| After an analysis of geological and development information of Yanshang reservoir of Kengiyak oil field, a pilot polymer flooding was proved to be practical from aspects such as laboratory test, numerical simulation, reservoir engineering calculation, economical effect evaluation and so on.This article studied the watered out condition, remain oil distribution, sedimentary facies, rhythmic, heterogeneity, porosity and permeability, characteristics of oil and water, the temperature and pressure system, these information is compared with polymer flooding in Daqing oil field. Although the oil viscosity and water salinity of the reservoir are high, which is not favor for polymer flooding; there are many advantages for polymer flooding. There is plenty of remain reserves, wide spread sedimentary sand, reservoirs with positive rhythm, heterogeneity and good pore permeability characteristics, good temperature and pressure system and good injection and production ability. It is worthwhile to try polymer flooding.Lab study showed that polymer solution formulated by clear water presented a high viscosity and good stability, which laid a basis for polymer flooding in high viscosity reservoir.Polymer solution formulated by fresh water also showed a good temperature resistivity. This made the application of polymer flooding in steam-assisted recovery practical. Lab test shows that polymer flooding has better effect on core flooding with high viscosity oil of 200 mpa.s than water flooding.Considering the results of lab research, the application of polymer flooding in Yanshang reservoir of Kengiyak oil field is feasible.Numerical simulation was given such standards as following. If the application of the polymer flooding in a reservoir of high oil viscosity of about 200 mpa.s can meet these standards, the application is considered worth trying. First, the recovery should be improved by 10 percent than the original water-flooding recovery of about 15 percent. Second, the water cut rate after the polymer has taken effect should be decreased by over 20 percent than water cut rate of 90 percent when injecting the polymer slug. Third, the recovery degree after polymer flooding should be above 20 percent.The 166 well in western part on the south limb of the field was choosed. The target zone is Γ. There are 4 injectors, 1 producer and 6 balance wells in the pilot. Considered the economical factor and in order to get technical affect as early as possible, the 4 injectors and 1 producer should be new wells. The producing thickness and the water cut of pilot field is high, surface condition is good. The reserve, geological condition, water cut, oil and water property is representative. Technical and economical effects should be considered in the plan of polymer flooding. Dense well space and movable injection-production system which is reusable is used.The polymer used in the pilot is decided to be a salt resistance polymer with amolecular weight of 38 million. The concentration is 1500mg/L, which is prepared by clear water, and the usage is 380PV.mg/L. And the inject intensity could be 5m3/d and the velocity could be 1Vp/a at the beginning of polymer flooding.Reservoir engineering calculation of pilot area suggested that Yanshang oil field has good injectivity and productivity. Polymer flooding is suitable.Economical benefit will increase after popularization, since and the expense of chemical will be decreased with the increase of incremental oil; Therefore the economical effect of polymer flooding will be considerable.Not only can separate zone polymer flooding be conducted on Yanshang reservoir of Kengiyak oil field, the oil field is suitable for planar popularization. This article is helpful for the efficiently development of this oil field and other oil field with similar conditions in Kazakhstan.Up to now, there is no literature about polymer flooding on similar reservoir with high oil viscosity. This study is helpful to enlarge the study domain of polymer flooding. |
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