The AAL-4XST1 appraisal well successfully drilled and intersected the primary G Sand and secondary K Sand targets. It has been proven that both reservoirs are of excellent quality and were fully cored for further analysis. 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 oilfields 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 programme was completed within the operator’s budget.
As previously reported, the G Sand DST was conducted over a 3.5 m perforated interval and exceeded expectations with an average stabilised flow rate of 828 bpd on a 64/64 in. choke over a nine hour period. Wellsite 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 6.5 m perforated interval recorded initial oil flow rates of 1120 bpd on a 64/64 in. 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 stabilised 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 bpd. Though disappointed not to complete the full K Sand DST work programme, the Joint Venture 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 wellsite 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.
Joint Venture activities
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.
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 (101 million bbls gross recoverable oil, net 24.3 million bbls of 2P reserves and 1.7 million barrels 2C contingent resources to AWE) and the underlying G Sand reservoir.
Adapted from a press release by Louise Mulhall
Read the article online at: https://www.oilfieldtechnology.com/drilling-and-production/08072016/aal-g-sand-appraisal-well-operations-complete/