The geomechanical behaviour of natural and synthetic gas hydrate bearing sediments

*从自然形成的水合物堆积中生产甲烷气体提供了大量环境可持续的非常规天然气供应，这是一种有前途的未来能源。天然气水合物是由氢键水分子组成的晶体化合物，形成由包裹的甲烷分子稳定的刚性晶格。这些类似冰的固体是在高压和低温下形成的；因此，它们被发现在北极永久冻土以下或大陆斜坡和边缘的海底之下的沉积物的孔隙空间中。*天然气水合物钻探和表征探险所使用的技术最近发生了巨大的变化，其结果是我们对天然气水合物系统的理解发生了巨大的飞跃。由于天然气水合物在用常规取心回收时会迅速分解，因此开发了压力取心技术，以“锁定”现场静水压力和压力室转移，并建立了分析系统，以随后表征未受干扰的沉积物岩心。利用这些系统，最近在今年夏天收集的全面数据集可能会为天然气水合物赋存系统提供改变游戏规则的见解。这个研究项目检验了这些新获得的关于含天然水合物沉积物的信息与它们合成的实验室模拟之间的联系，进一步加深了我们对这两个系统的理解，并最终促进了我们在甲烷生产过程中对天然水合物积累的储集层地质力学进行建模的能力。*研究方法包括实验室测试、数值模拟和与来自天然气水合物岩心的最新数据的关键比较/分析相结合。通过仔细检查在最近的北极和海洋天然气水合物探险中积累的数据集，将建立我们对自然水合物性质知识的新基线。创造力、创新和合作将推动开发高度新颖的实验室工艺，以生产模拟自然样品的含有合成水合物的样品。重点实验计划的目的是定义基本性质和检查介观水平的响应，并最终为本构模型提供输入、校准和验证数据。通过扩大到储集层水平的模拟，可以探测、了解和预测从水合物积累的天然气生产过程中的沉积物响应(储集层稳定性、沉降和相关的地质灾害)。*天然气水合物是加拿大非常规能源供应的重要组成部分；研究和开发这种前沿天然气符合我们的优先事项，即增加北部开发，行使北极主权，并在减少经济和环境影响的同时优化能源回收。**

***Production of methane gas from naturally occurring hydrate accumulations offers a vast supply of environmentally sustainable unconventional gas, a promising future energy resource. Gas hydrates are crystalline compounds comprised of hydrogen-bonded water molecules forming a rigid lattice stabilized by encaged methane molecules. These “ice-like” solids form at high pressures and low temperatures; hence they are found within the pore space of sediments located below the permafrost in the Arctic or beneath the seafloor on the continental slopes and margins.***The technology used during gas hydrate drilling and characterization expeditions has recently undergone colossal change, the result of which has been a quantum leap in our understanding of natural gas hydrate systems. Because gas hydrate dissociates rapidly when recovered with conventional coring, pressure-coring techniques were developed to “lock in” the in-situ hydrostatic pressures and pressure chamber transfer and analyses systems built to subsequently characterize the undisturbed sediment core. Utilizing these systems, comprehensive datasets, gathered as recently as this summer, may offer game-changing insights into natural gas hydrate bearing systems. This research program examines the link between this newly available information on natural hydrate bearing sediments and their synthetically constructed laboratory analogs, furthering our understanding of both systems, and ultimately our ability to model reservoir geomechanics in natural hydrate accumulations during methane gas production. ***The research approach involves a combination of laboratory testing, numerical modeling, and critical comparison/analysis with the most up-to-date data from natural gas hydrate core. A new baseline of our knowledge of natural hydrate properties will be established through careful scrutiny of the datasets amassed during recent arctic and marine gas hydrate expeditions. Creativity, innovation, and collaboration will be the instigation for developing highly novel laboratory processes to produce synthetic hydrate-bearing specimens that mimic natural samples. Focused experimental programs aim to define fundamental properties and examine the meso-level response, and to ultimately provide the input, calibration, and verification data for constitutive models. Up scaling to reservoir-level simulations enables probing, understanding, and prediction of the sediment response (reservoir stability, subsidence, and associated geohazards) during gas production from hydrate accumulations.***Gas hydrates are an important component of Canada's unconventional energy supply; research and development of this frontier gas aligns with our priorities to increase northern development, exercise arctic sovereign rights, and optimize energy recovery while reducing economic and environmental impacts. **