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作者简介:

闫炎(1993-),男,博士研究生,研究方向为油气井力学、井筒完整性。E-mail:yansanbao302@163.com。

通讯作者:

管志川(1959-),男,教授,博士,博士生导师,国家“万人计划冶教学名师,研究方向为油气井力学、井下测控技术、深井超深井钻井和深水钻井。E-mail:guanzhch@upc.edu.cn。

中图分类号:TE21

文献标识码:A

文章编号:1673-5005(2020)03-0066-08

DOI:10.3969/j.issn.1673-5005.2020.03.007

参考文献 1
刘奎,王宴滨,高德利,等.页岩气水平井压裂对井筒完整性的影响[J].石油学报,2016,37(3):406-414.LIU Kui,WANG Yanbin,GAO Deli,et al.Effects of hydraulic fracturing on horizontal wellbore for shale gas [J].Acta Petrolei Sinica,2016,37(3):406-414. 
参考文献 2
田中兰,石林,乔磊.页岩气水平井井筒完整性问题及对策[J].天然气工业,2015,35(9):70-76.TIAN Zhonglan,SHI Lin,QIAO Lei.Research and countermeasure for wellbore integrity shale gas horizontal well[J].Natural Gas Industry,2015,35(9):70-76. 
参考文献 3
沈吉云,石林,李勇,等.大压差条件下水泥环密封完整性分析及展望[J].天然气工业,2017,37(4):98-108.SHEN Jiyun,SHI Lin,LI Yong,et al.Analysis and per-spective of cement sheath integrity under a high differenti-al pressure[J].Natural Gas Industry,2017,37(4):98-108. 
参考文献 4
李军,席岩,付永强,等.利用分段固井方法提高页岩气井筒完整性[J].钻采工艺,2017,40(4):21-24.LI Jun,XI Yan,FU Yongqiang,et al.To improve well-bore integrity of shale gas wells with stage cementing method[J].Drilling & Production Technology,2017,40(4):21-24. 
参考文献 5
李进,龚宁,李早元,等.射孔完井工况下固井水泥环破坏研究进展[J].钻井液与完井液,2016,33(6):10-16.LI Jin,GONG Ning,LI Zaoyuan,et al.Progress in stud-ying cement sheath failure in perforated wells[J].Drill-ing Fluid & Completion Fluid,2016,33(6):10-16. 
参考文献 6
WANG H Y.Numerical investigation of fracture spacing and sequencing effects on multiple hydraulic fracture in-terference and coalescence in brittle and ductile reservoir rocks[J].Engineering Fracture Mechanics,2016,157:107-124. 
参考文献 7
XI Y,LI J,LIU G,et al.A new numerical investigation of cement sheath integrity during multistage hydraulic fracturing shale gas wells[J].Journal of Natural Gas Sci-ence & Engineering,2018,49:331-341. 
参考文献 8
刘建伟,张佩玉,廖天彬,等.马58H致密油藏水平井分段多簇射孔压裂技术[J].石油钻采工艺,2015,37(3):88-92.LIU Jianwei,ZHANG Peiyu,LIAO Tianbin,et al.Staged multi-cluster perforation fracturing technology for horizontal well Ma-58H in tight reservoir[J].Oil Drilling & Production Technology,2015,37(3):88-92. 
参考文献 9
张广明,刘合,张劲,等.油井水力压裂流-固耦合非线性有限元数值模拟[J].石油学报,2009,30(1):113-116.ZHANG Guangming,LIU He,ZHANG Jin,et al.Simu-lation of hydraulic fracturing of oil well based on fluid-sol-id coupling equation and non-linear finite element [J].Acta Petrolei Sinica,2009,30(1):113-116. 
参考文献 10
龚迪光,曲占庆,李建雄,等.基于ABAQUS平台的水力裂缝扩展有限元模拟研究[J].岩土力学,2016,37(5):1512-1520.GONG Diguang,QU Zhanqing,LI Jianxiong,et al.Ex-tended finite element simulation of hydraulic fracture based on ABAQUS platform[J].Rock and Soil Mechan-ics,2016,37(5):1512-1520. 
参考文献 11
王海洋,卢义玉,夏彬伟,等.射孔水压裂缝在层状页岩的扩展机制[J].中国石油大学学报(自然科学版),2018,42(2):95-101.WANG Haiyang,LU Yiyu,XIA Binwei,et al.Propa-gation mechanism of hydraulic fracture of perforation in laminated slate[J].Journal of China University of Pe-troleum(Edition of Natural Science),2018,42(2):95-101. 
参考文献 12
潘林华,张士诚,张劲,等.基于流-固耦合的压裂裂缝形态影响因素分析[J].西安石油大学学报(自然科学版),2012,27(3):76-80.PAN Linhua,ZHANG Shicheng,ZHANG Jin,et al.A-nalysis of factors influencing the shape of hydraulic frac-turing fracture based on fluid-solid coupling[J].Journal of Xi’ an Shiyou University(Natural Science Edition),2012,27(3):76-80. 
参考文献 13
张建光,李湘萍,王传睿,等.页岩气藏水力压裂中应力-流压耦合效应及人工裂缝扩展规律[J].中国石油大学学报(自然科学版),2018,42(6):96-105.ZHANG Jianguang,LI Xiangping,WANG Chuanrui,et al.Numerical simulation of rock formation stress-fluid pressure coupling and development of artificial fractures during hydraulic fracturing of shale gas reservoirs [J].Journal of China University of Petroleum(Edition of Natural Science),2018,42(6):96-105. 
参考文献 14
曲占庆,田雨,李建雄,等.水平井多段分簇压裂裂缝扩展形态数值模拟[J].中国石油大学学报(自然科学版),2017,41(1):102-109.QU Zhanqing,TIAN Yu,LI Jianxiong,et al.Numeri-cal simulation study on fracture extension and morpholo-gy of multi-cluster staged fracturing for horizontal wells [J].Journal of China University of Petroleum(Edition of Natural Science),2017,41(1):102-109. 
参考文献 15
LECAMPION B,BUNGER A,KEAR J,et al.Interface debonding driven by fluid injection in a cased and ce-mented wellbore:modeling and experiments[J].Inter-national Journal of Greenhouse Gas Control,2013,18(7):208-223. 
参考文献 16
李勇,陈瑶,靳建洲,等.页岩气井体积压裂条件下的水泥环界面裂缝扩展[J].石油学报,2017,38(1):105-111.LI Yong,CHEN Yao,JIN Jianzhou,et al.Cement ring interface crack propagation under volume fracturing in shale gas well[J].Acta Petrolei Sinica,2017,38(1):105-111. 
参考文献 17
FENG Y,LI X,GRAY K E.Development of a 3D nu-merical model for quantifying fluid-driven interface debonding of an injector well[J].International Journal of Greenhouse Gas Control,2017,62:76-90. 
参考文献 18
MARTINEZ R E,KIM J,MORIDIS G J.Numerical in-vestigation of potential cement failure along the wellbore and gas leak during hydraulic fracturing of shale gas res-ervoirs:the 50th US Rock Mechanics/Geomechanics Symposium,Houston,USA.2016 [ C].Washington D C:American Rock Mechanics Association,2016. 
参考文献 19
WANG W,TALEGHANI A D.Impact of hydraulic frac-turing on cement sheath integrity:a modelling approach [J].Journal of Natural Gas Science & Engineering,2017,44:265-277. 
参考文献 20
ZHU H,DENG J,ZHAO J,et al.Cementing failure of the casing-cement-rock interfaces during hydraulic frac-turing[J].Computers and Concrete,2014,14(1):91-107. 
参考文献 21
张广明,刘合,张劲,等.储层流固耦合的数学模型和非线性有限元方程[J].岩土力学,2010,31(5):1657-1662.ZHANG Guangming,LIU He,ZHANG Jin,et al.Mathematical model and nonlinear finite element equa-tion for reservoir fluid-solid coupling[J].Rock and Soil Mechanics,2010,31(5):1657-1662. 
参考文献 22
连志龙,张劲,吴恒安,等.水力压裂扩展的流固耦合数值模拟研究[J].岩土力学,2008,29(11):3021-3026.LIAN Zhilong,ZHANG Jin,WU Heng ‘ an,et al.A simulation study of hydraulic fracturing propagation with a solid-fluid coupling model[J].Rock and Soil Mechan-ics,2008,29(11):3021-3026. 
参考文献 23
张广明,刘合,张劲,等.水平井水力压裂的三维有限元数值模拟研究[J].工程力学,2011,28(2):101-106.ZHANG Guangming,LIU He,ZHANG Jin,et al.Three-dimensional finite element numerical simulation of horizontal well hydraulic fracturing [J].Engineering Mechanics,2011,28(2):101-106.
目录contents

    摘要

    射孔完井作业中射孔会对水泥环完整性造成破坏,尤其是固井界面微环隙的产生,导致后续压裂过程中出现环空带压与环空窜流的问题。 针对此问题,建立压裂过程中水泥环界面微环隙扩展三维模型,通过 Cohesive 单元损伤模型模拟固井界面在体积压裂过程中微环隙的扩展,对界面微环隙的扩展长度进行分析计算,研究不同参数对压裂过程中固井界面失封长度的影响。 结果表明:适当降低水泥环弹性模量,提高水泥石与套管、地层的胶结强度有利于减小水泥环界面微环隙扩展长度,保证水泥环有效封固;研究结果能够对体积压裂条件下的水泥环封固性能进行评价和预测。

    Abstract

    During well completion, perforation can cause damage to the integrity of cement sheath, especially the debonding of cement interface and the micro-annulus induced can lead to problems of crack propagation and annulus turbulence in se- quential hydraulic fracturing process. In this study, a three-dimensional model was established in order to simulate the crack propagation of cement interface during volume fracturing process based on a Cohesive element damage model. The interface debonding length was analyzed and calculated and its influencing factors during the fracturing process were investigated. The simulation results show that it is beneficial to reduce the crack propagation length of the cement sheath interface by decreasing the elastic modulus of cement and increasing the cohesive strength of casing-cement and cement-formation interfaces, thus en- suring an effective sealing of the cement sheath. The model can be used to evaluate and predict the sealing performance of the cement sheath under volume fracturing conditions, and also can provide guidance for the design of the fracturing scheme.

  • 井筒密封完整性对于油气田生产开发过程至关重要[1-4]。 射孔完井作为建立油气流动通道并提高油气采收率的一项必要工艺技术,在侵彻井筒与地层的过程中会导致水泥环产生裂纹、固井界面局部脱黏等机械损伤[5]。 在页岩气、煤层气的勘探开发中,由于储层孔隙度、渗透率低,必须通过水力压裂的手段进行开采。 此时,射孔孔眼附近的初始裂缝在压裂液的驱动下逐渐扩展,使射孔段水泥环密封完整性逐渐失效[6-8]。 因此有必要针对压裂过程中水泥环界面的扩展规律进行分析。 目前,学者们较多关心水力压裂地层裂缝的扩展与缝间干扰问题[9-14],而针对压裂过程中井筒密封完整性的失效分析较少。 Lecampion等[15]、 李勇等[16]通过理论模型计算水力压裂过程中固井界面的扩展长度,并通过室内试验验证了模型的可靠性; Feng等[17]、Martinez等[18] 和Wang等[19] 采用有限元软件ABAQUS中Cohesive单元模拟压裂工况下固井界面微环隙的扩展长度。 但上述学者大都忽视了射孔初始损伤对于后期压裂过程中界面微环隙扩展的影响,同时缺乏对影响界面微环隙扩展因素的分析。 针对上述问题,笔者充分考虑射孔对水泥环界面的初始损伤,在此基础上分析水力压裂过程中水泥环界面微环隙扩展演化规律,利用有限元软件ABAQUS,建立基于Cohe-sive单元的三维固井界面微环隙扩展模型,模拟计算水平井段体积压裂工况下固井界面微环隙的扩展过程,得出井筒界面完整性的失封长度,同时分析水泥石弹性模量、围岩弹性模量及固井界面抗拉强度对微环隙扩展长度的影响。

  • 1 微环隙扩展模型建立

  • 1.1 物理模型

  • 在压裂过程中,当射孔导致固井界面出现微小缝隙后,从井口注入的高压压裂液会进入微裂缝中, 并克服界面胶结强度引起界面微环隙,如图1 所示。基于该现象,建立图2 所示水平井水力压裂水泥环微环隙扩展三维模型,套管外径为139.7 mm,内径为127.9 mm,水泥环厚度为30 mm,出于网格数量与计算时间的考虑,地层尺寸设为5 m×5 m×10 m的长方体。 其中套管单元类型设置为C3D8R,水泥、岩石的单元类型设置为C3D8P,在套管与水泥环的分界面、水泥环与岩层的分界面插入Cohesive单元层[20]。初始损伤单元用以表示由于射孔对固井界面造成的初始损伤,即初始损伤单元处固井界面已经产生微环隙。模型中的网格均采用结构化网格,为减小计算时间,网格由内向外逐渐稀疏。 同时在套管、水泥环和地层上、下底面以及地层外侧施加固定约束。

  • 图1 固井一界面初始微环隙示意图

  • Fig.1 Schematic diagram of micro-annulus at casing-cement interface

  • 图2 几何模型

  • Fig.2 Geometric model

  • 1.2 孔隙与裂缝中流体流动方程

  • 数值模型中,水泥和围岩视为多孔连续介质。压裂过程中,压裂液会沿着固相骨架与孔隙中的流体发生交换。因此需要通过流固耦合方程表征这一过程。忽略岩石与水泥的塑性变形,将其视为各向同性的弹性体。根据虚功原理[21],岩石骨架应力的平衡关系式为

  • V(σ¯-ppI):εδdV=StvδdS+VfvδdV
    (1)
  • 式中, σ¯为有效应力矩阵;I为二阶单位张量;pp 为孔隙压力; εδ 为虚应变率矩阵;t、f、vδ分别为表面力向量、体积力向量和虚速度向量。

  • 流体在岩石孔隙中的渗流过程遵从达西定律, 流体连续性方程的微分形式[19]

  • ddt(ρwnwdV)+ρwnwn(-1nwgρwk(pw-ρwg))dS=0
    (2)
  • 式中,ρ 为孔隙中流体密度,kg/m 3 ;n为孔隙度;p为流体压力,Pa;k为渗透率矩阵;g为自由落体加速度,m/s 2;n为垂直于表面S的单位向量。

  • 图3 为Cohesive单元损伤机制示意图。 图3 中, δn为位移,m; δn0δnf分别为Cohesive单元初始损伤时和完全破坏时的位移,m;Tn 为抗拉强度,Pa; Tn0为Cohesive单元的抗拉强度,Pa;D为Cohesive单元的损伤因子。 图3(a)中既有垂直于单元上、下表面的法向流动,又有平行于单元表面的切向流动。 本文中采用幂律模型来表征压裂液的切向流,其本构关系[19]

  • τ=Kγ˙n'
    (3)
  • 式中, τ为流体切应力,Pa;γ 为切向应变率;K为稠度系数,Pa·s n;n'为幂律系数。

  • 图3 Cohesive单元损伤机制示意图

  • Fig.3 Damage law of Cohesive element

  • Cohesive单元内切向流的体积流率[20]定义为

  • qd=(2n1+2n)(1K)1n(d2)1+2nn|p|1-nnp
    (4)
  • 式中,d为界面微环隙的开度,m; p为流体压降, Pa。

  • 单元内流体的法向流动表现为沿Cohesive单元上、下表面的滤失[15],其计算公式为

  • {q1=c1(pi-pt)qb=cb(pi-pb)
    (5)
  • 式中,q和qb 分别为Cohesive单元上、下表面的体积流率,m 3/s;c和cb 分别为Cohesive单元上、下表面的滤失系数;pi 为Cohesive单元内的流体压力, Pa;p和pb 分别为上、下表面的孔隙压力,Pa。

  • 1.3 Cohesive单元损伤模型

  • 界面微环隙的产生与扩展是基于图3(b)中线弹性Traction-separation准则[20],通过Cohesive单元出现的损伤程度实现量化表征。 当Cohesive单元上、下表面的法向位移小于Cohesive单元初始损伤时的位移时,单元上、下表面承受的法向应力随着位移的增加而线性增大直至达到单元的抗拉强度;当Cohesive单元上、下表面的法向位移处于初始损伤时的位移与Cohesive单元完全破坏时的位移之间时,Cohesive单元所能承受的法向应力随着位移的增加而减小,此时Cohesive单元处入损伤阶段;当位移增加到Cohesive单元完全破坏时的位移时,Cohe-sive单元无法承受应力而完全破坏,界面出现微环隙。

  • 本文中采用二次应力起裂准则[20] 作为固井界面微环隙是否出现的判据。 假设当Cohesive单元的3 个方向上的应力与其临界应力比值的平方和达到1 时,Cohesive单元开始起裂,即

  • {TnTn0}2+{TsTs0}2+{TtTt0}2=1
    (6)
  • 式中, Ts0和T分别为Cohesive单元两切向的抗剪强度,Pa。

  • 为表征Cohesive单元的损伤程度,模型中引入损伤因子D。 D从0 到1 的取值表示材料从未损伤到完全损伤。 基于线性位移扩展准则的单元损伤因子[20]表达式为

  • D=δmf(δmm-δm0)δmm(δmf-δm0)
    (7)
  • 式中,δmm为Cohesive单元的最大位移,m;δmf为Co-hesive单元起裂时的位移,m;δm0为Cohesive单元开始出现损伤时的位移,m。

  • 引入损伤因子后,基于Traction-separation准则的Cohesive单元损伤演化模型表示为

  • Ts=(1-D)T¯sTt=(1-D)T¯tTn={(1-D)T¯n,T¯n0T¯n,T¯n<0

  • 式中, T¯nT¯sT¯t 分别为3 个方向Cohesive单元按图3(b)中AB段线弹性变形时计算得到的应力,Pa。

  • 1.4 材料参数与求解过程

  • 参考威远-长宁区块某页岩气井的施工参数与地质数据,模型中垂向地应力、最大水平地应力与最小水平地应力分别设置为20、35 和25 MPa,地层的孔隙压力梯度为9.8 MPa·km -1,套管的泊松比为0.25,弹性模量为210 GPa,水泥与地层的泊松比分别为0.2 和0.22,弹性模量分别为20 和30 GPa,孔隙度分别为0.08 和0.15,渗透率分别为0.01×10-3 和10×10 -3 μm 2 ,水泥石与地层岩石的饱和度均设为1。 套管-水泥环界面与水泥环-地层界面的抗拉强度、抗剪强度与胶结刚度分别为0.5、2 和8500 MPa,单元临界破裂能量为100 J·m -2。经过前期试算发现界面微环隙扩展发生在水力压裂初期,考虑到计算时间成本,本文模型中压裂施工时间设置为30 min。压裂液的密度为1.2 g·cm -3,压裂液稠度系数、流变指数和滤失系数分别为1、0.4、1×10 -11。 界面中压裂液的注入流量为8×10 -5 m 3·s -1

  • 1.5 模型验证

  • 为验证模拟结果的可靠性,利用Lecampion在2013 年进行的井筒界面微环隙扩展模拟试验[15] 进行验证。 图4 为模拟井筒固井界面微环隙扩展装置示意图。 分别用铝管、环氧基树脂、聚甲基丙烯酸甲酯模拟套管、水泥环和地层,在环氧基树脂和聚甲基丙烯酸甲酯界面预设3 mm的初始缺口。 压力泵将从右侧管道泵入清水,清水通过过滤器驱动染色液进入环氧基树脂和聚甲基丙烯酸甲酯界面,通过高速摄像机记录界面扩展过程。 图5 中试验结果与模拟结果高度吻合,说明Cohesive单元损伤模型用于模拟固井界面微环隙具有可靠性。

  • 图4 井筒界面微环隙扩展压裂模拟装置示意图

  • Fig.4 Fracturing simulation device of micro-annulus propagation

  • 图5 模拟结果与试验结果对比

  • Fig.5 Comparison of experimental results with simulation

  • 2 微环隙扩展演化过程

  • 压裂液进入界面后,克服界面胶结强度带来的摩阻向前不断扩展。 图6 为射孔孔眼处压裂液注入点压力随压裂时间的变化曲线。 由图6 可知,注入点压力短时间内快速上升,随后逐渐稳定在某一数值。 套管-水泥环界面注入点压力稳定在21 MPa, 水泥环-地层界面注入点压力稳定在35 MPa。 即水泥环-地层界面需要更高的注入点压力才可以使界面微环隙开始扩展。

  • 图6 注入点压力随时间变化曲线

  • Fig.6 Pressure of fracturing fluid at injection point

  • 沿井筒方向界面微环隙扩展长度(损伤值大于0 的长度)随时间变化曲线如图7 所示。 由图7 可知,在界面扩展初期,微环隙的轴向扩展速度较快, 随着扩展过程的进行,界面微环隙的轴向扩展速度逐渐下降,最后扩展长度达到极限值,微环隙扩展停止。 在给定条件下,套管-水泥环界面微环隙轴向扩展长度为16.2 m,水泥环-地层界面微环隙轴向扩展长度为8.1 m。 说明相同条件下,固井第一界面完整性在体积压裂过程中受到的破坏程度更大。

  • 图7 沿井筒方向界面微环隙扩展长度随时间变化曲线

  • Fig.7 Micro-annulus propagation length along wellbore at different times

  • 为进一步说明压裂液驱动下界面微环隙的演化过程,绘制如图8 所示损伤值沿轴向距离的变化曲线。 套管-水泥环界面轴向的损伤值随着扩展距离的增大不断波动,但基本稳定在约0.9,直至扩展过程结束,迅速降低至0;水泥环-地层界面轴向的损伤值随着扩展距离的增大振荡下降至约0.8,直至扩展过程结束,迅速降低至0。

  • 图8 损伤值沿轴向距离的变化曲线

  • Fig.8 Curve of damage value along axial distance

  • 图9 为压裂初始阶段固井界面微环隙演化过程。 由图9 可以看出,界面微环隙前缘呈现锥状,0 方位处扩展最为迅速。 值得注意的是,图9 中界面微环隙的扩展范围并未覆盖整个环空周长,主要原因:流体沿井筒轴线方向所受摩阻远小于沿井筒周向流动摩阻,因此界面微环隙倾向于在垂直方向上扩展而不是圆周方向;未覆盖的方位角范围位于最大剪切应力侧,而压裂液更倾向于在最小剪切应力侧克服沿程摩阻向前扩展。

  • 图9 压裂初期固井界面微环隙演化过程

  • Fig.9 Debonding evolution process of cementing interface during hydraulic fracturing

  • 3 影响因素

  • 3.1 水泥石弹性模量

  • 不同水泥石弹性模量条件下,套管-水泥环界面与水泥环-地层界面轴向损伤值随微环隙扩展长度的变化曲线如图10 所示。 由图10 可知,随着水泥石弹性模量的增加,套管-水泥环界面与水泥环地层界面微环隙扩展长度均有所增大,但水泥环地层界面微环隙扩展长度增加的幅值十分有限。 这说明水泥石的弹性模量主要影响套管-水泥环界面微环隙的扩展长度,对水泥环-地层界面微环隙的扩展长度影响很小。

  • 图10 界面微环隙扩展长度与水泥石弹性模量关系曲线

  • Fig.10 Relationship between micro-annulus propagation length and cement elastic modulus

  • 3.2 岩石弹性模量

  • 不同地层围岩弹性模量条件下,套管-水泥环界面与水泥环-地层界面轴向损伤值随微环隙扩展长度的变化曲线如图11 所示。 由图11 可知,随着围岩弹性模量的增加,套管-水泥环界面与水泥环地层界面微环隙扩展长度均有所增大,但增加的幅值逐渐减小。 同时围岩弹性模量对套管-水泥环界面微环隙扩展长度的影响程度同样大于水泥环-地层界面微环隙扩展长度。

  • 图11 界面微环隙扩展长度与岩石弹性模量关系曲线

  • Fig.11 Relationship between micro-annulus propagation length and rock elastic modulus

  • 3.3 界面抗拉强度

  • 不同界面抗拉强度下套管-水泥环界面与水泥环-地层界面轴向损伤值随微环隙扩展长度的变化曲线如图12 所示。

  • 图12 界面微环隙扩展长度与界面抗拉强度关系曲线

  • Fig.12 Relationship between micro-annulus propagation and interface tensile strength

  • 由图12 可知,随着界面抗拉强度的增加,套管-水泥环界面与水泥环-地层界面微环隙扩展长度均急速减小,但减小的幅值逐渐减小。 说明界面抗拉强度是影响界面微环隙扩展长度的主要影响因素,同时界面的抗拉强度对套管-水泥环界面微环隙扩展长度的影响程度大于水泥环-地层界面微环隙扩展长度。 原因在于第二界面受地层围压影响更大,在压裂液到达孔眼处时,由于水泥环-地层界面压实程度更大,压裂液更容易进入套管-水泥环界面,这使第二界面更多的Cohesive单元达到临界损伤值,从而使第一界面微环隙扩展长度更大。

  • 4 结论

  • (1)压裂过程中界面微环隙前缘呈锥状,且沿井筒周向各处微环隙扩展速度不同,沿孔眼处的方位扩展速度最快。

  • (2)适当降低水泥石弹性模量,提高水泥石与套管、地层的胶结强度有利于减小水泥环界面微环隙的扩展长度,保证水泥环有效封固。 弹性模量越大的地层,压裂过程中水泥环界面微环隙的扩展长度越大。

  • 参考文献

    • [1] 刘奎,王宴滨,高德利,等.页岩气水平井压裂对井筒完整性的影响[J].石油学报,2016,37(3):406-414.LIU Kui,WANG Yanbin,GAO Deli,et al.Effects of hydraulic fracturing on horizontal wellbore for shale gas [J].Acta Petrolei Sinica,2016,37(3):406-414. 

    • [2] 田中兰,石林,乔磊.页岩气水平井井筒完整性问题及对策[J].天然气工业,2015,35(9):70-76.TIAN Zhonglan,SHI Lin,QIAO Lei.Research and countermeasure for wellbore integrity shale gas horizontal well[J].Natural Gas Industry,2015,35(9):70-76. 

    • [3] 沈吉云,石林,李勇,等.大压差条件下水泥环密封完整性分析及展望[J].天然气工业,2017,37(4):98-108.SHEN Jiyun,SHI Lin,LI Yong,et al.Analysis and per-spective of cement sheath integrity under a high differenti-al pressure[J].Natural Gas Industry,2017,37(4):98-108. 

    • [4] 李军,席岩,付永强,等.利用分段固井方法提高页岩气井筒完整性[J].钻采工艺,2017,40(4):21-24.LI Jun,XI Yan,FU Yongqiang,et al.To improve well-bore integrity of shale gas wells with stage cementing method[J].Drilling & Production Technology,2017,40(4):21-24. 

    • [5] 李进,龚宁,李早元,等.射孔完井工况下固井水泥环破坏研究进展[J].钻井液与完井液,2016,33(6):10-16.LI Jin,GONG Ning,LI Zaoyuan,et al.Progress in stud-ying cement sheath failure in perforated wells[J].Drill-ing Fluid & Completion Fluid,2016,33(6):10-16. 

    • [6] WANG H Y.Numerical investigation of fracture spacing and sequencing effects on multiple hydraulic fracture in-terference and coalescence in brittle and ductile reservoir rocks[J].Engineering Fracture Mechanics,2016,157:107-124. 

    • [7] XI Y,LI J,LIU G,et al.A new numerical investigation of cement sheath integrity during multistage hydraulic fracturing shale gas wells[J].Journal of Natural Gas Sci-ence & Engineering,2018,49:331-341. 

    • [8] 刘建伟,张佩玉,廖天彬,等.马58H致密油藏水平井分段多簇射孔压裂技术[J].石油钻采工艺,2015,37(3):88-92.LIU Jianwei,ZHANG Peiyu,LIAO Tianbin,et al.Staged multi-cluster perforation fracturing technology for horizontal well Ma-58H in tight reservoir[J].Oil Drilling & Production Technology,2015,37(3):88-92. 

    • [9] 张广明,刘合,张劲,等.油井水力压裂流-固耦合非线性有限元数值模拟[J].石油学报,2009,30(1):113-116.ZHANG Guangming,LIU He,ZHANG Jin,et al.Simu-lation of hydraulic fracturing of oil well based on fluid-sol-id coupling equation and non-linear finite element [J].Acta Petrolei Sinica,2009,30(1):113-116. 

    • [10] 龚迪光,曲占庆,李建雄,等.基于ABAQUS平台的水力裂缝扩展有限元模拟研究[J].岩土力学,2016,37(5):1512-1520.GONG Diguang,QU Zhanqing,LI Jianxiong,et al.Ex-tended finite element simulation of hydraulic fracture based on ABAQUS platform[J].Rock and Soil Mechan-ics,2016,37(5):1512-1520. 

    • [11] 王海洋,卢义玉,夏彬伟,等.射孔水压裂缝在层状页岩的扩展机制[J].中国石油大学学报(自然科学版),2018,42(2):95-101.WANG Haiyang,LU Yiyu,XIA Binwei,et al.Propa-gation mechanism of hydraulic fracture of perforation in laminated slate[J].Journal of China University of Pe-troleum(Edition of Natural Science),2018,42(2):95-101. 

    • [12] 潘林华,张士诚,张劲,等.基于流-固耦合的压裂裂缝形态影响因素分析[J].西安石油大学学报(自然科学版),2012,27(3):76-80.PAN Linhua,ZHANG Shicheng,ZHANG Jin,et al.A-nalysis of factors influencing the shape of hydraulic frac-turing fracture based on fluid-solid coupling[J].Journal of Xi’ an Shiyou University(Natural Science Edition),2012,27(3):76-80. 

    • [13] 张建光,李湘萍,王传睿,等.页岩气藏水力压裂中应力-流压耦合效应及人工裂缝扩展规律[J].中国石油大学学报(自然科学版),2018,42(6):96-105.ZHANG Jianguang,LI Xiangping,WANG Chuanrui,et al.Numerical simulation of rock formation stress-fluid pressure coupling and development of artificial fractures during hydraulic fracturing of shale gas reservoirs [J].Journal of China University of Petroleum(Edition of Natural Science),2018,42(6):96-105. 

    • [14] 曲占庆,田雨,李建雄,等.水平井多段分簇压裂裂缝扩展形态数值模拟[J].中国石油大学学报(自然科学版),2017,41(1):102-109.QU Zhanqing,TIAN Yu,LI Jianxiong,et al.Numeri-cal simulation study on fracture extension and morpholo-gy of multi-cluster staged fracturing for horizontal wells [J].Journal of China University of Petroleum(Edition of Natural Science),2017,41(1):102-109. 

    • [15] LECAMPION B,BUNGER A,KEAR J,et al.Interface debonding driven by fluid injection in a cased and ce-mented wellbore:modeling and experiments[J].Inter-national Journal of Greenhouse Gas Control,2013,18(7):208-223. 

    • [16] 李勇,陈瑶,靳建洲,等.页岩气井体积压裂条件下的水泥环界面裂缝扩展[J].石油学报,2017,38(1):105-111.LI Yong,CHEN Yao,JIN Jianzhou,et al.Cement ring interface crack propagation under volume fracturing in shale gas well[J].Acta Petrolei Sinica,2017,38(1):105-111. 

    • [17] FENG Y,LI X,GRAY K E.Development of a 3D nu-merical model for quantifying fluid-driven interface debonding of an injector well[J].International Journal of Greenhouse Gas Control,2017,62:76-90. 

    • [18] MARTINEZ R E,KIM J,MORIDIS G J.Numerical in-vestigation of potential cement failure along the wellbore and gas leak during hydraulic fracturing of shale gas res-ervoirs:the 50th US Rock Mechanics/Geomechanics Symposium,Houston,USA.2016 [ C].Washington D C:American Rock Mechanics Association,2016. 

    • [19] WANG W,TALEGHANI A D.Impact of hydraulic frac-turing on cement sheath integrity:a modelling approach [J].Journal of Natural Gas Science & Engineering,2017,44:265-277. 

    • [20] ZHU H,DENG J,ZHAO J,et al.Cementing failure of the casing-cement-rock interfaces during hydraulic frac-turing[J].Computers and Concrete,2014,14(1):91-107. 

    • [21] 张广明,刘合,张劲,等.储层流固耦合的数学模型和非线性有限元方程[J].岩土力学,2010,31(5):1657-1662.ZHANG Guangming,LIU He,ZHANG Jin,et al.Mathematical model and nonlinear finite element equa-tion for reservoir fluid-solid coupling[J].Rock and Soil Mechanics,2010,31(5):1657-1662. 

    • [22] 连志龙,张劲,吴恒安,等.水力压裂扩展的流固耦合数值模拟研究[J].岩土力学,2008,29(11):3021-3026.LIAN Zhilong,ZHANG Jin,WU Heng ‘ an,et al.A simulation study of hydraulic fracturing propagation with a solid-fluid coupling model[J].Rock and Soil Mechan-ics,2008,29(11):3021-3026. 

    • [23] 张广明,刘合,张劲,等.水平井水力压裂的三维有限元数值模拟研究[J].工程力学,2011,28(2):101-106.ZHANG Guangming,LIU He,ZHANG Jin,et al.Three-dimensional finite element numerical simulation of horizontal well hydraulic fracturing [J].Engineering Mechanics,2011,28(2):101-106.

  • 参考文献

    • [1] 刘奎,王宴滨,高德利,等.页岩气水平井压裂对井筒完整性的影响[J].石油学报,2016,37(3):406-414.LIU Kui,WANG Yanbin,GAO Deli,et al.Effects of hydraulic fracturing on horizontal wellbore for shale gas [J].Acta Petrolei Sinica,2016,37(3):406-414. 

    • [2] 田中兰,石林,乔磊.页岩气水平井井筒完整性问题及对策[J].天然气工业,2015,35(9):70-76.TIAN Zhonglan,SHI Lin,QIAO Lei.Research and countermeasure for wellbore integrity shale gas horizontal well[J].Natural Gas Industry,2015,35(9):70-76. 

    • [3] 沈吉云,石林,李勇,等.大压差条件下水泥环密封完整性分析及展望[J].天然气工业,2017,37(4):98-108.SHEN Jiyun,SHI Lin,LI Yong,et al.Analysis and per-spective of cement sheath integrity under a high differenti-al pressure[J].Natural Gas Industry,2017,37(4):98-108. 

    • [4] 李军,席岩,付永强,等.利用分段固井方法提高页岩气井筒完整性[J].钻采工艺,2017,40(4):21-24.LI Jun,XI Yan,FU Yongqiang,et al.To improve well-bore integrity of shale gas wells with stage cementing method[J].Drilling & Production Technology,2017,40(4):21-24. 

    • [5] 李进,龚宁,李早元,等.射孔完井工况下固井水泥环破坏研究进展[J].钻井液与完井液,2016,33(6):10-16.LI Jin,GONG Ning,LI Zaoyuan,et al.Progress in stud-ying cement sheath failure in perforated wells[J].Drill-ing Fluid & Completion Fluid,2016,33(6):10-16. 

    • [6] WANG H Y.Numerical investigation of fracture spacing and sequencing effects on multiple hydraulic fracture in-terference and coalescence in brittle and ductile reservoir rocks[J].Engineering Fracture Mechanics,2016,157:107-124. 

    • [7] XI Y,LI J,LIU G,et al.A new numerical investigation of cement sheath integrity during multistage hydraulic fracturing shale gas wells[J].Journal of Natural Gas Sci-ence & Engineering,2018,49:331-341. 

    • [8] 刘建伟,张佩玉,廖天彬,等.马58H致密油藏水平井分段多簇射孔压裂技术[J].石油钻采工艺,2015,37(3):88-92.LIU Jianwei,ZHANG Peiyu,LIAO Tianbin,et al.Staged multi-cluster perforation fracturing technology for horizontal well Ma-58H in tight reservoir[J].Oil Drilling & Production Technology,2015,37(3):88-92. 

    • [9] 张广明,刘合,张劲,等.油井水力压裂流-固耦合非线性有限元数值模拟[J].石油学报,2009,30(1):113-116.ZHANG Guangming,LIU He,ZHANG Jin,et al.Simu-lation of hydraulic fracturing of oil well based on fluid-sol-id coupling equation and non-linear finite element [J].Acta Petrolei Sinica,2009,30(1):113-116. 

    • [10] 龚迪光,曲占庆,李建雄,等.基于ABAQUS平台的水力裂缝扩展有限元模拟研究[J].岩土力学,2016,37(5):1512-1520.GONG Diguang,QU Zhanqing,LI Jianxiong,et al.Ex-tended finite element simulation of hydraulic fracture based on ABAQUS platform[J].Rock and Soil Mechan-ics,2016,37(5):1512-1520. 

    • [11] 王海洋,卢义玉,夏彬伟,等.射孔水压裂缝在层状页岩的扩展机制[J].中国石油大学学报(自然科学版),2018,42(2):95-101.WANG Haiyang,LU Yiyu,XIA Binwei,et al.Propa-gation mechanism of hydraulic fracture of perforation in laminated slate[J].Journal of China University of Pe-troleum(Edition of Natural Science),2018,42(2):95-101. 

    • [12] 潘林华,张士诚,张劲,等.基于流-固耦合的压裂裂缝形态影响因素分析[J].西安石油大学学报(自然科学版),2012,27(3):76-80.PAN Linhua,ZHANG Shicheng,ZHANG Jin,et al.A-nalysis of factors influencing the shape of hydraulic frac-turing fracture based on fluid-solid coupling[J].Journal of Xi’ an Shiyou University(Natural Science Edition),2012,27(3):76-80. 

    • [13] 张建光,李湘萍,王传睿,等.页岩气藏水力压裂中应力-流压耦合效应及人工裂缝扩展规律[J].中国石油大学学报(自然科学版),2018,42(6):96-105.ZHANG Jianguang,LI Xiangping,WANG Chuanrui,et al.Numerical simulation of rock formation stress-fluid pressure coupling and development of artificial fractures during hydraulic fracturing of shale gas reservoirs [J].Journal of China University of Petroleum(Edition of Natural Science),2018,42(6):96-105. 

    • [14] 曲占庆,田雨,李建雄,等.水平井多段分簇压裂裂缝扩展形态数值模拟[J].中国石油大学学报(自然科学版),2017,41(1):102-109.QU Zhanqing,TIAN Yu,LI Jianxiong,et al.Numeri-cal simulation study on fracture extension and morpholo-gy of multi-cluster staged fracturing for horizontal wells [J].Journal of China University of Petroleum(Edition of Natural Science),2017,41(1):102-109. 

    • [15] LECAMPION B,BUNGER A,KEAR J,et al.Interface debonding driven by fluid injection in a cased and ce-mented wellbore:modeling and experiments[J].Inter-national Journal of Greenhouse Gas Control,2013,18(7):208-223. 

    • [16] 李勇,陈瑶,靳建洲,等.页岩气井体积压裂条件下的水泥环界面裂缝扩展[J].石油学报,2017,38(1):105-111.LI Yong,CHEN Yao,JIN Jianzhou,et al.Cement ring interface crack propagation under volume fracturing in shale gas well[J].Acta Petrolei Sinica,2017,38(1):105-111. 

    • [17] FENG Y,LI X,GRAY K E.Development of a 3D nu-merical model for quantifying fluid-driven interface debonding of an injector well[J].International Journal of Greenhouse Gas Control,2017,62:76-90. 

    • [18] MARTINEZ R E,KIM J,MORIDIS G J.Numerical in-vestigation of potential cement failure along the wellbore and gas leak during hydraulic fracturing of shale gas res-ervoirs:the 50th US Rock Mechanics/Geomechanics Symposium,Houston,USA.2016 [ C].Washington D C:American Rock Mechanics Association,2016. 

    • [19] WANG W,TALEGHANI A D.Impact of hydraulic frac-turing on cement sheath integrity:a modelling approach [J].Journal of Natural Gas Science & Engineering,2017,44:265-277. 

    • [20] ZHU H,DENG J,ZHAO J,et al.Cementing failure of the casing-cement-rock interfaces during hydraulic frac-turing[J].Computers and Concrete,2014,14(1):91-107. 

    • [21] 张广明,刘合,张劲,等.储层流固耦合的数学模型和非线性有限元方程[J].岩土力学,2010,31(5):1657-1662.ZHANG Guangming,LIU He,ZHANG Jin,et al.Mathematical model and nonlinear finite element equa-tion for reservoir fluid-solid coupling[J].Rock and Soil Mechanics,2010,31(5):1657-1662. 

    • [22] 连志龙,张劲,吴恒安,等.水力压裂扩展的流固耦合数值模拟研究[J].岩土力学,2008,29(11):3021-3026.LIAN Zhilong,ZHANG Jin,WU Heng ‘ an,et al.A simulation study of hydraulic fracturing propagation with a solid-fluid coupling model[J].Rock and Soil Mechan-ics,2008,29(11):3021-3026. 

    • [23] 张广明,刘合,张劲,等.水平井水力压裂的三维有限元数值模拟研究[J].工程力学,2011,28(2):101-106.ZHANG Guangming,LIU He,ZHANG Jin,et al.Three-dimensional finite element numerical simulation of horizontal well hydraulic fracturing [J].Engineering Mechanics,2011,28(2):101-106.

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