Effect of absorption boundary layer on nonlinear flow in low permeability porous media

Taking low permeability cores of Daqing oilfield for example,the flow characteristics at low velocity were studied with the self-designed micro-flux measuring instrument.Considering the throat distribution and capillary model,the thickness of fluid boundary layer under different pressure gradients was calculated,and the mechanism and influencing factors of nonlinear percolation were discussed.The results show that the percolation curve of ultra-low rocks is nonlinear,and apparent permeability is not a constant which increases with pressure gradient.The absorption boundary layer decreases with the increase of pressure gradient,and changes significantly especially in low pressure gradient,which is the essence of nonlinear percolation.The absorption boundary layer is also found to be impacted by the surface property of rocks.

管式预脱在稠油处理中的应用

随着油田发展到中后期,井口采出液含水逐年上升,使联合站进液量增多,造成地面工艺设施超负荷运行,特别是加热系统、库容、以及其他耗能设备必须更新,由于资金限制,往往不能满足现场需要,使油水处理成本年年上升,且指标控制越来越难,为了合理利用现有设备设施,减少处理难度,将部分联合站的油井产出液进行初步分离,一部分含油极少的污水直接进入后端处理,可以最大化使用现有设备,达到油水合格分离。