对川西北地区下二叠统茅口组野外露头和钻井岩心等资料的分析表明,储层段主要为茅口组三段,孔隙度平均为0.895,,渗透率平均为1.696× 10-3 μm2,总体属于低孔低渗储层.储集岩的类型可分为白云岩、生物碎屑灰岩及泥—粉晶灰岩三类,储集空间主要为晶间孔、晶间溶孔、粒内溶孔、粒间溶孔和裂缝(主要为构造缝).将储集空间划分为孔隙(直径小于2 mm)、孔洞(直径大于或等于2mm)及裂缝三大类,其中溶蚀孔洞为茅口组最主要的储集空间,裂缝是重要的渗滤通道.沉积相带和成岩作用是控制储层发育的主要因素,台地高能生物滩最有利于储层发育,白云石化作用和溶解作用是主要的建设性成岩作用.

Based on analysis of the Lower Permain Maokou outcrops and drilling cores in the northwest of Sichuan Basin, it is shown that the main reservoir belongs to Maokou Member 3 and exhibits the low porosity (average 0.895,) and low permeability (average 1.696×10-3μm2). The reservoir rocks consist of dolostone, bioclastic limestone and crystal limestone. Reservoir space, which includes intercrystal pores, intercrystal solution pores, intragranular and intergranular solution pores and cracks, is divided into pores (less than 2mm in diameter), holes (greater than or equal to 2mm in diameter) and cracks. Solution pores are the common reservoir space and cracks are the important infiltration channels in Maokou reservoir. Diagenesis and sedimentary facies control the reservoir development, in which high-energy biological beach facies in platform is the most favourable to reservoir development and dolomitization and dissolution are the constructive diagenesis.