Abstract The stratification split grouting foam mortar method (SSGFM) was first proposed to stimulate the low-permeability gas hydrate reservoir through constructing the fast flow channel for enhancing gas production. Based on the low-permeability hydrate-bearing sediments (HBS) at SH2 site in the Shenhu area of South China Sea, the foam mortar layer (FML) reservoir model was constructed. The numerical simulation that coupled thermal-hydraulic-mechanical processes was employed to evaluate the efficiency and feasibility of this method. Results show that the FML could effectively promote the expansion of the low-pressure zone into the hydrate reservoir, and enhance gas hydrate dissociation rate, cumulative gas production and energy efficiency. The foam mortar layers (FMLs) have significant influence on the spatial distribution and the evolution characteristics of reservoir thermophysical and geomechanical parameters during gas production. The sensitivity analysis of FML shows the number of FMLs, thickness and permeability of FML exist the critical values for meeting the demand of promoting hydrate dissociation and gas production. Although the cumulative gas production and gas production rate will greatly increase with enlarging the radius, the gas-to-water ratio increase slightly. In view of the hydrate reservoir at SH2 site, the recommended number of FMLs is 4–6, and the distance between the FML and overburden/underburden should be more than 7.5 m. In addition, the optimal values of thickness, radius and permeability of FML are 5 cm, 40 m and 1 × 10−10 m2, respectively. The geomechanical response indicates that the FMLs are beneficial for reservoir stability while improving gas production.

中文翻译：

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分层分裂注浆泡沫砂浆法储层增产增产天然气水合物储层

摘要 首次提出分层劈裂注浆泡沫砂浆法（SSGFM），通过构筑快速流道增产，对低渗透天然气水合物储层进行增产改造。以南海神狐海域SH2站点低渗透水合物沉积物（HBS）为基础，构建泡沫砂浆层（FML）储层模型。采用热-水-机械耦合过程的数值模拟来评估该方法的有效性和可行性。结果表明，FML能有效促进低压带向水合物储层扩张，提高天然气水合物的解离速率、累计产气量和能源效率。泡沫砂浆层（FMLs）对采气过程中储层热物理和地质力学参数的空间分布和演化特征具有显着影响。FML的敏感性分析表明，FML的数量、厚度和渗透率存在满足促进水合物解离和产气需求的临界值。虽然随着半径的扩大，累计产气量和产气率会大大增加，但气水比略有增加。针对 SH2 站点的水合物储层，建议 FML 数量为 4-6，FML 与上覆/下覆地层的距离应大于 7.5 m。此外，FML 的厚度、半径和渗透率的最佳值分别为 5 cm、40 m 和 1 × 10−10 m2。