川东地区二叠系火山岩石油地质特征及天然气勘探有利区  

Analysis on petroleum geology characteristics and favorable exploration directions of Permian volcanic rocks in eastern Sichuan Basin

作　　者：张志宇 熊治富[1] 季春辉[1] 蒋艳霞 杨焓 ZHANG Zhiyu;XIONG Zhifu;JI Chunhui;JIANG Yanxia;YANG Han(Sinopec Exploration Company,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石化勘探分公司,四川成都610041

出　　处：《天然气技术与经济》2024年第3期17-25,共9页Natural Gas Technology and Economy

摘　　要：为了研究四川盆地东部地区火山岩的岩相展布规律、储层发育主控因素、油气成藏富集模式等问题,以野外露头、钻井、测井、分析化验等资料为基础,分析了该区二叠系火山岩成储成藏模式,指出了天然气勘探有利区。研究结果表明:(1)受峨眉地裂运动影响,川东地区中二叠统茅口组—上二叠统吴家坪组发育两类火山岩相关的有利储层,一类是近火山口的火山碎屑熔岩储层,发育于茅三段中部及上部,主要分布在涪陵北部大竹—梁平—兴隆场喷溢相区,储层厚10~35 m,测井解释孔隙度介于3.4%~8.0%;另一类是远离火山口的火山—沉积碎屑岩储层,为火山灰与正常沉积物的混合沉积,发育于茅三段底部及吴家坪组,平面上分布于普光—涪陵北—建南地区,储层厚16~35 m。(2)茅三段底部和吴家坪组火山—沉积碎屑岩作为储层的同时,也是优质的烃源岩,自身具有高孔隙度、高有机碳含量、自生自储、大面积连片分布的特点,能够源内成藏。茅三段火山碎屑熔岩储层被下伏茅三段底部和上覆吴家坪组烃源岩所包裹,形成“夹心”式的源储配置关系,具有“近源成藏”的有利条件。结论认为:(1)涪陵北部为火山碎屑熔岩气藏勘探有利区,可进行老井复查、复试或优选有利构造位置部署探井;(2)围绕开江—梁平陆棚及其边缘的涪陵北、建南、普光地区是火山—沉积碎屑岩气藏勘探有利区,对于此类储层可采用非常规油气勘探思路,避开高陡构造区,优选保存条件好、埋深小于6 000 m的甜点区进行天然气勘探开发。To figure out the lithofacies distribution,main controls on reservoir extension,and reservoir-forming modes of volcanic rocks in eastern Sichuan Basin,both forming modes and hydrocarbon accumulation were analyzed for the Permian volcanic rocks in this area according to outcrop,drilling,logging and experimental data.Moreover,favorable exploration belts were pointed out.Results show that,affected by the Emei taphrogenesis,there developed two sets of favorable volca-nic reservoirs in the Middle Permian Maokou Formation and the Upper Permian Wujiaping Formation of eastern basin.Mainly located in Dazhu-Liangping-Xinglongchang effusive-facies block of northern Fuling area,the volcaniclastic lava reservoirs around volcano seat are developed at the middle and upper parts of the third member of Maokou Formation(Ma-okou 3 Member).And they are 10 m to 35 m in thickness and their logging-interpreted porosity between 3.4%and 8.0%,respectively.Situated in Puguang-Fuling North-Jiannan area,the volcanic-sedimentary clastic reservoirs,also as the com-pound deposition of volcanic ash and regular sediments,far away from the seat,are developed at Maokou 3 Member bottom and in Wujiaping Formation.And their thickness varies from 16 m to 35 m.These volcanic-sedimentary clastic rocks are regarded as not only reservoirs but also quality source rocks.For sake of their own natures in high porosity and TOC,self-generation and self-storage,and massive and successive extension,it is possible to form reservoirs inside source.The vol-caniclastic lava reservoirs of Maokou 3 Member are trapped by the source rocks of both underlying Maokou 3 Member bot-tom and overlying Wujiaping Formation,forming one source-reservoir assembly like a sandwich available for reservoirs near source.It is concluded that(i)in northern Fuling area,as the favorable exploration belt for the volcaniclastic lava res-ervoirs,old wells'resurvey and retesting or deploying exploration wells at advantageous structural points can be carried out;and(ii)surrounding Kaijiang-Liangpi

关 键 词：四川盆地 涪陵北部 二叠系 火山岩 勘探方向 

分 类 号：P618.13[天文地球—矿床学]