四川盆地开江——梁平海槽两侧长兴组储层溶蚀分类及模式分析  

Classification and development mode of reservoir dissolution in Changxing Formation on either side of Kaijiang-Liangping trough, Sichuan Basin

作　　者：邓思思[1] 徐亮[1] 王跃祥[1] 张奇[1] 张云峰[2] 谢林[2] Deng Sisi;Xu Liang;Wang Yuexiang;Zhang Qi;Zhang Yunfeng;Xie Lin(Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China;Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]中国石油西南油气田分公司勘探开发研究院 [2]西南石油大学

出　　处：《天然气勘探与开发》2019年第4期66-74,共9页Natural Gas Exploration and Development

基　　金：国家科技重大专项“四川盆地二叠系—中三叠统天然气富集规律与目标评价”（编号：2016ZX05007-004）

摘　　要：四川盆地上二叠统长兴组储层明显受控于礁、滩发育程度,并非所有礁、滩均能成为有效储层。储层质量及分布是沉积、成岩作用共同控制的结果。勘探表明,白云石化及溶蚀作用是长兴组礁、滩储层发育最主要的控制因素。以往研究认为埋藏溶蚀作用是形成优质储层的关键,主要围绕与埋藏溶蚀有关的有机酸水和热液的分布及溶解能力开展研究。本次通过对开江-梁平海槽两侧21口井的岩心精细描述及岩矿分析,分析不同时期溶蚀作用的识别标志和发育特征,研究结果表明:①长兴组礁、滩体普遍经历了准同生期、早成岩期与埋藏期三个阶段的溶蚀作用。三期溶蚀作用对储层的改造作用明显,并建立溶蚀作用发育模式图。②准同生期和早成岩期溶蚀明显受控于礁、滩体沉积微相,呈现"相控"特征。其中准同生期大气淡水溶蚀多发生在礁顶滩,台缘带早、晚期礁都存在,横向上呈透镜状分布。③早成岩期近地表岩溶发生在成岩早期,晚期礁比早期礁发育,说明在礁、滩体形成后曾经有较长时间的暴露地表的岩溶过程。④埋藏期岩溶作用主要对断层附近溶蚀带有利,该期岩溶相控特征不明显,与断裂带有关,具层控叠加效应,叠加前两期溶蚀作用,使优质储层更加发育。Most reservoirs of Upper Permian Changxing Formation, Sichuan Basin, are mainly controlled by the development of both bioreef and beach. However, it doesn’t mean that all bioreef and beach can be effective reservoirs. Reservoir quality and distribution are affected by a combination of sedimentation and diagenesis. Some exploration results show that dolomitization and dissolution are the most important factors controlling the development of Changxing bioreef and beach reservoirs. It was previously deemed that burial dissolution is the key factor to form high-quality reservoirs. So, some cores from 21 wells located on either side of Kaijiang-Liangping trough were analyzed, and identification benchmark and development feature of dissolution in different periods were also studied. Results show that(1) Changxing bioreef and beach bodies commonly experienced three dissolution periods, i.e., penecontemporaneous period, early diagenetic period, and burial period, which have significant reworking action on reservoirs. And development mode diagram of dissolution is established;(2) the dissolution in penecontemporaneous and early diagenetic periods is obviously controlled by the sedimentary microfacies of bioreef and beach, presenting the features of "facies control". And in penecontemporaneous period, the dissolution by meteoric fresh water mostly happened at the beach of top bioreef. There is early and late bioreef in marginal platform belts, and bioreef is laterally distributed in the shape of lens;(3) near-surface karstification at early diagenesis happened in early diagenetic period, and late bioreef is more developed than early one, indicating that these bioreef and beach bodies experienced a prolonged period of karstification exposed to surface after their forming;and(4) burial karstification is mainly favorable for dissolution zones near fault. During burial period, facies-controlled karstification characteristics are not obvious and related to faulting zones, which are featured by layer-controlled synergistic eff

关 键 词：晚二叠世 长兴期 礁、滩储层 溶蚀作用 准同生期 早成岩期 埋藏期 相控 

分 类 号：P61[天文地球—矿床学]