Total group starts big 3D program in Thai gulf

The Total-led group has launched the largest 3D seismic survey campaign undertaken in the Gulf of Thailand as part of the bid to investigate the extension of its Bongkot gas field.

More than 2,000 sq km of 3D seismic have been shot and processed the last few months. The campaign is carried out over the prospective northern part of the field and the southern prospect known as Ton Sak (Teak Three) by Geco Prakla's 80 m long Geco-Emerald seismic vessel.

Sixth 3D survey

Upon completion of the campaign this month, the group will have complete 3D coverage of the Bongkot concession in six surveys totaling 4,700 sq km and costing $30 million, said officials of Total Exploration & Production Thailand.

The data will be used to determine Bongkot's future during the next decade (OGJ, May 19, 1997, p. 34). More specifically, their interpretation will define new gas prospects and allow proposal and design of new wells to be drilled next year to raise Bongkot field's reserves with the launch of further development phases.

Preliminary data are very encouraging, a Total official said.

The group will decide later this year on the time frame and exact details of Phase IIIb development. It could start in 1998 and be completed in 2000.

The group is considering Phases IIIb and IIIc to sustain a high level of gas and condensate production from Bongkot, Thailand's largest gas field, during the next century. The two phases are estimated to cost a combined $500 million.

Meeting gas demand

The group launched Phase IIIa development in mid-1996 at a cost of $270 million. It awarded a contract to Nippon Steel to supply two wellhead platforms and the associated pipelines.

Overall objective of Phase III development is to meet new contractual gas delivery of 550 MMcfd to PTT in July 1998 under the deal signed in August 1996, said J.P. Azalbert, general manager, Total E&P Thailand. Phase III will help boost Bongkot's production capacity to 630 MMcfd of gas and 13,000 b/d of condensate from the present 420 MMcfd and 10,000 b/d.

The ongoing Phase IIIa development involves two additional wellhead platforms, drilling 47 new wells, and installing new processing equipment on the existing production complex including a third gas train, additional gas-liquid separator, and relevant utilities.

Remaining development

Phase IIIb calls for installation of five wellhead platforms with one special gathering platform and drilling of 54 wells. Phase IIIc may call for five well platforms, two with 12 slots each and three with six slots each.

The Bongkot consortium, including Thailand's PTT Exploration & Production plc, British Gas, and Norway's Statoil, has spent $675 million on phases I and II, completed in 1993 and 1995. Room remains for further development, and that could lead Bongkot into a fourth development phase next century.

With all the development phases, the group anticipates being able to produce gas from Bongkot at its plateau rate of 550 MMcfd throughout most of the concession period that ends in 2012.