基于生长曲线的大庆长垣油田特高含水期开发指标预测方法

Predicting method of the developing indexes based on the growth curve for extra-high watercut period of Daqing Placanticline Oilfields

大庆长垣油田进入特高含水期后,由于注入流体的长期冲刷,储层物性和渗流特征均发生变化,水驱特征曲线直线规律也相应发生改变,现有水驱曲线预测方法难以满足油田实际生产需求。根据油藏工程基本原理,在分析现有预测方法存在问题的基础上,从研究油层渗流规律出发,建立了适用于特高含水期油藏的预测方法,其中含水上升规律应用生长曲线描述,并推导出了生长曲线含水率上升规律微分方程式,解决了特高含水期水驱曲线上翘问题;通过实验资料和矿场试验资料检验,预测精度大幅度提高,生长曲线法预测产油量相对误差仅为1%~7%,而水驱曲线法预测产油量相对误差高达20%~57%。该方法可准确预测油田开发指标变化趋势,为油田编制开发规划方案和制定开发战略提供技术支持。

After Daqing Placanticline Oilfields entering the extra-high watercut period,due to the long-term flush of the injected fluid,the reservoir physical properties and seepage characteristics have changed,and the straight line rule of the water-flooding characteristic curve has also changed accordingly.The existing water-flooding curve predicting method is difficult to meet the actual production demand of the oilfields.According to the basic principles of the reservoir engineering,on the basis of analyzing the problems for the existing predicting methods,the predicting method suitable for the extra-high watercut oil reservoirs is established from the viewpoint of the study on the reservoir percolation law,in which the water cut rising law was described by the growth curve,and moreover the differential equation of the watercut rising law by the growth curve was deduced,which solves the up-warping problem of the water-flooding curve in the extra-high watercut period;through the laboratory and field test data,the predicted precision has been greatly improved,the relative error of the oil production prediction by the growth curve method is only 1%-7%,while the relative error of the oil production predicted by the water-flooding curve method is up to 20%-57%;this method can accurately predict the variation trend of the oilfield development indexes and provide the technical supports for the formulations of the development planning program and development strategy of the oilfields.