Modeling gas production from hydrates

Three models were used to fit the Mallik 2002 production data, and to extrapolate the results for long-term gas production (1) the Kurihara et al. (2005) model, frequently called the JOE (Japan Oil Engineering Co., Ltd.) model, which was fit to the thermal stimulation and one pressure-stimulation test, (2) theMoridis et al. (2005) model, labeled LBNL (Lawrence Berkeley National Laboratory), which was used to model the thermal stimulation test, and (3) the Hong and Pooladi-Darvish (2005) model, which was used to predict production from first principles, rather than to fit data of the production itself. 

FIGURE 7.43 Mallik 5L-38 gas production on thermal test. (From Hancock, S.H., et al., in Scientific Results from the Mallik 2002 Gas Hydrate Production Research Well Program, Mackenzie Delta, Northwest Territories, Canada, Geological Survey of Canada Bulletin 585, including CD (2005b). With permission.) 

FIGURE 7.44 Flared gas from Mallik 5L-38 thermal stimulation test. 

Finally, it is important to note that, while both the JOE and LBNL model fit the Mallik production data acceptably, as shown in Table 7.15 both extrapolate to significantly different long-term production values, perhaps due to the short-term and transient nature of the Mallik production test. 

Two things should be noted from Table 7.15 (1) while both the JOE and LBNL models fit the short-term Mallik 2002 data, the variation in predicted gas production varies from a factor of 3.7 to 290 and (2) the long-term gas production varies between 0.9 and 325 m3/day. 

---