四川盆地中部侏罗系大安寨段含有机质泥质介壳灰岩储层的认识及其意义

作    者:倪超,郝毅,厚刚福,谷明峰,张力涛
单    位:中国石油杭州地质研究院
基金项目:
摘    要:
四川盆地中部下侏罗统大安寨段可划分为三个亚段,主要由暗色泥页岩、结晶介壳灰岩、泥质介壳灰岩三种岩性构成。暗色泥页岩形成于深湖—半深湖相环境,是主要的烃源岩,滨浅湖高能滩相结晶介壳灰岩一向被认为是主要储层,其储集空间以裂缝为主。露头地质调查、岩心和薄片观察、物性资料及试油资料的分析表明,浅湖—半深湖较低能滩相含有机质泥质介壳灰岩是主要的储集层和产层,单层厚度薄,但累积厚度较大,分布面积广,常夹于暗色泥页岩中,源储一体,更有利于成藏。这类泥质介壳灰岩的壳间孔构成了主要的储集空间,壳间孔平行于壳体的长轴方向排列,并常见黑色有机质充填。认为四川盆地大安寨段的油气勘探方向可由结晶介壳灰岩向含有机质的泥质介壳灰岩拓展,浅湖—半深湖较低能滩沉积相带可成为新的勘探领域。初步预测大安寨段上部的一亚段新增有利勘探面积6100km2,中部的一三亚段新增有利勘探面积6600km2。
关键词:四川盆地中部;下侏罗统;大安寨段;介壳灰岩;碳酸盐岩储集层;储层特征

Cognition and Significance of Lower Jurassic Daanzhai Organic Muddy Shell Limestone Reservoir in Central Sichuan Basin

Author's Name: Ni Chao, Hao Yi, Hou Gangfu, Gu Mingfeng, Zhang Litao
Institution: PetroChina Hangzhou Institute of Geology
Abstract:
The Lower Jurassic Daanzhai Member in Sichuan Basin can be divided into Dayi, Dayisan and Dasan Submembers from top to bottom, which is constituted by dark clay shale, crystalline shell limestone and muddy shell limestone. The dark clay shale that formed in deep to semideep lacustrine environment is the main source rock. The crystalline shell limestones(CSL) that formed in high-energy beach to shallow lacustrine environment has been deemed to be the major hydrocarbon reservoir for fractures are dominant in it. Through the geological survey of outcrops, the observation of cores and thin sections, the analysis of physical parameters and formation tests, it is indicated that the shallow to semideep lacustrine organic muddy shell limestones(OMSL) that formed in lower-energy beach are the main reservoirs or payzones. They are of thin single layers but large accumulative thickness with a wide range of distribution. These limestones are usually intercalated within the dark clay shales which comprise the integrative source/reservoir rocks to be beneficial to hydrocarbon accumulation. In this type of muddy shell limestone, intershell pores make up the main reservoir space and the intershell pores are commonly filled with dark organic matter. It is suggested that the exploration target may be extended from the CSL to the OMSL in Daanzhai Member. If the OMSL formed in lower-energy beach zone becomes a new prospecting domain, a preliminary prediction shows that the favorable exploration area will increase 6100km2 and 6600 km2 espectively in Dayi and Daysan Submembers.
Keywords: Lower Jurassic; Daanzhai Member; Shell limestone; Carbonate reservoir; Reservoir characteristics; Central part of Sichuan Basin
投稿时间: 2011-10-27  
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