Conrad upgrades resource estimates for Mako gas field
Conrad Petroleum Ltd. has updated resource estimates for Mako gas field, which forms part of Duyung PSC in the West Natuna basin, offshore Indonesia, following an appraisal drilling campaign in fourth-quarter 2019.
The drilling campaign saw the Tambak-1 and Tambak-2 wells demonstrate the presence of well-developed, high quality reservoir sandstones with a common gas water contact across the Mako structure (OGJ Online, Oct. 25, 2019).
Both the internal estimate and the still-to-be-finalized Gaffney Cline & Associates (GCA) analysis use new data acquired from the fourth-quarter 2019 appraisal drilling program, including the drill stem test at Tambak-1, which flowed at 11.4 MMscf/d.
highlights from the operator’s updated assessment of Mako gas field include:
- Gross (full field) 1C (Contingent) Resource estimate of 323 bcf of recoverable raw gas, representing an increase of 76% on the pre-appraisal estimate of 184 bcf in the 2019 Gaffney Cline & Associates assessment.
- Gross (full field) 2C (Contingent) Resource estimate of 493 bcf of recoverable raw gas, a 79% increase on the pre appraisal estimate of 276 bcf.
- Gross (full field) 3C (Contingent) Resource estimate of 666 bcf of recoverable raw gas, a 70% increase on the pre appraisal estimate of 392 bcf.
- Appraisal drilling in fourth-quarter 2019 confirmed the presence of a thicker and better-quality reservoir with a gas water contact measured (from electric logs) to be 5 ft deeper than previous contact, which was estimated from pressure data.
- Revised development scenarios are under review that may be able to achieve a plateau production rate of 150 MMscf/d, significantly higher than the previously modelled 44 MMscf/d.
Full field resources are classified as contingent given key commercial milestones have not yet been achieved, such as execution of a gas sales agreement and a final investment decision.
Mako gas field reservoir is a Pliocene-age sandstone, with a gas-water contact at 391 m true vertical depth subsea.
Commercial viability of Mako gas field was demonstrated by the Mako South-1 well drilled by Conrad and Empyrean in 2017. The well was drilled to core and test the Mako reservoir, flowing up to 10.8 MMscf/d of dry gas on test.
Efforts are being made to ensure GCA delivers its report in a timely fashion, but as movement and travel restrictions affect all parties involved, the report is no longer expected to be received in April.
Mako field lies close to the West Natuna pipeline system and gas from the field can be marketed to buyers in both Indonesia and in Singapore. A heads-of-agreement with a gas buyer in Singapore is in place. Approval of a revised plan of development by the Indonesian authorities and the conclusion of GSA negotiations will move the project closer to final investment decision.
Partners in the Duyung PSC are Conrad (76.5%), Coro Energy Plc (15%), and Empyrean (8.5%).
