低渗透砂砾岩储集层粒内缝成因机制及油气勘探意义——以准噶尔盆地玛湖凹陷三叠系百口泉组为例
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摘要
准噶尔盆地西北缘玛湖凹陷三叠系百口泉组砂砾岩属于低孔低渗储集层,粒内缝是百口泉组储集层重要的渗流通道,国内外对于粒内缝的成因机制、发育规律的研究成果较少。根据粒内缝发育的宏观和微观特征、结合钻井和地震资料,采用古构造应力值—粒内缝关系表征、粒内缝发育物理模拟实验等手段,系统分析了低孔低渗砂砾岩储集层粒内缝的识别特征、成因机制、发育过程及分布规律。认为百口泉组砂砾岩储集层粒内缝从成因上属于构造-成岩缝,其形成与颗粒抗压性、抗剪-抗扭性、内部缺陷、构造应力大小和应力作用方式有关;粒内缝对百口泉组砂砾岩储集层的影响主要在于提高渗透率,粗粒的砾级颗粒粒内缝与砂级颗粒粒间基质孔-微孔的有效配置是形成百口泉组优质高效储集层的关键;粒内缝垂向上主要发育于以百口泉组为主的中—下三叠统,平面上乌夏断裂带粒内缝最为发育,克百断裂带因应力作用方式及刚性颗粒含量的变化,粒内缝发育程度与乌夏断裂带存在明显差异,受逆冲断裂带展布控制,自断裂带至斜坡区粒内缝发育程度逐渐变弱,但在走滑断裂发育处,粒内缝发育程度局部增强。
The sandy conglomerate reservoirs of Baikouquan formation of Mahu sag in northwestern margin of Junggar basin are low-porosity and low-permeability reservoirs,where the intragranular fractures act as the important flow paths.Less researches have been made in terms of genetic mechanism and development of intragranular fractures at home and abroad.This paper systematically analyzes the identifying characteristics,genetic mechanism,development process and distribution of intragranular fractures in low-porosity and low-permeability sandy conglomerate reservoirs,according to themacroscopic and microscopic characteristics of intragranular fractures development,combining with drilling and seismic data,by means of relationship characterization of the palaeotectonic stress value-the intragranular fractures,and intragranular fracture physical modeling experiment.It is considered that the intragranular fractures in Baikouquan formation are structural-diagenetic fractures genetically,the generation of the fractures is related to the properties of compression,shearing and torsion,internal defect of grains,tectonic stress and stress effect;the main influence of intragranular fractures on the reservoir is to improve reservoir permeability,and the effective configuration of intragranular fractures in coarse grains-intergranular matrix pores among sand grainsmicrofissures is the key factor to generate high-quality and high-efficiency reservoirs of Baikouquan formation;the intragranular fractures are mainly distributed in Middle-Lower Triassic Baikouquan formation vertically and mostly in Wuerhe-Xiazijie faulted belt in plane.The development degrees of intragranular fractures in Karamay-Baikouquan and Wuerhe-Xiazijie faulted belts are different due to the changes of stress effect mode and rigid grain content.Constrained by thrust fault distribution,the development degree of intragranular fractures is weakening from the faulted zone to slope area,but tends to increase at strike-slip faults.
The sandy conglomerate reservoirs of Baikouquan formation of Mahu sag in northwestern margin of Junggar basin are low-porosity and low-permeability reservoirs,where the intragranular fractures act as the important flow paths.Less researches have been made in terms of genetic mechanism and development of intragranular fractures at home and abroad.This paper systematically analyzes the identifying characteristics,genetic mechanism,development process and distribution of intragranular fractures in low-porosity and low-permeability sandy conglomerate reservoirs,according to themacroscopic and microscopic characteristics of intragranular fractures development,combining with drilling and seismic data,by means of relationship characterization of the palaeotectonic stress value-the intragranular fractures,and intragranular fracture physical modeling experiment.It is considered that the intragranular fractures in Baikouquan formation are structural-diagenetic fractures genetically,the generation of the fractures is related to the properties of compression,shearing and torsion,internal defect of grains,tectonic stress and stress effect;the main influence of intragranular fractures on the reservoir is to improve reservoir permeability,and the effective configuration of intragranular fractures in coarse grains-intergranular matrix pores among sand grainsmicrofissures is the key factor to generate high-quality and high-efficiency reservoirs of Baikouquan formation;the intragranular fractures are mainly distributed in Middle-Lower Triassic Baikouquan formation vertically and mostly in Wuerhe-Xiazijie faulted belt in plane.The development degrees of intragranular fractures in Karamay-Baikouquan and Wuerhe-Xiazijie faulted belts are different due to the changes of stress effect mode and rigid grain content.Constrained by thrust fault distribution,the development degree of intragranular fractures is weakening from the faulted zone to slope area,but tends to increase at strike-slip faults.
引文
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[12]宋永东,戴俊生,吴孔友.准噶尔盆地乌夏断裂带构造特征与油气成藏模式[J].西安石油大学学报(自然科学版),2009,24(3):17-20.SONG Yongdong,DAI Junsheng,WU Kongyou.Study on the structural features and hydrocarbon accumulation modes of Wuxia fault belt in the northwest margin of Junggar basin[J].Journal of Xi’an Shiyou University(Natural Science Edition),2009,24(3):17-20.
[13]唐勇,徐洋,瞿建华,等.玛湖凹陷百口泉组扇三角洲群特征及分布[J].新疆石油地质,2014,35(6):628-635.TANG Yong,XU Yang,QU Jianhua,et al.Fan-delta group characteristics and its distribution of the Triassic Baikouquan reservoirs in Mahu sag of Junggar basin[J].Xinjiang Petroleum Geology,2014,35(6):628-635.
[14]吴胜和,熊琦华.油气储层地质学[M].北京:石油工业出版社,1998:129.WU Shenghe,XIONG Qihua.Hydrocarbon reservoir geology[M].Beijing:Petroleum Industry Press,1998:129.
[15]柳广弟,张厚福.石油地质学[M].北京:石油工业出版社,2009:40-41.LIU Guangdi,ZHANG Houfu.Petroleum geology[M].Beijing:Petroleum Industry Press,2009:40-41.
[16]郭沫贞,朱国华,寿建峰,等.碎屑岩压裂缝的特征、成因与油气勘探意义[J].沉积学报,2006,24(4):483-487.GUO Mozhen,ZHU Guohua,SHOU Jianfeng,et al.Features,origin and petroleum explorative significance of crushed fracture in clastic rock[J].Acta Sedimentologica Sinica,2006,24(4):483-487.
[17]孟祥超,陈能贵,苏静,等.砂砾岩体不同岩相油气充注期储集性能差异及成藏意义——以玛湖凹陷西斜坡区百口泉组油藏为例[J].沉积学报,2016,34(3):606-614.MENG Xiangchao,CHEN Nenggui,SU Jing,et al.Reservoir property diversity of different lithofacies in sandy conglomerate during oil-gas injection period and reservoir-formation significance:a case from Baikouquan formation in west slope of Mahu depression,Junggar basin[J].Acta Sedimentologica Sinica,2016,34(3):606-614.
[18]吴孔友,瞿建华,王鹤华.准噶尔盆地大侏罗沟断层走滑特征、形成机制及控藏作用[J].中国石油大学学报(自然科学版),2014,38(5):41-47.WU Kongyou,QU Jianhua,WANG Hehua.Strike-slip characteristics,forming mechanisms and controlling reservoirs of Dazhuluogou fault in Junggar basin[J].Journal of China University Petroleum(Edition of Natural Science),2014,38(5):41-47.
[19]陈永波,潘建国,张寒,等.准噶尔盆地玛湖凹陷斜坡区断裂演化特征及对三叠系百口泉组成藏意义[J].天然气地球科学,2015,26(增刊1):11-24.CHEN Yongbo,PAN Jianguo,ZHANG Han,et al.Characteristics of fault evolution in Mahu slope area of Junggar basin and its implications to the reservoir in the Lower Triassic Baikouquan formation[J].Natural Gas Geoscience,2015,26(Supp.1):11-24.
[20]邵雨,汪仁富,张越迁,等.准噶尔盆地西北缘走滑构造与油气勘探[J].石油学报,2011,32(6):976-984.SHAO Yu,WANG Renfu,ZHANG Yueqian,et al.Strike-slip structures and oil-gas exploration in the NW margin of the Junggar basin,China[J].Acta Petrolei Sinica,2011,32(6):976-984.
[2]赵贤正,朱洁琼,张锐峰,等.冀中坳陷束鹿凹陷泥灰岩-砾岩致密油气成藏特征与勘探潜力[J].石油学报,2014,35(4):613-622.ZHAO Xianzheng,ZHU Jieqiong,ZHANG Ruifeng,et al.Characteristics and exploration potential of tight calcilutite-rudstone reservoirs in Shulu sag,Jizhong depression,North China[J].Acta Petrolei Sinica,2014,35(4):613-622.
[3]杨超,张金川,唐玄.鄂尔多斯盆地陆相页岩微观孔隙类型及对页岩气储渗的影响[J].地学前缘,2013,20(4):240-250.YANG Chao,ZHANG Jinchuan,TANG Xuan.Microscopic pore types and its impact on the storage and permeability of continental shale gas,Ordos basin[J].Earth Science Frontiers,2013,20(4):240-250.
[4]NARR W.Fracture density in the deep subsurface:techniques with application to Point Arguello oil field[J].AAPG Bulletin,1991,75(8):1 300-1 323.
[5]BAI T,POLLARD D D.Fracture spacing in layered rocks:a new explanation based on the stress transition[J].Journal of Structural Geology,2000,22(1):43-57.
[6]曾联波,高春宇,漆家福,等.鄂尔多斯盆地陇东地区特低渗透砂岩储层裂缝分布规律及其渗流作用[J].中国科学D辑:地球科学,2008,38(增刊1):41-47.ZENG Lianbo,GAO Chunyu,QI Jiafu,et al.Distribution and its seepage effect of the fracture in low-permeability sand-stone reservoir in Longdong area,Ordos basin[J].Science in China Series D:Earth Sciences,2008,38(Supp.1):41-47.
[7]张丽娟,朱国华,魏燕萍,等.乌什凹陷神木1井白垩系储层微观特征[J].中国石油勘探,2010,15(3):22-24.ZHANG Lijuan,ZHU Guohua,WEI Yanping,et al.Characteristics of Cretaceous reservoir in Shenmu-1 well by microscopic chips observation[J].China Petroleum Exploration,2010,15(3):22-24.
[8]宫清顺,倪国辉,芦淑萍.准噶尔盆地乌尔禾油田百口泉组储层特征及控制因素分析[J].中国石油勘探,2010,15(5):11-16.Gong Qingshun,NI Guohui,LU Shuping.Analysis on features and controlling factors of reservoir in Baikouquan formation of Wuerhe oilfield,Junggar basin[J].China Petroleum Exploration,2010,15(5):11-16.
[9]李丕龙,冯建辉,陆永潮,等.准噶尔盆地构造沉积与成藏[M].北京:地质出版社,2010:114-117.LI Pilong,FENG Jianhui,LU Yongchao,et al.Structure,sedimentation and reservoir in Junggar basin[M].Beijing:Geological Publishing House,2010:114-117.
[10]雷振宇,卞德智,杜社宽.准噶尔盆地西北缘扇体形成特征及油气分布规律[J].石油学报,2005,26(1):8-12.LEI Zhenyu,BIAN Dezhi,DU Shekuan,et al.Characteristics of fan forming and oil-gas distribution in west-north margin of Junggar basin[J].Acta Petrolei Sinica,2005,26(1):8-12.
[11]雷振宇,鲁兵,蔚远江,等.准噶尔盆地西北缘构造演化与扇体形成和分布[J].石油与天然气地质,2005,26(1):86-91.LEI Zhenyu,LU Bing,WEI Yuanjiang,et al.Tectonic evolution and development and distribution of fans on northwestern edge of Junggar basin[J].Oil&Gas Geology,2005,26(1):86-91.
[12]宋永东,戴俊生,吴孔友.准噶尔盆地乌夏断裂带构造特征与油气成藏模式[J].西安石油大学学报(自然科学版),2009,24(3):17-20.SONG Yongdong,DAI Junsheng,WU Kongyou.Study on the structural features and hydrocarbon accumulation modes of Wuxia fault belt in the northwest margin of Junggar basin[J].Journal of Xi’an Shiyou University(Natural Science Edition),2009,24(3):17-20.
[13]唐勇,徐洋,瞿建华,等.玛湖凹陷百口泉组扇三角洲群特征及分布[J].新疆石油地质,2014,35(6):628-635.TANG Yong,XU Yang,QU Jianhua,et al.Fan-delta group characteristics and its distribution of the Triassic Baikouquan reservoirs in Mahu sag of Junggar basin[J].Xinjiang Petroleum Geology,2014,35(6):628-635.
[14]吴胜和,熊琦华.油气储层地质学[M].北京:石油工业出版社,1998:129.WU Shenghe,XIONG Qihua.Hydrocarbon reservoir geology[M].Beijing:Petroleum Industry Press,1998:129.
[15]柳广弟,张厚福.石油地质学[M].北京:石油工业出版社,2009:40-41.LIU Guangdi,ZHANG Houfu.Petroleum geology[M].Beijing:Petroleum Industry Press,2009:40-41.
[16]郭沫贞,朱国华,寿建峰,等.碎屑岩压裂缝的特征、成因与油气勘探意义[J].沉积学报,2006,24(4):483-487.GUO Mozhen,ZHU Guohua,SHOU Jianfeng,et al.Features,origin and petroleum explorative significance of crushed fracture in clastic rock[J].Acta Sedimentologica Sinica,2006,24(4):483-487.
[17]孟祥超,陈能贵,苏静,等.砂砾岩体不同岩相油气充注期储集性能差异及成藏意义——以玛湖凹陷西斜坡区百口泉组油藏为例[J].沉积学报,2016,34(3):606-614.MENG Xiangchao,CHEN Nenggui,SU Jing,et al.Reservoir property diversity of different lithofacies in sandy conglomerate during oil-gas injection period and reservoir-formation significance:a case from Baikouquan formation in west slope of Mahu depression,Junggar basin[J].Acta Sedimentologica Sinica,2016,34(3):606-614.
[18]吴孔友,瞿建华,王鹤华.准噶尔盆地大侏罗沟断层走滑特征、形成机制及控藏作用[J].中国石油大学学报(自然科学版),2014,38(5):41-47.WU Kongyou,QU Jianhua,WANG Hehua.Strike-slip characteristics,forming mechanisms and controlling reservoirs of Dazhuluogou fault in Junggar basin[J].Journal of China University Petroleum(Edition of Natural Science),2014,38(5):41-47.
[19]陈永波,潘建国,张寒,等.准噶尔盆地玛湖凹陷斜坡区断裂演化特征及对三叠系百口泉组成藏意义[J].天然气地球科学,2015,26(增刊1):11-24.CHEN Yongbo,PAN Jianguo,ZHANG Han,et al.Characteristics of fault evolution in Mahu slope area of Junggar basin and its implications to the reservoir in the Lower Triassic Baikouquan formation[J].Natural Gas Geoscience,2015,26(Supp.1):11-24.
[20]邵雨,汪仁富,张越迁,等.准噶尔盆地西北缘走滑构造与油气勘探[J].石油学报,2011,32(6):976-984.SHAO Yu,WANG Renfu,ZHANG Yueqian,et al.Strike-slip structures and oil-gas exploration in the NW margin of the Junggar basin,China[J].Acta Petrolei Sinica,2011,32(6):976-984.