Australian oil and gas exploration and production company Santos has wrapped up all operations related to the AAL-4XST1 appraisal well in the Natuna Sea, offshore Indonesia.
AWE, a partner in the project, said on Friday that the well was successfully drilled and intersected the primary G Sand and secondary K Sand targets.
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.
The company said that both reservoirs were fully cored for further analysis. Drill Stem Tests (DSTs) were performed on both reservoirs and oil flowed successfully to the surface, assisted by Electrical Submersible Pumps (ESPs) which is standard procedure in heavy oil fields.
Logging of the well has been completed and the well has been plugged and abandoned according to Production Sharing Contract (PSC) requirements. The well program was completed within the Operator’s budget.
AWE also said that the Raniworo jack-up drilling rig was released on July 7, 2016 upon completion of the appraisal well operations.
The company previously reported that the G Sand DST was completed and that the well exceeded expectations with an average stabilized flow rate of 828 bopd.
A second DST was performed in the K Sand over a 6.5m perforated interval recorded initial oil flow rates of 1120 bopd on a 64/64 inch choke, consistent with previous tests at AAL-3X. However, mechanical failure of a downhole sand screen prevented the DST from running to its conclusion and a stabilized flow rate could not be achieved. Following the mechanical failure, the DST continued for five hours with oil flow rates varying from 536 to 1959 bopd.
Though the K Sand DST program was not completed, it was determined that there was sufficient data to conclude that all objectives were met and the decision to plug and abandon the well was made.
Technical analysis and evaluation of this new data will be incorporated in the Development Plan studies for the G Sand reservoir which could be developed together with the already approved K Sand development.
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).