Exxon Co. U.S.A. has taken another step in the decade long effort to increase oil output from Santa Ynez Unit (SYU) in Santa Barbara Channel off California.
Two Arows (Advanced Remotely Operated Work Systems) class remotely operated vehicles (ROVs) completed diverless deflection tie-ins of 20 in. pipelines to the jackets of Exxon's Harmony and Heritage platforms earlier this year.
PIPELINE TIE-INS
Diverless Systems Inc. (DSI), Houston, completed the tie-ins in water depths of 1,250 ft at Harmony and 1,070 ft at Heritage.
The pipelines will transport heavy, sour crude to an onshore oil treating plant under construction in Las Flores Canyon in Santa Barbara County, Calif. Nearshore and onshore segments of the gathering system have been installed.
DSI said the platform tie-ins are the deepest water installations by ROV of 20 in. pipelines. The company, an affiliate of Sonsub Inc., Houston, performed the work under a contract from Allseas Marine Contractors SA, Chatel-St. Denis, Switzerland.
Completion of Harmony and Heritage pipeline tie-ins marked Exxon's latest milestone in plans announced in November 1982 to boost SYU production with further development of Hondo field and new development of Sacate and Pescado fields in the unit (OGJ, Nov. 22, 1982, p. 59). Exxon managed to start SYU production from Hondo Platform A in April 1981 after more than a decade of regulatory delays (OGJ, May 4, 1981, p. 104).
The company in 1969-70 announced discovery of the three fields after extensive exploratory drilling on acreage leased in 1968. SYU is a consolidation of 19 federal tracts in Santa Barbara Channel (OGJ, Feb. 14, 1983, p. 64). Exxon estimates SYU economic reserves at 400-500 million bbl of oil and 700-900 bcf of gas.
SYU UPDATE
Exxon installed Harmony jacket 6/2 miles offshore in july 1989 and Heritage jacket 8-1/2 miles offshore in October 1989.
Harmony and Heritage oil and gas production is expected to begin in late 1994. Exxon plans to begin drilling wells from the two platforms earlier that year.
Exxon said it is on schedule to begin installing topsides on Harmony and Heritage platforms in fourth quarter 1992. The topsides are being built at Corpus Christi, Tex.
With Harmony and Heritage at full capacity, SYU production will peak at about 90,000 b/d and 90 MMcfd of gas. Production from Hondo Platform A in 1991 averaged more than 20,000 b/d and 30 MMcfd of gas.
Exxon transports oil from Hondo Platform A to an offshore storage and treatment (OST) vessel permanently moored near the platform. Oil is off-loaded at intervals from the OST to a tanker for delivery to refineries in the Los Angeles area. Plans call for oil from Hondo platform to move to shore through a 20 in. pipeline already in place when Las Flores oil treatment plant is completed.
Hondo gas production is delivered by pipeline to an onshore gas processing plant on the same Las Flores Canyon site. Total project cost of SYU development--the largest Exxon U.S.A. managed project--is estimated at $2.5 billion.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
