水合物开采储层出砂数值模拟研究进展

Progress in numerical simulation of sand production from hydrate reservoirs

出砂是水合物安全、高效、长期、可控开采面临的主要风险之一,也是制约水合物产业化发展的瓶颈难题之一。通过数值模拟手段对水合物开采过程中井眼出砂的发生、发展及防控效果进行研究是揭示开采过程中储层出砂机理并厘清出砂规律的经济有效手段,对科学设计防砂控泥完井方式、推进水合物产业化进程具有重要作用。据此,本文系统梳理了水合物开采储层出砂数值模拟研究现状。首先简要分析了水合物开采出砂多场耦合作用机理,然后以出砂判断准则为切入点分析了连续介质理论在水合物出砂数值研究中的应用,接着扩展到基于离散介质理论的出砂行为机理分析和规律预测,总结了离散单元法构建水合物出砂模型的核心要素,包括水合物赋存模式、水合物分解效应和流固耦合作用。最后讨论了当前数值模拟研究存在的主要问题,对今后水合物开采储层出砂数值模拟研究提出了相应的建议。

Sand production is one of the critical issues that threaten safe,efficient,controllable and long-term gas production from hydrate reservoirs.Numerical simulation of the occurrence,development and control of sand production from hydrate reservoirs is considered to be an effective and economicmethod to reveal the sand production mechanism and clarify the sand production behaviors.It is of great significance for the scientific design of completion modes for sand control and the promotion of hydrate industrialization.Therefore,this paper systematically summarizes the research status of numerical simulation of the sand production from hydrate reservoirs.We first briefly discuss the multi-field coupling mechanism of sand production from hydrate reservoirs.Then we analyze the numerical study of sand production based on the continuum theory for sand production criteria.Furthermore,weintroduce the sand production mechanism and the prediction of sand production behavior based on the discrete medium theory.We summarize the key factors of sand production models established by the discrete element method(DEM),including hydrate pore habits,hydrate dissociation and fluid-solid coupling.Finally,the shortcomings of the current study are discussed,and some suggestions are provided for more accurate models of sand production from hydrate reservoirs in the future.