江汉盆地新沟泥质白云岩储集层特征分析——以新沟地区新下段Ⅱ油组为例

Feature Analysis of Xingou Argillaceous Dolomite Reservoir in Jianghan Basin

江汉盆地新沟嘴组下段Ⅱ油组为泥质白云岩油藏,岩石矿物成分复杂多样,主要为白云石、粘土和长英质,储层以泥质白云岩、泥质粉砂岩为主,属于中-低孔超低渗储层,特小孔喉储集岩,储集空间以白云石晶间孔、粉砂岩粒间孔为主。声波时差>240μs/m、密度<2.5g/cm3,中值孔喉半径>0.04μm,渗透率>0.2×10-3μm2,孔隙度>14%,定义为储层。江汉盆地勘探开发实践证明,陆相湖盆泥质白云岩具有良好的勘探开发前景,也预示着陆相泥质白云岩必将成为今后我国陆相湖盆油气田勘探开发增储上产的新领域。

Oil Set 2 of the lower segment of Xingouzui Formation in Jianghan Basin is an argillaceous dolomite oil res- ervoir with characteristics of wide distribution and complex and varied rock mineral ingredients dominated by dolo- mite, clay and arkosite. Reservoirs are predominantly composed of argillaceous dolomite and argillaceous siltstone and belong to moderate--low porosity reservoirs with ultra--low permeability. Reservoir spaces take on types of dolomite intercrystalline pores and siltstone intergranular pore. Reservoir is defined by acoustic travel time bigger than 240μs/m, density less than2. 5g/cm3,mean pore throat radius bigger than 0. 04μm,permeability bigger than 0. 2×10--3/an2 and porosity bigger than 14%. Practice of exploration and development in Jianghan Basin indicates that continental argillaceous dolomites would be future exploration and development target for increasing reserves and production in oil and gas fields of continental lake basin in China.