ONGC readies to drill 2 exp. wells in Tripura

Vol 23, PW 16 (18 Jun 20) Exploration & Production

Despite a sharp drop in local gas demand, ONGC appears determined to realise the full potential of its 33-sq km Konaban PML in gas-rich Tripura with two new exploration wells.

This month (June) ONGC will spud the first well at location ROAH using a 2000-hp rig (Rig-5) from Delhi-based contractor Quippo. With nine months before the rig contract ends in March 2021, ONGC wants to reach 4800 metres TD, targetting Lower Bhuban sands at ROAH_SUB, site of an earlier well, drilled and abandoned in 2012.

Next in line is a 'substitute' or new exploration well at location ROBN, where ONGC called off drilling a development well in September last year (2019) after encountering high temperature, high-pressure (HP/HT) formations at 3500 metres in Middle Bhuban sands. "When drilling (ROBN) went beyond 3500 metres," says a source, "we encountered new prospective (Middle Bhuban) sands, so the location was converted from development to exploration location; this is quite rare."

No spud date is yet available for the substitute ROBN location well. In a March 2019 pre-feasibility report, ONGC describes Konaban, discovered in 1986, as, "one the biggest gas producers" in west Tripura which "still holds huge scope (to) establish its full production potential."

In May 2018, ONGC announced 'new pool gas discovery well' RO-75 (ROBE) drilled to 3230 metres final TD which tested 186,000 cm/d from a seven-metre 'pay' at 3035-3042 metres depth and a six-metre 'pay' at 3042-3048 metres.