Research On EOR Technology Of Hongnan Reservoir With Bottom Water In Tuha Oilfield

Tuha-Hongnan reservoir is located in south central of Turpan Hami basin in Xinjiang, with bottom water. It has the characteristics of complex geological structures, more faults and more strata. And bottom water affects its development. At present, Hongnan reservoir is flooded at large area, especially the oil wells close to the edge water, which should be taken measures for high efficient development. Firstly, for reservoir with bottom water, this paper deeply studied influencing factors on bottom water coning and technology on coning inhibition. Secondly, it analyzed the reservoir character, and summarized its development process, development status and existing problems. Finally, it carried out research on EOR technology of Hongnan reservoir with bottom water, with physical chemistry, polymer materials and reservoir engineering theory as the guide, physical simulation and numerical simulation as technical means, Hongnan reservoir geological and fluid as research object.Physical simulation results show that: for reservoir with bottom water, the recovery efficiency by depletion development is low, and that by water flooding with appropriately increasing injection velocity or pressure can enhance oil recovery, but the growth rate is small; polymer flooding and polymer-surface compound flooding can greatly improve oil recovery; to adapt the target reservoir pore size and heterogeneity, the compatible polymer relative molecular mass is 2500×104, and the type of surface active agent is non ionic “Da-SUN”; comparing with polymer solution, resistance coefficient and residual resistance coefficient of polymer-surfactant compound system are higher, and in the system polymer dynamic adsorption capacity value is smaller, which is related to surfactant participating competition adsorption; under the same size of slug injection, comparing with polymer solution, polymer-surfactant compound system flooding recovery increases greatly; at the equal chemicals cost, recovery increasement of polymer flooding is larger; considering the technical and economic point of view, the polymer flooding technology is recommended as the alternative development technology for the target reservoir; the bottom water taken plugging measures can further improve the effect of water and chemical flooding. at the equal chemicals cost, compared with separate water well profile control and oil well water plugging, the combined operation of “water plugging and water well profile control” can obtain good effect of water and chemical flooding.Numerical simulation results show that: at the equal chemicals cost, the oil increasing effect with combined operation of “water plugging and water well profile control” is better, comparing with separate water well profile control or oil well water plugging; optimization results of injection parameters for target well group HN209 pilot test are as follows: slug size of water plugging agent(ionic polymer gel, polymer concentration CP=2500mg/L,the crosslinking agent0.2%, stabilizer0.02%) is 0.01 PV, slug size of oil displacement agent(polymer solution, relative molecular mass being 2500×104, concentration being 1600mg/L) is 0.25 PV, drive time interval one year and injection rate 100m3/d; after taking the above measures to improve oil recovery, the expected cumulative oil production can reach20.42×104m3,cumulative oil increment 4.660×104m3,ratio of output to input 4.856,recovery increasement(compared with depletion type development)10.06%?...