For the first time, ConocoPhillips explained on Tuesday what went wrong to trigger an unexpected natural gas leak at a drilling pad in the Alpine field on Alaska’s North Slope that began in March and continued for weeks.
The leak was discovered on March 4 at the CD1 drilling pad and was caused by excessive pressure during a drilling operation, according to the business. According to a nine-page technical analysis, it led a well component to collapse roughly half a mile below the surface.
The company stated that “Pressure restrictions were exceeded” during the surgery. Increased pressure was felt after pumping diesel fluid into the well to protect it from permafrost (frozen earth), which can cause pipes to burst.
Furthermore, for three days before the leak was discovered, the corporation missed an opportunity to reduce the leak by detecting and responding to the rising pressure, according to the report.
There was no enquiry or remedial action during that period because “the pressure increases were not noticed or handled,” the report stated.
Residents in the adjoining village of Nuiqsut were frightened by the gas leak, which led to the temporary evacuation of 300 workers from the drilling site.
As a result of this, the Alaska Oil and Gas Conservation Commission and the House Natural Resources Committee are currently conducting investigations.
A spokesperson for the company, Rebecca Boys, described the experience as one-of-a-kind.
There has never been an incident like this before, she claimed.
Company officials didn’t expect to find a large volume of gas in a region of shallow subterranean formation. The gas travelled through a variety of paths to reach the drill pad’s surface in different places.
On March 8, the business used a waste disposal well to pump gas to the surface and stop the leak. According to an announcement made on April 8th, the release’s source had been brought under control.
As a result, ConocoPhillips continued to discover trace levels of gas across the drilling site for several weeks, the company has revealed.
At 2,300 feet below the surface, a component known as a casing shoe failed, according to ConocoPhillips.
According to Dan Seamount, a former oil and gas commision commissioner, the shoe is a cement-encased device at the end of a length of pipe that aids in stabilising the pipe in the rock.
On Wednesday, Seamount indicated that the commision is still investigating and gathering information on the incident.
According to Seamount, “We haven’t reached a determination as to whether or not what they’re stating is correct or not.”
In their report, ConocoPhillips stated that it complied with the regulations to apply protective cement to certain portions of pipe.
However, the pipe was not encased in cement in the area where the gas originated.
The corporation has stated that it was not necessary to do so because it didn’t expect that area to be a substantial gas source.
According to the company’s eight-page answer letter to House legislators, the gas leak was not caused by a shortage of cement around the pipe in that area or any other well design problems.
A deeper look at drilling dangers and subsurface zones requiring “cement isolation” is one of the future remedial measures ConocoPhillips plans to take to avoid another catastrophe like this.
Improved detection and corporate communication when pressures rise outside the pipe are other corrective methods. Improving well planning prior to drilling activities and during drilling operations are other corrective measures.
As Boys put it, “We don’t anticipate this to happen again.”
As part of its enquiry, the oil and gas commision may schedule a hearing, Seamount, a representative of the commision, stated. As far as I know, the commision hasn’t released its own report yet.
To get it out as quickly and accurately as possible, he remarked, “We’re doing our best.”
A total of 7.2 million cubic feet of natural gas had been released into the atmosphere by ConocoPhillips since their disposal well was able to begin operating on March 4th.