Ravva drilling programme at prospect LO-110

Vol 15, PW 20 (19 Apr 12) Exploration & Production

Cairn India is also preparing to drill three wells at the elongated 21-sq km Late Oligocene-110 ‘prospect’ (LO-110) at its eastern offshore Ravva oil and gasfield.

In February, the Ravva Operating Committee approved Cairn’s proposal to drill one exploratory well and two ‘contingent’ appraisal wells. But before Cairn’s proposal can be considered by the Management Committee next month (May) partner ONGC must approve.

Cairn estimates LO-110 holds 368-bn cubic feet (10-bn cubic metres) of ‘recoverable gas’ and 16m barrels of ‘condensate’. It plans to drill the exploration well to 4000 metres TD and drill two appraisal wells to ‘delineate’ the prospect before drilling three development wells.

If all goes to plan, Cairn will develop LO-110 at a cost of $1.08bn and land first gas in 2016-17 after which ‘plateau’ production levels are likely to be 200m cf/d (5.67m cm/d) and 8480 b/d of condensate over 39 months. LO-110 is likely to produce until 2022-23.

Cairn has received EoIs to hire a jack-up with a 15,000-psi BoP (Blow out Preventer) for the drilling programme, expected to begin in 2012-13. The company needs a rig that can drill 'high temperature/high pressure' wells in water depths of up to 20 metres and expects to pay $160,000/day.

Internal estimates suggest the exploration well could take 110 days to drill and cost $87m plus $12m ‘mobilisation/demobilisation’ charges. ONGC drilled seven wells between 1984 and 1988 at LO-110 but did not develop the prospect.

ONGC had doubts over LO-110’s production potential given the ‘low porosity and permeability’, despite recording ‘bottom hole pressures’ of 13,000-psi.