川西北地区下二叠统栖霞组滩相储层特征及其分布  

Features and distribution of shoal facies reservoirs in the Lower Permian Qixia Formation,northwest Sichuan Basin

作　　者：曾德铭[1] 石新[2] 王兴志[1] 黄勇[1] 杨跃明[3] 

机构地区：[1]"油气藏地质及开发工程"国家重点实验室.西南石油大学 [2]川庆钻探工程有限公司地质勘探开发研究院 [3]中国石油西南油气田公司川西北气矿

出　　处：《天然气工业》2010年第12期25-28,共4页Natural Gas Industry

基　　金：西南石油大学校级科技基金(编号:2007XJZ047);四川省重点学科建设项目(编号:SZD0414)

摘　　要：四川盆地西北部下二叠统栖霞组白云岩储层为生物颗粒滩储层,目前对该套地层中的滩体类型及其特征研究较少。为此,在分析该区栖霞组储层特征的基础上,重点研究生物颗粒滩在纵向上的岩相组合、储集空间发育情况和物性特征,探讨滩体的储集性能与储层的平面分布。根据野外露头资料及钻井岩心的宏观及微观特征,结合物性分析结果,认为滩体形成时的古地理背景及经历的成岩作用不同,导致沉积的岩性组合、储集性能和分布差异极大。天井山—矿2井—西北乡一带的浅水高能生物滩位于栖霞组二段的中部,形成于龙门山古断裂上升盘的局部高地,由中—粗晶白云岩、生屑白云岩和云质"豹斑"石灰岩组成,累计厚度为60～90 m,滩体频繁暴露于水体之上,发生混合水云化作用和溶解作用,物性较好,是最有利的储层分布区;通口—水根头、余家沟—曾家山和鱼洞河—旺苍—巴中一带的深水低能生物滩发育于栖二段的顶部,形成于浅缓坡下部的浪基面附近,水体较深,能量较低,储集空间欠发育,为区内差—非储层分布区。The dolomite reservoirs in the Lower Permian Qixia Formation,northwest Sichuan Basin,are of biogenetic grain shoal facies and mainly occur in the second member of this Formation.The lighologies of reservoir rocks are dominated by crystalline dolomite and dolomitic leopard limestone.The reservoir spaces are mainly of intercrystalline pore,intercrystalline dissolution pore,solution cavity and sheet-like throat.Based on the macroscopic and microscopic features of field outcrop and core and in combination with an analysis of petrophysical properties,it is believed that the differences in palaeogeography and diagenesis resulted in discrepancies of in lithologic assemblage,reservoir quality,and distribution.In the area of Tianjingshan-Kuang 2 well-Xibeixiang,reservoirs of shallow-water high-energy(exposed) organic bank facies are in the middle of the second member of the Qixia Formation.They were deposited on the local highs on the hanging wall of the fossil fault in the Longmen Mountain,and consist of moderate and coarse crystalline dolomite,bioclastic dolomite and dolomitic leopard limestone.The net thickness is 60-90 m.They experienced mixed water dolomitization and dissolution due to frequent exposure,thus their reservoir qualities are relatively good.In contrast,in the areas of Tongkou-Shuigentou,Yujiagou-Zengjiashan,and Yudonghe-Wangcang-Bazong,reservoirs of deep-water low-energy(unexposed) organic bank facies occur on the top of the second member of the Qixia Formation.They were deposited near the wave base at the lower part of shallow ramp,and their reservoir qualities are poor.

关 键 词：四川盆地西北 早二叠世 碳酸盐岩 沉积特征 生物颗粒滩 沉积岩相 储集层特征 分布 

分 类 号：P618.13[天文地球—矿床学]