中亚北乌斯丘尔特盆地成藏组合划分与资源潜力评价
Division of Hydrocarbon Plays and Resources Evaluation in the North Ustyurt Basin, Central Asia

摘要： 根据北乌斯丘尔特盆地主要地质特征和油气聚集规律，并以储集层为核心，在始新统、下白垩统、中侏罗统、下侏罗统和石炭系等储集层内划分出7个成藏组合。然后采用蒙特卡洛模拟法对不同成藏组合中的石油和天然气的待发现可采资源量分别进行模拟计算。结果表明，北乌斯丘尔特盆地待发现可采资源量可达2102 MMboe，其中石油为1201 MMbbl，天然气为5406 Bcf。同时参考对储层、圈闭、运移和保存等成藏要素的地质风险评价结果，应用资源－地质风险概率双因素法进行有利区带的优选。共划分出1个Ⅰ类成藏组合，1个Ⅱb类成藏组合，2个Ⅲ类成藏组合，2个Ⅳa类和1个Ⅳc类成藏组合。综合分析认为盆地西部北布扎奇隆起是最有利的勘探区，中生界的勘探目标主要是发育于隆起北坡及顶部的拉长型断背斜构造，古生界巴什基尔阶和阿赛尔阶碳酸盐岩和礁体储层的勘探潜力也不容忽视。而在盆地东部的局部地区，可能会在始新统和中侏罗统砂岩储层以及石炭系维宪阶碳酸盐岩储层中发现一定量的油气资源。
Abstract: Based on the integrated analysis of the basic geological features and oil and gas fields distribution, and cored by reservoirs, seven hydrocarbon plays are divided in the Eocene, Lower Cretaceous, Middle and Lower Jurassic, and Carboniferous reservoirs in the North Ustyurt basin. The undiscovered recoverable petroleum resources of the plays have also been reevaluated by the Monte Carlo method. The result reveals that the total amount of the undiscovered resources is about 2 102 MMboe, of which oil is 1 201 MMbbl and gas is 5 406 Bcf. Geological risks evaluation of key elements including reservoirs, traps, migration and preservation have also been completed. Then, the seven hydrocarbon plays are ranked by the double factors method of resources-risks. According to the classification criterion, there are one Ⅰ-class play, one Ⅱb-class play, two Ⅲ-class plays, two Ⅳa-class plays and one Ⅳc-class play in the North Ustyurt basin. The most favorable exploration objectives in the Mesozoic should be faulted anticlinal traps in the northern slope and on the top of the North Buzachi uplift, where the Paleozoic Bashkirian and Asselian carbonate reservoirs may also have potentials. In addition, it is hopeful to find oil and gas reserves in the local Eocene and Middle Jurassic sandstone and the Carboni-ferous Visean carbonate reservoirs in the eastern basin