Experimental Study On Profile Control Performance Of Composite Reinforced Foam

The technique of profile control and water plugging is an effective measure to improve the oil recovery of a high water cut reservoir.The foam fluid has achieved remarkable results in profile control and water plugging,while the stability of the conventional foam system is poor and its period of validity is shorter in the reservoir condition.The compound strengthening foam system is a compound system composed of solid particle stabilizer,foaming agent and water.The foam will generate when gas is injected into the compound system.Then the solid particles achieves the effect of stabilizing the bubble.Finally,Foam stability was improved.First,The forming performance of four combination foaming agents were conducted by comparing the forming permance in deionized water,different salinity foaming contrast and different aging time.The foam agengt?HY-2?was selected and the optimum foaming agent concentration is 0.6%,then,the solid particles were screened and 800-1000 clay particles were chosen.The optimization concentration was 5%and the composite enhanced foam system was"foaming agent HY-2?0.6%?+clay?5%?+Nitrogen".Moreover,the migration state and plugging effect in pore throat for ordinary foam and reinforced foam were compared in artificial etching micro model.The microscopic states of different foams were observed by microscope.Finally,manual filling core and manual pressing core were applied in flooding experimeng and the permeability range was chosen which showed good compatibility with reinforced foam system.Futhermore,several experiments were conducted,including the injection process of gas-liquid ratio range,bubble period,clay concentration effect on injection plugging result,formation temperature effect on the permeability range,and the injection methods effect on the blocking results,the plugging effect of composite reinforced foam in the stratum is studied.Gas-liquid ratio should be maintained within 1:1-1:2 in the injection process.The critical permeability of the composite reinforced foam can be injected into the core with a critical permeability of 1500×10^-3?m².With the permeability increasing,composite reinforced effect of foam injection is continuously enhanced and it showed sealing effect on the deep core.The plugging effect of composite reinforced foam increased 3-7 time compared with the conventional foam.In the later water flooding process,the sealing ability increased 2-4 times compared with the conventional foam.For one thing,with the reservoir temperature increasing,composite enhanced foam injection effect becomes lower.For another thing,plugging effect to the deep core show good performance first and then become worse with the clay concentration increasing.The optimal concentration is approximately 5.0%.Experiment results show that both the forward injection and backward injection can reduce the water content in the liquid and enhanced oil recovery.The composite enhanced foam showed obvious profile control ability in permeability contrast at the range of less than 15.At the same time,the Composite reinforced foam system can improve the profile control effect at the period of high water cut in oil field.Reinforced foam system can improve the profile control effect in percentage extremely high water percentage oil fields.