High hopes from 4 exploration wells in Assam

Vol 24, PW 18 (29 Jul 21) Exploration & Production

ONGC's Nazira-based Assam asset is pinning its hopes on four exploration wells as it struggles to maintain crude production of around 2100 tonnes/day (15,400 b/d).

On July 25 (2021), ONGC spud exploration well LKBI at the 172.49-sq km Lakwa PML using Quippo Rig-31. "ONGC initially wanted the rig to drill a development well but the well was in a pond, so ONGC gave Quippo well LKBI instead," says a source.

Despite poorly executed civil works, Quippo began "real work" at LKBI on June 27, after re-deploying Rig-31 from the Charali PML on June 19 following completion of exploration well CHAS to 4900 metres TD. ONGC estimates CHAS holds 1.15m tonnes (8.4m barrels) of crude.

At LKBI, ONGC wants to drill to 4040 metres TD to explore oil prospects in two lower Barail sand zones. Expected to take 130 days, ONGC believes LKBI drilling will take longer because of the peculiar nature of the location.

Most promising is exploration well LKBG, also in the Lakwa PML, spud on May 17 (2021) using company-owned rig EV-2000-5 where ONGC wants to drill to 4897 metres TD to explore Kopili and Tura formations. "Because of its depth and geology, this is an expensive well that will cost ONGC more than Rs64cr ($8.6m) when normally the cost of drilling a well is between Rs30-Rs40cr ($4m-$4.5m)," admits an ONGC source.

"But it's worth it because the potential of this well is 2.2m tonnes (16m barrels crude)." By end-June (2021), ONGC had drilled LKBG to 2500 metres TD, with drilling expected to stretch into mid-October.

Elsewhere, ONGC spud exploration well CHAT at the 54.86-sq km Charali PML on June 6 (2021) using ONGC-owned rig E-1400-1. ONGC will drill to 3053 metres TD at CHAT to explore oil prospects in two Tipam sand zones.

Finally, on June 15 (2021), ONGC spud exploration well RSAN in the Rudrasagar area where it wants to explore Barail and Tipam sands at 3375 metres TD.