Abstract: The frontal uplift of Kuqa foreland basin is located at the southern end of the basin, which is rich in oil and gas resources. It is an important field for oil-gas exploration in Kuqa foreland basin. At present, oil and gas discoveries have been made in exploration of both marine cratonic tectonic strata and continental foreland tectonic strata in the lower and upper parts of the frontal uplift, respectively. The complex geological background leads to significant differences in oil and gas accumulation characteristics between the two sets of tectonic strata, thus restricting the further oil-gas exploration. Based on the data of drilling, rock thin section and source rock tests, reservoir property analysis, and hydrocarbon assay, this paper systematically investigates the oil and gas source, hydrocarbon accumulation period, oil and gas migration direction, and transport system characteristics of the western section of the frontal uplift of Kuqa foreland basin, and clarifies the hydrocarbon accumulation conditions of the western section of the frontal uplift. Further, in combination with the analyses of typical reservoirs, the types and distribution characteristics of reservoirs in the study area are determined. The findings show that:(1) The oil and gas in the western section of the frontal uplift of Kuqa foreland basin are mainly originated from the Triassic-Jurassic lacustrine source rocks and coal-measure source rocks in the northern part of the basin; (2) Mesozoic-Cenozoic sand body and tectonics co-controlled reservoirs and marine paleoweathering crust dominated buried hill reservoirs are developed in the study area; according to the differences of depositional setting and lithology, the latter can be further divided into marine carbonate paleoweathering crust type buried hill reservoirs and marine clastic paleoweathering crust type buried hill reservoirs; (3) Based on various hydrocarbon accumulation factors, the favorable exploration area of marine palaeoweathering crust buried hill reservoirs (Type I), that of the Paleogene basal sandstone sand body and tectonics co-controlled reservoirs (Type II), and that of the Cretaceous Baxigai Formation sandbody-structure co-controlled reservoirs (Type III) are optimized in the study area, aiming to provide theoretical guidance for further oil-gas exploration.

Key words: Kuqa foreland basin, frontal uplift, oil and gas migration, transport system, oil and gas accumulation types

摘要： 库车前陆盆地前缘隆起位于库车前陆盆地的南端，油气资源丰富，是库车前陆盆地重要的油气勘探领域。目前在前缘隆起下部的海相克拉通构造层系和上部的陆相前陆构造层系中均获得油气勘探发现，复杂的地质背景使两套构造层系的油气成藏特征差异明显，制约了进一步油气勘探。综合钻井、岩石薄片和烃源岩测试、储集物性分析及油气化验资料，系统研究了库车前陆盆地前缘隆起西段的油气来源、油气成藏期、油气运移方向及输导体系特征，阐明了前缘隆起西段的油气成藏条件，并结合典型油气藏剖析，明确了研究区油气藏类型及分布特征。研究结果表明：①库车前陆盆地前缘隆起西段的油气主要来源于盆地北部三叠系—侏罗系湖相烃源岩和煤系烃源岩；②研究区发育中生界—新生界砂体—构造共控型油气藏和海相古风化壳主控型潜山油气藏，根据沉积背景与岩性差异，可将后者进一步划分为海相碳酸盐岩古风化壳型潜山油气藏和海相碎屑岩古风化壳型潜山油气藏；③综合各成藏要素，在研究区优选出海相古风化壳潜山有利勘探区（Ⅰ类有利区）、古近系底部砂岩砂体—构造共控型勘探有利区（Ⅱ类有利区）和白垩系巴西改组砂体—构造共控型勘探有利区（Ⅲ类有利区），以期为下一步油气勘探提供理论指导。

关键词: 库车前陆盆地, 前缘隆起, 油气运移, 输导体系, 油气成藏类型