吐哈盆地石油地质条件、资源潜力及勘探方向

Petroleum geological conditions, resource potential and exploration direction in Turpan-Hami Basin

通过对吐哈盆地生储盖组合配置、成藏模式等石油地质条件的综合研究,认为吐哈盆地主要发育侏罗系西山窑组、八道湾组煤系烃源岩,以及二叠系桃东沟群湖相烃源岩,这2套烃源岩生油强度较大的地区均位于台北凹陷主体沉降区,具备形成大油田的烃源基础。盆地主要发育侏罗系、三叠系和二叠系等3套储层,侏罗系储层主要为辫状河三角洲分流河道粗砂岩,二叠系梧桐沟组、三叠系克拉玛依组储层主要为扇三角洲、辫状河三角洲前缘水下分流河道的细砂岩、砂砾岩。侏罗系主要有正向分异、逆向分异、垂向分异及混合型等4种成藏模式;二叠系为侧向长距离运聚-古斜坡成藏模式;三叠系为源内垂向运聚-自生自储油气成藏模式。采用类比法、统计法、成因法及特尔菲加权法综合得到吐哈盆地常规石油地质资源量为10.09×10^8t,剩余资源量为6.07×10^8t。通过地质评价、原油剩余资源量和剩余资源丰度的分布预测,提出了鄯善弧形带、鲁克沁-红连带、西部弧形带3个勘探方向及有利目标区。

Based on the systematic study of petroleum geological condition, such as source-reservoir-cap assemblage and reservoir-forming pattern in Turpan-Hami Basin, it is considered that the source rocks are mainly coal-bearing source rocks of Jurassic Xishanyao Formation and Badaowan Formation, and lacustrine source rocks of Permian Taodonggou Group. These two sets of source rocks with high hydrocarbon-generating intensity are located in the main subsidence area of Taipei Sag,and have the source conditions for forming large-scale oil field. Of the three sets of reservoirs, Jurassic reservoirs are mainly coarse sandstone of braided river delta distributary channel, the reservoirs of Permian Wutonggou Formation and Triassic Karamay Formation are mainly sandstone and conglomerate of the subaqueous distributary channels in the fan delta and braided river delta front. According to main factors controlling hydrocarbon accumulation, four types of accumulation patterns are classified in Jurassic: forward differentiation, reverse differentiation, vertical differentiation and mixed pattern. The Permian hydrocarbons accumulate in pattern of lateral long-distance and trapping in paleoslope. The Triassic hydrocarbons accumulate in pattern of vertical migration and self-generation and self-storaging in source rocks. By using analogy, statistics, genesis and Delphi weighting method, it is calculated out that the amounts of conventional petroleum resources and the remaining resources are 10.09×10^8 t and 6.07×10^8 t, respectively. Through evaluating geological conditions, predicting remaining resource distribution, three exploration directions and favorable target areas of Shanshan arc play, Lukeqin-honglian play and western arc play are proposed.