Horizontal subsea trees allow frequent deepwater workovers

• Published in: The Oil & gas journal Vol. 93; no. 18; pp. 68 - 74
• Main Authors: FRENEK, M, HAAL, G, SHENG, W. Z
• Format: Magazine Article
• Language: English
• Published: Tulsa, OK Pennwell 01.05.1995; PennWell Publishing Corp; Endeavor Business Media
• Subjects: Advantages; Applied sciences; Crude oil, natural gas and petroleum products; Design; Design and construction; Drilling; Drilling platforms; Energy; Exact sciences and technology; Fuels; Industrial equipment; Maintenance and repair; Methods; Offshore; Offshore drilling and production; Offshore oil wells; Offshore support vessels; Oil fields; Oilfield equipment & services; Petroleum; Petroleum engineering; Petroleum in submerged lands; Petroleum industry; Production increases; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Trees; Valves; South China Sea; China; Design; Performance evaluation; Offshore production; Completion; Deep water; Offshore well; Subsea wellhead; Workover
• ISSN: 0030-1388; 1944-9151

Horizontal subsea wellheads have found application in the Liuhua oil field in the South China Sea. These trees allow installation and retrieval of downhole equipment through the tree without having to disturb the tree or its external connections to flow lines, service lines, or control umbilicals. This access to the well is important because the Liuhua wells will be produced with electrical submersible pumps (ESPs), which may have relatively short intervals between maintenance, leading to frequent well work. The large bore, horizontal trees allow all downhole equipment to be pulled without removal of the subsea tree. Amoco Orient Petroleum Co., China Offshore Oil Nanhai East Corp., and Kerr McGee Liuhua Ltd. are jointly developing the Liuhua field, the largest offshore oil deposit in the South China Sea. The Liuhua development will have about 20 wells, all of which will be produced through horizontal subsea trees with ESPs.