时深效应指数在超压储层孔隙度预测中的应用

摘要

孔隙度是油气藏描述的一个重要参数,储层孔隙度主要受沉积相和成岩作用影响和控制.笔者研究了利用时深效应指数TDI( time-depth index)预测超压储层孔隙度的方法,超压储层孔隙度预测的重点在于埋藏史恢复,即剥蚀恢复、去压实恢复和孔隙度预测模型的建立.在计算时深效应指数的过程中,根据三维速度场以及压力系数的分布预测超压场,将超压值引入到有效埋深的计算公式,实现了超压环境对孔隙度影响的校正,建立了适合于超压地层的孔隙度预测模型,为深层油气勘探提供了科学的依据.%Porosity is an important parameter in reservoir description. Reservoir porosity is mainly influenced and controlled by sedimentary facies and diagenesis. In this paper the method of porosity prediction in the overpressure environment by utilizing TDI (time-depth index) has been studied. The key to this method lies in establishing the correlation model and recovering burial history curve including recovering denudation and decompaction correction,[n the process of calculating TDI,the overpressure value is predicted according to the 3D velocity field and pressure coefficient,and is introduced into the formula of effective burial depth calculation to correct the affect caused by the overpressure environment. Porosity prediction model suitable for overpressure formation has been established. It can provide scientific basis for oil and gas exploration of deep zones.