Evaluation and application of resistance characteristics of foam system in reservoir porous media

In order to develop an effective evaluation method of resistance characteristics of foam in porous media and its application, the performance of foam in porous media and its mechanism for production stabilization and water-cut control in reservoir were studied. The experimental factors were selected according to physical properties of fluid and reservoir in Haiwaihe block, Liaohe Oilfield. The equilibrium resistance coefficient and the porous volume of water injection before foam failure were defined as the indexes representing plugging strength and valid period respectively. The influence of slug size, gas liquid ratio, slug combination on plugging effect was studied. Then, those factors were optimized using orthogonal test. The function of optimized foam to improve sweep efficiency, stabilize production, control water-cut and enhance oil recovery efficiency were also studied. The results show that, two defined indexes objectively reflect the real characteristics of foam in porous media and can be effectively referenced. Gas liquid ratio and slug combination are the most important factors influencing plugging strength and valid period under the given conditions in the case. Two rounds of plugging after water flooding all have effects on decreasing water-cut and increasing oil production. The oil recovery efficiency can be enhanced by 10% in average.