Ground movements associated with gas hydrate production. Progress report, January 1--March 31, 1993

摘要

The grantee will evaluate the influence of hydrate production on ground subsidence near the wellbore and the surface. The objective of this research will be achieved by using computer simulations of what is expected in a hydrate reservoir during the production stage as reported by hydrate production models and available data. The model will be based on theories of continuum mechanics, thermomechnanics of hydrate production, principles of rock mechanics and geomechanics, and special features of geomaterials under cold temperatures such as those found in permafrost regions. The research work involved in the proposed investigation will be divided into three major tasks: mechanics of subsidence in permafrost regions; modeling of subsidence; and parametric studies. Under task 1, the literature survey was completed, and following factors were identified influencing subsidence: overburden depth; extent of dissociated (or depleted) hydrate reservoir; rock/frozen soil mechanical properties and strength; and reservoir compaction characteristics. Under task 2, technical progress is reported for studies on: mechanical properties; simulation of reservoir compression; and computer modeling effort.