Australian oil and gas company Santos has observed oil shows in the AAL-4X appraisal well at the Northwest Natuna production sharing contract (PSC), offshore Indonesia.

The appraisal well was spud on May 14, 2016. Santos is the operator of the Northwest Natuna PSC with 50% interest.

According to AWE, a partner in the project with 50% interest, as at 09:00 hours (9.00am) AEST on May 30, 2016, the AAL- 4X appraisal well had reached Total Depth (TD) at 1246m Total Vertical Depth Sub Sea (TVDSS) and wireline logging operations are underway across the target K Sand and G Sand reservoirs.

The company said that the primary target G Sand reservoir was intersected on prognosis at 1176m TVDSS after encountering the secondary target K Sand at 1131m TVDSS. Both reservoirs have been fully cored for further analysis and oil shows have been observed in both sands. Following wireline logging, each reservoir is planned to be Drill Stem Tested, AWE added.

The well is being drilled in water depth of approximately 72m using the Raniworo jack-up drilling rig, owned by Indonesian drilling contractor Apexindo, and is forecast to take approximately 48 days in total to complete.

The Northwest Natuna PSC is located offshore Indonesia in the Natuna Sea and includes the Ande Ande Lumut (AAL) oil project. The AAL project comprises the K Sand reservoir (101 million barrels gross recoverable oil, net 24.3 million barrels of 2P Reserves and 1.7 million barrels 2C Contingent Resources to AWE) and the underlying G Sand reservoir.

The AAL-4X appraisal well’s primary target is the G Sand reservoir, which is estimated to contain 289 million barrels gross oil in place with 36 million barrels gross recoverable oil (net 8.4 million barrels 2C Contingent Resources to AWE).

AWE explained that appraisal of the G Sand will facilitate the preparation of a Plan of Development for this resource, which could be developed in conjunction with the already approved K Sand development.