Vietnam offshore fields exceeding expectations

Premier Oil expects the Chim Sao and Dua oil fields offshore Vietnam to continue producing until 2030, a decade longer than in the original development plan, according to new partner Ophir Energy.

Ophir came onboard following its recent acquisition of Santos’ producing interests in fields in the Asia/Pacific region.

Last year Chim Sao outperformed budget by 18%, the company said, adding that Premier had now started a field-life extension assessment of all the facilities and expects to complete all required modifications by 2020.

Most critical are the wellhead platform and main field flowlines which originally had ten-year design lives.

This year a series of well interventions should help offset the natural reservoir decline rates.

Ophir plans to work with Premier to determine how to optimise production from the fields during the coming decade.

Also, as part of the Santos package, Ophir gained operating interests in the Madura Offshore and Sampang PSCs in East Java.

In Madura Offshore, the Maleo gas field came onstream in 2006 and is now in the decline phase. Its output is sold to PGN and PLN through the East Java pipeline.

Another field, Peluang, is currently on plateau production.

Ophir has decided to develop the Meliwis field, discovered in 2016, 11 kilometres (6.8 miles) south of Maleo, via a single-well wellhead platform tieback to Maleo.

In Sampang, the Oyong field has produced gas since 2007 while the Wortel field has delivered gas and condensate since 2012. All production is piped to the onshore processing site at Grati.

Both fields produced at 33% above budget last year, mainly due to higher than forecast gas demand. Ophir plans to revise the subsurface models next year, with a view to adding further gas reservoirs.

It also believes that pressure-lowering projects at Grati could generate added value by extending the production lives of Oyong and Wortel.

There are two undeveloped discoveries on Sampang and exploration upside in both this and Madura Offshore, but exploiting it would entail seeking extensions to both PSCs, which are currently set to expire in 2027.

At Ophir’s Bualuang field in the B8/38 concession offshore Thailand, production averaged 8,100 boe/d during 2018, and last summer the company initiated the Phase 4 development, divided into two sub-phases.

Phase 4A, designed to boost production from the existing facilities, involved drilling three new producer wells and four workovers.

Under Phase 4B a new 12-slot, conductor-supported platform (Bualuang Charlie) will be installed and the field’s water disposal capacity will be increased from 75,000 b/d to 100,000 b/d to boost recovery.

BJC Heavy Industry is building the new platform at Sattahip: it should be installed at the offshore location in June allowing drilling to start in July.

During the associated field centre shutdown Ophir plans repairs and upgrades to the Alpha and Bravo platform equipment.

First oil from the Charlie platform is due in October. On completion of Phase 4 output from the field should peak at 14,000 b/d.

Source: Offshore Magazine