Dynamic Analysis And Development Adjustment For GuangHua Reservoir

The low permeability oil resource is quite rich in China. It is estimated that the undeveloped low permeability, which is less than 50mD, and non-heavy oil reserve accounts for 40% of the total unexploited. Efficient development of low permeability reservoirs plays a significant role in maintaining our growing energy resource demand. The average permeability of GuangHua reservoir is 7.9mD, belonging to low permeability reservoir. From the statistical analysis of the producing data, it shows that most of the currently producing wells are characteristic by high water cut and low-yielding and the proportion of low water cut wells is small and the daily oil production of individual well is not high, also, oil production is mainly from the high water cut oil wells. Meanwhile the injection-production pressure difference is relatively large,the reservoir pressure has dropped significantly and the pressure distribution is uneven. Water cut rising fast in oil wells and it is out of sync with injection-production time, thus the effective water drive system is difficult to form. Therefore, based on the current situation of the GuangHua reservoir, which is high water cut and low production. A comprehensive analysis of reservoir development characteristics and mining effects, understanding reservoir exploitation constraints, mining law and mining potential, determining the optimal adjustment and to maximize economic benefits.GuangHua reservoir of target zone is located in the southeast of GuangHua temple QianJiang, HuBei province. Geotectonic position is located in the north of QianJiang sag. The surface oil density is 0.866g/cm3, together with 3.3mPa·s of viscosity and 0.66% of sulfur. There is low viscidity formation crude oil and good formation oil properties. It belongs to high pressure and low saturation reservoir, which initial formation pressure is 4.38MPa,formation pressure coefficient is 1.212 and saturation pressure is 4.32MPa.Oil-bearing area is 8.69km2 and average effective thickness is 7m.GuangHua reservoir contributes greatly to the building of the national oil industry. But after years of mining, the reservoir’s contradiction becomes sharper and sharper; the development difficulty becomes increasingly big; the oil-water distribution has undergone tremendous changes. For this type of high water-cut reservoirs, how to develop more effectively and how to increase ultimate recovery are currently the research problems, this paper does the following work:1. An analysis of reservoir geological characteristics and reservoir characteristics for target zone. The reservoir’s constructed background, constructed features and the types of deposition phase are introduced and the features of the deposition micro phase are analyzed. According to the analysis of rock cores at hand, the features of the storage layer rock learn are summarized. Through analyzing porosity and permeability of core samples from core wells, an overview of storage layers’physical features is made; a description is made for physical properties of formation crude oil, underground water, natural gas and reservoir fluid nature.2. The analysis of reservoir development characteristics for target zone. Focus on the current development situation of the reservoir, a detailed analysis of the main problems in the development process has been made, which laid the foundations for later adjustment and improvement. A study is made for different regular patterns, such as production decline law. Moreover, experience formula method and dynamic analysis method are used to forecast the recovery efficiency of target zone in GuangHua reservoir. Type A water-drive curve method, Tong’s chart method and production decline method are used in dynamic analysis method to forecast the recovery efficiency and recoverable reserves of target zone in GuangHua reservoir, which potential is determined.3. On the basis of reservoir development characteristic analysis and interwell dynamic connectivity.3D fine geological model of target zone in GuangHua reservoir has been set up by the fine geological modeling software. And through fitting analysis of the reserve, whether the model is reasonable has been analyzed. The numerical model of the target reservoir has been established by using the Eclipse reservoir simulation software. After fitting of production history (pressure, water cut, liquid production, etc.), the quality of history matching has been evaluated. Water cut rising fast in oil wells and it has been out of sync with injection-production time. Remaining oil distribution is mainly controlled by reservoir edge area and the potential residual oil zones.4. According to the result of remaining oil distribution, through real-time reservoir production optimization, optimization adjustment programs have been designed. A relatively perfect system of research and development has formed, which is of great instructional significance to the development of old oil field.