苏里格气田苏120区块低渗致密砂岩储层微观特征精细描述

FINE DESCRIPTION OF MICROSCOPIC FEATURES FOR LOW-PERMEABILITY TIGHT SANDSTONE RESERVOIR,SU 120 BLOCK,SULIGE GASFIELD

通过岩石薄片、铸体薄片、扫描电镜、X射线衍射、恒速压汞、核磁共振等测试数据详细分析,精细表征了苏里格气田苏120正块低渗致密砂岩储层微观特征。研究表明:储层岩石类型主要为岩屑石英砂岩和石英砂岩,储集空间主要为岩屑溶孔和晶间孔。在孔隙半径相差较小的情况下,毛管半径分布相差很大,说明渗透率变化重点受喉道控制,喉道是低渗致密砂岩储层有效开发的关键因素。引起储层差异的原因是受沉积微相、成岩作用、构造因素及地层水的共同影响。

For the low-permeability tight sandstone reservoirs in Su 120 block,Sulige gasfield,the fine characterization of their microscopic features was finished by means of analyzing plenty of data from thin section,casting thin section,SEM,X-ray diffraction,constant-rate mercury penetration,and NMR.Results show that(1)they are mainly composed of both lithic quartz sandstone and quartzose sandstone;(2)their reservoir space includes dissolution and intercrystalline pore;(3)the capillary radius distribution has a big difference under the condition that pore radius has a little difference,showing that permeability change is affected by throat,and throat is the key factor for effectively developing this low-permeability tight sandstone reservoir;(4)the reasons causing reservoir difference contain sedimentary microfacies,diagenesis,tectonic factors,and formation water.