Distinct Element Method Simulation of Bonded type Methane Hydrate Bearing Sediments Exploitation by Thermal Recovery depressurization Combined Method

Abstract:

A newly proposed 2D bond model, which took the coupled effects of temperature hydraulic mechanical into consideration, was implemented into the distinct element method (DEM) software Particle Flow Code (PFC2D) to generate methane hydrate bearing sediment (MHBS) that only the bond type methane hydrate (MH) existed. MHBS samples in this simulation were in good drainage and exhaust condition. Then a series of biaxial compression tests were conducted. Results show that when the deviator stress is smaller than the peak deviator stress of pure sand sample, the sample won’t be damaged after dissociation; when the deviator stress is larger than the peak deviator stress of pure sand sample, the MHBS sample will be damaged and several undeveloped shear bands occur. In addition, several micro variables such as contact distribution, averaged pure rotation rate(APR) and quasi static velocity field, were analyzed in four dissociation phases.

Key words:methane hydrate bearing sediments; thermal recovery depressurization combined method; macro and micro mechanical property