ANALYSIS OF THE JOGMEC/NRCAN/AURORA MALLIK GAS HYDRATE PRODUCTION TEST THROUGH NUMERICAL SIMULATION

Methane hydrate (MH) production tests were conducted using the depressurization method in the Mallik production program in April 2007 and in Mach 2008. In addition to attaining the first and the only successful methane gas production to the surface from a MH reservoir in the world, various data were obtained. The results of the production test were analyzed using a numerical simulator (MH21-HYDRES). This paper evaluates these test results through the analyses of production test data, numerical modeling and a series of history matching simulations. In 2007, a certain amount of gas and water were produced from a 12 m perforation interval in one of the major MH reservoirs at the Mallik site in Canada, by reducing the bottomhole pressure down to about 7 MPa. However, because of the irregular pumping operations, the produced gas was not directly delivered to the surface via the tubing, but was accumulated at the top of the casing. In 2008, much larger and longer gas production was accomplished with a stepwise reduction of the bottomhole pressure down to about 4.5 MPa, resulting in the gas and water produced to the surface. The flow rates of gas and water from the reservoir sand face in these tests were estimated by the comprehensive analysis of the continuously monitored data. The test results were then analyzed using MH21-HYDRES. The reservoir model was tuned through history matching so as to reproduce the flow rates of gas and water estimated in the above, not only by simply adjusting reservoir parameters, but by introducing the concept of the improvement/reduction of nearwellbore permeability reflecting the creation/deformation of high permeability zones associated