Arctic Hydrates

Gas hydrates are found within and beneath permafrost on the North Slope of Alaska, in the Canadian Arctic, and in northern Siberia. The Arctic hydrates have the potential to become economically viable sources of natural gas. The best do­cumented Alaskan accumulations are in the Prudhoe Bay-Kuparuk River area, which contains approximately 30 trillion standard cubic feet of natural gas, about twice the volume of conventional gas found in the Prudhoe Bay field (Collett 2002). The proximity to highly developed oilfield infrastructure makes the Prudhoe Bay-Kuparuk River accumulation particularly attractive. The main technology barrier is the lack of validated methods for economically viable production of natu­ral gas from hydrate. An Arctic site capable of supporting multiyear field experi­ments would enable significant progress beyond the present state of knowledge.

Arctic hydrate reservoirs are potentially high quality sources of natural gas. The most important Arctic hydrate reservoirs accumulate in the Prudhoe Bay-Kuparuk River region on the North Slope of Alaska. Other reservoirs exist elsewhere on the North Slope of Alaska, in northern Canada, and in Siberia. Some important Arctic hydrate accumulations have good porosity and good gas saturation, and are pre­dominantly found in coarse sands that have high intrinsic permeability. Overlying permafrost may provide a low-permeability barrier to gas leakage during extraction. These factors are favorable for production. One of the few fields in which gas pro­duction has been attributed to hydrates is the Messoyakha gas field in West Siberia.

A heavily monitored gas hydrate production experiment was carried out in 2002 at the Mallik site in the Mackenzie Delta, Northwest Territories, Canada (Dalli – more and Collett 2005). During a period of 1 week, both depressurization and ther­mal stimulation were used to produce gas from hydrate. Although a technical suc­cess, the experiment was too brief to serve as a guide to reservoir-scale production.

In the absence of a gas pipeline, Arctic gas hydrate is a stranded resource. Generically there are three ways to destabilize gas hydrate to produce free gas from an Arctic gas hydrate reservoir. These are heating, depressurization, and chemical inhibition. Reservoir simulators have been developed to predict the efficacy of these techniques, singly or in combination (Masuda et al. 2002). Al­though consistent with each other, the simulators have yet to be validated by field test data (Moridis 2003).

There are several strong arguments in favor of a long-term gas hydrate produc­tion test facility in an Arctic area (AGHPW 2005):

• Because there are a number of ways of destabilizing hydrate, multiple tests will be required to identify the best technique or the best combination of techniques.

• Reservoir simulations suggest that these tests will need to be of long duration (1 year or more) to properly assess the success of a technique (Masuda et al. 2002; Moridis 2003).

• There are many advantages to drilling multiple wells from a single pad. Produc­tion tests in the Arctic can also serve as an early and relatively low cost indicator of how the potentially larger marine hydrate resources might be produced.

Updated: September 22, 2015 — 8:13 pm