Research To Improve Heavy Oil Recovery Of Air Foam Flooding

Therefore,the air foam flooding is a effective oil displacement technique that is mainly to expanded sweep efficiency,supplemented by improving oil displacement efficiency and effectively control the flow to improve the recovery of heavy oil reservoirs.The exploit of heavy oil mainly through steam huff and puff and steam drive in China.But for the ultra deep heavy oil reservoirs,heat loss is large as a constraint to development efficiency of the important reasons.And the conventional water flooding development effect is not ideal,because the high viscosity of crude oil,severe reservoir heterogeneity.In this case,often used in the injection water by adding chemicals to control water shutoffand to enhance oil recovery But for ultra-deep conventional heavy oil fields,it formation temperature is high.On this account,the impact of chemicals such as polymers,it's molecules are readily texturing and apparent viscosity decreased quickly.So the displacement effect is poorFor this reason,Study the develop technique that suitable for reservoir buried depth,high temperature,serious heterogeneity and high viscosity crude oil relying on Lukeqin Oilfield that is a typical representative of ultra-deep conventional heavy oil field.In order to solve low recovery efficiency are caused by the waterflood sweep efficiency is low and water is fingering or channeling.The evaluation of laboratory screening test to commonly used 19 kinds of oil foaming agentv by WaringBlender method in the paper.The results showed that foaming agent FA-4 has strong foaming ability and stability at reservoir temperatures.And to evaluate the impact of reservoir characteristics of foam systems.The results showed that the foaming agent FA-4 at from 0.0001%to 0.10%concentration conditions still have a certain foaming capacity and stability;effective concentration of 0.80%while the FA-4 foaming system in a high temperature?78??and ultrahigh salt(160599mg/L,Ca²⁺+Mg²⁺ion concentration of 8620mg/L)and the test area porous media still has a good oil displacement effect.The concentration is far below the current thin oil reservoirs foam flooding's implant concentration that is from 0.1%to 0.5%.It Foam flooding technology in large-scale application of heavy oil reservoir of the foundation.To solve the flooding system with heavy adverse mobility ratio,study mobility control mechanism in simulate the actual reservoir characterization by the modified single-tube core flooding apparatus.First,according to the experimental data and related flow equation is derived to calculate the effective viscosity of air bubble flow in porous media.Study injection line velocity and shear rate to affect foam viscosity and mobility ratio.And to obtain a suitable injection rate in the test area.In this injection rate,to study the effective migration distance that Air foam seepage in the formation.The results show that when injected into the linear velocity of 0.9m/d to2m/d,effective viscosity of air bubble is from 12mPa·s to 403mPa·s.This time with the oil flow ratio less than 1,can effectively control flooding system to plane forward,can not occur channeling or fingering phenomenon.Among them,when the linear velocity of 1.2m/d,the flow of the air bubble and crude oil than the minimum,is only 0.46 to0.70.When the air foam injection enough,the foam and crude oil ratio less than 1 at any location,so the dimensionless effective migration distance is 1.When the shear rate is less than 60s^-1,the lowest effective viscosity was 19mPa·s,the flow of crude oil ratio is still less than 1.And it in favor of mobility control in air bubble EOR process.Besides,this paper had researched to air foam improve the heavy oil recovery technology using parallel twin-tube core flooding experiments and microscopic displacement experiment.The study found that the air bubble to improve heavy oil recovery relies mainly on the expansion of the sweep efficiency,minor improve oil displacement efficiency.And also shows that the air bubble can effectively plug high permeability layer and start low permeability layers to expand vertical swept volume.At the same time the air bubble also improve sweep efficiency flat by peeling oil film and gas block phenomenon.And improves the heavy sweep area is three times the light oil.And frother activation of residual oil droplets and emulsification entrainment can also improve oil displacement efficiency.FA-4 air foam system can be activated in residual oil that exist in 13.75%the test area reservoir porous medium.And 0.30PV bubble liquid flooding enhanced oil displacement efficiency of3.48%,far below the air foam flooding increased 14.21%.Finally,Established a three-dimensional geological model based on the actual reservoir,combined with the actual development of the situation oilfield to make waterflood history matching and results forecasting.On this basis,further study of the foam slug,pre-slug,gas liquid ratio,alternating cycle and speed of injection effecting to oil displacement.And combined with the actual situation to design two rational development plans and predict the development effect.Further validate the feasibility of air foam flooding in heavy oil reservoirs to enhance oil recovery.Then it provide a strong theoretical and technical support for conducting field test.