页岩油储集层数字岩心重构及微尺度下渗流特征——以吉木萨尔凹陷二叠系芦草沟组页岩油为例
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摘要
为深入认识页岩油储集层孔隙结构特征和渗流特性,以吉木萨尔凹陷二叠系芦草沟组页岩油储集层为研究对象,利用微CT扫描技术和聚焦离子束电镜扫描技术,构建三维数字岩心模型,获得孔喉结构参数,并基于该结构特征建立多孔介质微尺度渗流物模装置,研究流体在微通道内的低速流动规律,同时利用该物模装置测量不同压裂液的流动特性和伤害程度。研究结果表明:页岩油储集层的孔隙结构具有非均质性强、孔隙连通性差等特点,储集空间主要为纳米级孔隙,储集层的流动能力取决于微米级孔隙的数量和大小;流体在微观尺度下的低速流动为非达西流,有启动压力梯度,且随着驱动压差增加,边界流体才能不断流出;胍胶破胶液的残渣和大分子结构的凝聚物易对储集层孔隙产生堵塞,建议页岩油储集层压裂时减少胍胶的用量,提高滑溜水比例,减少储集层伤害。
To make clear pore structures and flow characteristics of shale oil reservoir, taking the shale oil reservoir of Permian Lucaogouformation in Jimsar sag as the study object, the paper uses Micro-CT and FIB-SEM scanning technologies to establish a 3D digital core mod-el and to obtain parameters of pore throat structures. Based on which a microscale physical simulation instrument for porous media is estab-lished to study the low-velocity flow laws of fluids in micro paths. Meanwhile, the physical simulation model is used to measure flow charac-teristics and damage degree of different fracturing fluids. The study results show that the pore structure of the shale oil reservoir is featuredwith strong heterogeneity and poor connectivity, the main reservoir space is dominated by nanoscale pores and the fluidity depends on theamount and sizes of the micron-scale pores; the low-velocity flow of fluid at micro scale is non-darcy flow with a threshold pressure gradi-ent, and with the increase of driving differential pressure, the fluid in more pores will continue to flow; the residue of guar gel breaker andthe aggregates of macromolecular structure are easy to block pores. It is suggested that less guar gel and more slick water should be used toreduce reservoir damage during shale oil reservoir fracturing.
To make clear pore structures and flow characteristics of shale oil reservoir, taking the shale oil reservoir of Permian Lucaogouformation in Jimsar sag as the study object, the paper uses Micro-CT and FIB-SEM scanning technologies to establish a 3D digital core mod-el and to obtain parameters of pore throat structures. Based on which a microscale physical simulation instrument for porous media is estab-lished to study the low-velocity flow laws of fluids in micro paths. Meanwhile, the physical simulation model is used to measure flow charac-teristics and damage degree of different fracturing fluids. The study results show that the pore structure of the shale oil reservoir is featuredwith strong heterogeneity and poor connectivity, the main reservoir space is dominated by nanoscale pores and the fluidity depends on theamount and sizes of the micron-scale pores; the low-velocity flow of fluid at micro scale is non-darcy flow with a threshold pressure gradi-ent, and with the increase of driving differential pressure, the fluid in more pores will continue to flow; the residue of guar gel breaker andthe aggregates of macromolecular structure are easy to block pores. It is suggested that less guar gel and more slick water should be used toreduce reservoir damage during shale oil reservoir fracturing.
引文
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[15]王晨晨,姚军,杨永飞,等.基于CT扫描法构建数字岩心的分辨率选取研究[J].科学技术与工程,2013,13(4):1 049-1 052.WANG Chenchen,YAO Jun,YANG Yongfei,et al.Resolution selection of digital core based on CT scanning method[J].Science Technology and Engineering,2013,13(4):1 049-1 052.
[16]张爽,周慧鑫,牛肖雪,等.基于非局部均值滤波与时域高通滤波的非均匀性校正算法[J].光子学报,2014,43(1):147-150.ZHANG Shuang,ZHOU Huixin,NIU Xiaoxue,et al.Temporal highpass filter nonuniformity correction algorithm based on non-local means filter for infrared focal plane array[J].Acta Photonica Sinica,2014,43(1):147-150.
[17]熊健,唐勇,刘向君,等.应用微CT技术研究砂砾岩孔隙结构特征--以玛湖凹陷百口泉组储集层为例[J].新疆石油地质,2018,39(2):236-242.XIONG Jian,TANG Yong,LIU Xiangjun,et al.Using Micro-CTscanning technology to study characteristics of pore structure in sandy conglomerate:a case from Baikouquan formation in Mahu sag,Jungger basin[J].Xinjiang Petroleum Geology,2018,39(2):236-242.
[18]ZHOU S W,YAN G,XUE H Q,et al.2D and 3D nanopore characterization of gas shale in Longmaxi formation based on FIB-SEM[J].Marine and Petroleum Geology,2016,73:174-180.
[19]KLAVER J,DESBOIS G,LITTKE R,et al.FIB-SEM porecharacterization of mature and post mature Posidonia shale samples from the Hils area,Germany[J].International Journal of Coal Geology,2016,158:78-89.
[20]黄延章,杨正明,何英,等.低渗透多孔介质中的非线性渗流理论[J].力学与实践,2013,35(5):1-8.HUANG Yanzhang,YANG Zhengming,HE Ying,et al.Nonlinear porous flow in low permeability porous media[J].Mechanics in Engineering,2013,35(5):1-8.
[21]李洋,雷群,刘先贵,等.微尺度下的非线性渗流特征[J].石油勘探与开发,2011,38(3):336-340.LI Yang,LEI Qun,LIU Xiangui,et al.Characteristics of micro scale nonlinear filtration[J].Petroleum Exploration and Development,2011,38(3):336-340.
[22]刘中春,侯吉瑞,岳湘安,等.微尺度流动界面现象及其流动边界条件分析[J].水动力学研究与进展,2006,21(3):339-346.LIU Zhongchun,HOU Jirui,YUE Xiang’an,et al.Interfacial phenomena in micro-scale flowing and its flowing boundary condition[J].Journal of Hydrodynamics,2006,21(3):339-346.
[23]邓庆军,朱维耀,王小锋,等.多孔介质中微观力的作用及渗流模型[J].北京科技大学学报,2014,36(4):415-423.DENG Qingjun,ZHU Weiyao,WANG Xiaofeng,et al.Seepage model considering micro force in porous media[J].Journal of University of Science and Technology Beijing,2014,36(4):415-423.
[2]付亚荣.中国页岩气发展现状及前景展望[J].石油地质与工程,2013,27(6):19-22.FU Yarong.Present situation and prospect of shale gas development in China[J].Petroleum Geology and Engineering,2013,27(6):19-22.
[3]付茜.中国页岩油勘探开发现状、挑战及前景[J].石油钻采工艺,2015,37(3):58-62.FU Qian.The status,challenge and prospect of shale oil exploration and development in China[J].Oil Drilling&Production Technology,2015,37(3):58-62.
[4]孙超,姚素平.页岩油储层孔隙发育特征及表征方法[J].油气地质与采收率,2019,26(1):153-164.SUN Chao,YAO Suping.Pore structure and characterization methods of shale oil reservoir[J].Petroleum Geology and Recovery Efficiency,2019,26(1):153-164.
[5]郝乐伟,王琪,唐俊.储层岩石微观孔隙结构研究方法与理论综述[J].岩性油气藏,2013,25(5):123-128.HAO Lewei,WANG Qi,TANG Jun.Research progress of reservoir microscopic pore structure[J].Lithologic Reservoirs,2013,25(5):123-128.
[6]张玉亮,范翠杰,谢安,等.数字岩心技术在页岩弹性模量计算中的应用[J].新疆石油地质,2017,38(1):103-104.ZHANG Yuliang,FAN Cuijie,XIE An,et al.Application of digital core technology in elastic modulus calculation for shale[J].Xinjiang Petroleum Geology,2017,38(1):103-104.
[7]宋睿,刘建军,李光.基于CT图像及孔隙网格的岩芯孔渗参数研究[J].西南石油大学学报(自然科学版),2015,37(3):138-145.SONG Rui,LIU Jianjun,LI Guang.Researches on the pore permeability of core sample based on 3D Micro-CT images and pore-scale structured element models[J].Journal of Southwest Petroleum University(Science&Technology Edition),2015,37(3):138-145.
[8]曹永娜.利用CT扫描技术实现对岩心微观驱替过程的研究[J].科学技术与工程,2015,15(6):64-77.CAO Yongna.Research on micro-displacement process of core by CT scanning technology[J].Science Technology and Engineering,2015,15(6):64-77.
[9]姚军,孙海,李爱芬,等.现代油气渗流力学体系及其发展趋势[J].科学通报,2018,63(4):425-451.YAO Jun,SUN Hai,LI Aifen,et al.Modern system of multiphase flow in porous media and its development trend[J].Chinese Science Bulletin,2018,63(4):425-451.
[10]李进步,王继平,王艳,等.致密砂岩储层中气体渗流规律实验研究[J].大庆石油地质与开发,2017,36(6):154-158.LI Jinbu,WANG Jiping,WANG Yan,et al.Experimental study on the seepage laws of the gas in tight sandstone reservoirs[J].Petroleum Geology&Oilfield Development in Daqing,2017,36(6):154-158.
[11]黄延章,于大森.微观渗流实验力学及其应用[M].北京:石油工业出版社,2001.HUANG Yanzhang,YU Dasen.Experimental mechanics of microseepage and its application[M].Beijing:Petroleum Industry Press,2001.
[12]于明旭,朱维耀,宋洪庆.低渗透储层可视化微观渗流模型研制[J].辽宁工程技术大学学报(自然科学版),2013,32(12):1 646-1 650.YU Mingxu,ZHU Weiyao,SONG Hongqing.Development of microscopic visualization flow model of low-permeability reservoir[J].Journal of Liaoning Technology University(Natural Science),2013,32(12):1 646-1 650.
[13]刘学锋,张伟伟,孙建孟.三维数字岩心建模方法综述[J].地球物理学进展,2013,28(6):3 066-3 072.LIU Xuefeng,ZHANG Weiwei,SUN Jianmeng.Methods of constructing 3D digital cores:a review[J].Progress in Geophysics,2013,28(6):3 066-3 072.
[14]屈乐.基于低渗透储层的三维数字岩心建模及应用[D].西安:西北大学,2014.QU Le.3D digital core modeling and application based on low permeability reservoir[D].Xi’an:Northwest University,2014.
[15]王晨晨,姚军,杨永飞,等.基于CT扫描法构建数字岩心的分辨率选取研究[J].科学技术与工程,2013,13(4):1 049-1 052.WANG Chenchen,YAO Jun,YANG Yongfei,et al.Resolution selection of digital core based on CT scanning method[J].Science Technology and Engineering,2013,13(4):1 049-1 052.
[16]张爽,周慧鑫,牛肖雪,等.基于非局部均值滤波与时域高通滤波的非均匀性校正算法[J].光子学报,2014,43(1):147-150.ZHANG Shuang,ZHOU Huixin,NIU Xiaoxue,et al.Temporal highpass filter nonuniformity correction algorithm based on non-local means filter for infrared focal plane array[J].Acta Photonica Sinica,2014,43(1):147-150.
[17]熊健,唐勇,刘向君,等.应用微CT技术研究砂砾岩孔隙结构特征--以玛湖凹陷百口泉组储集层为例[J].新疆石油地质,2018,39(2):236-242.XIONG Jian,TANG Yong,LIU Xiangjun,et al.Using Micro-CTscanning technology to study characteristics of pore structure in sandy conglomerate:a case from Baikouquan formation in Mahu sag,Jungger basin[J].Xinjiang Petroleum Geology,2018,39(2):236-242.
[18]ZHOU S W,YAN G,XUE H Q,et al.2D and 3D nanopore characterization of gas shale in Longmaxi formation based on FIB-SEM[J].Marine and Petroleum Geology,2016,73:174-180.
[19]KLAVER J,DESBOIS G,LITTKE R,et al.FIB-SEM porecharacterization of mature and post mature Posidonia shale samples from the Hils area,Germany[J].International Journal of Coal Geology,2016,158:78-89.
[20]黄延章,杨正明,何英,等.低渗透多孔介质中的非线性渗流理论[J].力学与实践,2013,35(5):1-8.HUANG Yanzhang,YANG Zhengming,HE Ying,et al.Nonlinear porous flow in low permeability porous media[J].Mechanics in Engineering,2013,35(5):1-8.
[21]李洋,雷群,刘先贵,等.微尺度下的非线性渗流特征[J].石油勘探与开发,2011,38(3):336-340.LI Yang,LEI Qun,LIU Xiangui,et al.Characteristics of micro scale nonlinear filtration[J].Petroleum Exploration and Development,2011,38(3):336-340.
[22]刘中春,侯吉瑞,岳湘安,等.微尺度流动界面现象及其流动边界条件分析[J].水动力学研究与进展,2006,21(3):339-346.LIU Zhongchun,HOU Jirui,YUE Xiang’an,et al.Interfacial phenomena in micro-scale flowing and its flowing boundary condition[J].Journal of Hydrodynamics,2006,21(3):339-346.
[23]邓庆军,朱维耀,王小锋,等.多孔介质中微观力的作用及渗流模型[J].北京科技大学学报,2014,36(4):415-423.DENG Qingjun,ZHU Weiyao,WANG Xiaofeng,et al.Seepage model considering micro force in porous media[J].Journal of University of Science and Technology Beijing,2014,36(4):415-423.