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Conoco applies for Meltwater waterflood Field began with waterflood, then miscible injection, lean gas flood; return to waterflood estimated to allow 1-2% more recovery
Kristen Nelson Petroleum News
Kuparuk River field operator ConocoPhillips Alaska has applied to the Alaska Oil and Gas Conservation Commission for permission to return the Meltwater satellite to waterflood.
Currently waterflood at Meltwater is allowed only for some specific purposes; ConocoPhillips has applied to return the field to waterflood for enhanced oil production.
Meltwater, a satellite at the southwestern corner of Kuparuk, was originally produced on waterflood. Then the line carrying water to the field became corroded. Returning the field to waterflood is projected to extend field life by five to 10 years and result in recovery of an additional 1-2 percent of original oil in place.
Amendment of AIO ConocoPhillips is asking for an amendment to the area injection order for Meltwater. Water was injected at the beginning of field production, but stopped in October 2009 because of corrosion in the water supply line. The company said there were no plans to replace the line due to high cost and a determination that miscible injectant was the best mechanism to maximize production at the field.
In 2014, miscible injectant was no longer imported to Kuparuk and only lean gas was sent to Meltwater for lift and enhanced oil production.
ConocoPhillips said the lean gas flood has matured and the gas oil ratio has increased, making the Meltwater wells uncompetitive, with declining production raising freezing concerns for the production line.
The company said it is pursuing water injection below 3,400 psi with the goal of extending field life by reducing the gas oil ratio, providing pressure support and alleviating freezing concerns on the production line.
The water issue ConocoPhillips said the commission made changes in the area injection order in 2012, listing fluids authorized for injection. Water was not included, the company said, because it did not plan to restore water injection capability.
In a 2015 order, water was authorized for injection, but only for limited purposes.
The change ConocoPhillips is requesting would authorize use of Beaufort Sea and Kuparuk produced water, eliminating the limited purposes listed in 2015.
ConocoPhillips said the lift mechanism at Meltwater would also be changed from lift gas to jet pump.
There is only one functional injection pipeline, so only one fluid can be injected at Meltwater at a time, the company said. The flooding would increase oil recovery compared to not injecting water, the company said. Original oil in place estimates given at a 2012 hearing were 60 million barrels, the company said.
In addition to increasing ultimate recovery by 1-2 percent, waterflood would extend field life. “If water cannot be injected, the field would likely go into depletion or be shut in as it has reached MI maturity and received a lean gas chase,” ConocoPhillips said. The injection line servicing Meltwater and other Greater Kuparuk Area drill sites will soon be switched back to MI “to pursue newly drilled targets, but Meltwater is not a target for MI,” the company said.
A return to waterflood at Meltwater would allow pursuit of a potential 2 million to 7 million barrels of targets for development drilling, and has the advantage of preventing low flows and freezing concerns in the 24-inch production line.
“With water injection, water can be recycled directly from the injection line to the production line,” ConocoPhillips said. “This continuous loop of injection water will keep the production line from freezing even as reservoir production rates decline.”
The commission has scheduled a public hearing on the application Feb. 8 at 10 a.m.at its Anchorage offices.
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