Remainling Oil Potential Distribution And Research Of Main Controlling Factors Of Zhaoao Oilfield Anpeng H3IV2Layer Reservoir

With the development of oilfield, eastern onshore oilfields in China have moved into the high water content stage. To the developed oilfields, in the case of available exploration area more and more limited, enhance oil recovery and increase production is a priority. However, to identify remaining oil distribution is more important.The main thick oil layer of Zhaoao oilfield Anpeng H3IV2layer’s development has entered particularly high water content stage since1986. It gradually revealed the following question:H3IV2thick oil layer thickness is large, interference within the layer is serious, water content is high, remaining oil is difficult to find, flooding situation is unclear, it’s difficult to improve development effectiveness.In this paper, based on a large number of studies in the past, the successful experience of their predecessors inherited summary, using a variety of research methods to predict the remaining oil is relatively rich region from the reservoir geology, reservoir engineering, and other point of view, through the combination of dynamic and static data and numerical reservoir comprehensive analysis of remaining oil simulation rules, predict the remaining oil’s relative rich region, analyze remaining oil distribution characteristics and the master factors which affect the distribution of remaining oil.Zhaoao oilfield Anpeng H3IV2layer reservoir is Fan delta depositional. It can be further subdivided into the fan delta front and the beforehand fan-delta two surfaces, fan delta front underwater distributary channel, River depressions and sheet sand microfacies. Heterogeneity in the reservoir layers is strong. Interlayer heterogeneity is middle. Plane heterogeneity is overall weak, strong in some areas. The larger throat which accounts for30%of the pore volume nearly85%, the pore radius which is larger than1.61um pore can be mobile by the capillary pressure curve obtained.The production of the reservoir in the Zhaoao oilfield Anpeng H3IV2layer reservoir increased gradually after put into production. The production of the reservoir showed a index decline after March1989.The reservoir into the high water cut stage after March1998. Currently, cumulative oil of the reservoir is84.66×104t, degree of reserve recovery is22.67%, and integrated water content is96.74%. Analyzing the Production profile and Injection profile, it is showed that Throughout the test, IV22(1-2) layers are relative output rate at a high level. They are main producing liquid layers. Hydroscopicity of IV21layer and IV22layer is better than other layers, water flushed of the layer IV21and IV22is fully, flooding is high, while water flushed of the layer IV23and IV24is poorer, so there are more oil. Calculating and analyzing the development index of Anpeng H3IV2layer reservoir that is storage rate of water, consumption rate, moisture content and degree of reserve recovery, growth rate of total injection volume, tons of fuel consumption rate. The result indicated that the reservoir’s effect of current water flooding is worse,1ton oil recovery needs7.66m3of water injection. The formation pressure of the reservoir kept stable and maintained in poor condition according to the datum of pressure and fluid level.Application of reservoir engineering method to evaluate saturation of remaining oil, recoverable reserves, the remaining reserves and other indicators in Anpeng H3IV2layer, and analyze the potential of remaining oil. The ultimate recovery is30.2%, recoverable reserves is113.11×104t, remaining recoverable reserves is28.45×104t.According to numerical simulation of Zhaoao oilfield Anpeng H3IV2layer reservoir, history match the original geological reserves of the reservoir, Integrated water content, production of per well, water content and other development indicators. The result of matching is good. Single well fitting coincidence is good. That the numerical simulation model of the reservoir can accurately reflect reservoir conditions. The simulated distribution of remaining oil is also reliable. The numerical simulation model can be used as the basic model of the predictedAccording to the oil saturation distribution map of Zhaoao oilfield Anpeng H3IV2layer, it can be found that IV21(1), IV21(2) layer’s remaining oil is gathered in the southeast. IV22(1), IV22(2) layer’s remaining oil is gathered in the northern edge region. IV23(1), IV23(2) layer’s remaining Oil is the small oil-bearing area of isolated sand body. IV24(1), IV24(2) layer’s remaining oil is gathered in the western edge region.According to history matching results, draw every small layer’s reserves abundance distribution map to analyze more intuitive of the plane remaining oil. That IV21(1), IV21(2) layer of the remaining reserves are mainly located in the central control area without wells. IV22(1), IV22(2) layer of the remaining reserves are mainly located near the southern region in the eastern. IV23(1), IV23(2) layer of the remaining reserves are mainly located in the central and eastern region. IV24(1), IV24(2) layer of the remaining reserves are mainly located in the eastern area.According to layer flooding level analysis, the high tectonic position and absorbent poor layers have high remaining oil saturation, such as IV24(1), IV24(2) layer.The main controlling factors of Anpeng H3IV2layer’s remaining oil distribution are sedimentary microfacies-lithofacies, reservoir heterogeneity, reservoir construction and edge water. In the areas of sheet-like sandstone facies, facies of the shallow lake dam, between the leading edge underwater shunt bay facies and shallow lake mud microfacies, because of its poor physical properties, the washed degree in water flooding is poor, the remaining oil saturation is high. All of this affect the degree of water flooding spread is low, even exist the area where the water flooding did not reach. An61southeast region is highly heterogeneous. In this area, the remaining oil saturation distribution is uneven and part of the area the remaining oil is rich. The southeast area of An61remaining oil is rich. Because the tectonic influence of north high south low, the injected water can not spread, northern regions remaining oil saturation is higher.Because edge water energy is low, south region flooding is serious, the remaining oil saturation is low.