Modelling of gas production from hydrate reservoirs

水合物储层天然气产量建模

• 批准号: 203325-2007
• 负责人: PooladiDarvish, Mehran
• 金额: $ 1.85万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=362230
• 关键词: Modelling; gas; production; hydrate; reservoirs

Gas hydrates are being evaluated for their potential as a future energy source.  To facilitate this evaluation, a few numerical reservoir simulators have been developed over the past decade.  These models are quite comprehensive and include the important mechanisms of multi-phase flow, convection and conduction, as well as intrinsic kinetics of hydrate decomposition.  Currently, three of these simulators, one of which has been developed in our group, are being used to evaluate the feasibility of suggested production methods.  This simulator will be enhanced as part of the research proposed here.Based on recent mechanistic studies using our hydrate simulators, we have identified a number of approximations which do not affect calculation of the gas-production rate from a hydrate reservoir that includes free gas at the bottom and a hydrate cap at top.  In such a reservoir, hydrates at top contribute to the produced gas once the reservoir pressure is reduced by gas production from the free-gas zone.  Large gas reservoirs of this type are known in Alaska and are believed to exist in the Mackenzie Delta of the Northwest Territories, Canada and.  Currently, planning for these reservoirs does not include the effect of additional gas generated by the decomposition of the gas hydrate.In this project, we invoke the above approximations and develop simple models to calculate the rate of gas production including that from the hydrates.   We will conduct extensive sensitivity studies using our comprehensive numerical simulator to examine the range of applicability of these simplified solutions, and to evaluate the impact of the hydrate on top of the gas reservoirs on productivity and life span of these reservoirs.Furthermore, the analytical solutions will be inverted, to develop methods for interpretation of tests performed on hydrate reservoirs, for determination of the in-situ properties of the hydrate reservoir.  Similar objectives are sought for the thermal stimulation technique.  As part of the research program proposed here, "equivalent" hydrate decomposition reaction parameters will be determined that are suitable for field-scale simulation.

人们正在评估天然气水合物作为未来能源的潜力。为了促进这种评价，在过去十年中开发了一些数值油藏模拟器。这些模型非常全面，包括多相流、对流和传导等重要机理，以及水合物分解的内在动力学。目前，这些模拟器中的三个，其中一个是在我们小组开发的，正在被用来评估建议的生产方法的可行性。该模拟器将作为本文提出的研究的一部分得到增强。根据最近使用水合物模拟器进行的力学研究，我们已经确定了一些不影响水合物储层产气速率计算的近似方法，其中包括底部的游离气和顶部的水合物顶。在这样的储层中，一旦储层压力因无气层的产气而降低，顶部的水合物就会成为产出气。这种类型的大型气藏已知存在于阿拉斯加，据信存在于加拿大西北地区的麦肯齐三角洲。目前，对这些储层的规划并未考虑天然气水合物分解产生的额外气体的影响。在这个项目中，我们调用上述近似并开发简单的模型来计算天然气产量，包括水合物的产量。我们将利用我们的综合数值模拟器进行广泛的敏感性研究，以检验这些简化解的适用范围，并评估气藏顶部水合物对气藏产能和寿命的影响。此外，将对解析解进行反转，以制定解释对水合物储层进行的测试的方法，以确定水合物储层的原位性质。热增产技术也寻求类似的目标。作为本文提出的研究计划的一部分，将确定适合现场规模模拟的“等效”水合物分解反应参数。