Salamander Energy Bualuang Oil Project, Gulf of Thailand, Thailand

The Bualuang field is located in the west of the Gulf of Thailand (block B8/38) in water depths of about 60m. It is 60km west of the Chevron-operated gas/condensate and oil fields and Pearl Energy-operated Jasmine oil field in the Pattani Trough.

The field is operated by Salamander Energy Plc, which holds a 60% interest in the field; the other 40% is held by SOCO International Plc. Both are UK-based companies.

Its development, including facilities, drilling and completion, is forecast to be about $90m.

The field (originally called Pornsiri) was discovered in 1992 and subsequently appraised by two further wells in 1997. The development plan for the field was approved by the Thailand Department of Mineral Fuels in 2006.

When it comes on stream, expected to be in July 2008, production is forecast to be 9,000 barrels/day during 2008, rising to more than 15,000 bpd in 2009.

The initial development wells, Bualuang 05 and 01, were drilled and logged to true vertical depths of about 1,220m and 1,270m respectively. Preliminary evaluation of the well logs confirmed the wells encountered oil pay over a 25m gross interval (about 21m of net pay) and 23m gross interval (about 20m of net pay).

Bualuang 05 encountered an average porosity of 29% and average permeability of 809 millidarcies, while the 01 well (which was not cored) indicated an average porosity of 27%.

GEOLOGY

The Miocene age sandstones that form the Bualuang field reservoir are predominantly lacustrine and fluvial in character.

Gross proven reserves attributable to the field are 11MMboe, and gross proven and probable reserves are 20MMboe. There is further step-out exploration potential in the East Bualuang fault terrace, which is undrilled and has a gross prospective resource potential of 6MMboe.

DEVELOPMENT

The development of the field was fast-tracked during 2007. The construction phase was completed in late December, and in January 2008 the jackets, topsides, pipelines and moorings for the field’s FPSO were installed by the Lewek Champion, which was chartered from Singapore-based Emas Offshore Construction and Production Pte Ltd.

The first phase of development drilling has a total of six wells, including five producers and one water injector. These wells encountered the oil column in a reservoir of better quality than that predicted by the appraisal wells, with average porosities of more than 30% and an average net to gross of more than 92%. The wells also found significantly greater oil saturation than the appraisal wells, and a field-wide oil-water contact has been established at 1,130m subsea. The Bualuang oil is about 27°API and has a low gas-to-oil ratio.

The production wells, which were completed by June 2008, are fitted with gravel packs and Centrilift down-hole electrical submersible pumps, and have been hooked up via an 800m, 10in pipeline to Singapore-based Rubicon Offshore International’s Rubicon Vantage FPSO, formerly the Nordic Trym, which underwent mechanical completion and pre-commissioning at Rayong port in Thailand before sailing to the field in late April. The 79,400t DNV-class vessel can store up to 570,000 barrels of oil.

The oil is "dead oil", with a gas-to-oil ratio of 3scf/bbl. It therefore needs little processing, except for possible water-oil emulsion. The FPSO’s oil processing capacity is up to 44,000 bpd with a water handling capacity of up to 20,000 bpd, which could be increased to as much as 30,000bwpd.

Engineering of the topsides and jackets was by WorleyParsons, of Australia, and they were built by Clough, also of Australia.