Ophir Energy has lined up Phase 4 of its development plan for the Bualuang oil field in Block B8/38 in the Gulf of Thailand with plans to drill development wells and install a new platform and associated offshore structures by 2019.

An infill drilling program will kick off the plan’s launch in second-half 2018 followed by installation of a 12-well slot platform in first-half 2019. This phase, set to run from 2018 to 2020, of the development is expected to cost about $138 million.

“The initial phase has five well activities planned for 2018 from the existing Alpha and Bravo platform, comprising three re-drills using existing slots and two well workovers,” Ophir Energy CEO Nick Cooper said in an operational update.

The operator intends to install the new 12-well slot platform near the Bravo platform, drill up to 14 new development wells and expand the water disposal capacity on the Bravo platform in 2019.

“We are planning to add an additional 12 well slots with the installation of the Charlie platform, a wellhead structure, bridge-linked to our existing Alpha and Bravo production platforms,” he added.

The plan includes laying a subsea pipeline from the proposed Charlie platform to the existing offshore production facilities, which include the Alpha (BLWPA) and Bravo (BLWPB) platforms, and the Rubicon Vantage FPSO. The produced liquid from the new wells will be transported to the FPSO for processing and storage until the oil can be offloaded onto a tanker.

Cooper said Ophir identified several prospects in the northern part of the Bualuang Field. “In light of the 2017 infill drilling and the addition of production from the deeper T2 reservoir interval, Ophir is looking at several near-field prospects with possible drilling in 2018. We have also identified a new satellite exploration target, which we are analyzing for potential drilling in 2018.”

The Phase 4 development plan aims to extract identified oil reserves of about 9.9 MMbbl located in the Miocene sandstones of the field, according to the company.

The Bualuang oil field consists of two distinct but related structures: the Main Fault Block and the East Terrace. Wells drilled in the central and northern culmination of the East Terrace indicated the presence of significant oil reserves.

The B8/38-9 exploration well, drilled in the northern culmination of East Terrace, found more than 43 m (141 ft) of oil pay in seven stacked sandstone reservoirs in the Miocene T4 and T5 intervals, with pressure data indicating a 14-m (46-ft) column in the key T4.1 reservoir. An exploration well in the Main Fault block encountered oil in the younger T5.2 sand.

Reservoirs in Bualuang Field have different parameters even though they were all deposited in fluvial settings. However, some of them have water at the bottom, and water breakthrough and water coning are considered to be the potential production issues.

The field is estimated to have remaining oil reserves of 28.3 MMbbl of 2P and 10.3 MMbbl of 2C even after the extraction of about 30 MMbbl from the start of production in August 2008.

The operator drilled more than 60 exploration and development wells and constructed two interconnected wellhead platforms, an FPSO, one product and one affluent pipeline in the field during the first three phases of development. The FPSO has a crude oil storage capacity of 570,000 bbl and processing capacity of 24,000 bbl.

However, crude oil production from the field has been decreasing for the last few years. The field produces about 8,300 boe/d, down from 8,700 boe/d in 2016 and 12,300 boe/d in 2013.

The Bualuang oil field, spread over an area of 376.56 sq km (145.39 sq miles), is located in Block B8/38 in the Western Basin of Gulf of Thailand in a water depth of about 60 m (197 ft).

Ophir Energy holds a 100% participating interest in the block.