天 然 气 工 业Natural Gas INdustry 第40卷第9期2020年 9月
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赵玉龙1 刘香禺1 张烈辉1 唐洪明1 熊钰1 郭晶晶1 单保超2
1. “油气藏地质及开发工程”国家重点实验室·西南石油大学
2. 煤燃烧国家重点实验室·华中科技大学
摘要：致密砂岩气藏储层渗透率低，在地面条件下开展真实岩心的驱替流动实验很困难，因而无法研究其微观流动机理。为此，基于格子Boltzmann方法（以下简称LBM），模拟地层高温高压条件下致密气驱替地层水的流动过程，得到了地层中束缚水的分布状况；然后采用激光刻蚀模型，进行储层干化实验，并借鉴该实验的可视化结果对储层干化数值模拟进行简化；在此基础上利用数值模拟手段研究储层干化对致密气渗流能力的影响。研究结果表明：①所采用的格子Boltzmann模型在地层高温高压条件下满足Laplace 定律，由该模型计算得到的两相Poiseuille流速度数值解与解析解结果基本一致，表明该模型可以用于地层条件下气水非混相驱替的模拟；②致密气在多孔介质连通的大孔道中优先突破，并且在突破后驱替地层水的速度显著下降；③地层水与岩石壁面的接触角显著影响气水两相流动，岩石亲水性 陶慕宁越强驱替速度越慢；④致密砂岩气藏中束缚水可分为吸附水膜、盲端孔隙水、死孔隙水和卡断水4类，在多孔介质中大量连通的微小通道被卡断水和吸附水膜占据，存在着明显的“水锁”现象，严重影响致密气在储层多孔介质中的渗流能力；⑤干化剂可与束缚水反应并且产生大量气泡，将吸附水膜、卡断水和盲端孔隙水消耗掉，从而提高气体的渗流能力；
麦德龙总裁⑥对于由卡断水形成的“水锁”区域，增大干化强度可以有效改善气体渗流能力，整体上随着干化强度的增大，致密气渗透率也增大，但干化强度超过一定的限度后，致密气渗透率的增幅逐渐减小。
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关键词：致密砂岩气藏；储集层；格子Boltzmann方法；气水两相；流动模拟；储层干化；干化强度；渗流能力
DOI: 10.3787/j.issn.1000-0976.2020.09.009
Laws of gas and water flow and mechanism of reservoir drying in
tight sandstone gas reservoirs
ZHAO Yulong1, LIU Xiangyu1, ZHANG Liehui1, TANG Hongming1, XIONG Yu1, GUO Jingjing1, SHAN Baochao2 (1. State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation//Southwest Petroleum University, Chengdu, Sichuan 610500, China;2. State Key Labora
力度记号
tory of Coal Combustion//Huazhong University of Science and Technology, Wuhan, Hubei 430074, China) NATUR. GAS IND. VOLUME 40, ISSUE 9, pp.70-79, 9/25/2020. (ISSN 1000-0976; In Chinese)
麦兜族
Abstract:The reservoir permeability of tight sandstone gas reservoirs is low, which makes it difficult to carry out displacement flow experiments on real cores underground conditions, so the microscopic flow mechanism can be hardly studied. Based on the lattice Boltzmann method (LBM), this paper simulated the flow process of formation water displaced by tight gas under the simulated reser-voir conditions of high temperature and high pressure to clarify the distribution of bound water in the reservoir. Then, reservoir drying was experimentally studied using the laser etching model, and numerical simulation of reservoir drying was simplified by referring to the visualization results of the experiment. Finally, the influence of reservoir drying on the seepage capacity of tight gas was studied by means of numerical simulation. And the following research results were obtained. First, when the lattice Boltzmann model is used for high temperature and high pressure reservoirs, it satisfies the Laplace law and its numerical solution of two-phase Poiseuille flow rate is basically consistent with the analytical solution, which indicates that this model can be used to simulate gas-water immiscible displace-ment under reservoir conditions. Second, tight gas preferentially breaks th
发酵饲料rough in large porous media connected channels, and after the breakthrough, the displacement rate of formation water decreases significantly. Third, the contact angle between formation water and rock wall has a significant influence on gas-water two-phase flow. The strong the water wettability of the rock is, the lower the displacement rate is. Fourth, the bound water in tight sandstone gas reservoirs can be classified into four types, including adsorbed water film, blind end pore water, dead pore water and trapped water. In porous media, a large number of connected micro-channels are occupied by trapped water and adsorbed water film and the phenomenon of "water lock" is obvious, which seriously influences the seepage capacity of tight gas in the porous media of reservoir. Fifth, drying agent can react with bound water to produce a large number of bubbles, which will con-sume adsorbed water film, trapped water and blind end pore water, so as to improve the gas seepage capacity. Sixth, in the "water lock" regions formed by trapped water, the gas seepage capacity can be effectively improved by increasing the drying strength. On the whole, the tight gas permeability increases with the increase of drying strength, but its increase amplitude decreases gradually when the drying strength exceeds a certain degree.
Keywords:Tight sandstone gas reservoir; Reservoir; Lattice Boltzmann method; Gas-water two-phase; Flow simulation; Reservoir dry-ing; Drying intensity; Seepage capacity
基金项目：国家自然科学基金重点项目“致密气藏储层干化、提高气体渗流能力的基础研究”（编号：51534006）。
作者简介：赵玉龙，1986年生，副教授，本刊青年编委，博士；主要从事非常规油气藏开发、数值模拟、试井分析等方面的科研与教学工作；地址：（610500）四川省成都市新都区新都大道8号。ORCID: 0000-0002-5621-6420。E-mail:****************
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