Technology Of Decreasing Injection Pressure And Increasing Injection Rate Of Liaohe Oilfield

Liaohe oilfield and ridge production 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,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 chaoyang 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 laboratory experiments,it was found that adding alkali and raising temperature both reduced interfacial tension and improved oil washing efficiency.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.