Research On Enhanced Oil Recovery With Non-alkali Binary Flooding In Block A Of Zaoyuan Oilfield

Block A of Zaoyuan oilfield has a reservoir temperature of 78?,formation water salinity of 26974 mg/L.It belongs to the high temperature,high salt,normal permeability and heavy oil reservoirs with an average formation permeability of 210×10^-3?m² and an oil viscosity of53.2 mPa.s in reservoir condition.The current problem is that it has a low level recovery with water flooding,and there are no more mature mining techniques and methods that can greatly improve oil recovery of this kind of reservoir.Polymer/surfactant combination flooding has a synergistic effect to give full play for the surfactant to reduce interfacial tension and to the polymer to increase swept volume.It is a tertiary oil recovery method that can greatly enhance oil recovery of the conventional reservoir.The development,evaluation and selection work for heat-resistant and salt-resistant binary system,is on the premise of application in type?,?reservoirs for polymer/surfactant binary flooding technology.In the face of interlayer contradiction,contradiction in plane,injection-production well spacing damage of fault block A,the development effect of water flooding becomes worse and worse.So the necessity and technical advantages of non-alkali binary flooding appling in this type of reservoir were first elaborated.Detailed discussion and applied research were carried out in four aspects,they are basic solution performance of binary oil-displacing system,flow ability and core displacement characteristics,reservoir numerical simulation and binary flooding matching technology.Associative polymer?JK-2?and sulfonate surfactant?SS-1?are suitable for reservoir conditions of block A from the performance testing and evaluation experiments results.The compatibility between JK-2 and SS-1,long-term to maintain system stability and viscosity method are also discussed;Through indoor flow test and core displacement experiment,the basic parameters required in numerical simulation are obtained,the composition and the injection parameters of binary system were also determined;The reservoir numerical model of block A was established by doing a fine research on reservoir geology and reservoir engineering,then injection-production well pattern was optimizated.From results of numerical simulation,forerunner area of block A with binary flooding has injection parameters of slug total dosage of 0.6 PV,injection rate of 0.12 PV/a.Then determined the binary flooding injection scheme,so that can forecast the development indexes and discuss economic benefits;Finally determined the binary flooding pilot test matching process.Expected form the project after implementation,the cumulative increase of oil can be 26.47×10⁴t.Economic evaluation shows that the project has good economic benefit,internal rate of return is 14.14%after tax,financial net present value is 13.5646 million yuan,it have a certain ability to resist risks of the price of crude oil and increased oil.The EOR technology research on block A of Zaoyuan oilfield with non-alkali binary compound systems,provides technical support to guide the block binary flooding pilot test.And it forms a production replacement technology in high temperature and high salt reservoir of Dagang oilfield and provide reference for development of other similar types of reservoir.