The brief
Stage 2 at Muara Laboh adds a scrubber and an atmospheric flash tank to an operating geothermal plant in Solok Selatan. Supreme Energy contracted the package through a three-party EPC consortium: Sumitomo, IKPT and Wasa Mitra.
SKM was retained for design, fabrication and the supporting seismic dossier. The work is sequenced across 2024 – 2026 to match the field outage window.
Multi-party coordination
A three-party EPC always carries a coordination tax. Design changes pass through Wasa Mitra to Supreme Energy, with IKPT and Sumitomo aligned at each revision. We carry one document register on our side and a parallel comment log per party.
The package is currently at Rev C. Each revision has cleared Wasa Mitra's QA review before transmission to the end client.
Seismic reconciliation: AMETank vs TANK 12
The tank was modelled in both AMETank V15.2.16 and Hexagon TANK 12. Convective and impulsive components, overturning moment and uplift were compared term-by-term against API-650 Annex E hand calculations.
Where the two solvers diverged, the controlling value was taken with a written rationale. The reconciliation is captured in SKM-ENG-SEISMIC-001 and forms part of the final design package.
API-650 Annex E compliance
The site is Class D with Ss = 1.25 g and Sds = 1.17 g. Anchorage, shell-to-bottom weld, foundation reaction and freeboard were all checked to Annex E. The anchor chair detail was iterated to satisfy both the seismic anchorage load and the standard shell-stability check.
Hot/cold cycling & thermal expansion
Atmospheric flash service swings the shell through a wide temperature range each cycle. Piping interface loads were taken from the EPC's pipe-stress model and superimposed on the tank nozzle allowables per API-650 Appendix P, with a documented review against the local nozzle-flexibility calculation.
Quality reporting
Inspection and test plans were issued through Wasa Mitra, with hold points routed to Supreme Energy for witness or monitor as elected. Daily QA reports and weld-map updates were transmitted on a fixed cadence so the EPC could track progress without unscheduled site visits.
“The seismic dossier was the deciding document — once Annex E was reconciled, the rest of the package moved.”
Delivered.
Design is at Rev C and tracking the contracted milestone for handover. The seismic reconciliation is closed and accepted by the EPC consortium.
Fabrication and field activities continue through 2026 against the Muara Laboh outage plan.