摘要
中国陆相沉积气藏储层普遍存在非均质性,常规地层压力计算方法具有很大局限性,难以准确评价井间地层压力.本文以均质地层中的点源解为基础,采用边界元思想,建立了一种可用于非均质气藏井间地层压力计算的半解析方法.基本思想是将非均质储层进行分块处理,分别建立单个均质区域的压力方程,通过各区交界面处的压力和流量连续条件,将各区压力方程耦合求解,并将求解结果回代至单个区域的压力方程,从而计算地层中任意一点的压力.建立了理论模型,对所提出的井间地层压力计算方法进行了数值验证,并将其应用于长庆靖边气田某区块.结果表明,本文所建立的非均质气藏井间地层压力半解析计算方法与数值模拟计算结果相吻合,仅在早期和井筒附近存在微小差异;半解析方法能很好地预测实际气藏中单井及井间的地层压力变化,与实测数据趋势一致.
Abstract
Heterogeneity is a widespread characteristic in terrestrial sedimentary gas reservoirs in China.Traditional methods for calculating formation pressure face significant limitations,particularly in accurately assessing inter-well formation pressure in heterogeneous reservoirs.This paper proposes a semi-analytical method for calculating inter-well formation pressure in heterogeneous gas reservoirs,built upon the point source solution in a homogeneous formation and inspired by the concept of boundary elements.The fundamental procedure involves partitioning the heterogeneous reservoir into homogeneous blocks based on geological features,establishing and solving the pressure equation for each block considering continuous conditions of pressure and flux at the interfaces,and finally obtaining the pressure at any point in the formation by substituting the solutions back into the pressure equation of each block.The proposed semi-analytical method for calculating inter-well formation pressure is verified with numerical solution by using an ideal model and applied to the Jingbian gas field in Changqing.Results demonstrate that the semi-analytical method closely aligns with the numerical simulation results,exhibiting only slight differences in the early stage and near the wellbore.Importantly,it accurately predicts the variation of formation pressure for single wells and inter-wells in actual gas reservoirs,consistent with the observed trend in measured data.
基金项目
中国石油天然气股份有限公司前瞻性、基础性重大科技专项(2021DJ1504)
维普
万方数据