Study On The Profile Control Of Oily Sludge In Combustion Reservoir

Combustion is a method to improve the recovery rate of heavy oil.It has the advantages to get injected media easily and to achieve high oil displacement efficiency.It has been tested and applied at domestic and foreign.However,gas injection wells are likely to occur severe steam uneven absorption and even gas channeling due to the influence of formation heterogeneity,which affecting the application of combustion.Therefore,it's necessary to have a profile control on the combustion gas well to improve injected gas profile,and also improve producing degree of the cross-well,and inhibit cross-well gas channeling.Existing foam and gel profile control agents when use in combustion gas injection well profile control have disadvantages of poor stability and high cost.Oily sludge is a highly toxic pollutant during the oil field development,oily sludge treatment process is complicated or costly and it also can pollute environment.The treatment of oily sludge has become a major problem in oil fields.The solid phase and the oil phase in oily sludge have blocking effect,which provides a new idea for the control of the gas injection well and the environmental pollution-free treatment of oily sludge.This article firstly measured and analyzed the composition,rheology,and plugging properties of oily sludge in Shuguang Oilfield,then optimized the additives such as emulsifiers and polymers.Secondly,to study the laws of the temperature change of the combustion reservoir and the variation law of the pore permeability parameters of the rock and the law of gas absorption in the way of reservoir numerical simulation.Thirdly,through combining laboratory experiments and numerical simulation results,the influence of the formation permeability grade,the amount of oily sludge injected,the timing of blocking and the location of plugging on the profile control effect of oily sludge is also studied.Oil sludge profile control mechanism is also studied.Finally,the key profile control parameters the profile control of oily sludge in combustion reservoirs are optimized.Under the condition of high temperature in combustion reservoirs,the permeability of high-temperature formations increases significantly,which increases the inter-layer permeability.Oily sludge profile control agent has good blocking performance and temperature resistance.When the oily sludge is injected to the formation,the oily sludge is separated in porous media,and the solid phase and oil phase remain in the pores and plug formation.The solid particles of oily sludge should be matched with the pore of plugging formation,the pore diameter of the best plugging stratum used in the experiment is 64~196?m.The numerical simulation results show that it is appropriate to use layer selection blocking for profile control of oily sludge in combustion reservoir,the best time for profile control is 6 years after combustion.The best injection strength of oily sludge plugging agent is 600~800m~3/m.The best way of profile control is to block the gas well and production well simultaneously.