塔中地区奥陶系走滑断裂体系解剖及其控储控藏特征分析

与常规构造和岩性油气藏相比,塔里木盆地碳酸盐岩缝洞型油气藏非常复杂和特殊,具有一洞一藏的特征。目前在断溶体研究思路指导下的储层钻遇率和投产成功率进一步提高,其中基于地震资料的断裂体系精细解剖发挥着至关重要的作用。但是,在塔中地区低地震资料信噪比情况下,基于常规地震解释方法和断裂模式认识,无法有效提升断裂解释精度和深化油气藏的认识。通过分析走滑断裂体系不同发育阶段的特征,建立了适合塔中地区走滑断裂解剖的两类三种模式,即右行走滑断裂模式和左行走滑断裂模式两类,局部主要发育“菱形”破碎模式、羽状破碎模式和马尾破碎模式三种,再结合对地震资料的叠前-叠后“串联式”解释性处理和对计算地震属性时多参数的“并联式”优化,提升基于地震数据的断裂的可解释性,指导了塔中地区断裂体系的细化,并分析不同模式的差异及优劣,有效地指导并深化研究区断裂控储、控藏的认识,按地震剖面特征及断裂分型、分段研究成果将断溶型油气藏划分为“灌木形态、直立形态、选择扩溶型”三种类型,支持了研究区油气藏效益开发。应用表明,该研究结果在塔中地区油气藏开发实践中取得了非常好的效果,有力支持了油田产能建设。

 Fractured-vuggy carbonate reservoirs in the Tarim Basin are complicated and unique because,there,one cavity forms one reservoir.At present,based on the concept of a fault-karst reservoir,the rate at which drilling has encountered reservoirs and production success rates have improved.The fine interpretation of fracture systems based on seismic data plays a crucial role in this improvement.However,based on the conventional seismic interpretation method and fault modes,it has been difficult to improve the accuracy of fault interpretation for seismic data with low SNR in the Tazhong area.First,by analyzing the features of the strike-slip fault system in different development stages,strike-slip faults can be classified into two types with three modes.The two types are right lateral strike-slip and left lateral strike-slip.The three modes are rhombus breaking,pinnate crushing,and horsetail breaking.Combining the “series” interpretative processing from prestack to poststack seismic data with the “parallel” optimization of multiple parameters for seismic attribute calculations,fault interpretations were improved in this study.The improved data were used to refine the fault system and analyze the differences in fault patterns to effectively and comprehensively understand fault-controlled reservoirs and hydrocarbon accumulation.Finally,based on the seismic section characteristics and fault classification and segmentation results,reservoirs could be divided into three types of fault-karst,namely shrub shape,vertical form,and selective expansion.The practical application showed that this method could significantly improve the success rate of well drilling in the Tazhong area and support the development of oil and gas reservoirs.

国家科技重大专项(2016ZX05053-17)资助。