充填天然裂缝对页岩受载过程中渗透率变化规律影响机理分析
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摘要
页岩气开采需要对储层进行大规模人工水力压裂改造,为了研究压裂过程中页岩渗透率变化规律及其机理,文章通过对含充填天然裂缝和不含天然裂缝两块页岩岩样进行流-固耦合物理模拟实验,并结合样品的全岩X-射线衍射分析,获得以下认识:加卸载过程中,应力-应变曲线中应力小平台的出现可以指示样品中微裂缝的形成与闭合,是渗透率变化的内在机制;当岩样达到破裂条件形成显裂缝后,样品发生永久性变形,从而达到渗透率增大的效果;受载过程中,微裂缝易沿着天然裂缝脆弱面发育,并不断积累连通成裂缝网络,是形成两块岩样渗透率变化差异的机理。
Shale gas exploitation requires large-scale artificial hydraulic fracturing of resevoirs. In order to study the variation law and mechanism of shale permeability during fracturing, fluid-solid coupling physical simulation experiments on two shale samples with and without filled natural fractures were carried out, and combined with the analysis of whole-rock X-ray diffraction of two samples, the following understandings were obtained:(1) During the loading and unloading process, the presence of small stress platforms in the stress-strain curve indicate the formation and closure of micro-fractures in the sample, which is the intrinsic mechanism of permeability change;(2) When the shale sample reaches the fracture condition to form visible fractures, the sample will be permanently deformed to increase the permeability.(3) In the process of loading, micro-fractures tend to develop along the fragile surface of natural fractures and continuously accumulate to form fracture networks, which is the mechanism for the difference of permeability changes between two shale samples.
Shale gas exploitation requires large-scale artificial hydraulic fracturing of resevoirs. In order to study the variation law and mechanism of shale permeability during fracturing, fluid-solid coupling physical simulation experiments on two shale samples with and without filled natural fractures were carried out, and combined with the analysis of whole-rock X-ray diffraction of two samples, the following understandings were obtained:(1) During the loading and unloading process, the presence of small stress platforms in the stress-strain curve indicate the formation and closure of micro-fractures in the sample, which is the intrinsic mechanism of permeability change;(2) When the shale sample reaches the fracture condition to form visible fractures, the sample will be permanently deformed to increase the permeability.(3) In the process of loading, micro-fractures tend to develop along the fragile surface of natural fractures and continuously accumulate to form fracture networks, which is the mechanism for the difference of permeability changes between two shale samples.
引文
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[21] 刘建军,刘先贵.有效压力对低渗透多孔介质孔隙度、渗透率的影响[J].地质力学学报,2001,7(1):41-44.LIU Jianjun,LIU Xiangui.The effect of effective pressure on porosity and permieability of low permeability porous media[J].Journal of Geomechanics,2001,7(1):41-44.(in Chinese with English abstract)
[22] 杨新乐,张永利.气固耦合作用下温度对煤瓦斯渗透率影响规律的实验研究[J].地质力学学报,2008,14(4):374-380.YANG Xinle,ZHANG Yongli.Experimental study of effect of temperature on coal gas permeability under gas-solid coupling[J].Journal of Geomechanics,2008,14(4):374-380.(in Chinese with English abstract)
[23] 龙鹏宇,张金川,李玉喜,等.重庆及周缘地区下古生界页岩气成藏条件及有利区预测[J].地学前缘,2012,19(2):221-233.LONG Pengyu,ZHANG Jinchuan,LI Yuxi,et al.Researvoir forming conditions and strategic select favorable area of shale gas in the Lower Paleozoic of Chongqing and its adiacent areas[H].Earth Science Forntiers,2012,19(2):221-233.(in Chinese with English abstract)
[24] 陈昀,金衍,陈勉.基于能量耗散的岩石脆性评价方法[J].力学学报,2015,47(6):984-993.CHEN Yun,JIN Yan,CHEN Mian.A rock brittleness evaluation method based on energy dissipation[J].Chinese Journal of Theoretical and Applied Mechanics,2015,47(6):984-993.(in Chinese with English abstract)
[25] RICKMAN R,MULLEN M J,PETRE J E,et al.A practical use of shale petrophysics for stimulation design optimization:All shale plays are not clones of the Barnett Shale[C]//SPE Annual Technical Conference and Exhibition.Denver,Colorado,USA:Society of Petroleum Engineers,2008.
[26] ZOBACK M D,KNECHT W N.Opportunities and challenges of shale gas development[R].Short course presented in Beijing,China,2012.
[2] 张东晓,杨婷云.页岩气开发综述[J].石油学报,2013,34(4):792-801.ZHANG Dongxiao,YANG Tingyun.An overview of shale-gas production[J].Acta Petrolei Sinica,2013,34(4):792-801.(in Chinese with English abstract)
[3] 康永尚,邓泽,王红岩,等.流-固耦合物理模拟实验及其对页岩压裂改造的启示[J].地球科学,2016,41(8):1376-1383.KANG Yongshang,DE Ze,WANG Hongyan,et al.Fluid-solid coupling physical experiments and their implications for fracturing stimulations of shale gas reservoirs[J].Earth Science,2016,41(8):1376-1383.(in Chinese with English abstract)
[4] 陈尚斌,朱炎铭,王红岩,等.中国页岩气研究现状与发展趋势[J].石油学报,2010,31(4):689-694.CHEN Shangbin,ZHU Yanming,WANG Hongyan,et al.Research status and trends of shale gas in China[J].Acta Petrolei Sinica,2010,31(4):689-694.(in Chinese with English abstract)
[5] CHONG K K,GRIESER W V,PASSMAN A,et al.A completions guide book to shale-play development:A review of successful approaches toward shale-play stimulation in the last two decades[C]//Canadian Unconventional Resources and International Petroleum Conference.Calgary,Alberta,Canada:Society of Petroleum Engineers,2010.
[6] 邹才能,朱如凯,吴松涛,等.常规与非常规油气聚集类型、特征、机理及展望—以中国致密油和致密气为例[J].石油学报,2012,33(2):173-187.ZOU Caineng,ZHU Rukai,WU Songtao,et al.Types,characteristics,genesis and prospects of conventional and unconventional hydrocarbon accumulations:taking tight oil and tight gas in China as an instance[J].Acta Petrolei Sinica,2012,33(2):173-187.(in Chinese with English abstract)
[7] 杨建,付永强,陈鸿飞,等.页岩储层的岩石力学特性[J].天然气工业,2012,32(7):12-14.YANG Jian,FU Yongqiang,CHEN Hongfei,et al.Rock mechanical characteristics of shale reservoirs[J].Natural Gas Industry,2012,32(7):12-14.(in Chinese with English abstract)
[8] CIPOLLA C L,WARPINSKI N R,MAYERHOFER M J.Hydraulic fracture complexity:diagnosis,remediation,and explotation[C]//SPE Asia Pacific Oil and Gas Conference and Exhibition.Perth,Australia:Society of Petroleum Engineers,2008.
[9] 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.The key index system of fracability evaluation in gas shale reservoir[J].Journal of Petrochemical Universities,2014,27(6):42-49.(in Chinese with English abstract)
[10] 张羽,范存辉,钟城,等.复杂地质特征中富有机质页岩脆性评价方法研究[J].地质与勘探,2018,54(5):1069-1083.ZHANG yu,FAN Cunhui,ZHONG Cheng,et al.Study on the evaluation method of organic-rich shale brittleness in complex geological conditions[J].Geology and Exploration,2018,54(5):1069-1083.(in Chinese with English abstract)
[11] 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 Science Frontiers,2012,19(5):356-363.(in Chinese with English abstract)
[12] 袁俊亮,邓金根,张定宇,等.页岩气储层可压裂性评价技术[J].石油学报,2013,34(3):523-527.YUAN Junliang,DENG Jingen,ZHANG Dingyu,et al.Fracability evaluation of shale gas reservoirs[J].Acta Petrolei Sinica,2013,34(3):523-527.(in Chinese with English abstract)
[13] 万晓龙,高春宁,王永康,等.人工裂缝与天然裂缝耦合关系及其开发意义[J].地质力学学报,2009,15(3):245-252.WAN Xiaolong,GAO Chunning,WANG Yongkang,et al.Coupled relationship between created and natural fractures and its implication to development[J].Journal of Geomechanics,2009,15(3):245-252.(in Chinese with English abstract)
[14] 刘洪林,王红岩.中国南方海相页岩超低含水饱和度特征及超压核心区选择指标[J].天然气工业,2013,33(7):140-144.LIU Honglin,WANG Hongyan.Ultra-low water saturation characteristics and the identification of over-pressured play fairways of marine shales in south China[J].Natural Gas Industry,2013,33(7):140-144.(in Chinese with English abstract)
[15] 董大忠,程克明,王玉满,等.中国上扬子区下古生界页岩气形成条件及特征[J].石油与天然气地质,2010,31(3):288-299,308.DONG Dazhong,CHENG Keming,WANG Yuman,et al.Forming conditions and characteristics of shale gas in the Lower Paleozoic of the Upper Yangtze region,China[J].Oil & Gas Geology,2010,31(3):288-299,308.(in Chinese with English abstract)
[16] 梁超,姜在兴,杨镱婷,等.四川盆地五峰组—龙马溪组页岩岩相及储集空间特征[J].石油勘探与开发,2012,39(6):691-698.LIANG Chao,JIANG Zaixing,YANG Yiting,et al.Characteristics of shale lithofacies and reservoir space of the Wufeng-Longmaxi Formation,Sichuan Basin[J].Petroleum Exploration and Development,2012,39(6):691-698.(in Chinese with English abstract)
[17] 王淑芳,董大忠,王玉满,等.四川盆地志留系龙马溪组富气页岩地球化学特征及沉积环境[J].矿物岩石地球化学通报,2015,34(6):1203-1212.WANG Shufang,DONG Dazhong,WANG Yuman,et al.Geochemical characteristics the sedimentation environment of the gas-enriched shale in the Silurian Longmaxi formation in the Sichuan Basin[J].Bulletin of Mineralogy,Petrology & Geochemistry,2015,34(6):1203-1212.(in Chinese with English abstract)
[18] 刘国军,鲜学福,周军平,等.页岩受载变形特性及矿物组分对岩石脆性影响实验[J].煤炭学报,2016,41(S2):369-375.LIU Guojun,XIAN Xuefu,ZHOU Junping,et al.Experimental study the impact of loading deformation characteristics and mineral composition on shale rock brittleness[J].Journal of China Coal Society,2016,41(S2):369-375.(in Chinese with English abstract)
[19] 张汉荣.川东南地区志留系页岩含气量特征及其影响因素[J].天然气工业,2016,36(8):36-42.ZHANG Hanrong.Gas content of the Silurian shale in the southeastern Sichuan Basin and its controlling factors[J].Natural Gas Industry,2016,36(8):36-42.(in Chinese with English abstract)
[20] 曹春辉,张铭杰,汤庆艳,等.四川盆地志留系龙马溪组页岩气气体地球化学特征及意义[J].天然气地球科学,2015,26(8):1604-1612.CAO Chunhui,ZHANG Mingjie,TANG Qingyan,et al.Geochemical characteristics and implications of shale gas in Longmaxi Formation,Sichuan Basin,China[J].Natural Gas Geoscience,2015,26(8):1604-1612.(in Chinese with English abstract)
[21] 刘建军,刘先贵.有效压力对低渗透多孔介质孔隙度、渗透率的影响[J].地质力学学报,2001,7(1):41-44.LIU Jianjun,LIU Xiangui.The effect of effective pressure on porosity and permieability of low permeability porous media[J].Journal of Geomechanics,2001,7(1):41-44.(in Chinese with English abstract)
[22] 杨新乐,张永利.气固耦合作用下温度对煤瓦斯渗透率影响规律的实验研究[J].地质力学学报,2008,14(4):374-380.YANG Xinle,ZHANG Yongli.Experimental study of effect of temperature on coal gas permeability under gas-solid coupling[J].Journal of Geomechanics,2008,14(4):374-380.(in Chinese with English abstract)
[23] 龙鹏宇,张金川,李玉喜,等.重庆及周缘地区下古生界页岩气成藏条件及有利区预测[J].地学前缘,2012,19(2):221-233.LONG Pengyu,ZHANG Jinchuan,LI Yuxi,et al.Researvoir forming conditions and strategic select favorable area of shale gas in the Lower Paleozoic of Chongqing and its adiacent areas[H].Earth Science Forntiers,2012,19(2):221-233.(in Chinese with English abstract)
[24] 陈昀,金衍,陈勉.基于能量耗散的岩石脆性评价方法[J].力学学报,2015,47(6):984-993.CHEN Yun,JIN Yan,CHEN Mian.A rock brittleness evaluation method based on energy dissipation[J].Chinese Journal of Theoretical and Applied Mechanics,2015,47(6):984-993.(in Chinese with English abstract)
[25] RICKMAN R,MULLEN M J,PETRE J E,et al.A practical use of shale petrophysics for stimulation design optimization:All shale plays are not clones of the Barnett Shale[C]//SPE Annual Technical Conference and Exhibition.Denver,Colorado,USA:Society of Petroleum Engineers,2008.
[26] ZOBACK M D,KNECHT W N.Opportunities and challenges of shale gas development[R].Short course presented in Beijing,China,2012.