海洋非成岩天然气水合物藏固态流化采空区安全性评价

发布时间：2018-05-06 22:42

本文选题：有限元 + 水合物　；参考：《天然气工业》2017年12期

【摘要】：为了解决固态流化法开采海洋非成岩天然气水合物(以下简称水合物)采空区安全性如何评估的问题,以中国南海神狐海域的水合物藏为例,根据水合物射流破碎流化开采工艺及流程,基于圣维南原理建立了采空区有限元模型并进行了网格精度验证,采用研究区水合物藏的物性参数和力学特征参数,模拟分析了垂直和水平采空区的稳定性问题,并探索了海洋非成岩水合物稳定层采空区的安全评价方法。结果表明:(1)基于圣维南原理建立的海底采空区有限元分析模型能够保证计算精度且计算工作量不大;(2)垂直采空区最大偏应力随采空区直径的增加呈现出先快速增加后缓慢增加的趋势,最大应变则随采空区直径的增加而呈线性增加;(3)垂直采空区的安全问题主要受到应力水平的控制,采空区直径不宜超过800 mm;(4)水平采空区最大偏应力和最大应变均随水平采空区直径的增加而呈现出单调增加的趋势。结论认为:垂直采空区的直径可以达到比较大的临界值,其安全性主要属于采空区井壁强度问题;而水平采空区的临界直径值则比较小,其安全性主要属于采空区稳定性问题。
[Abstract]:In order to solve the problem of how to evaluate the safety of mining goaf of marine non-diagenetic gas hydrate (hereinafter referred to as hydrate) by solid-state fluidization method, the gas hydrate reservoir in Shenhu area of South China Sea is taken as an example. According to the technology and process of hydrate jet fluidization mining, the finite element model of goaf is established based on the principle of San Venant, and the grid accuracy is verified. The physical and mechanical parameters of hydrate reservoir in the studied area are adopted. The stability of the vertical and horizontal goaf is simulated and analyzed, and the safety evaluation method of the goaf in the stable layer of marine non-diagenetic hydrate is explored. The results show that: 1) the finite element analysis model of undersea goaf based on the principle of Saint Venant can guarantee the calculation accuracy and the calculation work is not big. 2) the maximum deflection stress of vertical goaf increases with the increase of the diameter of the goaf. The tendency to increase slowly after adding, The maximum strain increases linearly with the diameter of the goaf. (3) the safety of the vertical goaf is mainly controlled by the stress level. The maximum deflection stress and the maximum strain of the horizontal goaf increase monotonously with the increase of the diameter of the horizontal goaf. The conclusion is that the diameter of vertical goaf can reach the critical value, and its safety mainly belongs to the problem of wellbore strength in goaf, while the critical diameter of horizontal goaf is relatively small, and its safety mainly belongs to the stability of goaf.
【作者单位】：西南石油大学;中国海洋石油总公司;中海油研究总院;
【基金】：国家重点研发计划项目“海洋水合物固态流化测试新技术”(编号:2016YFC0304008) 四川省教育厅重点项目(编号:16ZA0069)
【分类号】：TE53

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