X挥发性油藏改善开发效果数值模拟研究

发布时间：2019-01-03 20:28

【摘要】：挥发性油藏不同于普通黑油油藏,是一类特殊的油藏,有其独特的性质。X挥发性油藏为低孔、低渗、强非均质性的异常高压层位,A井为三分支水平井,A井的生产动态具有间歇式生产、产量较小和地层产水三个特点,日产油约3m3/d,日产气小于1×104m3/d,且波动幅度大,平均日产水约为20m3/d左右,开发效果不理想。本文以X挥发性油藏为研究对象,在国内外挥发性油藏研究现状调研的基础上,以实现单井增产和改善区块开发效果为目标,以油气藏数值模拟技术为研究方法,运用油藏数值模拟软件,主要进行了注气实验模拟研究、挥发性油藏机理模型开发方式研究、单井增产措施和区块开发调整对策数值模拟研究,完成的研究工作及取得的成果如下： (1)分析认为造成A井低产的原因是储层物性差,需要对储层进行改造,如全井段深穿透射孔、压裂(分段压裂)等,彻底改造油藏产能。 (2)在相态实验拟合的基础上,通过注气膨胀实验模拟研究得出注入天然气会使流体饱和压力升高、膨胀系数增大、饱和压力下黏度降低、界面张力降低,且天然气中不同组分(CH4、C2-C3、C4-C6)对流体物性影响程度不同,通过p-X相图判定地层油与注入天然气要达到一次接触混相的最小压力为60MPa。 (3)通过多次接触实验模拟计算了在地层温度、不同压力下(42MPa、46MPa)向地层油中注天然气的向前多次接触过程,分析了气、液两相界面张力、黏度、密度及不同组分含量的变化,且通过拟三元相图判定在42MPa下注天然气为多次接触非混相驱,在46MPa下注天然气为多次接触近混相驱。 (4)采用机理模型对比研究了挥发性油藏的不同开发方式(衰竭式、连续水驱、连续气驱、先气驱后水驱),并对采油速度、渗透率级差等参数进行敏感性分析,认为先气驱后水驱是该挥发性油藏最合适的开发方式。 (5)在历史拟合的基础上,对A井进行了补孔和压裂优化设计数值模拟研究,经过补孔和压裂后,A井能够正常生产,优化后的设计参数为：对三个分支均进行补孔,总计增加射孔长度670m,压裂裂缝3条(分支二1条,分支一2条),相邻裂缝间距50m,裂缝导流能力100D·cm,裂缝半长为175m。 (6)对研究区域进行了开发调整对策数值模拟研究,在区块南部补充一口水平井,同时部署六口直井,形成混合注采井网,经过三个不同开发方式对比(连续水驱、连续气驱、先气驱后水驱),推荐方案为先气驱后水驱,20年末原油采出程度为22.74%,开发效果得到明显提高。
[Abstract]:The volatile reservoir is different from the ordinary black oil reservoir, it is a kind of special reservoir, and has its unique properties. X volatile reservoir is an abnormal high-pressure layer with low porosity, low permeability and strong heterogeneity, and well A is a three-branch horizontal well. The production performance of well A has three characteristics of intermittent production, small production and formation water production. Daily oil production is about 3 m3 / d, daily gas production is less than 1 脳 10 4 m 3 / d, and the fluctuation is large, the average daily water production is about 20m3/d, and the development effect is not ideal. In this paper, X volatile reservoir is taken as the research object, on the basis of domestic and international research status of volatile oil reservoir, the goal is to achieve single well production increase and improve the development effect of block, and the numerical simulation technology of oil and gas reservoir is taken as the research method. By using the software of reservoir numerical simulation, the simulation of gas injection experiment, the development mode of volatile reservoir mechanism model, the measures of increasing production of single well and the adjustment countermeasure of block development are studied. The results obtained are as follows: (1) the analysis shows that the low productivity of well A is due to the poor physical properties of the reservoir, so the reservoir needs to be reconstructed, such as deep perforation in the whole well section, fracturing (fracturing), etc. Remake reservoir productivity thoroughly. (2) on the basis of the simulation of phase state experiment, it is found that injection of natural gas can increase the saturation pressure, increase the coefficient of expansion, decrease the viscosity and decrease the interfacial tension. Different components (CH4,C2-C3,C4-C6) in natural gas have different influence on fluid physical properties. It is determined by p-X phase diagram that the minimum pressure of primary contact miscibility between formation oil and injected natural gas is 60 MPA. (3) the forward and multiple contact processes of injecting natural gas into formation oil under different pressure and formation temperature are calculated by multiple contact experiments, and the interfacial tension and viscosity of gas and liquid are analyzed. The change of density and content of different components, and through pseudo-ternary phase diagram, it is determined that natural gas injected in 42MPa is multi-contact immiscible phase flooding, while natural gas injected in 46MPa is multi-contact near-miscible flooding. (4) the different development modes of volatile reservoirs (exhaustion type, continuous water drive, continuous gas drive, first gas drive and then water drive) are compared by using the mechanism model, and the sensitivity of the parameters such as oil recovery rate and permeability difference are analyzed. It is considered that first gas flooding and then water flooding is the most suitable development method for the volatile reservoir. (5) on the basis of historical fitting, a numerical simulation study was carried out on the hole filling and fracturing optimization design of well A. After mending and fracturing, A well can be produced normally. The optimized design parameters are as follows: all the three branches are filled with holes. The total length of perforation is 670m, the fracture length is 175m, the distance between adjacent fractures is 50m and the fracture conductivity is 100D cm,. (6) A numerical simulation study of development adjustment countermeasures was carried out in the study area. A horizontal well was added to the southern part of the block, and six straight wells were deployed at the same time to form a mixed injection-production well pattern, which was compared with three different development modes (continuous water drive). Continuous gas drive, first gas drive and then water drive), the recommended scheme is first gas drive and then water drive, the degree of crude oil recovery at the end of 20 years is 22.74, and the development effect is improved obviously.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.7

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