Fabrication and Testing of Apparatus for Laboratory Simulation of Alaska Frozen Rock Encountered during Hydrate Gas Reservoir Coring

• Published in: Journal of cold regions engineering Vol. 18; no. 2; pp. 53 - 69
• Main Authors: Goel, Naval, De Sousa, Joao Tadeu V, Flenniken, Joseph, Shah, Subhash, Liddell, Bill
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.06.2004
• Subjects: Applied sciences; Buildings. Public works; Exact sciences and technology; Geotechnics; Measurements. Technique of testing; Soil investigations. Testing; TECHNICAL PAPERS; Alaska; United States; North America; America; Drilling; Temperature distribution; Prototype; Computer simulation; Porous medium; Experimental device; Permafrost; Energy development; Full scale mockup test; Fabrication; Porous media; Gas well; Experimental result; Research program; Frozen soils; Frozen ground; Alaska; Manufacturing; Simulation model; Wells; Heat transfer; Thermocouple
• ISSN: 0887-381X; 1943-5495
• DOI: 10.1061/(ASCE)0887-381X(2004)18:2(53)

Gas hydrates are inclusion compounds in which gas is trapped in ice. They are widely found in nature in permafrost and deep-sea sediments and hold huge potential as a methane gas resource. As a result, a National Methane Hydrate R&D program was launched in 2000 by the United States Department of Energy. One of the projects under the program, run by the National Energy Technology Laboratory (NETL/DOE DE-FC26-01NT41331), is to drill, core, and test one gas hydrate well in the Prudhoe Bay/Kuparuk River area of northern Alaska. In this project, cores are studied to gather field data on a hydrate reservoir in permafrost regions. Tests were required to develop coring techniques and handling procedures on frozen rocks prior to actual coring in Alaska. These tests were performed at a Houston research facility where frozen rocks were prepared using an apparatus fabricated to simulate hydrate reservoir in permafrost. The permafrost formation was simulated with a water-saturated sand pack, which was frozen using liquid nitrogen. Frozen rocks of up to 3.6 m (12 ft) high and 0.254 m (10 in.) diameter were prepared with the apparatus. The setup was designed and evaluated in several stages. First, a computer model was developed to understand the rock-freezing process. Then a prototype setup was constructed to have similar radial dimensions as the full-scale apparatus, but with a smaller height. Several experiments were performed to test the prototype and the full-scale apparatus. The apparatus has been successfully employed to prepare frozen rock, thereby assisting in development of improved coring methodology for Alaskan permafrost hydrates exploration.