低渗透油藏中水平井的非稳态产能研究

Study on Horizontal Well's Unsteady State Productivity in Low Permeability Reservoirs

用水平井开发低渗透油藏可以建立有效的驱替压差,提高单井产能。正确预测低渗透油藏中水平井的产能对水平井的优化设计具有重要意义。针对低渗油藏的特征,考虑启动压力梯度,建立了低渗透油藏中水平井开发时的不稳定渗流数学模型,采用拉普拉斯变换及数值反演技术,得到低渗透油藏中水平井的非稳态产能,并分析了无因次井底压力和无因次产量的变化规律及影响因素。研究成果对低渗透油藏水平井的开发具有重要的指导意义。

The displacement pressure drawdown can be established and the productivity can be improved when the low permeability reservoir is developed using horizontal well. To predict the horizontal well＇ s productivity is important for the optimization design of horizontal well. According to the characteristic of low permeability reservoir, the unsteady flow mathematical model of horizontal well is established in which the threshold pressure gradient is taken into consideration. The Laplace transform and inversion is adopted to solve the model and the horizontal well＇ s unsteady state productivity is obtained. And the dimensionless bottom hole pressure and production are analyzed. The research result is instructive for the development of horizontal well in low permeability reservoirs.