塔里木盆地轮南低凸起断裂系统与复式油气聚集

FAULT SYSTEMS AND MULTIPLE OIL-GAS ACCUMULATION PLAY OF THE LUNNAN LOWER UPLIFT,TARIM BASIN

塔里木盆地轮南低凸起复式油气聚集区的提出对高效指导轮南地区的油气勘探起了促进作用。基于区域石油地质研究成果,充分利用成像测井、高分辨三维地震断裂精细描述和有机地球化学等新技术新方法,本文系统研究了轮南低凸起复式油气聚集成藏的关键地质条件,全面刻画了轮南断裂系统的复杂特征,明确了轮南多含油层系具有相同的寒武系海相烃源,证实了在多期次成藏过程中,断裂系统既是早期成藏的油气充注通道,又是晚期调整气侵的输导体系。对轮南海相碳酸盐岩大型油气田的成藏,断裂系统既是有效的储集空间,又是储集性能改善和连通性增强的重要条件,提出复杂断裂系统多期活动下油气渐进幕式成藏和跨越动态成藏模式。从前提(古隆起)、基础(多套储盖组合)和关键(断裂系统)3方面探讨了复式油气聚集成藏的机理,并指出轮古东走滑断裂带是近期扩大轮南复式油气聚集区规模、实施天然气勘探的现实领域。

The concept of ＂multiple oil-gas accumulation play＂ for the Lunnan Lower Uplift, Tarim Basin, promoted the oil-gas exploration and development in the area. The paper aimed to develop the theory of multiple oil-gas accumulation play, and to promote the oil and gas exploration and increase the production and reservoir by analyzing an example of the Ordovician in the eastern slope of the Lunnan Lower Uplift. Based on the recent achievements of regional petroleum geology, and to integrate the recent fruits of new technique and method such as imaging logging, high resolutional 3D seismic description on fault systems, and organic geochemistry, the paper systematically studied the key geological factors for the multiple oil-gas accumulation play in area of the Lunnan Lower Uplift, comprehensively described complicated features of the fault systems in the Lunnan Lower Uplift. It was represented that the reservoirs of Ordovician, Carboniferous, Triassic, and Jurassic might be from the same hydrocarbon supply of the Cambrian marine origin, and it was confirmed that during the formational process of the multiple accumulation play, the fault systems might be either the migration pathways in early petroleum accumulation, or the migration pathway of gas-filling adjustment in later stages. Especially for the Lunnan Lower Uplift, the fault systems were effective reservoir space, as well as the important factor to improve the reservoir behaviors and to enhance the connectivities. Two models for the oil-gas accumulation under the control of multiple-activity of complicated fault systems in the Lunnan Lower Uplift were put forward, namely, the gradual-episodic model and the leaping and dynamic model. Three main aspects as the mechanics for the multiple oil-gas accumulation play were explored, namely, the paleo-uplift being a prerequisite, the multiple reservoir-cap rock associations being a foundation, and the fault systems being a key. Furthermore, the paper pointed out the strike-slip fault zone in the eastern slope of Lunnan Lower Uplift should be a realistic field for expanding the scale of Lunnan multiple oil-gas accumulation play and nature gas exploration.