羌塘盆地隆鄂尼-昂达尔错地区中侏罗统布曲组碳酸盐岩储层特征研究

Study on Reservoir Characteristics of the Carbonate Rocks in the Middle Jurassic Buqu Formation in Longeni-Angdaercuo Area,Qiangtang Basin

在隆鄂尼-昂达尔错地区新近发现了3个古油藏带,这使得古油藏带在原来的基础上向东延伸了30～40 km。综合地表和井下布曲组碳酸盐岩储层数据研究表明,古油藏带具有“东西分区,南北分带”的特点;储层岩石类型主要为灰黑色砂糖状白云岩,浅灰色、灰黑色泥晶灰岩、微晶灰岩、藻灰岩、生物碎屑灰岩、介壳（藻）灰岩;储集空间主要有晶间孔、晶间溶孔、溶蚀孔洞、构造裂缝、压溶缝和溶蚀缝;孔隙结构类型以中孔中喉或细孔中喉型为主;储层总体达到Ⅱ类储层标准;隆鄂尼区块储层潜力最大,其次是昂达尔错区块,最后是赛仁区块;新发现的赛仁区块具有三个区块中最好的物性,有进一步工作的潜力;白云岩储层物性优于灰岩,是羌塘盆地最有价值和潜力的目标储层。

The newly discovered three palaeo-oil-reservoirs, which are located in Longeni-Angdaercuo area, makes the boundary of palaeo-oil-reservoirs stretch to the east about 30 -40 km. Based on analysis of the Middle Jurassic Buqu Formation outcrops and drilling cores in Longeni-Angdaercuo area, it is shown that the palaeo-oil-res- ervoirs has the characteristics of ＂difference in east and west, zonal distribution in south and north＂. Carbonate rocks of Buqu Formation consist dominantly of saccharoidal dolomite, micritic hmestone, microcrystalline lime- stone, algal limestone, bioclastic limestone and shell limestone. Reservoir space consist dominantly of dolomite in- tercrystalline pore and suture, solution cavity, corroded hollow and crack porosity. The pore is structured mainly by middle pore middle throat or thin pore middle throat. Carbonate rocks overall belong to the lI types of reservoir, ac- cording to the evaluating criteria. The potential of carbonate rocks from good to bad in the order are Longeni Block, Angdaercuo Block, Sairen Block. The newly discovered Sairen Block which has the best physical property has the potential of further work. Dolomite reservoir physical properties are better than that of limestone, so the dolomite reservoir will be the most valuable and the potential of the reservoir in Qiangtang basin.