四川盆地中三叠统雷口坡组天然气勘探方向  

Direction of gas exploration in the Middle Triassic Leikoupo Formation of the Sichuan Basin

作　　者：周进高[1,2,3] 辛勇光[1,3] 谷明峰[1] 张建勇[1,3] 郝毅[1] 李国军[1] 倪超[1] 吕玉珍[1] 

机构地区：[1]中国石油勘探开发研究院杭州地质研究院 [2]西南石油大学 [3]中国石油天然气集团公司碳酸盐岩储层重点实验室

出　　处：《天然气工业》2010年第12期16-19,共4页Natural Gas Industry

摘　　要：2008年以来,在四川盆地LG地区中三叠统雷口坡组顶部风化壳取得勘探突破,揭开了雷四段岩性气藏的勘探序幕。为寻找近期雷口坡组天然气勘探的方向,对该区雷口坡组各层段残余地层分布特征、岩相古地理的恢复、储层类型和分布以及气藏解剖等进行了综合分析。通过井震结合的层序格架下的沉积储层、成藏等综合分析,认为:①该区雷口坡组残余地层厚度一般为600～1200 m,川西凹陷保存较全,华蓥山断裂以东地区剥蚀强烈,沿泸州—开江古隆起整个雷口坡组已被剥蚀殆尽;②雷口坡期四川盆地为障壁蒸发澙湖沉积,由雷一—雷四期,膏盐湖中心从川中南充地区,逐渐扩大至简阳,最后迁移至盐亭—蒲西地区,围绕膏盐湖分布白云岩坪及颗粒滩;③发育风化壳岩溶型白云岩和颗粒白云岩2类储层,前者分布在大川中地区,后者分布于川中磨溪—广安地区及龙门山前缘带;④存在构造气藏和岩性气藏2种气藏类型;⑤雷口坡组顶部风化壳和雷一、雷三段颗粒滩是有利勘探领域,大川中地区(包括LG和九龙山地区)是风化壳勘探的主要方向。The gas exploration of lithological reservoirs in the fourth member of the Leikoupo Formation started in 2008 with a breakthrough in gas discovery in the weathering crust of the top Leikoupo Formation of Middle Triassic in the eastern Sichuan Basin.In order to search for the direction of gas exploration in this area,this paper studies the distribution of remnant strata in each member of the Leikoupo Formation,reconstructs lithofacies paleogeography,identifies reservoir types and distribution,and dissects gas reservoirs.Near-term direction of exploration is defined based on these comprehensive research results.a.The remnant strata in the Leikoupo Formation of the Sichuan Basin,generally ranging in thickness from 600-1200 m,are relatively completely preserved in the Chuanxi Depression,strongly eroded to the east of Huayingshan fault,and almost completely eroded on the Luzhou-Kaijiang palaeohigh.b.During the deposition of the Leikoupo Formation,the sedimentary environment was barrier evaporative lagoon.c.From the deposition of the first member to the fourth member of the Leikoupo Formation,the depocenter of the lagoon migrated progressively from Nanchong in the central Sichuan Basin to Jianyang,and finally to Yanting-Puxi area,and dolomite flat and grain shoal deposits were developed around the lagoon.d.Two types of reservoirs are identified: one is karstic dolomite reservoirs distributed in the whole central Sichuan Basin,and the other is granular dolomite reservoirs distributed in the area of Moxi-Guang'an and the frontal zone of the Longmen Mountain.e.Two types of gas reservoirs,including structural trap and lithologic trap,are identified.f.The weathering crust on the top Leikoupo Formation and the grain shoals in the first and third members of the Leikoupo Formation are favorable exploration targets,and weathering crust reservoirs are the major exploration target in the whole central Sichuan Basin.

关 键 词：四川盆地 中三叠世 勘探方向 风化壳 储集层特征 岩相古地理 气藏类型 颗粒滩 

分 类 号：P618.13[天文地球—矿床学]