India’s Hindustan Oil Exploration Co. Ltd. (HOEC) is preparing to launch a new drilling campaign in the PY-1 Field, located in the Bay of Bengal’s Cauvery Basin, to increase oil and gas production.

“The proposed project entails drilling eight additional development wells and connecting them to the existing unmanned platform and subsea pipeline to offset the decline in production in the PY-1 Field,” HOEC said in a pre-feasibility report.

Launched in 2009, the PY-1 Field is producing about 1.6 million standard cubic feet per day (MMscf/d) of gas from three wells. The amount is down from about 20 MMscf/d in 2011 due to accelerated pressure decline and water breakthrough in existing wells.

PY-1 is spread across 75 sq km (29 sq miles) in water depths that range from 40 m to 250 m (131 ft to 820 ft) in the Bay of Bengal, about 18 km (11 miles) from Port Novo on Tamil Nadu coast.

Development Plan

The proposed development plan involves drilling eight development wells in the field up to a target depth of 3,000 m (9,843 ft) in a water depth of 10 m to 75 m (33 ft to 246 ft).

The wells to be drilled will be tied back to the existing offshore platform, subsea pipelines and onshore processing facilities developed during the initial phase of development. Gas produced from the new wells will be transported through 55-km (34-mile), 24-in. subsea pipeline to the onshore processing plant at Pillaiperumalnallur on Tamil Nadu coast.

Drilling will target the proven gas reserves in the “granitic basement structural high” reservoirs located in four hills and ridges (Jupiter, Pluto, Saturn, and Venus) of the PY-1 Field.

Gas reserves are contained in the heterogeneous, Precambrian, weathered granite sediments, sealed by Cretaceous to Eocene shales, on the crest of a northeast-southwest basement ridge of the field.

The additional eight wells are expected to increase production from the field to 60 MMscf/d.

The wells drilled in the ridges (Earth and Mercury) during the first phase development encountered pay zones as thick as 61 m (200 ft) at depths of 1,524 m (5,000 ft) to 1,676 m (5,500 ft). The first discovery well, PY-1-1, flowed 13 MMscf/d during testing.

PY-1, originally discovered by ONGC in 1980, has nine hills and each is filled with hydrocarbons, which are estimated to contain gas reserves of 4.1 Bcm (146 Bcf) and 1.16 MMbbl of condensate.

Besides, the operator has a plan to take up reentry drilling in the less-producing PY-1-12 well during the April-June quarter to revive the gas production from the PY-1 Field.

Sharing Infrastructure

HOEC has proposed sharing its PY-1 Field offshore infrastructure with the adjoining PY-3 oil and gas field in the CY-OS-90/1 Block, in which it holds a non-operating stake (21% PI), to optimize operating costs.

“We have submitted an alternative integrated development plan to revive 3,000-plus barrels of oil production from the shut-in well in the PY-3 Block for approval by the stakeholders,” the company said.

HOEC, according to the plan, has proposed to transport the gas that comes out along with the oil, which would otherwise be flared, from the PY-3 Field by integrating its existing subsea pipeline of PY-1 through a 6-km (4-mile) pipeline. The plan, estimated to cost about $28 million, includes refurbishing the existing production units along with construction of a pipeline.

The company has made a provision in the installed subsea pipeline as part of the PY-1 development project to potentially receive associated natural gas from the PY-3 Field operated by Hardy Exploration & Production India Inc.

PY-3 was producing 3,200 bbl/d of crude and 3.5 MMscf/d of gas through a floating production unit before the suspension of operations in 2011 due to a commercial dispute. It is a conventional sandstone reservoir with a potential to produce more than 7,000 bbl/d of high-quality light crude oil with low sulphur content along with the significant quantity of gas.

HOEC has participating interest in nine oil and gas fields in the onshore and offshore basins of Cambay, Cauvery, Assam Arakan and Rajasthan in India.

—Ravi Prasad