塔河油田中深部缝洞体油藏控制因素分析

Analysis of controlling factors over the medium- deep fracture- cavern type oil reservoir in the Tahe oilfield

为进一步加大中深部缝洞体油藏储量动用程度,改善中深部缝洞体油藏开发效果,以奥陶系油藏古岩溶模式为基础,研究了不同岩溶发育区中深部缝洞体的控制因素.通过提取中下奥陶统顶面以下0～100 ms振幅变化率,识别岩溶管道,发现中深部缝洞体主要受控于管道内部下切深度及空间组合形式.提取尖灭线附近复合控制区O1-2y2—O1-2y1-2、O1-2y1-2—O1-2y1这2个时窗下的振幅变化率,明确了空间上存在上、下2套相互独立缝洞体,该中深部缝洞体主要受控于附近地表沟谷下切深度.同时,中深部缝洞体发育程度与地震反射体能量强度直接相关,表现为反射体能量越强,缝洞体越发育.

To further expand the reserve producing from the medium- deep fracture- cavern bodies and improve their development effects,the controlling factors over the medium- deep fracture- cavern bodies in various karstified areas are studied on the basis of the palaeokarst mode in the Ordovician oil reservoir. From extraction of the variation rate of 0 – 100 ms amplitudes below the mid- lower Ordovician top and identification of karst conduit,it is found that the medium- deep fracture- cavern bodies are mainly controlled by the dissection depth and spatial assemblage style within the conduit. By extraction of the amplitude variation rate at two time windows of O1- 2y2—O1- 2y1- 2and O1- 2y1- 2—O1- 2y1in the compound control area nearby the pinchout line,it is identified that there are two independent fracture- cavern bodies spatially,upper and lower,and the medium- deep fracture- cavern bodies are mainly controlled by the dissection depth of the adjacent surface trough and valley. Meanwhile,the developing of the medium-deep fracture – cavern bodies are directly correlated with the energy intensity of seismic reflector,as shown by the fact that thestronger is the reflector energy,the better is the fracture- cavern body developed.