Physical property studies in the USGS GHASTLI Laboratory

One of the many challenges in studying methane hydrate is that it is unstable at typical surface pressure and temperature conditions. To enable methane hydrates and hydrate-bearing sediments to be formed, analyzed, and experimented with, the National Energy Technology Laboratory (NETL), and the U.S. Geological Survey (USGS) in Woods Hole, MA collaborated in the development of the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI). Over the past decade, the USGS has been operating GHASTLI and collaborating in the development of new sample handling tools and procedures, in an effort to improve our ability to analyze methane hydrate in the lab. These tools will enable hydrate researchers to more confidently link field studies (for example geophysics or drilling) with theoretical and predictive studies, leading to a better understanding of the geological conditions and processes that control the growth and concentration of natural gas hydrates, how hydrates affect the properties of the host sediments, and how the hydrate-sediment system changes when hydrate dissociates and releases the previously bound gas. To date, GHASTLI has been used to measure natural samples from ODP Leg 164 (Blake Ridge off the U.S. southeast Atlantic margin), Leg 204 (Hydrate Ridge off the Pacific Northwest margin) and the Mallik well (Mackenzie Delta in northwestern Canada). Additional samples in the queue for analysis are from the Chevron Joint Industry Project Experiment in the Gulf of Mexico and most recently, from IODP Leg 311 off Vancouver Island. Several foreign nations have asked whether GHASTLI will be available to analyze samples that might be recovered during national drilling programs. The ability to perform lab testing of hydrates within sediments is one of the unique capabilities of GHASTLI that separates it from other simulators at NETL and elsewhere.