Good gas flow rates recorded at ONGCآ’s KG gas find

Vol 8, PW 24 (09 Mar 05) Exploration & Production

ONGC might have at last found the big deepwater discovery it has been waiting for.

On 4th March, ONGC confirmed in a statement to the Bombay Stock Exchange speculation that Transocean drillship Discoverer Seven Seas had struck gas at deepwater block KG-OS-DW-IV. Not many relevant details were made available.

ONGC said the well was spudded on 28th January in 553 metres water depth and drilled to a target depth of 2449 metres. ONGC has named this discovery well as Vashishta-1.

PETROWATCH has obtained further details. We learn conventional testing began on Monday, 7th March of a 24-metre interval between the 1962-metres and 2182-metres zone and that the first choke (8/64-inches) flowed 30,000 cm/d at 3157-psi pressure between 7am and 4pm after which a 12/64-inch choke was put in place at about 4.45 pm.

The second choke flowed 84,000 cm/d at 3160-psi pressure for about eight hours, PETROWATCH was told late Tuesday. Subsequently, a third choke of 16/64 inches was put in place and flowed 161,000 cm/d at 3140-psi.

This is much better than expected, reveals a source. Already people (at ONGCs Mumbai office) are opening champagne bottles.

The well will now be shut-in for 24 hours to get correct formation pressure. Later, ONGC will begin higher bean studies.

This will see chokes of 20/64-inches and 32/64-inches put in place for about six to eight hours each. The idea is to estimate optimum gas production.

A final 24-hour shut in will follow and testing will be called off. ONGC fears possible sand influx during testing with higher choke sizes.

But the higher choke sizes could also reveal condensate, which is expected to add value. ONGC expects Discoverer Seven Seas to be on location until the end of the week.

On Thursday we plan to pull out the equipment, we learn. Well need another day to plug the well, another day to pull out the Blow Out Preventor and the riser and then the rig will move to the next location.