黔北凤冈二区块下志留统石牛栏组储层特征研究

Study on Reservoir Characteristics of the Lower Silurian Shiniulan Formation in in Fenggang Block Ⅱ in the Northern Guizhou Province

黔北凤冈二区块石牛栏组广泛发育台地边缘浅滩相沉积,生物礁灰岩、生物碎屑灰岩为储层发育的有利层段。文章通过扫描电镜、薄片观察、孔渗和压汞实验,发现研究区内储层虽然有孔隙不发育,孔隙度和渗透率较低,孔隙的分选性较差,孔喉较粗等特点,但其构造裂缝较为发育,裂缝孔隙度较高,使其具备有形成裂缝型油气藏的条件;对储层的影响因素和勘探前景进行的分析表明:在黔北地区的石牛栏组裂缝较为发育,构造保存条件和烃源岩层发育较好的地段具备形成天然气藏的条件,且以凤冈残留向斜为石牛栏组储层勘探的有利部位。

The Shiniulan Formation in the Fenggang Block Ⅱin the north Guizhou province are extensively developed shoal facies sediments at the edge of the platform. The hiothermal limestone and hioclas tic limestone are favorahle for the development of reservoir. Scanning electron microscopy analysis, thin film observation, porosity and mercury injection experiments show that although pores in the study area are not developed and the porosity and permeability low, the pore separation poor, and the pore throat coarse, the structural fractures are relatively developed and the fractural porosity is relatively high. Therefore, condition of fracture type oil and gas reservoir exists in the Shiniulan formation. In addition there is better condition for structure preservation and hydrocarbon source bed developed here. The Fenggang residual syncline is the favorahle structure to locate reservoir.