Transco Exploration Partners Ltd. (TXP), Houston, and an independent engineering firm have cut estimates of Chalkley field proved reserves in Cameron Parish, La., after TXP completed delineation drilling there.
TXP's Chalkley reserves are on the auction block.
Although independent and TXP estimates of Chalkley field Oligocene Miogyp gas equivalent reserves were reduced, both revisions estimated TXP owned reserves to be greater than at yearend 1990.
Logs and other data from TXP's last Chalkley well, 1 TXP, indicate about 263 ft of net gas pay in Oligocene Miogyp B sands at 14,000-600 ft and 67 ft of net gas pay in Miogyp sands at 15,300450 ft. It was drilled to 19,500 ft.
As a result, TXP reduced Chalkley's estimated gross remaining Miogyp reserves as of June 30, 1991-to 635 bcf proved, 172 bcf probable, and 11 bcf possible of gas equivalent, of which TXP's interest is about 119 bcf proved, 45 bcf probable, and 8 bcf possible. TXP's estimate includes 9 million bbl of condensate, of which its share is about 1.9 million bbl.
As of the same date, independent engineers estimated Chalkley's gross Miogyp reserves at 504 bcf proved, 95 bcf probable, and 31 bcf possible, with TXP's interest estimated at 90 bcf proved, 20 bcf probable, and 22 bcf possible. The estimate includes 7 million bbl of condensate, of which TXP's share is about 1.5 million bbl.
Both revised estimates are based on results of 1 TXP, data from other wells in Chalkley field, and cumulative production of 33 bcf of gas equivalent.
Last March TXP estimated Miogyp gas equivalent reserves as of yearend 1990 at 762 bcf proved, 136 bcf probable, and 24 bcf possible, with TXP's interest set at 100 bcf proved, 22 bcf probable, and 4 bcf possible. The estimate included 10.5 million bbl of condensate, of which TXP's share was estimated at 1.4 million bbl.
Independent engineers placed Miogyp reserves at about 570 bcf proved, 200 bcf probable, and 37 bcf possible, with TXP's interest about 75 bcf proved, 32 bcf probable, and 6 bcf possible. That estimate included 8.6 million bbl of condensate, about 1.1 million bbl of which was estimated to be TXP's share.
LIQUIDATION PLANS
TXP last month unveiled plans to sell its remaining oil and gas assets and liquidate the partnership (OGJ, June 24, p. 35).
TXP holds 1 00% interest in Chalkley production from the 1 TXP below Miogyp reservoir B sands. Exxon Co. U.S.A. retains an overriding royalty interest, convertible to a working interest upon payout.
TXP has opened a data room at its headquarters in Houston where qualified bidders may review field data from all Chalkley wells in which it holds interest.
Bids for the property are due early in September. TXP expects to close the sale of its interest in Chalkley field by yearend 1991.
Transco Energy Co. owns 56.6 million units of TXP, 73% of TXP's outstanding shares.
Transco Energy Chairman W.J. Bowen cautioned that the reserves revisions should not be used to estimate the price TXP might receive for its interest in Chalkley field because additional drilling, testing, or production could result in further revisions.
Bowen noted TXP and independent engineers calculated TXP's net Chalkley reserves using the same net revenue interest. While overall reserve estimates are lower, evaluation of additional data indicates that a greater share of reserves lies under acreage in which TXP has an interest, he said.
Bowen also said both reserve estimates are based on assumptions that could be affected by the timing and ultimate outcome of anticipated unitization proceedings and more drilling.
Copyright 1991 Oil & Gas Journal. All Rights Reserved.
