Faced with the pending expiry of some state leases southwest of Soldotna on Alaska’s Kenai Peninsula, Aurora Gas has filed paperwork with Alaska’s Division of Oil and Gas to re-enter the Cohoe No. 1 well, to test for natural gas.
The company is negotiating with the Alaska Department of Natural Resources over possible unitization of the leases, which expire on Sept. 30, Aurora Gas President Scott Pfoff told Petroleum News Aug. 18. The unitization agreement would include a commitment to shoot some 3-D seismic in the leases, Pfoff said.
But Aurora has filed the drilling paperwork in case the unitization deal falls through.
“We think it makes more sense to unitize the acreage and shoot 3-D seismic,” Pfoff said. “However, as an alternative we are seeking the necessary permits to conduct a re-entry.”
Pfoff said that Aurora had just finished a workover and recompletion of its Moquawkie No. 4 gas well and planned to start testing that well “within the next day or two.” Moquawkie is one of five gas fields that Aurora operates on the west side of Cook Inlet.
Aurora does not yet have any approvals for drilling rig operations after the Moquawkie well but plans to use a coiled tubing unit to clean out several wells. The company is also busy with maintenance projects on its surface facilities, Pfoff said.
Drilled in 1973
Unocal drilled the Cohoe well in 1973 about four miles northeast of the community of Kasilof to a vertical depth of 15,680 feet in an unsuccessful search for oil. In a classic “bypass play,” Aurora plans to determine if there are viable gas resources in rock horizons at some height above the original deep oil prospect.
“Like so many other wells drilled in the Cook Inlet, this well was drilled deeper, looking for oil and with heavier (drilling) mud,” Pfoff said. “We see evidence of bypassed gas pay, but testing was minimal and we suspect negatively impacted by mud invasion into the formation.”
The Cohoe well is relatively close to the existing Kenai Peninsula natural gas infrastructure, including the Kenai Kachemak pipeline, the line that any gas production from Cohoe would likely hook into.
Aurora says that it will use its AWS No. 1 drilling rig for the Cohoe re-entry, operating from the well’s exiting gravel pad and starting the drilling operation on Sept. 15, depending on rig availability. There are existing gravel roads for access to the pad, Aurora said in its plan of operation.
The rig will drill down through some of the old cement plugs in the well before perforating the well casing to test for gas in the Beluga, Tyonek and Sterling gas sands, at depths ranging from 8,241 feet to 4,922 feet.
“The well is considered to be a development well because the well was logged during drilling and identified several gas targets,” Aurora said in its plan of operations. “2-D seismic has been reprocessed to delineate several gas reservoirs.”
ACMP consistency
In its plan, Aurora asserted that because it would simply be re-entering an existing well in an operation similar to a well rework, at a location some distance from the coast, a review for consistency under the Alaska Coastal Management Program would not be necessary.
But DNR appears to have taken different position on this issue. In an Aug. 17 letter to Aurora Gas, Alaska’s Division of Coastal and Ocean Management told the company that the Division of Oil and Gas would coordinate an ACMP consistency review. And on the same day DNR issued a notice, inviting public comments on ACMP consistency by Sept. 15.
—Alan Bailey
