疏松砂岩中微粒迁移问题的研究

Particle migration in loose sandstone reservoirs

疏松砂岩储集层出砂是石油开采中的严重问题,砂岩微粒被冲蚀形成的大孔道会造成严重水窜,迁移的微粒被捕获会导致地层堵塞,使渗透率和产油量下降。为了详细研究疏松砂岩中微粒迁移问题,修正了孔隙介质中微粒冲蚀和捕获的毛细管模型,采用特征线方法给出了模型的解析解,利用有限差分方法求出了模型的数值解,并且将数值解与解析解进行了对比。根据对模型的研究得出结论,对于渗透率较低的油藏,出砂时砂微粒浓度在达到峰值以前就已经发生了地层堵塞,胶结疏松且渗透率较高的油藏更容易形成大孔道。

Particle migration in loose sandstone reservoirs causes serious results in reservoir development. The sand fines are flushed out and consequent large channels may result in serious water breakthrough. The capture of sand fines may block the pores and decrease the permeability and production. A modified capillary model is developed to describe the mechanisms ofparticle migration. The model is a system of non-homogeneous quasi-linear equations. The analytic solution is derived by typical line method and the numerical solution is obtained by finite difference method. The analytic and numerical solutions are compared. Research of the model reveals that, for low permeability reservoirs, formation blockage occurs before the particle content reaches the peak value, and large channels tend to form in high permeability reservoirs.