Santos forced to drill sidetrack on Ande Ande Lumut due to mechanical obstacle
Australian oil and gas company Santos is planning to start a sidetrack well on the AAL-4X appraisal well, at the Northwest Natuna production sharing contract (PSC) offshore Indonesia, after a mechanical obstruction prevented the completion of the current well bore.
Santos is the operator of the Northwest Natuna PSC, that includes the Ande Ande Lumut (AAL) oil project, with 50% interest, and AWE holds the other 50% interest. The AAL-4X appraisal well was spud on May 14 and Santos observed oil shows in the well at the end of May.
According to AWE, due to a mechanical obstruction in the well bore the proposed Drill Stem Tests (DST) in the K-sand and G-sand reservoirs cannot be completed in the current hole of the AAL-4X appraisal well. The joint venture is now planning to start sidetrack operations to allow completion of the project scope and complete the planned DSTs, AWE said on Wednesday.
The company noted that prior to the obstruction, the well had achieved all other objectives of the AAL-4X well, having intersected oil-bearing sands in both the primary G Sand and secondary K-sand objectives. The evaluation program has 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.
The AAL-4X well was drilled to a maximum total depth of 1,246m TVDSS and was forecast to take approximately 48 days to complete. The well is being drilled in water depth of approximately 72m using the Raniworo jack-up drilling rig. AWE said that the AAL-4X well is still expected to be completed within the operator’s budget, as the well has been drilled in a shorter timeframe than planned.
The AAL project comprises the K Sand reservoir (101 million barrels 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 million barrels gross oil in place with 36 million barrels gross recoverable oil. AWE explained that appraisal of the G Sand will facilitate the preparation of Plan of Development for this resource, which could be developed in conjunction with the already approved K Sand development.