Liwan Gas Project: South China Sea Deepwater Case Study
- Dennis Denney (JPT Senior Technology Editor)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- May 2013
- Document Type
- Journal Paper
- 94 - 98
- 2013. International Petroleum Technology Conference
- 1 in the last 30 days
- 158 since 2007
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This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper IPTC 16722, "The Liwan Gas Project: A Case Study of a South China Sea Deepwater Drilling Campaign," by David Triolo, SPE, and Tracy Mosness, SPE, Husky Energy, and Rana Khalid Habib, Schlumberger, prepared for the 2013 International Petroleum Technology Conference, Beijing, 26-28 March. The paper has not been peer reviewed.
The Liwan gas reservoir was discovered in the South China Sea Block 29/26 in September 2006. A sixth-generation, deepwater semisubmersible platform was contracted that subsequently drilled 26 deepwater wells (700- to 1600-m water depth) between November 2008 and November 2011. During the 1,011 days of drilling and testing activity, the rig and onshore supporting teams incurred no lost-time incidents. The rig team drilled 61 593 m of hole below the mudline and ran the associated strings of casing. Nonproductive time consumed 265 days (26.6 %), comprising 65 days waiting on weather, 147 days of rig repair, and 53 days of other unscheduled events.
In April 2006, a dynamically positioned drillship drilled exploration Well Liwan 3-1-1 in 1500 m of water to a depth of 3843 m, discovering the Liwan 3-1 sand-stone, a gas-bearing reservoir. The Liwan 3-1 field is approximately 320 km south-east of Hong Kong in 1300- to 1500-m water depth, as shown in Fig. 1. The nearest field was 64 km northwest. The main reservoir in the Liwan 3-1 gas field (Sand 1) is the Zhujiang formation.
Weather and Ocean Environments. The South China Sea presents significant weather conditions that affect offshore operations. Tropical cyclones, typhoons in the western Pacific, occur throughout the year over the northern South China Sea. China’s offshore operators evacuate personnel from permanent and moored offshore facilities when typhoons approach. For dynamically positioned drilling rigs, the typhoon is monitored as it forms and a judgment is made as to when to suspend operations. While drilling, the average time required to suspend operations and recover the lower-marine-riser package (LMRP) or blow-out preventer (BOP) is approximately 72 hours. Nonessential crew are evacuated, and the rig moves out of the path of the typhoon, generally in a southwest direction. There are two monsoons that affect the South China Sea: Northeast (between November and March) and Southwest (between May and September) monsoons, the nomenclature deriving from the predominant wind direction.
|File Size||290 KB||Number of Pages||4|