Technology Of Laboratory Research On Decreasing Injection Pressure And Increasing Injection Rate By Surfactant Of Chang 10 Block

Chaoyanggou 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,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 interface tensiometer,determination of different single surfactant and sunrise trench oil field distribution system and interfacial tension between crude oil and choose suitable for chaoyang step-down augmented injection groove oilfield surfactant system,screening,with DYF-SH to SC-1 and join the DCN-4 as a assistant of surfactant compound system,system formula is: 0.4% SC-1 + 0.4% DYF-SH + 0.03% DCN-4,the best concentration of surfactant used is0.5%.;Then the stability of the distribution system,adsorption properties,effect of wash oil is evaluated,and studied the composition of formation water and alkaline conditions on the interfacial tension of distribution system found that the influence of the distribution system under formation temperature 30 d,no precipitation,its stability is good,and adding alkali and raise the temperature will reduce the interfacial tension and improve the efficiency of washing oil.After screening and selecting the complex system,the laboratory evaluation of the effect of surfactant reducing pressure on surfactant was carried out by means of core damage experiment,phase permeability curve measurement and validity determination experiment.60℃ condition,0.5% surface active agent,washing oil efficiency can reach 82.5%,the adsorption quantity of 40%,60% of the surfaceactive 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 0.5PV,at this point the average depressurization rate 37.49%,the period of validity of17.67 PV.In the process of field application test Wells in injection allocation effect after 90 d,injection-production pressure difference on average dropped by 1.2 MPa,water-intake hundreds of scores on average increased by 6.7%,rose by an average of7.9 %,the effective thickness of water quantity has played a good antihypertensive augmented injection effect,and the development of similar reservoir provides practical guidance.