Alaska gas-hydrate test exposes failures in pumps and sand control

What the test found

The test facility operated from September 2023 to July 2024, with 315 days of operation and 64 days without production because of mechanical failures, sand-production problems and replacement of the electric pump with a jet pump.

During electric-pump operation, pressure could not be reduced below about 850 psi, or roughly 400 psi of drawdown, because gas-production surges caused the pump to stop functioning in a condition known as gas lock. The team therefore maintained a constant pressure of about 850 psi for 60 days. Gas production remained near 70 thousand cubic feet per day and water production near 10 barrels per day, with no significant variation.

The test showed no upward or downward trend in production during that period. With the jet pump, pressure at the well bottom was reduced to about 200 psi, but this had only a limited effect on pressure in the formation. Researchers attributed the result to a fine-grained, low-permeability layer associated with the sand-control system. Attempts to remove it with injected chemicals were unsuccessful, leading to higher pressure differences and low productivity. Post-test operations confirmed the ultimate failure of the sand-control system.

Lessons for future tests

The test provides direct operational information about the equipment needed to produce gas from hydrate-bearing formations over an extended period. It shows that both the pump used to lift fluids and the system designed to control sand can restrict production or stop operations. These findings will inform the design of future gas-hydrate production tests, although the test did not establish whether production would rise or fall over longer periods.

Evidence and limits

This is an operational field test, not a controlled comparison of different well designs. The facility ran for 10 months, but production was interrupted for 64 days by mechanical and sand-related problems and by the pump replacement. The stable 60-day production period showed no significant rate change, but it was not long enough to resolve the longer-term production behavior. The explanation involving a fine-grained layer was an assumption based on the observed pressure response and the sand-control system; chemical treatment did not remove the problem. The post-test inspection confirmed failure of the sand-control system, but the abstract does not provide a separate production test to compare alternatives.