Investigation on Flow Rule and Productivity in Poorly Consolidated Reservoirs

Based on the production data and statistical information of a practical oilfield, it is proved that the flow rule in wormhole or extra wormhole can be regarded as a high speed Non-Darcy flow, and used the Forchheimer equation to represent. The Forchheimer model is superior to the exponent model and Mazaheri model. Then, the productivity equation of poorly consolidated reservoir with wormhole is derived based on the Forchheimer eqation. Finally, the productivity equation is used to investigate the effect of viscosity ratio of crude oil to displacing fluid, the permeability ratio of wormhole to non-wormhole and injection-production pressure gradient on the yield percentage of the wormhole. The viscosity has the strongest effect on the yield distribution, and the injection-production pressure gradient has the weakest effect. Also, several improvement measures for enhancing oil recovery in poorly consolidated reservoirs with wormhole or extra wormhole are presented, such as polymer flooding, cross-linked polymer flooding, body gel blocking, pre-gelled particles flooding and foam flooding.