Observation of natural gas hydrate dissociation with X-ray CT

摘要

Dissociation of gas hydrate, which has drawn much attention as an unconventional energy resource, in natural core samples from permafrost was observed with an X-ray CT scanner. Both depressuriz-ing and heating processes, which are considered as typical potential production processes, were simulated in laboratory scale for the field gas production tests from gas hydrate. Dissociation of the gas hydrate was clearly observed as difference of CT values. The difference was mainly caused by gas phase formation. Obtained three-dimensional CT data of inside of the cores were processed to visualize dissociation behavior. Consequently it was observed that dissociation behavior depended on quantity and distribution of hydrates. These results suggested that X-ray CT scanning was suitable for observation of natural gas hydrate dissociation in sediments and useful for evaluation of gas hydrate as an unconventional energy in future.