川中高磨地区灯影组微孔结构及可动流体饱和度特征

四川盆地中部高石梯—磨溪地区灯影组储集层微观孔隙结构复杂，可动流体赋存特征研究薄弱，是制约该区气藏进一步提高采收率的关键因素。利用铸体薄片、扫描电镜、高压压汞、核磁共振等分析手段，对研究区灯影组灯四段储集层微观孔隙类型及结构特征开展研究，并分析可动流体饱和度与微观孔隙结构之间的关系。结果表明：研究区储集空间主要发育粒间溶孔、残余粒间孔、晶间孔、溶蚀孔洞等4类孔隙，平均总面孔率为2.5%；不同孔隙组合类型对应不同微观孔隙结构，其中粒间溶孔—残余粒间孔储集层孔隙结构最好，排驱压力与中值压力较低，分别为4.1 MPa和18.7 MPa，平均孔喉半径为0.059 μm，可动流体饱和度较高，为41.5%；渗透率大小及粒间溶孔发育程度是影响可动流体饱和度的重要因素，可动流体饱和度与孔喉半径和孔喉连通性均呈正相关关系。

Analysis of Micropore Structure and Movable Fluid Saturation Characteristics of Dengying Formation in GaoshitiMoxi Area of Central Sichuan Basin

The micropore structure of the reservoir of Dengying formation in Gaoshiti—Moxi area of central Sichuan basin is complicated. Weak study on movable fluid is the key factor constraining further EOR in the area. Using analysis means such as cast thin section, SEM, high pressure mercury injection and NMR etc., the paper studies the type and structure of the micropores in the 4th member of Dengying formation in the study area, and analyzes the relationship between movable fluid saturation and micropore structure. The results show that the accumulation spaces in the study area are dominated by intergranular dissolved pore, residual intergranular pore, intercrystalline pore and dissolved cave with the average total surface porosity of 2.5%; various pore combinations have different micropore structures, among which the pore structures of the reservoir dominated by intergranular dissolved pore–residual intergranular pore are the best, and the displacement pressure and median pressure are 4.1 MPa and 18.7 MPa, respectively, which are relatively low. The average pore throat radius is 0.059 μm and the movable fluid saturation is relatively high, which is 41.5%. The permeability and the development degree of intergranular dissolved pore are the key factors influencing movable fluid saturation which shows a positive correlation with radius and connectivity of pore throat