-hydrodynamic" ternary control model for CBM accumulation is proposed and verified. In this model, structural evolution controls the preservation of coal-bearing strata and the sealing capacity of faults; mudstones in the roof and floor provide effective sealing conditions; and NaHCO3-type formation water creates a highly mineralized retention environment, forming a dynamically closed accumulation system. The results indicate that the coal seams in the study area possess favorable reservoir characteristics, including large cumulative thickness (average 76 m), high vitrinite content (87.8%), and low ash yield(7.69%). The reservoirs are characterized by medium-porosity and low-permeability, with an average porosity of 13.95% and permeability ranging from 0.28×10 -3 μm2 to 4.03×10-3 μm2, providing suitable conditions for CBM enrichment. In terms of gas-bearing properties, the gas is dominated by biogenic methane, with methane purity exceeding 96%. The IV coal group exhibits an average gas content of 2.4 m3/t, gas saturation of 80.07%, and average resource abundance of 2.81×106 m3/km2, indicating considerable development potential. Based on multi-parameter integrated evaluation, the study area is divided into three categories of favorable zones. Among them, the Class I favorable zone is located in the JM3-JM10-JM11 well area, covering approximately 3.57 km2. This area is characterized by high resource abundance and stable structural conditions, making it the primary target for future development deployment.
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ZOU Caineng, YU Rongze, SUN Qinping, ZHAO Suping, WANG Meizhu, DONG Dazhong, ZHAO Qun, ZHANG Xiaowei, CHEN Yanpeng
2026,50(3):94-108 ,DOI: 10.3969/j.issn.1673-5005.2026.03.008
Abstract:
To improve the development technology of coalbed methane (CBM) and coal-rock gas under complex geological conditions, this study integrated the dynamic production data of 8204 CBM wells and 639 coal-rock gas wells from the Totalsoph unconventional oil & gas platform(UOG). The resource endowment, development status and key technologies of these two types of gas reservoirs were systematically reviewed using comparative analysis and machine learning methods. The differences in development indicators were quantified, and the challenges and prospects were analyzed. The results show that the total geological resources of CBM and coal-rock gas in China is of 71.5×1012 m3 with technically recoverable resources of 22.5×1012 m3. Two major industrial gas production bases have been constructed in Qinshui Basin and the eastern margin of Ordos Basin. The breakthrough of coal-rock gas in Ordos Basin in 2019 marked the industry 's entry into a new stage of coordinated shallow and deep gas development. A full-process technical system has been established, covering exploration and evaluation, drilling and completion, reservoir stimulation, drainage and production, enhanced recovery and digital intelligence. CBM horizontal wells exhibit the characteristics of "slow peak arrival and gentle decline", with main intervals of single-phase water drainage period of 4-120 d, gas breakthrough pressure of 0.07-1.02 MPa, first-year average daily production of 2120-7592 m3, first-year production decline rate of -31% to 21%, and single-well estimated ultimate recovery(EUR) of (963-2714)×104 m3. Coal-rock gas horizontal wells show a production feature of "gas breakthrough rapidly after well startup", with "fast peak arrival and high peak production" having gas breakthrough pressure of 5.4-8.7 MPa, first-year average daily production of 44 077-62 288 m3, first-year decline rate of 27%-56%, and single-well EUR of (4 547-6 232)×104 m3. The two types of gas reservoirs are highly complementary and can be synergistically build into a production capacity model combining "rapid response and stable supply". The industry currently faces many challenges, such as strong reservoir heterogeneity, immature development technology of deep reservoirs, economic dependence on subsidies, insufficient digital intelligence integration and environmental constraints. However, the development models of "integrated coal mining and gas extraction" and "carbon sequestration with resource development" have broad prospects driven by the dual carbon goals, policy coordination and technological iteration.
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GUO Xiaoqiang, YANG Kelun, JIANG Zhefu, XU Jie, Lü Junlin, LI Xinye
2026,50(3):109-122 ,DOI: 10.3969/j.issn.1673-5005.2026.03.009
Abstract:
An experimental simulation platform for the vibration of double-layer mining riser in deep-sea hydrate wells under internal and external flow excitation was developed in this study based on the principle of similarity to effectively explore its vibration mechanism. The influences of solid particle size, phase ratio, three-phase flow velocity, and external flow velocity on the vibration response characteristics and nonlinear behavior of internal continuous tubing were investigated. It is found that, the strong vibration positions of the vertical and horizontal sections of the mining string are different. In the vertical section, it is mostly located below the middle section (e.g. 1880 mm from the bottom), while in the horizontal section, it is mostly located 500 mm from the bend position. The vertical section of the mining riser can exhibit a motion trajectory of oblique straight line, wide oblique straight line, or approximately wide oblique straight line, while the horizontal section is mostly of a chaotic trajectory or an "8" - shaped chaotic trajectory. The decrease in particle mesh size and the increase in solid phase proportion can be reflected in the difficulty and accumulation of particle transport, leading to a decrease in vibration displacement amplitude and vibration energy (such as the root mean square displacement reduced from 280 mm to 120 mm). The increase of the proportion of gas phase can lead to changes in the flow state of multiphase flow inside the pipe, resulting in more obvious internal multiphase flow disturbances. The vibration displacement of the mining riser shows an increasing trend. The increase in three-phase flow velocity can further induce vibration of the mining string, and there is a certain flow velocity that will resonate with the string system (such as 1.75 m/s for vertical section and 2.00 m/s for horizontal section), resulting in a sudden increase in the amplitude of vibration displacement.
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WEI Jianguang, DAI Xiaodong, YANG Ying, CAI Meng, LI Yuwei
2026,50(3):123-130 ,DOI: 10.3969/j.issn.1673-5005.2026.03.010
Abstract:
In order to investigate the effects and mechanisms of supercritical CO2 on storage and permeability properties, as well as the wettability of shale reservoirs, in this study, a series of experiments were conducted on the lacustrine shale oil reservoirs of Songliao Basin, with focus on the synergistic effects of CO2 and water-based fracturing fluids (slick-water, guar gel) on shale permeability and wettability. The results show that for laminated shale with well-developed bedding, the improvement on permeability by different fluids followed the order from high to low of CO2 + slick-water, CO2 + guar gel, supercritical CO2, guar gel, slick-water. For the ordinary laminated shale, the improvement was highest with supercritical CO2, followed by CO2 + slick-water, CO2 + guar gel, slick-water, and guar gel. The permeability enhancement of the matrix in laminated shale with well-developed bedding is generally superior to that in ordinary laminated shale, with supercritical CO2 showing the largest improvement, while water-based fracturing fluids can cause significant deterioration. Preceding CO2 injection can effectively mitigate the negative effects of fracturing fluids. The initial oil and water contact angles of the shale samples measured were 11.7° and 79.3°, respectively. After CO2 treatments, the wettability shifted towards neutral to oil-wet. Slick-water and CO2 + slick-water treatments resulted in a wettability alteration, significantly enhancing the rock 's hydrophilicity. Preceding CO2 injection can increase the hydrophilic mineral content in the shale, which is beneficial for improving microscopic oil recovery efficiency during imbibition. The findings of this study can provide valuable insights for optimizing shale oil fracturing processes.
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GONG Jincheng, ZHAO Fangjian, SHU Qinglin, YUAN Fuqing, JI Yanfeng, XU Hui, DONG Wen, SONG Qian
2026,50(3):131-141 ,DOI: 10.3969/j.issn.1673-5005.2026.03.011
Abstract:
Microencapsulated polymers can resist borehole shear by their slow-release and thickening effects, which can improve polymer flooding efficiency. However, the time-varying characteristics of the microencapsulated polymers can lead to significant differences in their flow behavior and oil recovery mechanisms compared to conventional polymers, and the mechanisms for enhancing oil recovery are not fully understood. In this study, the time-varying characteristics of microencapsulated polymers were studied in terms of morphology and rheological properties. The results show that microencapsulated polymers can undergo a morphological change from swelling particles-particle network to polymer network and a rheological change from weak viscous elastic expanding fluid to low viscous elastic pseudo-plastic fluid and to high viscous elastic pseudo-plastic fluid, which are beneficial for injection in the early stage, migration in the middle stage, and volume sweeping in the later stage of the polymer flooding process. The results of core displacement experiments show that microencapsulated polymers are suitable for the permeability range of (300-500)×10-3 μm2 and heterogeneous conditions with a gradient of less than or equal to 5. During the thickening process, a kind of time-varying flow characteristics can appear via mainstream expansion, and the oil recovery rate was increased from 4.32% to 19.29%. Using CT scanning displacement experiments to study the dynamic residual oil utilization mechanism, the results show that the microencapsulated polymer can advance to the back of the high permeability core before thickening, and gradually spread to the low-permeability core during the thickening process. The degree of residual oil recovery after thickening is significantly higher than that of conventional polymer flooding, proving that it can further significantly improve the recovery rate.
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XIONG Yuhao, CAO Renyi, ZHENG Xinyi, LIN Yanbo, CHENG Linsong, JIA Zhihao
2026,50(3):142-150 ,DOI: 10.3969/j.issn.1673-5005.2026.03.012
Abstract:
The tight reservoirs in Ordos Basin have insufficient natural energy and small pore throats, so it is difficult to achieve effective displacement through water flooding. Advanced or preceding CO2 injection is a development method with high efficiency and environmental benefits. In this study, core displacement experiments with advanced CO2 injection were conducted using nuclear magnetic resonance (NMR) imaging and T2 spectrum representation for investigating pore throat distribution. Comparative analyses were made on oil displacement effects between simultaneous and advanced CO2 injection modes, with different gas injection volumes and well shut-in time period after advanced CO2 injection. The displacement performance and pore throat mobilization characteristics of different CO2 injection methods were clarified, revealing the microscopic mechanisms for enhancing oil recovery. The results show that compared with simultaneous CO2 injection, advanced CO2 injection can mobilize residual crude oil at near the injection site earlier, delaying gas channeling and increasing displacement efficiency in medium and small pores. The advanced gas injection volume should be moderate, too little has limited production effects, while too much can lead to early gas breakthrough and decrease displacement efficiency. Well shut-in after advanced gas injection can fully leverage the effects of CO2 diffusion and dissolution, promoting oil and gas front migration and further enhancing displacement efficiency in medium and small pores. Therefore, advanced CO2 injection combined with well shut-in is feasible for field application.
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GENG Yuan, ZHANG Zhilei, YAN Zhiyuan, HU Min, YUAN Shi, QI Yingxiang, WANG Xiaohui
2026,50(3):151-159 ,DOI: 10.3969/j.issn.1673-5005.2026.03.013
Abstract:
Molecular dynamics simulation (MD) was employed to select an appropriate water molecular model for ultrahigh-temperature and high-pressure conditions. The bulk phase properties (density and viscosity) of water and the microstructure between water molecules (number of hydrogen bonds, water phase structure and diffusion coefficient ) were investigated to reveal the variation characteristic parameters of ultrahigh-temperature and high-pressure water. The results show that the average error of SPC/E water molecules for fitting the viscosity and density of the aqueous phase is about 3%. Under low-temperature and low-pressure conditions, the pressure has no influence on water molecular mobility, whereas the effect of temperature on the diffusion coefficient of water is more than 3 times that of pressure under high-temperature and high-pressure. With the increase of temperature, the thermal motion of water molecules increases, the number and lifetime of intermolecular hydrogen bonds decrease, and the diffusion coefficient increases, which changes the distribution structure of water molecules around the central water molecules. The changes of the characteristic parameters of the aqueous phase under high-temperature and high-pressure can affect the viscosity and rheological properties of water phase, which may further weaken the ability of polymer additives to capture water molecules. Consequently, the hydrogen-bonding interactions between polymer additives and water molecules may be reduced, leading to reduced solubility and accelerated reactions between polymer additives and the surrounding medium.
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JI Yanfeng, LI Bin, HE Dongyue, YIN Qi, MA Haoyu, LI Zhen, YAN Youguo
2026,50(3):160-168 ,DOI: 10.3969/j.issn.1673-5005.2026.03.014
Abstract:
Quantum chemical calculation and molecular dynamics simulation were employed to investigate the reaction kinetic mechanism of controlled phase-transition polymers and the viscosity variation before and after phase transition. The results show that the probability of phase transition of crosslinked polymers of dimethylaminoethyl methacrylate and diallyl phthalate is higher at the same temperature. In the ester-containing crosslinker system, the ester C—O bond is more prone to cleavage than other candidate reaction sites, indicating higher phase-transition potential. After phase transition, the maximum viscosity loss of each cross-linked polymer system under conditions increases. Among them, the shear resistance of pentaerythritol triacrylate system decreases most obviously, whereas the initial shear resistance of dimethylaminoethyl methacrylate system was relatively poor. The viscosity of the pentaerythritol triacrylate system increases significantly after phase transition. However, in terms of phase-transition probability, viscosity release and shear resistance, the diallyl phthalate crosslinked polymer demonstrates higher phase-transition possibility and better viscosity-enhancement ability.
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WANG Bowen, LI Muyi, XU Jiafang, QU Jingxuan, WANG Jian, CHEN Jie, YANG Xiaolong, WANG Yahua
2026,50(3):169-176 ,DOI: 10.3969/j.issn.1673-5005.2026.03.015
Abstract:
The phase transition experiments were conducted on cyclopentane hydrates through the emulation of subsurface porous media via a microfluidic chip by means of microscopic observation, the influence of an applied electrostatic field under identical subcooling conditions on hydrate morphology, growth rate, induction time, and equilibrium temperature were analyzed. The results show that the electrostatic field has the ability to alter the growth morphology of CP hydrate crystals and significantly shorten the induction time, but slightly reduce the phase equilibrium temperature. With the increase of electric field intensity, the hydrate induction time is prolonged and the phase equilibrium temperature is increased. Under the influence of an electrostatic field, the growth rate of CP hydrates exhibits a noticeable enhancement.
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XU Yunfei, WANG Zhihua, ZHANG Hongqi, LIU Xiaoyu, CHANG Zhenbo
2026,50(3):177-186 ,DOI: 10.3969/j.issn.1673-5005.2026.03.016
Abstract:
Based on the analysis of the basic physical properties of condensates, different molecular dynamics simulation systems of waxy condensates covering different condensate gas fluid environments of methane, methane-ethane and methane-ethane-propane were constructed. The dynamic behavior of wax molecules in the presence of condensate gas was studied considering the phase transition temperature and pressure conditions. The results indicate that the solubility of condensate gas in the system is the dominant factor affecting the diffusion behavior of wax molecules, and the synergistic effect of temperature and pressure exhibits can promote the wax molecules diffusion. The diffusion ability of wax molecules in different systems is methane-ethane-propane system>methane-ethane system>methane system. Different from the increase of temperature, the binding energy between wax molecules decreases and the thermal motion intensifies, which further weakens the aggregation and deposition behavior of wax molecules. The increase of pressure not only compresses the spacing of wax molecules and promotes the aggregation of wax molecules, but also hinders the aggregation of wax molecules by increasing the solubility of gas in the system.High pressure can make the wax molecular layer deposited on the wall become dense, but it also increases the number of gas molecules dissolved in the oil phase, which will hinder the movement of wax molecules to the wall and weaken the deposition behavior to a certain extent.
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LIU Jianlin, ZHAO Da, GU Zewen
2026,50(3):187-196 ,DOI: 10.3969/j.issn.1673-5005.2026.03.017
Abstract:
During the process of oil and gas production, the accurate identification of shale parameters has become a key challenge in improving the quantitative analysis accuracy of hydraulic fracturing and horizontal drilling. In response to the characteristics of complex composition and strong heterogeneity in shales, a digital core based on CT scanning was constructed in this study. Through grayscale processing, the volumetric proportions of structural components were extracted to establish a geometric model, and the matrix and bedding planes were introduced to characterize its heterogeneous features. By integrating deep neural networks (DNN) and genetic algorithms (GA), a cross-scale bidirectional correlation model between microscopic and macroscopic parameters of heterogeneous shale was established. Furthermore, uniaxial compression simulations of shale were conducted using the discrete element method (DEM), and the influences of micro-parameters on macroscopic mechanical behavior were quantitatively analyzed. The results demonstrate that this model enables the prediction of macroscopic mechanical parameters and the identification of microscopic parameters in shales. The uniaxial compression simulations can successfully predict the shale fracture behavior.
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WANG Zengli, GUAN Yuping, SUN Jiaxuan, LIU Xiaoyu, WANG Zongming, LIU Zhaozeng, WANG Zenghua
2026,50(3):197-207 ,DOI: 10.3969/j.issn.1673-5005.2026.03.018
Abstract:
A fully self-driven 8-shaped disc seal screw pump has been proposed for the efficient and reliable pumping of marine oil spills. During its operation, the sliding friction characteristics are the decisive factors affecting its operational stability and service life. However, the research in this area has not yet been carried out. Based on the meshing principle of the 8-shaped disk sealed screw pump, the instantaneous contact line equation of the 8-shaped disk-screw rotor meshing pair and the calculation model of the relative sliding velocity between the meshing pairs were established, and the distribution laws and influencing factors of the instantaneous contact line and the relative sliding velocity between the meshing pairs were studied. The results indicate that the severity of fluctuation in the instantaneous contact line between the meshing pairs increases with larger major arc radius of the infinity-shaped seal disk and centre distance, and the fluctuation range increases with a larger edge arc radius of the seal disk. The fluctuation amplitude of the instantaneous contact line reaches its maximum at the deepest meshing point where the infinity-shaped seal disk engages with the screw. The relative sliding velocity along the instantaneous contact line of the meshing pair increases with the increase in the centre distance. The spatial curve of the instantaneous contact line provides a more intuitive representation of the contact and friction characteristics between the meshing pairs during operation.
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LIU Ruihao, CHEN Yanfei, NI Heng, LIU Yu, GAO Zhihao, ZHONG Rongfeng, WANG Xin, YIN Yi, ZHANG Zuomin
2026,50(3):208-216 ,DOI: 10.3969/j.issn.1673-5005.2026.03.019
Abstract:
Hydrogen energy is a crucial component of the future national energy system and plays a supporting role in the realization of the carbon peaking and carbon neutrality goals. Pipeline transportation is considered as the best way to achieve low-cost and large-scale transportation. However, under the effect of hydrogen embrittlement, hydrogen pipeline is more prone to fatigue failure. In response to the current uncertainty regarding the mechanism of fatigue crack propagation in hydrogen pipelines, and the challenges associated with simulating the process and the high computational costs involved, this study derived the Paris formula based on energy release rate using fracture mechanics theory. The extended finite element method (XFEM) was then employed to investigate the fatigue failure mode of hydrogen pipeline with cracks, and an analysis of factors influencing the fatigue life of hydrogen pipeline was conducted. The results show that the fatigue failure behavior of hydrogen pipeline is controlled by the crack depth rather than the energy release rate. The fatigue life of hydrogen pipeline decreases with the increase of hydrogen pressure and the decrease of stress ratio. The initial crack size also affects the fatigue life of hydrogen pipeline, with the variation in crack depth having a more significant impact on the fatigue life of the pipeline.
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ZHENG Jianqin, DU Jian, WU Lianghong, CAI Qingwen, LIAO Qi, LIANG Yongtu
2026,50(3):217-226 ,DOI: 10.3969/j.issn.1673-5005.2026.03.020
Abstract:
The sequential transportation of multi-product pipelines inevitably forms mixed oil segment. Accurate prediction of mixed oil concentration is an important measure to ensure oil quality and reduce processing energy consumption. However, the engineering pipeline conditions change complexly, and the development of oil mixing is affected by multiple factors. The variable association information mined by existing models is limited, resulting in lower accuracy and effectiveness. In this work, the multivariate influence mechanism was fully considered to extract the mechanism characteristics of mixed oil concentration distribution. Then, a self-learning-based virtual sample generation model was established to fill in the missing information of the original samples. The generated and original samples were coupled to fully characterize the high-dimensional nonlinear correlation information of the mixed oil concentration variables, and the model accuracy was improved. The results show that the performance of the proposed method is superior to the existing methods for predicting oil mixture concentration, with a mean square error reduction of 40%. Compared to existing sample generation methods, the proposed method generates samples of higher quality and improves prediction accuracy by 33%, 23% and 29%, respectively. The proposed model can achieve accurate prediction of mixed oil concentration under different operating conditions and characteristics under small samples, with desirable accuracy and versatility, and can help to improve the intelligent level of station mixed oil monitoring and control.
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SUN Huadong, LIU Heng, XIAO Yingjie, SUN Xin, LUAN Hewei, KANG Jiefen, LI Kangwen, LI Youkai, DING Yongling
2026,50(3):227-236 ,DOI: 10.3969/j.issn.1673-5005.2026.03.021
Abstract:
The characteristic particle sizes (D10, D50, D90), standard viscosity, and Engler viscosity parameters of emulsified asphalt were selected to study their correlation with the 1 d and 5 d storage stability of emulsified asphalt using the grey relational entropy and Pearson correlation coefficient analysis methods. The results show that the stronger the surface activity of the emulsifier, the more conducive to the stability of emulsified asphalt. When the emulsifier dosage is 3%, the 1 d and 5 d storage stability of emulsified asphalt is the best, and its D10, D50, D90 characteristic particle sizes, standard viscosity, and Engler viscosity tend to be stable. SQ-1 emulsified asphalt particles do not appear aggregation phenomenon, whereas SQ-2 and SQ-3 emulsified asphalt particles exhibit demulsification and aggregation, respectively. The grey entropy correlation degree of characteristic particle size with 1 d and 5 d storage stability is D90>D50>D10. The Engler viscosity and standard viscosity oresent the highest grey entropy correlation with 1 d and 5 d storage stability, and the characteristic particle size shows a strong correlation with standard and Engler viscosities. It is also found that D90 has the highest grey entropy correlation with the 1 d and 5 d storage stability of emulsified asphalt and exhibits a strong correlation. The D90 particle size can reflect the storage stability of emulsified asphalt to a certain extent.
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DU Feng, KONG Jingwen, SONG Dawei, YAN Wenjuan, JIN Xin
2026,50(3):237-242 ,DOI: 10.3969/j.issn.1673-5005.2026.03.022
Abstract:
The process of using KOH as a depolymerization agent to degrade polyethylene terephthalate (PET) was studied. Methanol was used as a cosolvent to make the reaction proceed under mild conditions, and the reaction conditions for chemical degradation of PET were optimized. The results show that the system could significantly improve the degradation efficiency. The optimum molar ratio of KOH to methanol is 1∶9.2. The highest conversion rate of PET reaches 99.6 % at 120 ℃ under atmospheric pressure, and the yield of solid product TPA is 97.2 %. Methanol can be directly distilled and reused at this temperature. The system is carried out in an anhydrous environment, and the reaction product is the hydrolysis product terephthalic acid (TPA) rather than the methanolysis product. The reaction is catalyzed by hydroxide ions rather than methoxy groups. The reaction mechanism of PET chemical degradation conforms to the alkaline hydrolysis mechanism.
Volume 50,2026 Issue 3
地质与勘查工程
地质能源开采工程
能源装备与控制工程
能源化学与材料工程
Volume 50,2026 Issue 3
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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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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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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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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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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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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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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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YANG Shaochun, NIU Hairui, SONG Mingshui, ZHAO Yongfu, WANG Yong
2017(5):1-8 ,DOI: 10.3969/j.issn.1673-5005.2017.05.001
Abstract:
Under the multi-phase compressional thrust structure setting in Chepaizi area, Junggar Basin, a large amount of fractures associated with local fault systems were formed within the Carboniferous volcanic rock. Using a comprehensive analysis of core, thin sections, image logs and seismic profiles data, a quantitative characterization and prediction of fault-related fracture development in Carboniferous of Chepaizi area was performed. The results show that the high angle shearing fractures and tensional fractures are the main types in Carboniferous.The fracture parameters, such as direction, dip angle, density, and opening width are closely correlated with the fault. Based on the derived fault-control fracture density function, the fault grades of the study area can be divided intoⅠ, II, andⅢ,with the effective control distancesas 5.5,3.0 and 0.9 km,respectively. A quantitative analysis of fault strength was also conducted, mainly using statistical and analytic methods to transform the regional fault information into the fracture information, resulting in a detailed description and a quantitative characterization of fault-related fracture development in the Carboniferous of Chepaizi area.
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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.
