页岩气藏渗流特征及数值模拟研究

发布时间：2018-04-28 14:11

本文选题：页岩气 + 数值模拟　；参考：《西南石油大学》2015年硕士论文

【摘要】：页岩气是一种非常规天然气,主要以吸附态和游离态保存于储层中,页岩气运移方式包括扩散、滑流、达西渗流、高速非达西渗流等,开展页岩气藏赋存、运移机理研究,旨在探索不同运移方式下流体渗流的内在规律,为提高产气速度和最终采收率创造理论依据。在对页岩气藏赋存、运移机理研究的基础上,建立考虑吸附、解吸、扩散的双重介质页岩气藏非稳态渗流数学模型,根据模型绘制页岩气多级压裂水平井压力响应曲线,分析裂缝间距、裂缝半长、解吸时间、表皮系数等参数对井底拟压力的影响情况。运用ECLIPSE数值模拟软件,对川南龙马溪组TJ1HF页岩气井进行单井数值模拟研究,评价压裂施工参数和气藏储层参数对单井30年累计产气量的影响程度。论文主要取得如下成果:1)对比、分析川南龙马溪组页岩气藏和美国主要页岩气藏地质特征、储层特征、储层深度、储层厚度、储层温度与压力,认为川南龙马溪组页岩气藏和Barnett页岩气藏性质相近,可以采用水平井大型水力压裂进行开采。2)页岩气的吸附受气体分子和固体分子间势能控制,根据吸附势理论可以建立吸附势和吸附量特征曲线,特征曲线对同一吸附体系是唯一的,根据实验测试出的某温度下的吸附数据,构造出这种体系的特征曲线,就能预测任意压力、温度下的吸附数据。3)根据K_n数划分运移方式,引入视渗透率来表示扩散作用、滑脱效应对渗透率的影响,通过视渗透率与绝对渗透率的比值来衡量扩散、滑脱对运移的影响大小。4)针对页岩气在赋存、运移和产出过程中的吸附、解吸、扩散、渗流等特征,建立考虑吸附、解吸、扩散的双重介质页岩气藏非稳态渗流数学模型,绘制了页岩气藏压裂水平井压力响应曲线,通过曲线分析把流动分为7个阶段,并分别研究了不同参数对拟压力曲线的影响。5)应用Eclipse数值模拟软件对川南龙马溪组TJ1HF页岩气井进行单井数值模拟研究,在历史拟合的基础上,对影响30年累计产气的敏感性参数进行分析。使用L_(27)(3~6)正交设计表对影响30年累计产气量的水平段长度、压裂缝长、吸附气含量、兰氏压力、扩散系数、窜流系数进行正交试验,研究每个敏感性参数的影响大小。
[Abstract]:Shale gas is a kind of unconventional natural gas, which is mainly stored in the reservoir in adsorption state and free state. The migration modes of shale gas include diffusion, slip flow, Darcy percolation, high-speed non-Darcy percolation and so on. The mechanism of shale gas reservoir occurrence and migration is studied. The purpose of this paper is to explore the internal law of fluid seepage under different migration modes, and to create a theoretical basis for increasing gas production rate and final recovery. On the basis of studying the mechanism of occurrence and migration of shale gas reservoir, a mathematical model of unsteady seepage of shale gas reservoir with dual medium considering adsorption, desorption and diffusion is established, and the pressure response curve of multistage fracturing horizontal well of shale gas is drawn according to the model. The influence of fracture spacing, half length of fracture, desorption time, skin coefficient and other parameters on bottom hole pseudo pressure is analyzed. The single well numerical simulation of TJ1HF shale gas well in Longmaxi formation in south Sichuan was carried out by using ECLIPSE software. The influence of fracturing operation parameters and reservoir parameters on the cumulative gas production of single well for 30 years was evaluated. The main achievements of this paper are as follows: 1) contrast, analyzing the geological characteristics, reservoir characteristics, reservoir depth, reservoir thickness, reservoir temperature and pressure of the shale gas reservoir in Longmaxi formation and the major shale gas reservoirs in the United States. It is considered that the properties of shale gas reservoirs in Longmaxi formation and Barnett shale reservoirs in south Sichuan are similar, and the adsorption of shale gas can be controlled by the potential energy between gas molecules and solid molecules. According to the theory of adsorption potential, the characteristic curves of adsorption potential and adsorption capacity can be established, and the characteristic curves are unique to the same adsorption system. According to the adsorption data at a certain temperature measured by experiments, the characteristic curves of this system are constructed. The adsorption data at any pressure and temperature can be predicted. 3) according to the Ks n number, the migration mode can be divided. The apparent permeability is introduced to express the diffusion, the slip effect affects the permeability, and the diffusion is measured by the ratio of apparent permeability to absolute permeability. The influence of slippage on migration. (4) aiming at the characteristics of shale gas adsorption, desorption, diffusion and seepage during occurrence, migration and production, a mathematical model of unsteady flow of shale gas reservoirs with dual media considering adsorption, desorption and diffusion is established. The pressure response curve of fractured horizontal well in shale gas reservoir is drawn, and the flow is divided into 7 stages through curve analysis. The influence of different parameters on the pseudo pressure curve is studied. 5) the single well numerical simulation of TJ1HF shale gas well in Longmaxi formation in south Sichuan is carried out by using Eclipse numerical simulation software. The sensitivity parameters affecting 30 years cumulative gas production were analyzed. The orthogonal design table is used to study the influence of each sensitivity parameter on the horizontal length, pressure crack length, adsorption gas content, Lang's pressure, diffusion coefficient and channeling coefficient of 30 years cumulative gas production.
【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】：TE312

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