准噶尔盆地吉木萨尔凹陷芦草沟组含油页岩岩石力学特性及可压裂性评价

doi:10.11743/ogg20190321

摘要/Abstract

摘要： 页岩油储层具有油气丰度低、渗透能力差、单井无自然产能或自然产能低于工业油流下限、能量衰减快等特点，在水平井或多分支井的基础上实施高效的压裂改造是实现页岩油效益开采的关键。围绕吉木萨尔凹陷芦草沟组含油页岩储层的可压裂性评价，实验测试与理论分析相结合，研究认识了岩石的变形破坏特征、力学强度特性及其纵向分布特征；在芦草沟组页岩储层可压裂性影响因素分析的基础上，建立了可压裂性指数评价方法。结果表明：芦草沟组含油页岩的变形破坏呈现显著的脆性特征，且层理、微裂缝等结构面发育，具备压裂改造形成复杂缝网的内在地质力学条件；芦草沟组页岩储层间存在岩石力学强度、地应力相对较高的隔层，对该类型储集体的压裂过程中在兼顾裂缝网络复杂化的同时还应强化压裂缝对上下储层的沟通能力，实现压裂改造有效体积的最大化；综合脆性指数、水平应力差、层间应力差以及断裂韧性等指标，建立了可同时表征水平井体积压裂缝网形成难易与压裂缝穿越隔层沟通纵向储层能力的可压裂性评价方法；基于微地震压裂监测结果的验证分析表明所建立的可压裂性指数评价方法在以吉木萨尔凹陷油页岩为代表的薄互层状页岩地层中具有较好适用性。

关键词: 脆性, 可压裂性指数, 体积压裂, 岩石力学, 页岩油, 芦草沟组, 吉木萨尔凹陷, 准噶尔盆地

Abstract: The shale oil reservoirs are characterized by low oil and gas abundance,poor permeability,no natural productivity or lower natural production capacity in single wells compared with the lower limit of commercial oil flow,and fast energy decay,etc.The application of efficient volumetric fracturing technique to horizontal or multi-lateral wells is the key to achieving efficient development of shale oils.In order to evaluate the fracability of the shale oil reservoir in the Lucaogou Formation in Jimusaer sag,sufficient experimental and theoretical studies were carried out.The characteristics of deformation and failure,mechanical strength and their lateral variations in the Lucaogou oil-bearing reservoir in Jimusaer sag were recognized.And a new method for evaluating the fracability indexes was established based on the analysis of the factors influencing the shale reservoir fracability in the Lucaogou Formation.The results show that due to the significant brittleness of shale under deformation and the well development of fabric planes such as bedding and micro-fractures,the intrinsic geological and mechanical conditions of the Lucaogou Formation are favorable for the formation of complex fracture networks under fracturing.There are interlayers characterized by high rock mechanical strength and in-situ stress in the Lucaogou shale reservoir.Therefore,to maximize the effective volume of fracturing in such reservoir,the artificial fractures should be designed to increase the connectivity between upper and lower reservoirs,while the fracture networks should be as complicated as possible.Besides,a new fracability evaluation method was established using brittleness index,horizontal stress difference,interlayer stress difference and fracture ductility,which can simultaneously characterize the ability of volumetric fracturing network in horizontal wells and the vertical connectivity of artificial fractures.The analysis based on microseismic fracturing monitoring shows that the fracability index evaluation method is very suitable to evaluate thin alternating shale formations typically shown in the oil shales in Jimusaer sag.

Key words: brittleness, fracability index, volumetric fracturing, rock mechanics, shale oil, Lucaogou Formation, Jimusaer sag, Junggar Basin

中图分类号:

TE357

王小军,梁利喜,赵龙,等. 准噶尔盆地吉木萨尔凹陷芦草沟组含油页岩岩石力学特性及可压裂性评价[J]. 石油与天然气地质, 2019, 40(3): 661-668. doi: 10.11743/ogg20190321 Wang Xiaojun,Liang Lixi,Zhao Long,et al. Rock mechanics and fracability evaluation of the Lucaogou Formation oil shales in Jimusaer sag, Junggar Basin[J]. Oil & Gas Geology, 2019, 40(3): 661-668. doi: 10.11743/ogg20190321

参考文献

[1] 邹才能,杨智,崔景伟,等.页岩油形成机制、地质特征及发展对策[J].石油勘探与开发,2013,40(1):14-26. Zou Caineng,Yang Zhi,Cui Jingwei,et al.Formation mechanism,geological characteristics and development strategy of nonmarine shale oil in china[J].Petroleum Exploration and Development,2013,40(1):14-26.
[2] Zou C N,Yang Z,Tao S Z.Continuous hydrocarbon accumulation over a large area as a distinguishing characteristic of unconventional petroleum:the ordos basin,north-central china[J].Earth-Science Reviews,2013,126:358-369.
[3] 杨智,侯连华,林森虎,等.吉木萨尔凹陷芦草沟组致密油、页岩油地质特征与勘探潜力[J].中国石油勘探,2018,23(4):76-85. Yang Zhi,Hou Lianhua,Lin Senhu,et al.Geologic characteristics and exploration potential of tight oil and shale oil in lucaogou formation in jimsar sag[J].China Petroleum Exploration,2018,23(4):76-85.
[4] 姜在兴,张文昭,梁超,等.页岩油储层基本特征及评价要素[J].石油学报,2014,35(1):184-196. Jiang Zaixing,Zhang Wenzhao,Liang Chao,et al.Characteristics and evaluation elements of shale oil reservoir[J].Acta Petrolei Sinica,2014,35(1):184-196.
[5] 卢双舫,李俊乾,张鹏飞,等.页岩油储集层微观孔喉分类与分级评价[J].石油勘探与开发,2018,45(3):436-444. Lu Shuangfang,Li Junqian,Zhang Pengfei,et al.Classification of microscopic pore-throats and the grading evaluation on shale oil reservoirs[J].Petroleum Exploration and Development,2018,45(3):436-444.
[6] 邹才能,丁云宏,卢拥军,等."人工油气藏"理论、技术及实践[J].石油勘探与开发,2017,44(1):144-154. Zou Caineng,Ding Yunhong,Lu Yongjun,et al.Concept,technology and practice of "man-made reservoirs" development[J].Petroleum Exploration And Development,2017,44(1):144-154.
[7] 匡立春,王霞田,郭旭光,等.吉木萨尔凹陷芦草沟组致密油地质特征与勘探实践[J].新疆石油地质,2015,36(6):629-634. Kuang Lichun,Wang Xiatian,Guo Xuguang,et al.Geological characteristics and exploration practice of tight oil of lucaogou formation in jimsar sag[J].Xinjiang Petroleum Geology,2015,36(6):629-634.
[8] 侯冰,陈勉,王凯,等.页岩储层可压性评价关键指标体系[J].石油化工高等学校学报,2014,27(6):42-49. Hou Bing,Chen Mian,Wang Kai,et al.2014.The key index system offracability evaluation in gas shale reservior[J].Journal of Petrochemical Universities(in Chinese),27(6):42-49.
[9] Chong K K,Grieser W V,Passman A,et al.A completions guidebook to shale-play development:A review of successful approaches towards shale-play stimulation in the last two decades[C].The Canadian Unconventional Resources and International Petroleum Conference.Calgary,Alberta,Canada.19-21 October 2010.CSUG/SPE 133874
[10] 任岩,曹宏,姚逢昌,等.吉木萨尔致密油储层脆性及可压裂性预测[J].石油地球物理勘探,2018,53(3):3-4,511-519. Ren Yan,Cao Hong,Yao Fengchang,et al.Brittleness and fracability prediction for tight oilreservoir in jimsar sag,junggar basin[J].OGP,2018,53(3):511-519.
[11] 高辉,张晓,何梦卿,等.基于测井数据体的页岩油储层可压裂性评价研究.地球物理学进展,2018,33(2):0603-0612. Gao Hui,Zhang Xiao,He Mengqing,et al.Study on evaluation of shale oil reservoir fracability based on well logging data volume[J].Progress In geophysics(In Chinese),2018,33(2):0603-0612.
[12] 唐颖,邢云,李乐忠,等.页岩储层可压裂性影响因素及评价方法[J].地学前缘,2012,19(5):356-363. Tang Ying,Xing Yun,Li Lezhong,et al.Influence factors and evaluation methods of the gas shale fracability[J].Earth ScienceFrontiers,2012,19(5):356-363.
[13] 蒋廷学,卞晓冰,苏瑗,等.页岩可压性指数评价新方法及应用[J].石油钻探技术,2014,42(5):16-20. Jiang Tingxue,BianXiaobing,Su Yuan,et al.A new method for evaluating shale fracability index and its application[J].Petroleum Drilling Techniques,2014,42(5):16-20.
[14] 高阳,王英伟,王玉多,等.吉木萨尔凹陷芦草沟组致密储集层岩石力学特征[J].新疆石油地质,2016,37(2):158-162. Gao Yang,Wang Yingwei,Wang Yuduo,et al.Rock mechanics characteristics of lucaogou tight oil reservoir in jimusaer sag,junggar basin[J].Xinjiang Petroleum Geology,2016,37(2):158-162.
[15] Claesson J,Bohloli B.Brazilian test:stress field and tensile strength of anisotropic rocks using an analytical solution[J].International Journal Rock Mechanics And Mining Sciences,2002,39(8):991-1004.
[16] 杨志鹏,何柏,谢凌志,等.基于巴西劈裂试验的页岩强度与破坏模式研究[J].岩土力学,2015,36(12):3447-3455. Yang Zhipeng,He Bai,Xie Lingzhi,Et Al.Strength and failure modes of shale based on brazilian test[J].Rock And Soil Mechanics,2015,36(12):3447-3455.
[17] 黄波,谢斌,李佳琦,等.吉木萨尔二叠系致密油岩石力学特性参数分析与压裂对策[J].科学技术与工程,2016,16(25):67-74. Huang Bo,Xie Bin,Li Jiaqi,etal.Rock mechanical parameters analysis of permian tight formations at jimusaer in xinjiang and the related measures for fracturing[J].Science Technology and Engineering,2016,16(25):67-74.
[18] 靳军,杨召,依力哈木·尔西丁,等.准噶尔盆地吉木萨尔凹陷致密油储层纳米孔隙特征及其含油性[J].地球科学,2018,43(5):1594-1601. Jin Jun,Yang Zhao,Yilihamu·Erxiding,et al.Nanopore characteristics and oil-bearing properties of tight oil reservoirs in jimsar sag,junggar basin[J].Earth Science,2018,43(5):1594-1601.
[19] 梁利喜,黄静,刘向君,等.天然裂缝对页岩储层网状诱导缝的控制作用[J].成都理工大学学报(自然科学版),2016,43(6):696-702. Liang Lixi,Huang Jing,Liu Xiangjun.Formation and control effect of natural fracture on network induced fracture in shale reservoir[J].Journal of ChengDu University of Technology(Science & Technology Edition),2016,43(6):696-702.
[20] 蒋廷学,周健,张旭,等.深层页岩气井裂缝扩展及导流特性研究及展望[J].中国科学:物理学力学天文学,2017,47(11):33-40. Jiang Tingxue,Zhou Jian,Zhang Xu,et al.Over view and prospect of fracture propagation and conductivity characteristics in deep shale gas wells[J].Scientia Sinica Physica,Mechanica & Astronomica,2017,47(11):33-40.
[21] Nagel NB,Gil I,Sanchez-Nagel M,et al.Simulating hydraulic fracturing in real fractured rocks-overcoming the limits of pseudo 3D models[C].SPE Hydraulic Fracturing Technology Conference.The Woodlands,Texas,USA.24-26 January 2011.SPE140480
[22] 陈勉.页岩气储层水力裂缝转向扩展机制[J].中国石油大学学报(自然科学版),2013,37(5):88-94. Chen Mian.Re-orentation and propagation of hydraulic fractures in shale gas reservoir[J].Journal of China University of Petroleum(Edition of Natural Science),2013,37(5):88-94.
[23] Gu HR,Weng X,Lund JB,et al.Hydraulic fracture crossing natural fracture at nonorthogonal angles:a criterion and its validation[J].SPE Production & Operations,2012,27(1):20-26.
[24] Meyer B R,Bazan L W.A Discrete fracture network model for hydraulically induced fractures:theory,parametric and case studies[J].SPE Hydraulic Fracturing Technology Conference and Exhibition.The Woodlands,Texas,USA.24-26 January 2011.SPE140514
[25] Nagel NB,Sanchez MA,Lee B.Gas shale hydraulic fracturing:A numerical evaluation of the effect of geomechanical parameters[C].SPE Hydraulic Fracturing Technology Conference.The Woodlands,Texas,USA.6-8 February 2012.SPE152192
[26] Warpinski N R,Mayerhofer M J,Vincent M C,et al.Stimulating unconventional reservoirs:maximizing network growth while optimizing fracture conductivity[J].Journal of Canadian Petroleum Technology,2009,48(10):39-51.
[27] 赵金洲,任岚,沈骋,等.页岩气储层缝网压裂理论与技术研究新进展[J].天然气工业,2018,38(3):1-14. Zhao Jinzhou,Ren Lan,Shen Cheng,et al.Latest research progresses in network fracturing theories and technologies for shale gas reservoirs[J].Natural Gas Industry,2018,38(3):1-14.
[28] 闫相祯,宋根才,王同涛,等.低渗透薄互层砂岩油藏大型压裂裂缝扩展模拟[J].岩石力学与工程学报,2009,28(7):1425-1431. Yan Xiangzhen,Song Gencai,Wang Tongtao,et al.Simulation of fracture propagation in large-scale reservoir with low permeability and thin interbedded sandstone[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(7):1425-1431.
[29] 高英.薄互层低渗透油藏压裂开发裂缝扩展规律及产能预测研究[D].北京:北京科技大学,2015. Gao Ying.Productivity prediction of fractured well and propagation law of hydraulic fractures in thin inter-bedded low permeability reservoirs[D].University of Science and Technology Beijing,2015.
[30] 赵海峰,陈勉,金衍.水力裂缝在地层界面的扩展行为[J].石油学报,2009,30(3):450-454. Zhao Haifeng,Chen Mian,Jin Yan.Extending behavior of hydraulic fracture on formation interface[J].Acta Petrolei Sinica,2009,30(3):450-454.
[31] 刘向君,梁利喜.油气工程测井理论与应用[M].北京:科学出版社,2015:38-44 Liu xiangjun,Liang lixi.Theory and application of oil and gas engineering logging[M].Beijing:Science Press,2015:38-44.
[32] 金衍,陈勉,张旭东.利用测井资料预测深部地层岩石断裂韧性[J].岩石力学与工程学报,2001,20(4):454-456. Jin Yan,Chen Mian,Zhang Xudong.Determination of fracture toughness for deep well rock with geophysical logging data[J].Chinese Journal of Rock Mechanics and Engineering,2001,20(4):454-456.
[33] 金衍,陈勉,王怀英,等.利用测井资料预测岩石Ⅱ型断裂韧性的方法研究[J].岩石力学与工程学报,2008,27(2):3630-3635. Jin Yan,Chen Mian,Wang Huaiying,et al.Study on prediction method of fracture toughness of rock mode Ⅱ by logging data[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(2):3630-3635.