Study On Emulsification Viscosity Reduction And Polymer Flooding System In Heavy Oil Reservoir Of Sheng Li Field

The Chenjiazhuang block is a key capacity-building area of Shengli Oilfield in Dongying Sag due to its rich oil and gas resources.The high structure of the northern part of the region has a viscosity of about 2000 mPa·s and a reservoir temperature of 70?.Water injection in this area cannot meet the requirements for enhanced oil recovery,because the formation is thin or the bottom water is not suitable for thermal recovery.In the process of heavy oil exploitation,there is a problem of poor temperature and salt resistance of the emulsified viscosity reducing agent and a problem that it is difficult for a single polymer to efficiently drive oil.In this paper,the emulsified viscosity reduction and synergistic polymer flooding system was studied in the case of the Chenjiazhuang block.The main research contents and results are as follows:This topic takes the heavy oil reservoir in Shengli oilfield as the object,through the indoor experiment,the microscopic displacement experiment and so on a variety of technical means.This paper analyzes the properties and influencing factors of different emulsifying viscosity inhibitors,establishes the structure-activity relationship between emulsified viscosity stabilizer,polymer and heavy oil,expounds the mechanism of oil displacement of emulsion to reduce viscosity,and gives the design direction of oil displacement system.The microscopic displacement process of oil flooding agent in pores was studied by using visual model device,and the microscopic displacement efficiency of emulsified viscosity reduction system and polymer composite system to heavy oil was preliminarily investigated.The effects of oil-water ratio,temperature,salinity and calcium and magnesium ions on emulsification viscosity reduction of heavy oil were studied for nonionic,anionic and anionic non-complex emulsified viscosity reducers.The stability of emulsified viscosity reducer was analyzed.Adsorption resistance.The emulsified viscosity reducer system suitable for the ordinary heavy oil reservoir of Chenjiazhuang in Shengli Oilfield is AS and NSA,and the mass ratio is 2:1.For the four types of polymers of associative polymer(APP5),conventional polyacrylamide(HJ),ultrahigh molecular polymer(BM)and novel polymer containing temperature and salt resistant monomer(C6725),High-temperature and high-pressure rheometers were used to study various properties of physicochemical properties,viscosity-increasing properties,viscoelastic properties,temperature and salt resistance and thermal stability of integrated polymers.Filtered C6725 and BM with good temperature and shear resistance.Based on the study of the compatibility of polymer and emulsified viscosity reducer,the viscosity reduction and synergistic polymer flooding system was optimized,and the viscosity reduction performance,interface stability and oil washing performance of the system were evaluated.The viscosity and viscosity reduction rate of the system were measured after compounding,and the 2000 mg/L C6725 and 0.1%AS+0.2%NSA compounding system were screened out.Relying on the microscopic water flooding process,the microscopic oil displacement experiment was used to simulate the emulsification and viscosity reduction effect of different emulsified viscosity reducer,polymer,emulsified viscosity reduction and synergistic polymer flooding system on the heavy oil of Chen 25 block,At the same time,it indicates that the displacement speed has little effect on the ultimate recovery of simulated oil.The type of oil displacement agent is the key to the ultimate recovery of simulated oil.The emulsified viscosity reduction and synergistic polymer flooding system has better oil displacement effect.