川西新场气田上沙溪庙组储层特征

RESERVOIR CHARACTERISTICS OF THE UPPER MEMBER OF SHAXIMIAO FORMETION AT XINCHANG IN WEST SICH UAN

通过对四川盆地西部新场气田侏罗系沙溪庙气藏储层特征 :包括岩性、孔隙性、渗透性、孔渗相关性、孔隙形态、毛管曲线参数特征、喉道类型及大小分布及成岩作用类型等方面多角度的分析、研究 ,对储层进行了孔隙结构分类 ,建立了评价标准 ,为勘探评价井部署提供了依据。其结果表明 :储层孔隙以大孔和中孔为主 ,喉道以微喉为主 ,储层 4种基本孔隙类型对应Ⅳ类储集岩 ,从Ⅰ类储集岩到Ⅳ类储集岩 ,孔隙度由好变坏 ,毛细管压力由较粗歪度到细歪度 ,排驱压力和饱和度中值压力由小变大 ,孔喉半径依次变小 ,储渗性依次下降 ,直至变为非储集岩 ;储渗性主要受方解石含量。

The reservoirs in Shaximiao formation of Middle Jurassic at Xinchang in west Sichuan, with porosities being generally 9.17%, average permeability being 0.184×10 -3 μm 2, inhomogeneity tight reservoirs of low to ultralow permeability. On the basis of all-aroundly analyzing and studing the reservoirs characteristics including lithology, por osity, permeability, porosity permeability correlativity,pore morphology, capillary curve parameter properties, pore-throat types, sizes and distributions, diagenesis types, etc.,a pore structure clasification of the reservoir is proposed, and evaluation is built,a ffording evidence for arrangment of exploration evaluation well. Four basic types of pores are found and big pores and mid pores are main,small pores are minor. From type-Ⅰ to type-Ⅳ reservoir, the pore stru cture is changed from good to the bad , the skewness capillary pressure curve from bold to gentle , the small displcement pressure and saturation midvalue pressure are changed into large ones, the pore throat radii become small successively and the storage property and permeability are uninterruptedly reduced till the reservo ir rock is changed into the non-reservoir one. The storage property and permeability are mainly affected by calcite and feldspar contents and microfissures.