低渗透油藏压裂井产量递减规律分析

Rate Decline Law for Vertical Fracture Wells in Low Permeability Reservoir

针对低渗透油藏水力压裂后形成的有限导流垂直裂缝,建立了考虑启动压力梯度低渗透油藏垂直裂缝井产量递减分析数学模型,并进行了求解,绘制了相应典型曲线,分析了曲线特征,并对参数敏感性进行了分析,同时分析了启动压力梯度对实例井产能的影响。研究表明,存在启动压力梯度低渗透油藏有限导流垂直裂缝井产量比不存在启动压力梯度时递减更快,这种差别在生产中后期尤为显著。实例分析表明,启动压力梯度对低渗透油藏压裂后产能影响较大,不应被忽略。

Since the finite conductivity vertical fractures in the low permeability reservoirs will be formed after fracture treatment of well, we setup the rate decline mathematical model in consideration with threshold pressure gradient and draw the rate decline type curves of fractured well after calculation. We discuss the tendency of curve change. We also illustrate the influence of threshold pressure gradient on productivityof example well in the low permeability reservoirs. The results show that the production decrease rate for the finite conductivity vertical fractures wells in the threshold pressure gradient reservoir is faster than thatof ordinary reservoirs, and this difference is especially significant in the middle or later stage of production. The case indicates that the influence of threshold pressure gradient should not be ignored when ratedecline for the finite conductivity vertical fractures well in the low permeability reservoirs.