Santos sees ‘better than expected’ well flow rates offshore Indonesia

Australian oil and gas company Santos has conducted a successful Drill Stem Test (DST) on the G Sand reservoir at the AAL-4XST1 appraisal well, in the Natuna Sea offshore Indonesia.

The company achieved an averaged stabilized flow rate of 828 barrels/day (bopd) on a 64/64 inch choke over a 9 hour period.

AWE and Santos hold a 50 percent stake each in the Northwest Natuna production sharing contract (PSC) with Santos as the operator.

The AAL-4X appraisal well was spud on May 14 using the Raniworo jack-up drilling rig, and Santos observed oil shows in the well at the end of May. AWE reported earlier this month that due to mechanical obstruction in the wellbore the proposed Drill Stem Tests of the AAL-4X were stopped through the current hole and would be completed via sidetrack wells.

AWE said the results exceeded pre-drill expectations and are 58% higher than the previous G-sand tests at AAL-3X (525 bopd).

The company said that the DST was successfully conducted over a 3.5m perforated interval in the sidetrack wellbore and was assisted by an electrical submersible pump (ESP), a standard for heavy oil fields due to the viscosity of the oil.

Bulk oil samples were recovered for further testing but wellsite measurements indicate the G-sand oil to have a specific gravity of 10.7 API at 60° F, consistent with previous samples from AAL-3X. Produced gas and water were at rates too low to measure.

AWE stated that the preliminary analysis indicates an excellent quality reservoir, the best encountered in the field to date with no oil-water-contact intersected in the well.

Operations are now underway to start a second DST test in the main AAL field K-sand reservoir, the company added.

AWE Managing Director and CEO, David Biggs, said: “The better than expected flow rates achieved and excellent reservoir quality underline the significant potential of the AAL oil project. The positive results of the G-sand DST, together with a forecast lower cost environment and an improving long-term outlook for the oil price are all encouraging in respect of a decision to develop the AAL field.”

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 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).

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