88 Energy boosts Charlie 1 reserves
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Says final petrophysical interpretation upgrades oil pay in shallow Seabee formation in Icewine test well drilled last winter
Kay Cashman Petroleum News
After using what it describes as “sophisticated laminated sand analysis,” Australian independent 88 Energy upgraded the potential net oil pay in its Charlie 1 exploration well’s shallow Seabee formation, the firm said Sept. 11.
The well was drilled earlier this year in the company’s Icewine project on Alaska’s North Slope, penetrating sandstones in seven stacked targets and shale in one target.
No flow tests were done; however, 88 Energy previously said gas condensate samples were “retrieved to surface from the Torok formation at 10,506 feet and 10,656 feet using a downhole sampling tool (Ora) run during the wireline operation.”
Pay rose from 280’ to 398’ Icewine encompasses nearly 500,000 contiguous acres in the central North Slope; Charlie 1 is one of three wells the company, in conjunction with partners, has drilled in the acreage - Icewine No. 1 in 2015, Icewine No. 2 in 2017 and Charlie 1 in the winter of 2019-20. None of the wells proved commercially successful, although according to 88 Energy the jury is still out on the Icewine unconventional targets in Icewine No. 2 and, of course, the shallow oil and gas condensate in Charlie 1.
In the Charlie well 88 Energy initially viewed the upper and lower Lima of the Seabee as secondary targets above the deeper, primary Torok formation objective which was initially tested for oil but instead found a thick interval of gas condensate.
Both upper and lower Lima “are confirmed as large oil discoveries by this interpretation and the lab results,” the company said Sept.11. “The results are particularly significant as these targets are the most extensive of the Icewine conventional horizons as well as being relatively shallow,” in comparison to the Torok formation.
The laminated sand analysis, or “thin-bed” evaluation of the wireline logs recorded across the Seabee and deeper Torok formations to look for discrete, thin sand layers that can often be “glossed over” by standard logging tools, 88 Energy noted in its Sept. 11 announcement.
These logging tools “take measurements over specific intervals of depth, often larger than the thickness of the sand layers themselves, missing these thinly bedded target horizons.”
“Encouragingly, the final interpretation provides a significant increase in net pay, compared to the initial interpretation, of 398 feet (vs 280 feet), with the largest contribution coming from the Lima discoveries in the Seabee formation. These improvements are despite using higher cut-offs for both reservoir and net pay,” the company said.
Not optimally located The company also said it has done advanced laboratory analysis of the cores taken during drilling of Charlie 1, including nuclear magnetic resonance, to calculate improved hydrocarbon saturations across most of the oil and gas-bearing zones.
All of this work resulted in a 42% bump in the net thickness of oil and gas-bearing pay throughout the well, from 85m to 121m, with the best result being a three-fold increase in the shallow oil pay zones of the Seabee from 22m to 71m, 88 Energy said.
The company’s managing director, Dave Wall, said: “The results from the Seabee, despite Charlie 1 not being optimally located, are outstanding. Whilst these may appear as a serendipitous by-product of the well, internal analysis prior to drilling had already significantly high graded this formation; however, it was too late to change the objectives/location of the well, meaning that work remained largely on the drawing board.”
“This final interpretation is a strong vindication of that internal effort. We are now looking forward to the conclusion of the evaluation of the Seabee oil discoveries as we integrate the petrophysics into the seismic inversion and subsequent mapping, which will ultimately yield updated volumetrics for our resources that will feed into the Icewine farm-out process.”
The Kuparuk remains a “prospective target, with anomalously good reservoir quality for its depth, however, no mapping has been done for this horizon” and it is considered gas prone.
The extent of the accumulations will be estimated over the coming weeks as “these final petrophysical numbers are integrated into the updated seismic inversion product,” 88 Energy said.
The upgrade in oil pay in the Seabee formation at Charlie 1 will likely give 88 Energy’s next Icewine project well, Heavenly 1, an advantage while it is being marketed for farm out as a Seabee test location.
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