低渗透油藏考虑压裂的合理注采井距研究

基于点源点汇渗流理论，推导了低渗透油藏考虑压裂措施的注采井间压力梯度分布方程，结合启动压力梯度 与低渗透油藏渗透率关系式提出了合理注采井距计算方法，并结合低渗透油藏实例，进行了注采井间压力梯度影响因 素分析，得到了低渗透油藏合理注采井距理论图版，验证了该方法的可靠性。结果表明：在渗透率、注采压差和压裂裂 缝长度一定的情况下，存在合理的注采井距，且合理井距随渗透率、注采压差和裂缝半长的增加而增大；认为采取压裂 等增产措施，有利于建立起有效的驱替压力系统，能较大幅度地提高合理注采井距。推导出的考虑压裂的注采井间压 力梯度表达式能够较准确地反映真实地层驱替压力系统，研究结果对合理开发低渗透油藏具有一定的实际意义。

Study on Reasonable Spacing Between Injection and Production Wells#br# Considering Fracturing in Low Permeability Reservoirs

Based on the seepage theory of point sources and sinks，the pressure gradient distribution equation between injection and production wells considering fracturing in low permeability reservoirs is derived. Combined with the correlated equation between threshold pressure gradient and permeability，the computational method of reasonable spacing is proposed，and influencing factors of pressure gradient between injector and fractured producer are analyzed with a case of low permeability reservoir. Here，the theoretical chart of reasonable spacing is obtained，which verifies the reliability of this method. Results demonstrate that there is a reasonable spacing under the condition of a certain reservoir permeability，injector-producer pressure difference and the fracture length，and the reasonable spacing increases with the increase of above three parameters. Besides， stimulation measures，like fracturing，can do favor to build the effective displacement pressure system，which could greatly improve reasonable spacing. In conclusion，this pressure gradient distribution equation can accurately reflect the displacement pressure system of real formation，and the results have certain practical significance for the reasonable development of low permeability reservoirs.