低渗透压敏油藏极限注采井距研究

确定合理注采井距对低渗透油田经济、有效地开发具有重要意义。考虑低渗透油藏压敏效应对渗透率的影响,基于渗透率与有效覆压的关系,以及启动压力梯度与渗透率的关系推导了低渗透应力敏感性油藏启动压力梯度分布公式。对油水井间压力分布公式进行修正,取压力等于供给压力处对应的半径分别为极限生产半径和极限注水半径,其和为极限井距。在此基础上,结合某油田实际数据,得到了油水井间压力分布及压力梯度分布特征,确定了技术极限井距。与没考虑压敏效应得到的结果相比,本方法更符合实际情况。

Determination of critical well spacing in low permeability and pressure-sensitive reservoir

Determination of rational well spacing is significant for exploiting the low permeability oilfield or reservoir economically and effectively.Influence of pressure variation on permeability is considered.Formula of pressure sensitivity for permeability and relational expression of the least start-up pressure gradient and permeability are utilized to calculate the least start-up pressure gradient at different location between production well and injection well which is used to correct pressure distribution.This paper takes the radius where the pressure is equal to supply pressure as the technology critical producing radius and critical waterflooding radius.The sum is critical well spacing.Based on this and combined with the real data of an oilfield,the distribution characteristics of pressure and dynamic least start-up pressure are obtained,and the technical critical well spacing is determined.Compared with the static method without considering the pressure sensitivity effect,this method is more realistic.