裂缝性低渗透油藏压力敏感性研究

压敏效应对含水平裂缝的低渗透油藏开发具有重要影响。随着油田开发的进行,地层压力逐渐下降,水平裂缝趋于闭合,渗透率大幅下降,严重影响了生产能力。以室内实验为基础,研究了压力变化对岩心渗透率的影响规律,分析对比了含水平裂缝的低渗透砂岩岩心与不含水平裂缝的低渗透砂岩岩心的压力敏感特征的异同,并建立了考虑压敏效应的稳态产能预测模型,用计算实例说明了压敏效应在此类油藏开发中对渗透率、压力分布、产能等生产指标的重要影响。该研究结果对含水平裂缝的低渗透油藏高效开发具有指导意义。

A Study on Pressure Sensitivity of Fractured Low-Permeability Reservoirs

A pressure-sensitive effect affects unfavorably the production performance of fractured low-permeability reservoirs with horizontal fractures. With continuing an oilfield development, its formation pressure tends to decline along with the horizontal fractures being closed, the permeability drawdown and the productivity being damaged. Based on the core lab data, this paper presents the affected trend of varied pressure on core permeability, the differences of pressure-sensitive features between low-permeability sand cores with/ without horizontal fractures, and develops a model for steady-state productivity prediction considering the pressure-sensitive effect. Furthermore, the influences of pressure sensitivity on permeability, pressure distribution and productivity of such reservoirs are discussed with calculated example. These results have important instructional significance to highly efficient exploitation of fractured low permeability reservoirs with horizontal fractures.