Methane Hydrates, page-8

Its important to be clear on the definition of hydrate in this instance.

Methane hydrates are ice-like solids that consist of methane and water. The methane molecules are enclosed in microscopic cages of water molecules. Methane hydrates are generally found under polar regions and in the sediments of deep-sea regions where the temperature is low and the pressure is great. JOGMEG is drilling into these structures and using hot water to melt the ice thus releasing the gas.

During drilling operations, if the conditions are favourable (pressure and temperature) the water in the drilling mud will mix with gas and create a hydrate. During well test operations you usually inject Methanol at the sub surface safety valve, and upstream of the choke manifold to manage hydrate issues. I am not a drilling engineer so I am not quite sure how you would manage this during drilling operations.

I just did some additional research and use of thermodynamic inhibitor additives (mainly salt and glycol additives) will help to inhibit hydrate formation. Its one of the reasons I was asking about the water depth as hydrates are generally more probable in deep drilling applications.

- Water depth 1,500 ft: Without inhibition, risk of hydrate occurrence
- Water depth 2,000 ft: Without inhibition, hyd rate occurrence
- Water depth >2,000 ft: Limited experience - salts alone not sufficient.

Maybe it has nothing to do with hydrates but the previous poster that mentioned this stated his anonymous source was credible.