四川盆地元坝地区茅三段岩溶体精细刻画  

Fine characterization on karsts of Maokou 3 Member,Yuanba area,Sichuan Basin

作　　者：陈会霞 潘蓓 季春辉[1] 李文成[1] 张志宇 郝祥礼 CHEN Huixia;PAN Bei;JI Chunhui;LI Wencheng;ZHANG Zhiyu;HAO Xiangli(Sinopec Exploration Company,Chengdu,Sichuan 610041,China;Changsha Research Institute of Mining and Metallurgy Co.Ltd.,Changsha,Hunan 410012,China)

机构地区：[1]中国石化勘探分公司,四川成都610041 [2]长沙矿冶研究院有限责任公司,湖南长沙410012

出　　处：《天然气技术与经济》2022年第6期9-15,共7页Natural Gas Technology and Economy

摘　　要：茅口组碳酸盐岩是四川盆地油气勘探的重点层系,钻井揭示四川盆地元坝地区下二叠统茅口组三段台缘浅滩储层受到岩溶作用改造,厚度薄、非均质性强,同时元坝地区茅口组地层埋深普遍大于7000 m,常规地震资料对于储层的识别能力不足。为了解决元坝地区茅口组岩溶储层刻画难度大的问题,以元坝工区三维地震资料及台缘相带内5口已钻井为研究对象,通过开展地震资料优化处理、古地貌恢复、结构张量属性分析来精细刻画茅三段岩溶体的展布。研究结果表明:(1)对地震资料开展基于压缩感知的提高分辨率处理和构造导向滤波处理可以提高对岩溶体的识别能力;(2)元坝地区茅三段不同岩溶地貌单元的岩溶缝洞系统发育程度和规模差异大,古地貌结合结构张量属性分析有效减少了预测结果的多解性,与已钻井吻合度高,是研究区岩溶体预测的有效技术手段;(3)元坝地区茅三段岩溶体主要发育于岩溶高地中—上层的垂向渗流带及岩溶峰丛沟谷两侧的水平潜流带内,残留岩溶孔洞主要发育于岩溶峰丛沟谷两侧的岩溶辐射区及高地内岩溶漏斗周围的岩溶辐射区,是岩溶储层的有利发育区。Carbonate rocks in Maokou Formation are the key strata for oil and gas exploration in Sichuan Basin.Their drilling practice reveals that,reworked by karstification,the marginal platform shoal reservoirs of the Lower Permian Maokou 3 Member,Yuanba area,Sichuan Basin,emerge such characteristics as small thickness and strong heterogeneity.And the burial depth of Maokou Formation in this area is generally greater than 7000 m,leading to insufficient reservoir identification through conventional seismic data.So,some 3D seismic data obtained from Yuanba area and 5 drillers in the marginal platform facies belt were taken as objectives to finely characterize the karst distribution in Maokou 3 Member by seismic-data optimization and processing,palaeogeomorphic restoration,and analysis on fabric tensor attribute.Results show that(1)the ability for karst identification can be perfected by performing compressive sensing-based resolution processing and the structure-oriented filter processing on seismic data;(2)the development degree and size of karst-fractured-vuggy system vary greatly in various karst units of Maokou 3 Member in Yuanba area.Palaeogeomorphy,combined with attribute analysis,can effectively reduce the ambiguity of prediction results and make these results in highly coincidence with drillers,so it is an effective prediction means for the karsts in this area;and(3)the karsts are mostly developed in vertical seepage zones of the middle to the upper of karst highland or in the horizontal underflow zones on both sides of the valley of karst peak cluster,and the residual karst vug is dominantly stretched in the karst radiation zones on both sides of karst peak cluster or in the karst radiation zones around the karst funnel inside the highland,which is favorable for the extension of karst reservoirs.

关 键 词：四川盆地 元坝地区 古地貌恢复 结构张量属性 岩溶体刻画 

分 类 号：P618.13[天文地球—矿床学]