大庆长垣西部基底断裂复活对油气运移控制作用分析
Analysis of the Control Effect of the Reactivation of Basement Faults in the Western Part of Daqing Changyuan on Oil and Gas Migration

大庆长垣西部高台子油层组蕴含丰富的油气资源潜力，齐家地区A区块是典型实例。勘探、评价实践表明：该区含油砂体均集中在高四油层组下部，高三油层组发育较少，成藏机理尚不清晰。因此，本文基于三维地震、测井、试油等资料，在构造地质学理论基础上，应用构造解析方法，分析研究区断裂系统形态特征及成因机制，对高台子油层油气成藏认识具有重要意义。研究表明：1) 基底先存深大断裂晚期发生走滑位移、且纵向存在多套非能干性软弱岩层，导致上覆地层中形成“基底诱导、纵向断续、平面雁列”的断裂体系特征；2) 基底断裂走滑复活，应力向上传导，导致上覆地层变形自下而上由强变弱，应力场强度决定纵向上变形的影响范围；3) 基底断裂走滑复活，走滑变形诱导上覆地层雁列式断裂带发育，形成“横向密集、纵向短距”的油气疏导体系，即为油气纵向运移提供了良好的疏导通道，又避免断穿层位过多导致油气资源溃散，更有利于油气藏形成。
The Gaotaizi oil layer formation in the western part of Daqing placanticline contains rich potential for oil and gas resources, and the region A is a typical example. Exploration and evaluation practices have shown that the oil-bearing sand in this area are concentrated in the lower part of the GIV oil layer group, while the GIII oil layer group is less developed, and the reservoir formation mechanism is still unclear. Therefore, based on three-dimensional seismic, lost of logging and oil testing data, this article applies structural analysis methods on the basis of structural geology theory to analyze the morphological characteristics and genetic mechanisms of fault systems in this area, which is of great significance for understanding the oil and gas accumulation in the Gaotaizi oil layer. Research has shown that: 1) When the deep and large faults formed in the early stage of the basement experience strike slip displacement in the later stage, and there are multiple sets of weak rock layers in the longitudinal direction, it can lead to the formation of a fault system characteristic of “basement induction, longitudinal discontinuity, and planar echelon” in the overlying strata; 2) The strike slip revival of the basement fault causes stress to propagate from bottom to top, resulting in the deformation of the overlying strata becoming weaker from bottom to top. The strength of the stress field determines the range of influence of longitudinal deformation; 3) The basement fault is reactivated through strike slip, and the strike slip deformation induces the development of an echelon-fault zone in the overlying strata, forming a “horizontally dense and vertically short distance” oil and gas diversion system. This provides a good diversion channel for the vertical migration of oil and gas, while avoiding the collapse of oil and gas resources caused by too many faults penetrating the strata, which is more conducive to the formation of oil and gas reservoirs.