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Marathon: 50 years in Alaska - Marathon designs completion technology for Kenai gas field Some 35% of current field production result of Excape-type completions, technology Marathon has now commercialized Kristen Nelson Petroleum News Editor-in-Chief
Marathon Oil developed a new completion technology for its Kenai gas field Beluga formation wells.
Marathon’s Alaska business unit manager, John Barnes, said Aug. 13 that the Excape technology received an award from “World Oil” as the best drilling and completion technology of the year. The technology “was developed specifically for our Kenai gas field, as an offshoot of how do you go into these older, tighter, less productive reservoirs,” Barnes said.
And is it successful? A “significant proportion of our ongoing expenditure is directed toward the Excape completions in the Beluga formation in the Kenai gas field,” Barnes said, with about 35 percent of gas now being produced at Kenai a result of Excape-type completions. A large portion of the Beluga formation, prior to Excape, was not regarded as commercial, Barnes said.
Excape is used extensively at Kenai, he said, and Marathon has commercialized the technology “and it’s starting to take off in some other locations” with other operators. Designed on a cocktail napkin Barnes described the technology in some detail in a talk to the Alaska Support Industry Alliance in March 2001.
The Kenai gas field wells are drilled through multiple pay intervals, he said, and within a single well you can have different qualities of rock, sometimes high-quality, prolific zones and sometimes lower quality zones that need to be stimulated to produce.
“You either pump some acid to clean them up or perhaps you pump a fracture treatment,” he said. Marathon’s approach was to stimulate each interval separately, because stimulating multiple intervals at once didn’t do as good a job as giving each interval a specific treatment designed for it. That might require a week’s work, he said, because of multiple wireline trips and multiple fracture treatments.
“So the goal here was obviously cost control,” Barnes said. Continuous completion The new completion system, Excape, is a continuous completion technique, he said. Perforating guns are run and cemented in place. The lowest interval is perforated and then treated. When the shots are fired for perforation of the next interval, an isolation valve closes, separating it from the lower, previously treated interval. When all of the intervals in the well have been treated, the isolation disks are broken out.
Although Excape was invented for the Kenai gas field Beluga formation, he said, the technique was first run in the Lower 48, and then in February 2001 it was used for the first time in the Kenai gas field.
“Oftentimes you’ll hear about inventions that have been conceived on a bar napkin and I’ve seen one actually happen now in my career,” Barnes said: “I didn’t see the napkin, but I … approved the business expense report for the bar.”
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