Research On Waterflooding Scheme Of Chang2Oil Layerin Wangjiawan Oil Region

By taking Chang2of Triassic Yangchang group in Wangjiawan well block of Haojiaping Oil Recovery Plant which located in northeast of the Ordos Basin as the research object, the thesis uses the theories of sedimentary petrology and petroleum geology, and bases on the analysis of drilling,logging and oil production testing data, and structure, sedimentary system characteristics, sedimentary micro-facies of the main oil layer, shape and distribution of the sand body and reservoir characteristics have been studied systematically. Based on the study of reservoir geological conditions and fine reservoir description, the thesis designs waternoocling development scheme, scheme comparison and optimal selection, which provides reliable evedence for waternoocling development and the layout of production wells, and also improve the development level and recovery ratio of oil production plant.Studies show thatthe sedimentary system of Chang2is fluvial deposition,and the reservoir is mainly fine sandstone, secondly medium sandstone,and the porosity is mainly between10%and18%, and the average porosity is13.7%, and the average permeability is11.7mD, the general result is low porosity and low permeability. The reservoir physical property has strong reservoir heterogeneity, strong plane heterogeneity and weak interlayer heterogeneity. Chang2reservoir is a lithologic-structural reservoir of elastic and solution gas combination drive, and the sand body is banding distribution, and the strike is mainly NE-SW. The closing area of Chang21-3-1、Chang21-3-2are4.04Km2、5.1Km, and the petroleum geological reserves of Chang21-3-1、Chang21-3-2calculating by volumetric method are137.3×104t、274.4x104t.The Chang2reservoir of Wangjiawan well block of Haojiaping Oil Recovery Plant has a low natural energy and the recovery factor of natural energy is just8.3%calculating by empirical formula,while the water injection recovery is20.2%, so it is necessary to use water injection development method.The water injection experiment suggests that the water drive efficiency reaches48.1%when1.5PV water is injected. The reservoir in Wangjiawan well block of Haojiaping Oil Recovery Plant have stable horizontal distribution, high connectivity degree, low formation pressure, good crude oil property and low oil and water viscosity ratio, which is beneficial to injection water going into the formation, and implement water injection development with a low water injection pressure. The reservoir which is the same type in Ansai Oilfield has obtained a good development effect. So the water injection development is feasible on the Chang2reservoir of Wangjiawan well block of Haojiaping Oil Recovery Plant.The abreast direction of well pattern the Chang2reservoir of Wangjiawan well block of Haojiaping Oil Recovery Plant is about NE470, and rhombus well pattern is used as well pattern type because of the low permeability, and the abreast distance ratio is1:1.87.The maximum water injection pressure allowed by injection wellhead is20Mpa.The thesis doing index predictions of three schemes by the Eclipse software of oil-gas reservoir numerical simulation, economical evaluation and economical optimization scheme:The tatal wells of scheme design is92, and71is oil well,20is water well, and the ratio of oil well and water well is1:3.6.