四川盆地及其邻区下二叠统栖霞阶层序-岩相古地理特征及油气地质意义  

Sequence-lithofacies paleogeographic characteristics and petroleum geological significance of Lower Permian Qixia Stage in Sichuan Basin and its adjacent areas,SW China

作　　者：李明隆 谭秀成 杨雨[4] 倪华玲 罗冰 文龙 张本健 肖笛 许强 LI Minglong;TAN Xiucheng;YANG Yu;NI Hualing;LUO Bing;WEN Long;ZHANG Benjian;XIAO Di;XU Qiang(CNPC Key Laboratory of Carbonate Reservoirs,Southwest Petroleum University Division,Chengdu 610500,China;Sichuan Province Key Laboratory of Natural Gas Geology,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploration,Southwest Petroleum University,Chengdu 610500,China;PetroChina Southwest Oil and Gas Field Company,Chengdu 610000,China;Southwest Geophysical Research Institute,BGP,CNPC,Chengdu 610213,China)

机构地区：[1]中国石油天然气集团有限公司碳酸盐岩储层重点实验室西南石油大学研究分室,成都610500 [2]天然气地质四川省重点实验室,西南石油大学,成都610500 [3]油气藏地质及开发工程国家重点实验室,西南石油大学,成都610500 [4]中国石油西南油气田公司,成都610000 [5]中国石油东方地球物理公司西南物探研究院,成都610213

出　　处：《石油勘探与开发》2022年第6期1119-1131,共13页Petroleum Exploration and Development

基　　金：中国石油-西南石油大学创新联合体科技合作项目“深层/超深层碳酸盐岩天然气勘探开发基础理论与关键技术研究”(2020CX010000);中国石油集团公司上游领域基础性前瞻性项目“残留型海相盆地构造-岩相古地理重建技术研究”(2021DJ0501);国家自然科学基金面上项目“四川盆地早中二叠世白云岩及储层差异成因与峨眉山大火成岩省幕式响应”(42172166)。

摘　　要：通过对野外露头、测录井、岩心及地球化学资料分析,基于海平面升降、层序充填、古地貌与岩相的相互关系研究,恢复四川盆地及周缘下二叠统梁山组—栖霞组(简称栖霞阶)层序-岩相古地理及其演化过程。研究结果如下:栖霞阶可划分为SQ0、SQ1、SQ2共3个三级层序,各层序厚度所反映的古地貌表明,早二叠世栖霞阶沉积前四川盆地周缘发育古隆/古陆,盆地内部则为高地与洼地相间的古地貌特征;SQ2为栖霞组主要的成滩期,高能丘滩相主要发育于沉积古地貌高地等处;白云质岩类(白云岩、灰质白云岩和白云质灰岩)储集层分布与沉积地貌高地等具有良好相关性;有利丘滩、白云质岩类储集层具有沿台缘带规模分布的特点。指出四川盆地西部台缘带依然是目前勘探的重点领域,而台内成都—绵阳、广旺以及川中—川南地区是下一步栖霞组白云质岩类储集层有利的发育区。Through the analysis of logging,field outcrops,cores and geochemical data,and based on the study of the relationships between sea level changes,sequence filling,paleo-geomorphy and lithofacies,the sequence lithofacies paleo-geography and evolution process of the Lower Permian Liangshan-Qixia Formation(Qixia Stage for short)in Sichuan Basin and its surrounding areas are restored.The Qixia Stage can be divided into three third-order sequences,in which SQ0,SQ1 and SQ2 are developed in the depression area,and SQ1 and SQ2 are only developed in other areas.The paleo-geomorphy reflected by the thickness of each sequence indicates that before the deposition of the Qixia Stage in the Early Permian,the areas surrounding the Sichuan Basin are characterized by“four uplifts and four depressions”,namely,four paleo-uplifts/paleo-lands of Kangdian,Hannan,Shennongjia and Xuefeng Mountain,and four depressions of Chengdu-Mianyang,Kangdian front,Jiangkou and Yichang;while the interior of the basin is characterized by“secondary uplifts,secondary depressions and alternating convex-concave”.SQ2 is the main shoal forming period of the Qixia Formation,and the high-energy mound shoal facies mainly developed in the highs of sedimentary paleo-geomorphy and the relative slope break zones.The distribution of dolomitic reservoirs(dolomite,limy dolomite and dolomitic limestone)has a good correlation with the sedimentary geomorphic highs and slope break zones.The favorable mound-shoal and dolomitic reservoirs are distributed around depressions at platform-margin and along highs and around sags in the basin.It is pointed out that the platform-margin area in western Sichuan Basin is still the key area for exploration at present;while areas around Chengdu-Mianyang depression and Guangwang secondary depression inside the platform and areas around sags in central Sichuan-southern Sichuan are favorable exploration areas for dolomitic reservoirs of the Qixia Formation in the next step.

关 键 词：四川盆地 下二叠统 栖霞阶 层序地层 三级层序 丘滩体 碳酸盐台地 储集层 岩相古地理 

分 类 号：TE122.2[石油与天然气工程—油气勘探]