Study On Technique Of Foam-assistedair Flooding For Compact Reservoir

This paper mainly researches about how to enhance oil recovery in Wuliwan block ofChangqing oil field. The block is a compact reservoir divided by the geologic criterion. Thecompact reservoirs have some features, such as: low porosity and permeability, huge andcontinuous oil-bearing area. It is difficult to inject water into these compact reservoirs.Traditional injection mode can hardly enhance oil recovery of the reservoir. Foam-assisted airflooding can solve these problems. It contains the mechanisms of both air flooding and foamflooding. The air injected can take low temperature oxidation reaction with the remaining oil.The reaction can deplete O2and generate CO2and CO. Those gases can displace oil as fluegas. Foam can control the fluidity of air, so it can avoid breakthrough. This paper researchsome papers about production、air foam injection and field application. We can get themechanism how air foam injection enhances oil recovery and find the problems anddeveloping direction. With the theoretical basis, I did some experiment about LTO for blockof234-46and234-47, and analyze the feasibility of air foam injection for the fields. From theexperiment, I found the influencing factors of LTO, such as: temperature and pressure. By themulti-tube experiment, the Arrhenius equation was simplified, and some kinetic parameterswas obtained. The dynamic experiment mainly compared the amplitude for EOR of threeinjection modes: air/water slug, water/foam slug and air/foam slug. By this experiment, wecan optimize the injection mode and the conversion time. The alternating injection ofwater/air used double tubes to simulate the vertically heterogeneous reservoir. By changingthe order of water/air injection, we can get the mechanism of EOR and the influencing factors,and optimize the injection modes for both positive rhythm and inverted layers.