松辽盆地龙西地区泉四段低孔低渗砂岩性及微观孔隙结构特征研究

通过岩心观察、镜下薄片、扫描电镜和X衍射、物性和压汞等资料分析，对松辽盆地龙西地区泉四段低孔低渗砂岩的岩石学特征、储层物性及微观孔隙结构特征进行了研究。研究表明，松辽盆地龙西地区泉四段砂岩主要为长石岩屑砂岩，其次为岩屑长石砂岩，成分和结构成熟度较低，储层物性明显呈现出低孔低渗特征，孔隙类型以残余粒间孔和溶蚀孔为主，孔喉半径较小，相对小孔喉所占比率较大，孔喉分选和连通性较差，非均质性强。在总体孔喉较小的背景下，随着较大孔喉半径的增大储层物性变好，而储层物性随着孔喉集中程度的增强而变差。根据经典的孔喉分类标准，将松辽盆地龙西地区泉四段低孔低渗透储层分为4类：细孔细喉型、微孔细喉型、微孔微细喉型和微孔微喉道型。

Characteristics of poroperm and microscopic pore structure of te low porosity and low permeability reservoir of Quan 4 formation sandstone in Longxi area, Songliao Basin

Lithological，poroperm and microscopic pore structure characteristics of low porosity and low permeability sandstone of Quan 4 formation in Longxi area，Songliao Basin were analyzed on the basis of core observation，identification and quantitative statistics of thin sections under microscope，analyses of electron scan microscope，X ray diffraction，poroperm and high pressure Hg injection etc.The results indicate that the main lithology of Quan 4 formation is feldspathic litharenite and lithic arkose sandstone，with low maturity of composition and texture，and low porosity permeability，most of the porous are residual intergranular pore and dissolved pore with a small pore throat radius，the small pore accounts for a large proportion，the pore throat has a poor sorting and strong heterogeneity.On the background of overall low porous，the reservoir poroperm becomes better with the augmenting of the bigger pore radius and becomes worse with the reinforcement of pore intensity.Based on the classic classification criterion of pore throat，the low porosity permeability reservoir of Quan 4 formation in Longxi area，Songliao Basin can be divided into fine pore and fine throat，micropore and fine throat，micropore and micro fine throat，micropore and microthroat.