3. CHALLENGE: Temperature control How can we produce from hydrate reservoirs without flow-assurance issues? Q : There are two factors that will cool a system during gas production from hydrates: The Joule-Thomson effect (expanding gas cools down); and hydrate dissociation (melting) is an endothermic reaction (absorbes heat). Since the reservoir will, by definition, be within hydrate stable thermodynamic conditions, a slight decrease in temperature may hydrate (either near, or in the wellbore).
4. Q: CHALLENGE: Sand control There is only one production test currently that has shown proof of concept in regards to gas production from gas hydrates. This test was done in Northern Canada – at the Mallik site. The hydrate reservoir is shallow below permafrost, so the sediments where unconsolidated. This showed that sand control is of great importance. This is also expected to be the case for some marine reservoirs. How can we produce gas from hydrate reservoirs in unconsolidated sediments more efficiently?
5. Q: CHALLENGE: Water control How do we dispose of the water in hydrate production? Hydrate production will most likely result in large amounts of water. This poses several issues not typically handled: The water has to be disposed some way (and reinjection is not an option initially due to the increase in reservoir pressure); there will be a “water lift” issue (due to large amounts of water and low pressure gas).
6. Where do we find hydrates? BGHZ GHSZ Depth Temperature Temperature hydrate stability GHOZ BGHZ GHSZ Depth Temperature Temperature hydrate stability Base Permafrost
Why sand-rich reservoir? Sand-dominated systems, due primarily to their intrinsic high permeability, that is necessary to enable the accumulation of gas hydrate to concentrations that are consistent with extraction (sand-hosted gas hydrates typically occur at saturations ranging from 50 to ~90% or more) The permeability of the sand matrix makes well-based production feasible Note : It is not reasonable to speculate on volumes that may ultimately be economically recoverable until a series of extended term production tests are conducted
