The Seepage Field Change Characteristics Of Air Foam Displacement

At present,due to long-term water injection development,most oilfields in China are already in high water cut period.In this oilfields,bottom hole pressure has fallen dramatically and production has declined accelerated.Effectively improve the ultimate recovery of the reservoir is facing huge challenges.As a new method to improve the recovery efficiency,the air foam displacement combined with the dual advantages of air displacement and foam displacement.However,no matter domestic or abroad the public reporting about air foam displacement of laboratory experiments,reservoir numerical simulation study and field application are rarely.The corresponding research system has not been formed.The mechanism of air foam flooding and the applicability of the various reservoir still need further discussion.This article uses the sand filling tube to simulate the seepage field change of air foam flooding.In view of the two groups of different permeability,the corresponding air foam flooding experiment has been conducted.The results show that: In the low permeability tube,air foam flooding is 1.84 times of water flooding oil recovery and in the medium permeability tube is 3.25 times.During the process of air foam displacement the pressure change range is very large and the pressure curve fluctuates significantly.Analysis suggests it was because of bubble slug block.After that,history matching and numerical simulation analysis is made,air foam flooding seepage state was divided into start-up phase,displacement phase,and breakthroughs phase.Analysis suggests that the second stage is the critical period of the displacement.In this period the fluid production and oil production increase rapidly,oxygen consume quickly,ground temperature increases slightly,CO2 and CO can be detected in the output end.After analyzing the seepage field change characteristics of air foam displacement,this article also uses numerical simulation to evaluate the influence which reservoir parameters,development and process parameters cause on the effect of injection air foam flooding.The results of the study can guide air foam flooding field test.