Research On The Technology Of R Educed Injection Fluid Pressure And Improved Injection Capacity By Surfactant In Some Oilfield

Due to small pore throat,low permeability,seepage resistance characteristics,combined with the sensitive minerals exist in the reservoir and compatibility of injected water is not cause reservoir damage,in Some Oilfield reservoir,the decrease of water absorbing capacity water injection pressure increasing,directly affect the speed of oil field production.Conventional fracturing acidizing augmented injection measures such as smaller scope and validity of short,surfactants and augmented injection with water injection,and treatment radius is bigger,has been in high permeability reservoirs development process to get a good development effect,therefore,to study surfactant flooding of low permeability reservoirs,step-down augmented injection mechanism and method,the effective development reservoir,alleviate the problems existing in the development has the vital significance.This paper through the determination of different surfactant system with the interfacial tension between crude oil and filter,with DYF-SH to SC-1 and join the DCN-4 as additives,the resulting applies to some oilfield step-down augmented injection groove oilfield surfactant system,system of the formula is: 0.4% + 0.07% DYF-SC-1 SH + 0.03% DCN-4,and the optimum concentration of surfactant used is 0.5%.After the stability of the surfactant system,such as compatibility was evaluated,found that the surfactant solution is placed under formation temperature 30 d,no precipitation,its stability is good,and good compatibility with blocks of crude oil and formation water;After through the indoor experiment in laboratory,found that adding alkali and raise the temperature will reduce the interfacial tension and improve the efficiency of washing oil.60 ? condition,0.5% surface active agent,washing oil efficiency can reach 82.5%,the adsorption quantity of 40%,60% of the surface active agent can have the effect of antihypertensive augmented injection,and the relative permeability of oil and water phase is increased when the formation water flooding,the range of oil-water two phase flow,ultimate recovery 9 ~ 21%,the water displacement and ultimately selected surfactants best injected slug size 0.5 PV,at this point the average depressurization rate 37.49%,the period of validity of 17.67 PV.Through field application,the test Wells in injection allocation work after three months,the average injection-production pressure difference fell by 1.2 MPa,and liquid uptake increased significantly,and has played a good antihypertensive augmented injection effect,and the development of similar reservoir provides practical guidance.