Santos will begin sidetrack operation offshore Indonesia after a mechanical obstruction in the well bore of the AAL-4X appraisal well halted the proposed drill stem tests (DSTs) in the K-sand and G-sand reservoirs.
The drilling of the sidetrack well will allow Santos and its parnter, AWE, to allow for completion of the project scope and planned DSTs.
Prior to the obstruction, AAL-4X in the West Natuna basin had achieved all other objectives, having intersected oil-bearing sands in both the primary G-sand and secondary K-sand objectives.
The evaluation program acquired all planned wireline logs, pressure data and oil samples from both reservoirs and also recovered approximately 63m of full core across the two reservoirs, joint venture partner AWE said.
The data acquired to-date has provided significant new information to further the development planning of the K-sand reservoir and to assist with the development potential of the G-sand reservoir.
AAL-4X was drilled to a maximum total depth of 1246m in May, using PT Apexindo's Raniworo jackup. The well is located within the Northwest Natuna permit area and includes the Ande Ande Lumut (AAL) oil project
The AAL project comprises the K-sand reservoir of 101 MMbbl gross recoverable oil and the underlying G-sand reservoir. The AAL-4X appraisal well is targeting the G-sand reservoir, which is estimated to contain 289 MMbbl gross oil in place with 36 MMbbl gross recoverable oil.
Appraisal of the G-sand will facilitate the preparation of development plan for this resource, which could be developed in conjunction with the already approved K-sand development, AWE said.
Both Santos and AWE are 50:50 joint venture partners in the Northwest Natuna production sharing contract.
Map of Natuna West, from AWE.
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