浅谈小断层对溱潼凹陷油气成藏的影响

Discussion on the influence of small faults on reservior in Qintong Sag

苏北盆地溱潼凹陷帅垛地区近油源,阜三段处于的有利三角洲前缘相带,砂体发育,总体受构造控藏,局部沉积微相略有变化,但垂向上单砂体厚度略薄,单层砂体5~15 m,20 m以下的断层就足以断开砂体。在该地区油藏勘探开发的过程中,发现小断层对该地区油气成藏起着疏导运移、封堵等重要作用。随着苏北地区勘探的日益成熟,该发现对小断块类型油藏的勘探及开发滚动扩边起到重要作用。将这个认识推广应用,优选成藏背景良好的广山-殷东地区,首先对研究区的沉积微相及地震反射特征进行分析,降低相变对小断层识别的影响,其次在剖面上采用瞬时相位与提高分辨率的方法,强化波组断点,平面上采用时间切片、相干切片、相位切片、倾角去噪增强等手段,再通过对周边大断层展布的分析,平剖结合精细刻画小断层的发育及组合并对断层发育期次作分析,判断断层对油气的疏导运移、封堵能力寻找类似帅垛地区小断层控制的油藏。

Shuaiduo area in Qintong Sag is near hydrocarbon source,and Ef3 is located in favorable delta front facies.Sandstone is developed,which are generally controlled by structure and have slight changes in sedimentary microfacies.However,the vertical single sandstone is slightly thin at 5~15 meters and a fault below 20 meters is enough to break the sandstone.In the process of oil reservoir exploration and development in this area,it is found that the small faults play an important role in hydrocarbon accumulation in this area,such as dredging migration and sealing.With the increasing maturity of exploration in Subei,this discovery plays an important role in the exploration and rolling expansion of small faultblock reservoirs.We popularize this understanding and apply it to the Guangshan-Yindong area,which has a good accumulation background.Firsyly,the sedimentary microfacies and seismic reflection characteristics of the study area are analyzed to reduce the ingluence of phase transformation on the recognition of small faults.To strengthen the breakpoints of wave group by using instantaneous phase and improving resolution in the profile,and to use time slicing,coherent slicing,phase slicing,dip angle denoising and other means in the plane,and then through the analysis of the distribution of the surrounding large faults.In order to find the oil reservoir controlled by small faults in Shuaiduo area,the development and combination of small faults are described in detail and the fault development stages are analyzed.