|
Anadarko plugs and abandons Altamura The spring project in NPR-A will close the books on the first Alaska exploration well drilled by the busy Houston independent Eric Lidji Petroleum News
As Anadarko Petroleum eyes its future in Alaska, it also took care of its past.
The company recently plugged and abandoned an old National Petroleum Reserve-Alaska well this spring. Originally spud on March 10, 2002, the Altamura No. 1 well was Anadarko’s first wildcat on the North Slope, drilled during a period of limited activity in northern Alaska.
Anadarko, which owned a 100 percent interest in the Altamura lease, reached the well by traveling along an existing ConocoPhillips ice road leading to the Rendezvous No. 2 well site. Anadarko built a new road to cover the remaining 5.5 miles leading south to Altamura No. 1, situated along the southern boundary of the Greater Mooses Tooth unit.
Anadarko also built a 900-square-foot ice pad, a 5,000-foot ice airstrip and a 25-man construction camp at the Altamura No. 1 well site.
In its environmental assessment of the Altamura prospect, the U.S. Bureau of Land Management said the purpose of drilling at Altamura was to delineate the potential southern extension of the oil and gas formation discovered on nearby leases owned by Anadarko and majority partner ConocoPhillips.
Altamura, BLM explained, was the farthest south of the NPR-A exploration wells, some four miles south of the Rendezvous discovery announced in 2001.
Altamura showed pay, but low permeability When Anadarko began exploring Altamura back in the early part of the decade, a company official said Anadarko hoped to repeat the success of the Alpine field.
But while the Altamura well reached a vertical depth of 9,041 feet and hit pay, the well also encountered low permeability, meaning liquids would have a tough time flowing through underground rocks up to the surface, suggesting the field would have produced at lower rates.
“Pay means they hit hydrocarbon bearing rocks or a formation,” which is good news, a state Division of Oil and Gas official told Petroleum News following Anadarko’s March 2003 report in a Securities Exchange Commission filing.
“Low permeability means the well would produce, in relative terms, at lower rates. Permeability affects the flow rate, but not how much oil and gas is in the reservoir,” he said.
There are two common ways to address permeability problems on the North Slope, where low permeability is not unusual. “You can drill vertical wells and fracture them or drill long, horizontal wells like they’ve done at Alpine, exposing a lot of the reservoir to well bore. Some of the Alpine horizontal wells are 3,000 feet long. … Either way, you can substantially increase your flow rate,” the state official said.
Anadarko suspended the Altamura No. 1 well on April 11, 2002. The company permitted, but never drilled, an Altamura No. 2 well, despite extending permits for the well when they first expired.
Anadarko also asking for ROW renewal An environmental assessment by the federal Bureau of Land Management said the “current need for the project is to take advantage of another operation in the vicinity of the well,” referring to those nearby NPR-A projects where Anadarko is a partner with ConocoPhillips.
When it asked for a permit to plug the old well, Anadarko also requested a one-year right of way renewal within the Northeast portion of the NPR-A.
| 