克深地区井壁稳定性评价及钻井工程应用
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摘要
塔里木盆地克深地区裂缝性储层埋藏深,井壁失稳问题严重,建立该区考虑地层各向异性的井壁稳定性评价方法非常重要。通过对现场井壁失稳与地层弱面的相关性研究,发现弱面在强应力、高孔隙压力背景下,将先于岩石本体破坏,产生掉块、垮塌、卡钻现象。若裂缝渗透性较好,钻井液液柱压力大于孔隙压力时即有可能发生漏失,漏失压力不再由破裂压力和最小水平主应力控制,而是取决于裂缝产状和三轴应力状态之间的关系。因此对于强各向异性地层,其强度软弱面上的坍塌压力和漏失压力是钻井稳定性评价中的关键。在核定该区井壁失稳的主控地质因素是强应力背景下的裂缝弱面错动破坏的基础上,评价了克深区带横向各向异性岩体力学的稳定性,建立适用于强各向异性复杂条件下的井壁稳定性评价方法。结果表明克深裂缝性储层的安全泥浆密度窗口普遍较窄甚至无理论安全窗口,提出改善钻井液性能或者采用定向井钻探方案以减少井壁失稳的工程应对方案。现场实践应用表明,钻井液密度调整至合理范围后,井壁失稳明显减少,现场复杂问题得到有效解决。
The borehole instability problems are serious in Keshen fractured reservoir with large buried depth in Tarim Basin. It is very important to establish the method of evaluating the stability of the borehole wall with anisotropic formation in this area. Through studies on the correlation of site wall instability and formation weak surface,the existence of the weak plane made the rocks damaged before the rock mass under strong stress and high pore pressure,it will be broken easily and cause collapse and sticking. If the fracture permeability is good,loss may occur when drilling fluid pressure is greater than pore pressure,then loss pressure is no longer controlled by fracturing pressure and minimum horizontal principal stress,but on the relationship between the occurrence of fractures and the triaxial stress state. So for the formation of strong anisotropy,the collapse pressure and loss pressure of weak strength plane is the key parameter in the evaluation of drilling stability. As the main controlling geological factor of the borehole instability in this area that is the failure of the weak surface of the crack under the strong stress background was determined,the stability of the mechanics of transverse anisotropic rock mass was evaluated in Keshen area. A method for evaluating the stability of wellbore under the complex condition of strong anisotropy was established in this paper. The results show that safety mud density windows of fractured reservoirs is generally narrower or even without theoretical safety windows in Keshen. The study shows that the wellbore instability be reduced by improving the performance of the mud or using a directional well drilling scheme. The field practice shows that after the drilling fluid density is adjusted to a reasonable range,the instability of the wellbore is obviously reduced,and the complex problems in the field are effectively solved.
The borehole instability problems are serious in Keshen fractured reservoir with large buried depth in Tarim Basin. It is very important to establish the method of evaluating the stability of the borehole wall with anisotropic formation in this area. Through studies on the correlation of site wall instability and formation weak surface,the existence of the weak plane made the rocks damaged before the rock mass under strong stress and high pore pressure,it will be broken easily and cause collapse and sticking. If the fracture permeability is good,loss may occur when drilling fluid pressure is greater than pore pressure,then loss pressure is no longer controlled by fracturing pressure and minimum horizontal principal stress,but on the relationship between the occurrence of fractures and the triaxial stress state. So for the formation of strong anisotropy,the collapse pressure and loss pressure of weak strength plane is the key parameter in the evaluation of drilling stability. As the main controlling geological factor of the borehole instability in this area that is the failure of the weak surface of the crack under the strong stress background was determined,the stability of the mechanics of transverse anisotropic rock mass was evaluated in Keshen area. A method for evaluating the stability of wellbore under the complex condition of strong anisotropy was established in this paper. The results show that safety mud density windows of fractured reservoirs is generally narrower or even without theoretical safety windows in Keshen. The study shows that the wellbore instability be reduced by improving the performance of the mud or using a directional well drilling scheme. The field practice shows that after the drilling fluid density is adjusted to a reasonable range,the instability of the wellbore is obviously reduced,and the complex problems in the field are effectively solved.
引文
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[2]陈勉,金衍,张广清,等.石油工程岩石力学[M].北京:科学技术出版社,2008.Chen Mian,Jin Yan,Zhang Guangqing,et al.Petroleum Engineering Rock Mechanics[M].Beijing:Science and Technology Press,2008.
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[7]Finkbeiner T D,Moos D,DeRose W.Wellbore Stability Evaluation for Horizontal Hole Completion-A Case Study[C]//Paper SPE-64409-MS Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition,16-18October 2000,Brisbane,Australia.New York:SPE,2000.
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[10]Yan Chuanliang,Deng Jingen,Yu Baohua,et al.Borehole Stability in High-Temperature Formation[J].Rock Mechanics&Rock Engineering,2014,47(6):2199-2209.
[11]管申,谭强,黄熠,等.海上复杂压力体系油田钻井安全密度窗口研究[J].天然气与石油,2015,33(5):52-55.Guan Shen,Tan Qiang,Huang Yi,et al.Study on Safe Drilling Density Window in Offshore Oilfield with Complex Pressure System[J].Natural Gas and Oil,2015,33(5):52-55.
[12]尹帅,丁文龙,杨文娜,等.考虑地层各向异性井壁稳定性研究进展[J].地球科学进展,2015,30(11):1218-1230.Yin Shuai,Ding Wenlong,Yang Wenna,et al.Progress of Borehole Stability Considering Strata Anisotropy[J].Advances in Earth Science,2015,30(11):1218-1230.
[13]Rahman M K,Naseby D,Rahman S S.Borehole Collapse Analysis Incorporating Time-Dependent Pore Pressure Due to Mud Penetration in Shales[J].Journal of Petroleum Science&Engineering,2000,28(1):13-31.
[14]梁利喜,丁乙,刘向君,等.硬脆性泥页岩井壁稳定渗流-力化耦合研究[J].特种油气藏,2016,23(2):140-143.Liang Lixi,Ding Yi,Liu Xiangjun,et al.SeepageMechanochemistry Coupling of Wellbore Stability in Hard-Brittle Shale[J].Special Oil and Gas Reservoirs,2016,23(2):140-143.
[15]刘向君,曾韦,梁利喜,等.页岩层理对井壁稳定性影响分析[J].中国安全生产科学技术,2016,12(11):88-92.Liu Xiangjun,Zeng Wei,Liang Lixi,et al.Analysis on Influence of Shale Bedding on Wellbore Stability[J].Journal of Safety Science and Technology,2016,12(11):88-92.
[16]田作基,宋建国.塔里木库车新生代前陆盆地构造特征及形成演化[J].石油学报,1999,20(4):7-13.Tian Zuoji,Song Jianguo.Tertiary Structure Characteristics and Evolution of Kuche Foreland Basin[J].Acta Petrolei Sinica,1999,20(4):7-13.
[17]耶格J C.岩石力学基础[M].北京:科学出版社,1981.Jaeger J C.Fundamental of Rock Mechanics[M].Beijing:Science Press,1981.
[18]张福祥,王新海,李元斌,等.库车山前裂缝性砂岩气层裂缝对地层渗透率的贡献率[J].石油天然气学报,2011,33(6):149-152.Zhang Fuxiang,Wang Xinhai,Li Yuanbin,et al.The Contribution of Fractures of Kuqa Foreland Fractured Sandstone Gas Reservoirs to Formation Permeability[J].Journal of Oil and Gas Technology,2011,33(6):149-152.
[19]Ito T,Zoback M D.Fracture Permeability and In Situ Stress to 7 km Depth in the KTB Scientific Drillhole[J].Geophysical Research Letter,2000,27(7):1045-1048.
[20]练章华,康毅力,徐进,等.裂缝面及井眼附近的应力分析[J].西南石油学院学报,2001,23(3):37-39.Lian Zhanghua,Kang Yili,Xu Jin,et al.Stress Analysis on Fracture and Near Wellbore.[J].Journal of Southwest Petroleum Institute,2001,23(3):37-39.
[2]陈勉,金衍,张广清,等.石油工程岩石力学[M].北京:科学技术出版社,2008.Chen Mian,Jin Yan,Zhang Guangqing,et al.Petroleum Engineering Rock Mechanics[M].Beijing:Science and Technology Press,2008.
[3]刘向君,罗平亚.岩石力学与石油工程[M].北京:石油工业出版社,2004.Liu Xiangjun,Luo Pingya.Rock Mechanics and Petroleum Engineering[M].Beijing:Petroleum Industry Press,2004.
[4]Donath F A.Experimental Study of Shear Failure in Anisotropic Rock[J].Geological Society of America Bulletin,1961,72(6):985-989.
[5]Jaeger J C,Cook N G W.Fundamentals of Rock Mechanics[M].2nded.New York:Publication of Chapman and Hall,1976.
[6]Willson S M,Last N C,Zoback M D,et al.Drilling in South America:A Wellbore Stability Approach for Complex Geologic Conditions[C]//Paper SPE-53940-MS Presented at the Latin American and Caribbean Petroleum Engineering Conference,21-23 April 1999,Caracas,Venezuela.New York:SPE,1999.
[7]Finkbeiner T D,Moos D,DeRose W.Wellbore Stability Evaluation for Horizontal Hole Completion-A Case Study[C]//Paper SPE-64409-MS Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition,16-18October 2000,Brisbane,Australia.New York:SPE,2000.
[8]刘向君,叶仲斌,陈一健.岩石弱面结构对井壁稳定性的影响[J].天然气工业,2002,22(2):41-42.Liu Xiangjun,Ye Zhongbin,Chen Yijian.Influence of Rock Weak Plane Texture on Sidewall Stability[J].Natural Gas Industry,2002,22(2):41-42.
[9]金衍,陈勉,柳贡慧,等.弱面地层斜井井壁稳定性分析[J].石油大学学报:自然科学版,1999,23(4):33-35.Jin Yan,Chen Mian,Liu Gonghui,et al.Analysis on Borehole Stability of Weak-Face Formation in Directional Wells[J].Journal of the University of Petroleum,China:Edition of Natural Science,1999,23(4):33-35.
[10]Yan Chuanliang,Deng Jingen,Yu Baohua,et al.Borehole Stability in High-Temperature Formation[J].Rock Mechanics&Rock Engineering,2014,47(6):2199-2209.
[11]管申,谭强,黄熠,等.海上复杂压力体系油田钻井安全密度窗口研究[J].天然气与石油,2015,33(5):52-55.Guan Shen,Tan Qiang,Huang Yi,et al.Study on Safe Drilling Density Window in Offshore Oilfield with Complex Pressure System[J].Natural Gas and Oil,2015,33(5):52-55.
[12]尹帅,丁文龙,杨文娜,等.考虑地层各向异性井壁稳定性研究进展[J].地球科学进展,2015,30(11):1218-1230.Yin Shuai,Ding Wenlong,Yang Wenna,et al.Progress of Borehole Stability Considering Strata Anisotropy[J].Advances in Earth Science,2015,30(11):1218-1230.
[13]Rahman M K,Naseby D,Rahman S S.Borehole Collapse Analysis Incorporating Time-Dependent Pore Pressure Due to Mud Penetration in Shales[J].Journal of Petroleum Science&Engineering,2000,28(1):13-31.
[14]梁利喜,丁乙,刘向君,等.硬脆性泥页岩井壁稳定渗流-力化耦合研究[J].特种油气藏,2016,23(2):140-143.Liang Lixi,Ding Yi,Liu Xiangjun,et al.SeepageMechanochemistry Coupling of Wellbore Stability in Hard-Brittle Shale[J].Special Oil and Gas Reservoirs,2016,23(2):140-143.
[15]刘向君,曾韦,梁利喜,等.页岩层理对井壁稳定性影响分析[J].中国安全生产科学技术,2016,12(11):88-92.Liu Xiangjun,Zeng Wei,Liang Lixi,et al.Analysis on Influence of Shale Bedding on Wellbore Stability[J].Journal of Safety Science and Technology,2016,12(11):88-92.
[16]田作基,宋建国.塔里木库车新生代前陆盆地构造特征及形成演化[J].石油学报,1999,20(4):7-13.Tian Zuoji,Song Jianguo.Tertiary Structure Characteristics and Evolution of Kuche Foreland Basin[J].Acta Petrolei Sinica,1999,20(4):7-13.
[17]耶格J C.岩石力学基础[M].北京:科学出版社,1981.Jaeger J C.Fundamental of Rock Mechanics[M].Beijing:Science Press,1981.
[18]张福祥,王新海,李元斌,等.库车山前裂缝性砂岩气层裂缝对地层渗透率的贡献率[J].石油天然气学报,2011,33(6):149-152.Zhang Fuxiang,Wang Xinhai,Li Yuanbin,et al.The Contribution of Fractures of Kuqa Foreland Fractured Sandstone Gas Reservoirs to Formation Permeability[J].Journal of Oil and Gas Technology,2011,33(6):149-152.
[19]Ito T,Zoback M D.Fracture Permeability and In Situ Stress to 7 km Depth in the KTB Scientific Drillhole[J].Geophysical Research Letter,2000,27(7):1045-1048.
[20]练章华,康毅力,徐进,等.裂缝面及井眼附近的应力分析[J].西南石油学院学报,2001,23(3):37-39.Lian Zhanghua,Kang Yili,Xu Jin,et al.Stress Analysis on Fracture and Near Wellbore.[J].Journal of Southwest Petroleum Institute,2001,23(3):37-39.