鄂尔多斯盆地中生界石油地质条件、资源潜力及勘探方向

The geological conditions, resource potential, and exploration direction of oil in Ordos Basin

鄂尔多斯盆地中生界油气资源丰富,三叠系延长组和侏罗系延安组是主力含油层系。在鄂尔多斯盆地石油地质条件研究的基础上,提出沉积相、输导体系、异常压力和构造为中生界成藏的主要控制因素,建立了三叠系延长组大型岩性油藏模式和侏罗系古地貌控藏模式,并结合盆地勘探成果,精细评价了鄂尔多斯盆地石油地质资源量,预测了油气资源的空间分布。结果表明:鄂尔多斯盆地石油地质资源量约为146.50×10^8t,其中常规油资源量为116.50×10^8t,致密油资源量为30.00×10^8t;按层系分,三叠系石油资源量为137.20×10^8t,侏罗系石油资源量为9.30×10^8t。盆地剩余资源量为96.93×10^8t,姬塬、陇东和志靖-安塞等地区,是长庆油田的规模储量区,仍然是未来勘探的主要区域。延长组长6、长8油层组和侏罗系是下一步勘探的重点层系;延长组下部的长9、长10油层组为新的目标层系;长7油层组致密油具有较大的勘探潜力。

The Triassic Yanchang Formation and the Jurassic Yan’an Formation are the main oil-bearing strata in Ordos Basin. Based on the study of petroleum geological conditions in Ordos Basin, sedimentary facies, oil immigration pathway, abnormal pressure, and tectonics are proposed as controlling factors of Mesozoic oil reservoir. The patterns of the Triassic oil accumulation in large-scale deltas and the Jurassic oil accumulation controlled by paleo-geomorphology are setup. Combining with the oil exploration results of the basin, the quantity and the spatial distribution of oil resource are predicted with the "layer zone" as the basic unit of resource evaluation. The results show that the amount of oil resource is 146.50×10^8 t, including 116.50×10^8 t of conventional oil and 30.00×10^8 t of tight oil. With respect to strata, the amounts of oil resources of the Triassic and the Jurassic are 137.20×10^8 t(including 30.00×10^8 t of tight oil) and 9.30×10^8 t respectively. The amount of the remaining oil resource is 96.93×10^8 t, most of which are distributed in Jiyuan, Longdong,and Zhijing-Ansai areas. Chang 6 and Chang 8 of the Yanchang Formation and the Jurassic are key strata for oil exploration in the future;Chang 9 and Chang 10 in the lower part of the Yanchang Formation are new target strata;the tight oil of Chang 7 has great potential for next exploration.