考虑水侵量时变的边底水油藏平均地层压力预测新方法

A New Method to Predict Average Reservoir Pressure for Oil Reservoir Subject to Edge or Bottom Water Drive Considering Time-Varying Water Influx

地层压力预测的准确性对于新井钻井安全评估及老井开发方案调整具有重要意义。传统平均地层压力预测方法未考虑水侵量随时间的变化,地层压力预测结果与实际偏差较大。针对这一问题,基于物质平衡方法建立了考虑水侵量时变的边底水油藏平均地层压力预测新方法。根据实际生产数据,计算对应的水侵量和油藏亏空体积,拟合得到水侵量及油藏亏空体积随时间的变化规律,最终预测任意时间的平均地层压力。以ZD油田C区块为例开展了实例应用,计算结果表明新方法预测误差小于4.60%,计算精度较高。该方法能够预测边底水油藏生产制度较稳定时的平均地层压力,从而为油田制定下步开发方案提供较为可靠的地层压力预测值。

The accuracy of reservoir pressure prediction is of great significance for safety evaluation of new well drilling and adjustment of water injection scheme of old well for offshore oil reservoir.The traditional prediction method of average reservoir pressure does not consider the variation of water influx over time,so the prediction result is quite different from the actual one.In order to solve this problem,based on the material balance method,a new method for predicting the average reservoir pressure of edge-bottom water reservoirs considering the time-varying water influx is established in this paper.Firstly,the water influx and reservoir deficit volume are calculated based on the production data.And then,the relationship between water influx and time,the relationship between reservoir deficit volume and time are calculated.Thus the average reservoir pressure at any time can be predicted.Taking Block C of ZD Oilfield as an example,the calculation errors of the average reservoir pressures are less than 4.60%,which shows that the calculation results are accurate.The method can predict the average reservoir pressure of water invasion high-permeability reservoir when producing stably,which can provide reliable pressure value for the development plan.