川西北地区下二叠统栖霞组滩相储层特征及其分布

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。

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

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 ...