A Soviet partner has committed another oil field in western Siberia to the White Night horizontal well joint venture with Anglo-Suisse Inc. (ASI), Houston.
ASI and Varyeganneftegaz, Varyegan Oil & Gas Association (VOGA) of the U.S.S.R. Ministry of Oil and Gas, June 8 formed White Night to study the feasibility of drilling a series of horizontal wells in West Varyegan and Tagrin oil fields (OGJ, June 25, p. 29).
Under an addendum signed July 20 by ASI and VOGA, VOGA will include Roslval oil field in the joint venture. That will add an estimated 200 million bbl of recoverable reserves for a total of 1.1 billion bbl, said ASI Pres. Gil Labbe.
DRILLING PROGRAM
White Night earlier planned to drill as many as 400 horizontal wells in West Varyegan and Tagrin fields. Labbe estimated another 50 horizontal wells could be drilled in Roslaval field, just south of Tagrin.
Labbe said White Night might redrill some West Varyegan and Tagrin wells as horizontal holes as early as next spring.
"The next step would be a two rig development program, with one in Tagrin and one in West Varyegan," he said.
Drilling could be under way by June 1991.
Under the original 25 year agreement, ASI and VOGA share White Night ownership 50-50.
VOGA is committed to add more fields to the venture to assure that ASI's share amounts to 550 million bbl of recoverable oil.
Adding Roslval oil field could fulfill that commitment.
Although early information received by ASI about Roslval was sketchy, Labbe said the field is very similar to West Varyegan and Tagrin. An unknown number of wells have been drilled there in search of Cretaceous-Jurassic reservoirs occurring at 8,500-9,000 ft.
Charles G. Brunet, ASI manager of engineering, said West Varyegan's gas:oil ratio is 1,550:1. Tagrin's GOR is 1,000:1.
ASI will begin planning development of Roslval early this month when more well data are known. A team of ASI engineers was to return from the U.S.S.R. at the end of July.
"Communications with our engineers in Radujny (Rainbow City) are almost nonexistent," Labbe said.
West Varyegan and nearby Varyegan are brachyanticlines on the Varyegan arch. Tagrin is an anticline on the Varyegan Tagrin megaarch.
In terms of productivity, fields on the Varyegan arch have been among the most disappointing in western Siberia.
MORE STEPS REQUIRED
A 10 member ASI-VOGA committee is to complete a charter and feasibility study by mid-October. The committee is negotiating items such as rights to install a satellite communications system and throughput and lifting agreements that are not under direct control of VOGA.
A delegation of VOGA officials will arrive in Houston in mid-September to complete the charter. White Night then will submit the document to Soviet ministries of oil, gas, finance, and foreign relations.
Joint venture partners expect approval by mid-December. Once the charter is approved, White Night could begin mobilizing equipment in January 1991.
Copyright 1990 Oil & Gas Journal. All Rights Reserved.