Salamander?s update on West Kerendan well drilling

By Romel S. Gurky

Drilling at the West Kerendan-1 well in Bangkanai PSC onshore Kalimantan has penetrated the primary target Upper Berai formation carbonates and it is planned to drill ahead to the deeper secondary targets, UK oil and gas firm Salamander Energy which holds a 70 percent operated interest in the block, said in an update on Monday.

All drilling, logging and other geological data collected to date points to the primary target being gas-bearing, with potential for a significant column of mobile gas at the WK-1 location, the firm said.

Key points in the update:
? Primary target Upper Berai carbonates first encountered 110 metres high to prognosis.
? Significant gas peaks throughout Upper Berai carbonates, gas ingress to wellbore from Upper Berai formation.
? Potential for 340 m gas column in primary target.
? Possible common gas-water contact with Kerendan field, located c. 10 km from WK-1.
? Lower Berai carbonate formation, a secondary target, first encountered 53 metres high to prognosis; evidence of good permeability.
? Gas-bearing sandstones logged and sampled in the secondary Miocene target

The well encountered the top of the Upper Berai carbonate formation at 2,514 m true vertical depth sub-sea (TVDSS), some 110 m high to prognosis. These carbonates at the WK-1 location are well developed with little mud content. Elevated background gas readings and gas peaks associated with high resistivity readings have been seen across the section, a signature that is consistent with the producing wells in the Kerendan gas field.

A 37 m core was cut and fully recovered from the primary reservoir at a depth of 2,650 m. The core exhibits intra-particle porosity in its basal section which is associated with gas influx to the drilling mud.

Drilling gas levels have markedly reduced below 2,890 m TVDSS, implying a base to the gas zone at a depth which is consistent with the gas-water contact in the producer wells in the Kerendan field, located some 10 km to the east. This would imply a potential 340 m mobile gas column at the WK-1 location.

The well encountered gas in the overlying secondary target Miocene sandstones. Wire-line logs, pressure & gas sampling was carried out across two gas-bearing sandstones between 1,400 and 1,490 m TVDSS. The top of the Lower Berai carbonates, which form an additional secondary target, was encountered at 2,915 m TVDSS, some 53 m high to prognosis. This formation exhibits signs of permeability, with mud losses experienced at current TD, corresponding with gas ingress into the wellbore from the Upper Berai formation.

The well is currently at 3,059 m TVDSS within the Lower Berai carbonate formation. Preparations are underway for an intermediate wire-line logging run ahead of casing this section of the hole. The plan would then be to drill ahead through the remainder of the Berai carbonates and into the deeper Eocene target.

WK-1 well was spudded on Oct. 9, 2013 with the DrillCo-1 land rig. The well is primarily targeting 330 Bcf of gas resources in West Kerendan prospect, which comprises the Oligocene-age Berai carbonates, which form the productive reservoir in the nearby Kerendan field. The well has a secondary target in the deeper Sungai Lahei prospect, which comprises a four way dip closure in the Eocene-age Tanjung sandstones with a mean prospective resource potential of 580 Bcf. As outlined above, the well has additional secondary targets in shallow Miocene-aged sandstones.

Editing by Johannes Simbolon