Khoraghat and Geleki well success for ONGC

Vol 24, PW 12 (06 May 21) Exploration & Production

Unable to announce them as discoveries, ONGC is still excited about promising results from three exploration wells in Assam.

Foremost among them is the exploration well Kohraghat-48, spud on December 25 (2020) using a 2000-hp ONGC-owned rig at the Khoraghat PML under the Jorhat asset to a final TD of 2800 metres. An ONGC source tells us Khoraghat-38, a directional or deviated well, tested an impressive 90 tonnes/day (660 b/d) in mid-February from Sylhet Limestone Formations but that the flow of oil had since stabilised to around 70-80 t/d by April 27 (2021).

"Unfortunately we can't term it as a new discovery," says a source. "The government's (classification) norms changed in 2020 so now we describe it as an extension appraisal."

Equally encouraging are the results from a second well drilled earlier this year (2021) to the northeast of Jorhat at the 172.49-sq km Lakwa PML under the Nazira-based Assam asset where ONGC is testing exploration well location NKAE and appears to have uncovered a 'new pool' or new reserves in Lower Barail or LBS-2 sands. Here again, ONGC is unable to classify this well in the western Lakhmani part of the Lakwa PML as a discovery because of the new rules.

Last but not least, at the Mekeypore-Santak-Nazira ML, which also falls under the Assam asset, ONGC is excited about the results from the exploration well NG-4 at the NGAD location, despite teething problems. "During logging we detected oil," says another source.

"There is definitely good oil saturation, but after perforation, it wouldn't flow to the surface, some re-adjustment is needed." Completed in February 2021, ONGC drilled well NG-4 to 3500 metres TD targeting Tipam or TS-4B sands.

No attempt was made to drill deeper to TS-5 or TS-6 sands. "There is no oil below in TS-6," he adds.

"TS-6 was not the object (target)."