| In this study,the chang8 oil-reservoir of the Zhenyuan aera is taken as the main research object.The Zhenyuan aera is located in the southwest of the Ordos basin.Zhen252 well area is a lithologic reservoir with extremely low permeability and microfracture development.It is the main production area of zhenyuan area,28%percentage of the reserves of zhenbeichang 8 reservoir.Because of the fracture development,rules of water flooding is complex,water flooding condition is complex in the process of oilfield development,recovery degree is only 7.3%,in order to improve the effect of oilfield development,this article raise Triassic reservoir to establish an effective policy and water control system of water injection pressure stabilizing oil as the theme of the slow rising water treatment,by a further understanding of the reservoir characteristics,analysising the main factors affecting seepage rule,to draw lessons from and summarizes the analysis evaluation on the reservoir development policies and measures in recent years to form the trias long 8 reservoir production and technical countermeasures.Based on reservoir characteristics study,fracture study,seismic logging,etc.,the fracture parameters of chang8 reservoir in zhen252 district were systematically analyzed,and the water-breakthrough characteristics of the fractured reservoir were defined through comprehensive analysis of water-breakthrough direction and water-breakthrough period of the reconstruction method.On the basis of summarizing the law of low porosity and low permeability,the law of water cut change and the law of production decline,combining with the problems existing in the actual development process,the appropriate rational development technical policies and the technical system of water control and oil stability were formulated,which provided the theoretical basis and technical support for the efficient development of zhenbeichang8 oil reservoir in the later period.Through this study,the following understandings are obtained:1?the sand body of chang8 in zhen252 district is dominated by braided river delta deposition,and the sand body is distributed from northeast to southwest.2?The fracture parameters of chang 8 ultra-low permeability reservoir in zhen252area were identified by a large number of microscopic thin sections,electron microscope scanning,core observation and sand body distribution,etc.:high-angle micro-fractures were developed,tensile fractures mainly,with the direction of 75degrees to the northeast,with the length of the main fractures is about 349m and the lateral fractures is about 194m.3?In view of the characteristics of low reservoir pressure coefficient,small ground saturation pressure difference and large start-up pressure difference,a set of technical policies that is suitable for the development of chang 81 ultra-low permeability reservoir district was formed in Zhen252:1.5-2.0m~3/d.m water injection intensity,and the time of advanced water injection was kept at 3-5 months and the pressure was kept at 110-115%.The initial productivity of a single well increased from1.0 tons to 2.2 tons,and the stable production situation was good.4?Reservoir reconstruction technology:in view of the characteristics of zhenbeichang 8 oil reservoir with large thickness,high brittleness index in some blocks,well developed reservoir fractures and good upper and lower shielding conditions,bidirectional reconstruction of oil and water Wells and application of broadband and temporary plugging fracturing can effectively expand the reservoir reconstruction volume and improve the reconstruction effect. |
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