随着塔里木盆地深层勘探领域的不断突破,顺托果勒地区超深层碳酸盐岩层系发现了一系列与走滑断裂有关的异常高压油气藏,但其超压成因和分布规律却少有讨论.相较于伸展盆地与挤压型前陆盆地体系,克拉通内走滑断裂与地层压力关系的研究相对较少,同时碳酸盐岩储层强烈的非均质性也进一步加剧了超压分布的复杂性.本次研究根据钻井测试与生产动态资料,分析了顺托果勒地区压力分布特征与超压储层特征;结合流体包裹体恢复的古压力、天然气地球化学特征与断裂活动期次讨论了顺托果勒地区不同二级构造单元间异常压力的成因机制差异.结果表明,顺北缓坡和顺托低凸起地层超压为天然气充注与构造增压作用产生,而顺南缓坡地层超压主要受原油裂解生气影响.天然气的生成与断裂活动特征决定了顺南地区整体超压、顺北与顺托地区局部超压的分布格局,走滑断控储层的发育模式使得顺托果勒地区中下奥陶统储层压力系统呈现分割状发育特征.
With the continual advancement in deep exploration in the Tarim Basin,a succession of anomalous high-pressure reservoirs associated with strike-slip faults have been discovered in the ultra-deep carbonate strata of the Shuntuoguole region,but the origin of the overpressure and its distribution pattern have rarely been discussed.Also,the relationship between strike-slip fault and formation pressure in cratons has seldom been studied compared to results for extensional basins and compressive foreland basin systems;whilst strong carbonate reservoir heterogeneity further complicates the overpressure pattern.In this study the characteristics of the present-day pressure field and the main features of overpressure reservoirs are analyzed based on data from drilling tests and production dynamics studies.Further,combined with paleopressure calculation(using fluid inclusions),gas geochemical characteristics and faults activity,the origin of overpressure and its differential distribution in secondary tectonic units of the Shuntuogole area are discussed.The results suggest that the overpressure in the Shunbei slope and Shuntuoguole low uplift is caused by gas charging and tectonic compression,with the former mainly affected by pyrolytic gas generation from crude oil cracking.The gas generation and faults activity determine the differential overpressure distribution,where overpressure occurs widely across the Shunnan area but only locally in the Shunbei and Shuntuoguole areas.The development pattern of the fault-associated reservoirs results in the division of the pressure system in the Shuntuoguole area.