二叠系下石盒子组天然气储集层特征及评价

The Characteristics and Evaluation of Gas Reservoir of Permian Lower Shihezi Formation in Hangjingqi Region

二叠系下石盒子组是鄂尔多斯盆地北部杭锦旗地区重要的天然气储集层之一,对其储集性能进行综合评价。依据其沉积特征可划分为3个岩性段,自下而上分别为盒1段、盒2段、盒3段;并对其岩石类型、物性特征、孔隙类型及结构、成岩作用等进行分析研究。下石盒子组储集层属低孔、低渗的致密储集岩。经综合评价后,储集岩类型以Ⅱ类(较好)、Ⅲ类(差)为主,不具Ⅰ类(好);3个岩性段中以盒1段储集层性能相对好而居首位。

The Permian Lower Shihezi Formation is one of important reservoir in Huangjingqi region of northern E'erduosi basin.A synthetical evaluation is made on its reservoir properties.According to its sedimental characteristics this gas reservoir can divided into three lithology sections,being He1,He2 and He3 sections from bottom to top;analyzing and studying are conducted on its petrographic types,physical properties,pore types and structures and diagenesis.The reservoir of Lower Shihezi formation comes under compact reservoir rock with low porosity and low permeability.The reservoir of Lower Shihezi Formation is classified as types Ⅰ,Ⅱ and Ⅲ,in which type Ⅱ(better) and Ⅲ(bad) are principal,no type I(good).Among the three lithology sections the He1 section ranks first due to relatively good reservoir properties.