Abstract Geologic reservoirs containing gas hydrate occur beneath permafrost environments and within marine continental slope sediments, representing a potentially vast natural gas source. Numerical simulators provide scientists and engineers with tools for understanding how production efficiency depends on the numerous, interdependent (coupled) processes associated with potential production strategies for these gas hydrate reservoirs. Confidence in the modeling and forecasting abilities of these gas hydrate reservoir simulators (GHRSs) grows with successful comparisons against laboratory and field test results, but such results are rare, particularly in natural settings. The hydrate community recognized another approach to building confidence in the GHRS: comparing simulation results between independently developed and executed computer codes on structured problems specifically tailored to the interdependent processes relevant for gas hydrate-bearing systems. The United States Department of Energy, National Energy Technology Laboratory, (DOE/NETL), sponsored the first international gas hydrate code comparison study, IGHCCS1, in the early 2000s. IGHCCS1 focused on coupled thermal and hydrologic processes associated with producing gas hydrates from geologic reservoirs via depressurization and thermal stimulation. Subsequently, GHRSs have advanced to model more complex production technologies and incorporate geomechanical processes into the existing framework of coupled thermal and hydrologic modeling. This paper contributes to the validation of these recent GHRS developments by providing results from a second GHRS code comparison study, IGHCCS2, also sponsored by DOE/NETL. IGHCCS2 includes participants from an international collection of universities, research institutes, industry, national laboratories, and national geologic surveys. Study participants developed a series of five benchmark problems principally involving gas hydrate processes with geomechanical components. The five problems range from simple geometries with analytical solutions to a representation of the world's first offshore production test of methane hydrates, which was conducted with the depressurization method off the coast of Japan. To identify strengths and limitations in the various GHRSs, study participants submitted solutions for the benchmark problems and discussed differing results via teleconferences. The GHRSs evolved over the course of IGHCCS2 as researchers modified their simulators to reflect new insights, lessons learned, and suggested performance enhancements. The five benchmark problems, final sample solutions, and lessons learned that are presented here document the study outcomes and serve as a reference guide for developing and testing gas hydrate reservoir simulators.

中文翻译：

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天然气水合物沉积物热、水、地质力学耦合过程国际规范比较研究

摘要 含有天然气水合物的地质储层出现在多年冻土环境下和海洋大陆坡沉积物中，是一个潜在的巨大天然气来源。数值模拟器为科学家和工程师提供了工具，用于了解生产效率如何取决于与这些天然气水合物储层的潜在生产策略相关的众多相互依赖（耦合）的过程。对这些天然气水合物储层模拟器 (GHRS) 的建模和预测能力的信心随着与实验室和现场测试结果的成功比较而增长，但这种结果很少见，尤其是在自然环境中。水合物社区认识到另一种建立对 GHRS 信心的方法：比较独立开发和执行的计算机代码之间针对结构化问题的模拟结果，这些问题专门针对与含天然气水合物系统相关的相互依赖的过程量身定制。美国能源部国家能源技术实验室 (DOE/NETL) 在 2000 年代初赞助了第一个国际天然气水合物代码比较研究 IGHCCS1。IGHCCS1 侧重于与通过减压和热刺激从地质储层生产天然气水合物相关的热和水文耦合过程。随后，GHRS 已经发展到对更复杂的生产技术进行建模，并将地质力学过程纳入现有的耦合热和水文建模框架。本文通过提供同样由 DOE/NETL 赞助的第二个 GHRS 代码比较研究 IGHCCS2 的结果，有助于验证这些最近的 GHRS 发展。IGHCCS2 包括来自国际大学、研究机构、工业、国家实验室和国家地质调查局的参与者。研究参与者开发了一系列五个基准问题，主要涉及具有地质力学组件的天然气水合物过程。这五个问题的范围从带有解析解的简单几何图形到世界上第一个甲烷水合物海上生产测试的表示，该测试是在日本沿海使用减压方法进行的。确定各种 GHRS 的优势和局限性，研究参与者提交了基准问题的解决方案，并通过电话会议讨论了不同的结果。随着研究人员修改他们的模拟器以反映新的见解、经验教训和建议的性能增强，GHRS 在 IGHCCS2 的过程中不断发展。这里介绍的五个基准问题、最终样本解决方案和经验教训记录了研究结果，并作为开发和测试天然气水合物储层模拟器的参考指南。