Experimental Investigation On Foam Flooding Performances For Lukqin Heavy Oil Reservoir,Tuha Oilfield

The Luke's oilfield is a high temperature(75?~90?),high salt(mineralization degree 170000 mg/L),heavy oil(crude oil viscosity 250mPa·s~600mPa·s)reservoir.Since the implementation of foam flooding in the TY block of lukqin reservoir on April 1,2015,the water content of the main production Wells has been greatly reduced(from 75% to 15%),and the daily oil production has been greatly increased(from 2t to 10t),and the effect of oil increase and precipitation is very obvious.However,the reservoir conditions and fluid characteristics of LT block and LY block are obviously different,especially the viscosity and permeability gradient of crude oil are very different.(the viscosity of LT block is 500mPa·s,which is much higher than 282mPa·s of LY block.LT permeability differential of 14.3 than LY in the block of 5.2),which are the main factors that influence the serious influence the effect of foam flooding,so it is necessary to carry out the differential permeability and crude oil viscosity and other characteristics of foam flooding and oil displacement effect,to further research and evaluation of foam flooding throughout the baruch seeps the application feasibility of oil field in tuha oil field large-scale implementation of foam flooding,provide reliable theoretical and experimental basis.In this paper,an experimental study on the improvement of heavy oil recovery by foam flooding was carried out for the characteristics of Luke's oil layer.Firstly,by studying the microscopic oil displacement experiment,the influence of crude oil viscosity on the residual oil saturation and residual oil type of water flooding and foam flooding is studied.On the basis of the visual microscopic oil displacement experiment,the effects of permeability difference and crude oil viscosity on the characteristics and effects of foam displacement in the longitudinal direction were further studied by parallel double-tube core flooding experiments.The experimental results show that for the heavy oil reservoir,due to the heterogeneity of the oil layer,the water flooding effect deteriorates sharply with the increase of the permeability difference;the final recovery degree of the foam flooding increases with the permeability difference.The gradual decline is also large,but in the range of the permeability difference of 2.1 to 24.6,the decrease is relatively small,and the permeability difference is in the range of 24.6 to 35.2,and the decrease is significantly increased.As the viscosity of crude oil increases,due to the effect of the fluidity ratio,the degree of waterflooding declines sharply and then decreases slightly.The final degree of foam flooding is different,firstly,it decreases slowly and then drops sharply.Finally,an experimental study on the effect of gravity differentiation on the gas/liquid ratio of the foam flooding system was also carried out.The results show that in the homogeneous oil layer of the same pressure system,the influence of gravity differentiation on the gas/liquid ratio has nothing to do with the formation pressure,only related to the formation permeability.The greater the permeability of the simulated oil layer,the gas/liquid ratio As the relative thickness of the oil layer increases,the tendency to decrease is faster.The experiment finally determined that the foam flooding method is basically applicable to the entire Luke field.