天然气水合物分解对井筒周围土层变形的影响

通过运用FLAC3D软件建立三维土体模型,采用具有塑性流动特性的摩尔库仑模型并参考我国近海海域地形和地质参数,分析水合物分解后的井筒周围土体变形,重点讨论天然气水合物分解范围、土层倾角、井筒与土体间的连接方式等因素对土体变形的影响,对深水天然气水合物的开采土体稳定性和安全性进行评估。结果表明:水合物分解范围对土体变形影响最大,水合物分解范围越大,储层的沉降越大;当分解范围超过某临界值时,井筒周围土体发生破坏。这些结论可为深水水合物开采及勘探时的井筒安全评估提供参考。

Deformation of Soil Around the Wellbore Caused by Gas Hydrate Dissociation

Stratum deformation around wellbore due to GH dissociation was numerically simulated by using FLAC 3D to de-velop a three-dimensional model of the soil and the model mohr-coulomb which has the plastic flow characteristics ,refer-ring as the offshore topographical and geological parameters in China .The effects of GH dissociation range ,stratum slope and the connection states between wellbore and stratum on the stratum deformation were mainly investigated to assess the stability and safety of the soil .The results show that the effect of dissociation scope is the greatest .If the dissociation scope exceeds a critical value ,the soil surrounding the wellbore can be failure .These results can be taken as the refer-ences to the safety assessments on the exploration and recovery of marine GH .