Petrocorp Exploration Ltd.'s discovery off Philippines may hold oil reserves of more than 100 million bbl.
Petrocorp, a unit of Fletcher Challenge Ltd., Wellington, N.Z., disclosed the 3,100 b/d 1B Calauit strike off Northwest Palawan Island in March (OGJ, Mar. 25, p. 60).
The company plans a second well on the adjacent Busuanga structure on its GSEC 49 acreage in November after the end of the typhoon season. Preparations to drill a possible third well immediately thereafter also were approved by Petrocorp and partners. This program would cost about $16 million.
If well results warrant, Petrocorp plans a 2-3 week production test. It has commissioned a reservoir/engineering feasibility study it expects to be complete this month.
If commercial, development of the Calauit-Busuanga reservoir probably would cost more than $150 million, Petrocorp said.
CALAUIT RESULTS
The 1B Calauit, drilled during Jan. 22-Mar. 11, went to 7,282 ft in 292 ft of water.
It tapped a hitherto unknown late Oligocene pay now called the Calauit limestone. Other limestone reefs have yielded hydrocarbons in the area.
Two drillstem tests were carried out in the 505 ft thick Calauit limestone. The first, in the upper portion of the reservoir, yielded a stabilized flow of 3,200 b/d of 32.6 gravity oil through a 1/2 in. choke. The second, near the base of the limestone, was a confirmation of the water zone.
The 1 B Calauit is near the western edge of a faulted anticline with an estimated areal closure of 15 sq km and a vertical relief of 820 ft.
Petrocorp thinks the Busuanga structure could be in communication with Calauit oil, thus comprising a single large reservoir. "If this were the case, there is a probability the Calauit discovery well has located a major oil find in excess of 100 million bbl," the company said.
Petrocorp's strategy in pursuing Pacific Rim exploration license areas was to focus on areas geologically similar to those it has explored in New Zealand. The Calauit structure is contained in rock similar to the fractured limestone productive at Petrocorp's Waihapa field in New Zealand.
Petrocorp plans more seismic surveys to further define the Calauit-Busuanga structure and delineate additional structural leads in the area.
As part of the Calauit exploration program, Petrocorp acquired 150 line km of reprocessed seismic data in 1990 and has acquired 400 line km of new data to date in 1991.
GROUP INTERESTS
Calauit was tested under a sole risk provision in the Petrocorp led joint venture.
Not all joint venture participants took part in the well, increasing Petrocorp's interest in the well to 51.6%.
Other interests in the well are Kirkland Resources (Holdings) plc 28.5%, Oriental Petroleum & Minerals Corp. (OPMC) 15%, and Basic Petroleum & Minerals Corp. (BPMC) 4.8%.
Interests in the concession's Block A, where 1 B Calauit was drilled, are Petrocorp 34.4%, Kirkland 21.1%, OPMC, Balabac Oil Exploration & Drilling Co. and Philodrill Corp. 11.1% each, and San Jose Oil Co. and Anglo Philippine Oil & Mining Corp. 5.6% each.
Interests in Block B are Petrocorp 30%, Kirkland 18.4%, OPMC, Balabac, and Philodrill about 11% each, BPMC 7.7%, and San Jose and Anglo Philippine 5.5%.
Copyright 1991 Oil & Gas Journal. All Rights Reserved.
