考虑液硫吸附作用的高含硫气藏地层条件气-液硫相对渗透率实验与计算模型研究

The reservoir temperature of high sulfur gas reservoirs in Sichuan basin is generally higher than the melting point of elemental sulfur, and the flow state is gas-water-liquid sulfur flow or/and gas-water-solid sulfur coupling flow during gas production. At present, there is no experimental test and theoretical model of gas-liquid sulfur relative permeability in high sulfur gas reservoirs under HPHT formation conditions at home and abroad. Conventional experimental test results can not reflect the true underground seepage characteristics of high sulfur gas reservoirs, and the effect of liquid sulfur adsorption on reservoir damage in near-wellbore area is rarely reported. By combining experimental with theoretical method, a theoretically study is used to determine the specific pressure-temperature conditions of liquid sulfur precipitation in high sulfur gas mixture, and a series of experiments is conducted to study the physical and chemical mechanism of liquid sulfur adsorption in porous media. In additions, this study will analyze the change of pore structure before and after liquid sulfur adsorption, and evaluate the influence of liquid sulfur adsorption on reservoir damage. The gas-liquid sulfur relative permeability of cores with different permeability at different temperatures, pressures and H2S contents was tested by physical simulation with a self-developed gas-liquid sulfur relative permeability testing device for high temperature and high pressure gas reservoirs with high sulfur content. The physical property parameters of fluids were corrected in real time and the experimental data acquisition method was improved. The calculation model of gas-liquid sulfur relative permeability with considering liquid sulfur adsorption will be established. Then the influence of different relative permeability on the development performance is studied in high sulfur gas reservoirs. The research results will lay a foundation for reasonable adjustment of development scheme of high sulfur gas reservoir.

四川盆地高含硫气藏储层温度普遍高于单质硫的熔点，开采过程中流动状态为气-水-液态硫流动或和气-水-固态硫耦合流动。目前国内外尚无地层条件高含硫气藏气-液态硫相对渗透率实验测试和相关理论模型，常规实验测试结果不能反映高含硫气藏真实的地下渗流特征，液态硫吸附对近井地带储层伤害影响亦鲜有报道。本申请书采用实验和理论相结合，理论研究高含硫气体中液态硫析出的具体压力-温度条件，实验研究多孔介质中液态硫吸附物理化学机制，分析液硫吸附前后孔隙结构变化，评价液硫吸附对储层伤害的影响；采用自研自制的高温高压高含硫气藏气-液硫相对渗透率测试装置，物理模拟测试不同渗透率岩心在不同温度、压力、H2S含量的气-液硫相对渗透率，实时校正流体物性参数，改进实验数据采集方法；并建立考虑液硫吸附作用高含硫气-液硫相对渗透率计算模型，研究不同相对渗透率对高含硫气藏开发动态影响。研究成果将为高含硫气藏开发方案合理调整奠定基础。

本项目采用实验和理论相结合，理论研究高含硫气体中液态硫析出的具体压力-温度条件，实验研究多孔介质中液态硫吸附物理化学机制，物理模拟测试不同渗透率岩心在不同温度、压力、H2S含量的气-液硫相对渗透率，实时校正流体物性参数，建立考虑液硫吸附作用高含硫气-液硫相对渗透率计算模型，研究不同相对渗透率对高含硫气藏开发动态影响。.按照研究计划完成了所有的研究工作，取得的重要成果如下:.（1）采用热力学定律中的熵判断准则，推导出硫元素析出的温度压力条件，确定硫沉积生成的具体温度和压力条件，并进行模型验证；.（2）研制了系列高含硫气藏开发渗流实验设备，首次开展液硫析出与沉积储层伤害、液硫吸附和气-液硫两相渗流实验，建立了高含硫气藏开发物理模拟系列实验新技术。.（3）建立了一套硫沉积实验及分析方法，研究出硫沉积实验中岩样渗透率的动态变化规律，定量分析硫沉积对岩石微观孔隙结构的影响。.（4）建立了高含硫气藏地层水-岩反应实验装置与方法，首次评价高温高压地层条件高含硫气藏水-岩反应过程中孔隙结构、离子浓度、矿物组成、孔隙度和渗透率变化规律。.（5）研制了抗硫高温高压相对渗透率测试仪，采用实时物性计算对地层条件下粘度、偏差因子、体积系数进行校正，并能考虑液硫对相渗曲线的影响。理论建立了实验室条件与地层条件相对渗透率曲线转换关系，模拟计算了不同温度压力对气水相对渗透率的影响。 .（6）选取川东北典型高含硫气井，开展考虑液态硫影响的高含硫双重介质气藏气-液渗流规律研究，研究了不同条件下相对渗透率对高含硫气藏开发动态的影响。.项目完成期间，发表期刊论文24篇，其中以第一/通讯作者发表SCI论文7篇，出版学术专著6部，授权美国发明专利1件，授权国内发明专利6件，获省部级奖励4项。项目负责人2019年享受国务院政府特殊津贴专家，2019年和2022年两次四川省二级教授，培养博士生1名，硕士生9名。