Integrated Separate Layer Injection Technology on ASP Full Term Flooding for II and III Kind Formation in Daqing Oilfield

Abstract

Abstract. With the development of ASP flooding in Daqing oilfield, the II and III formation with low permeability and apparent interlamination contradictory has been developed as the main target. Due to the worse technology adaptation, the big difficulty of testing, the low successful ratio of running and fishing, the high cost of changing the strings for water flooding and ASP flooding, the original separate layer ASP injection failed to be applicated extensively. In order to resolve the problems mentioned above, the integrated separate layer injection technology on ASP flooding was researched in this paper. The eccentric injection regulator, the pressure regulator with low viscosity loss ratio and high pressure choke, the molecular weight regulator with high viscosity loss ratio and low pressure loss are designed, the injection of high permeable interval and the molecular weight of medium and low permeable interval can be controlled at the same time. The separate injection string is compatible with water flooding technology and it can be satisfied the requirement of the blank water flooding、ASP flooding and sequent water flooding, the investment and operation cost are dropped. The field application of 56 injection wells shows that the running and fishing, the verifying sealing and the flowrate allocation technology can be operated by production company by themselves, the average testing time of single well is about 2-3 days.The Daqing oilfield practice shows that [1,2] : ASP flooding compare with water flooding can be more increased the oil recovery over 20 percent. At present, Daqing Oilfield totally have 728 ternary production wells and 625 injection wells, the oil production maintain keeps more than one million tons for three consecutive years, the cumulative oil production of 6.135 million tons. With the deepening of the development of ASP flooding, permeability differences, second and third grade reservoirs with much interlayer difference has become the main development of the object. Original ASP flooding stratified injection technology, has poor process adaptability, difficulty of throwing-in and pulling test and low success rate, the water flooding turning into ASP flooding and ASP flooding turning into subsequent water flooding due to high cost, it needs to replace the string, and is unable to scale application.In order to solve the above problems, this paper researches the ASP flooding integration separate layer injection technology, to achieve the dual control of the Injection volume of the high permeability interval and the molecular weight of the low permeability interval, researches the pressure regulator with low viscosity loss ratio and high pressure choke, the