Following a mechanical error, Santos has completed drilling the AAL-4XST1 appraisal well in the Northwest Natuna permit area, offshore Indonesia.
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Map from AWE. |
The joint venture was able to intersect the primary G Sand and secondary K Sand targets. Both reservoirs are of excellent quality and were fully cored for further analysis, according to partner AWE Ltd.
Drill stem tests (DSTs) were performed on both reservoirs and oil flowed successfully to surface, assisted by electrical submersible pumps (ESPs), which is standard procedure in heavy oil fields due to the viscosity of the oil.
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 budget.
Previously, the G Sand DST was conducted over a 3.5m perforated interval and exceeded expectations with an average stabilized flow rate of 828 bo/d on a 64/64in choke over a nine-hour period. Well site measurements indicated the G Sand oil to have a specific gravity of 10.7 API at 60° F.
A second DST performed in the K Sand over a 6.5m perforated interval recorded initial oil flow rates of 1120 bo/d on a 64/64in choke, consistent with previous tests at AAL-3X. However, mechanical failure of a down-hole sand screen prevented the DST from running to 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 536-1959 bo/d. Though disappointed not to complete the full K Sand DST work program, AWE said the joint venture was determined that sufficient data had been obtained to meet all objectives of the well and therefore a decision was made to plug and abandon the well as planned.
Oil samples were recovered for further testing, and well site measurements indicated the K Sand oil to have a specific gravity of 13.1 API at 60° F, consistent with previous tests at AAL-3X.
The joint venture will undertake technical analysis and evaluation of this newly acquired data to be incorporated in development plan studies for the G Sand reservoir, which could be developed in conjunction with the already approved K Sand development.
Thw well was spudded in mid-June. In late-June, Santos announced it had achieved an averaged stabilized flow rate of 828 bo/d, revealed in a drill stem test (DST) conducted on the G Sand reservoir at AAL-4XST1. The results exceeded pre-drill expectations and came in at 58% higher than the previous G-sand tests at AAL-3X of 525 bo/d.
Santos is the operator of the Northwest Natuna PSC with 50% stake. AWE holds the remaining 50%.
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