India’s state-run Oil and Natural Gas Corp. Ltd. (ONGC) is set to launch a 45 development well drilling program in the deepwater KG-DWN-98/2 Block in the Bay of Bengal in fourth-quarter 2016 with the Aban Abraham drillship.

The company recently issued a firm letter of award to Aban Offshore Ltd. for the Aban Abraham drillship for a period of two years. The dynamically positioned class-2 drillship is capable of drilling wells in water depths of up to 2,000 m (6,600 ft).

Confirming the order, Aban Offshore said it would deploy Aban Abraham in the KG-DWN-98/2 deepwater block in fourth-quarter 2016.

This is one of three the company intends to procure for development well drilling in the KG block. Selection of the remaining two rigs is expected to be completed soon.

The operator will initially use Aban Abraham to drill development wells in the Cluster-II zone of the Northern Discovery Area (NDA) in the KG-DWN-98/2 Block

Oil and Natural Gas Corp. is planning to invest about US $5 million for the Cluster-II area development in the Krishna-Godavari (KG) Basin, India’s Petroleum and Natural Gas Minister Dharmendra Pradhan said in a written reply to Parliament recently.

“Gas and oil production is expected to commence from June 2019 through March 2020, respectively, from Cluster-II area,” the minister added.

During exploratory drilling, the operator made significant deepwater oil and gas discoveries in the NDA’s Cluster-I and Cluster-II. Discoveries in Cluster-I, located in the northern section, are mainly gas, while finds in Cluster-II, located in the southern section, are mix of oil and gas.

Plans are to develop Cluster-I during a later stage.

NDA is spread across an area of 3,494 sq km (1,349 sq miles) in a water depth up to 1,800 m (5,905 ft) in the Bay of Bengal. The block is located about 25 km to 80 km (15.5 miles to 50 miles) from Andhra coast.

Cluster plan

The operator will initially develop oil and gas fields in Cluster-II, which is further divided into Cluster-IIA (oil fields) and Cluster-IIB (gas fields). The plan includes drilling 23 producer wells and 12 water injection wells as well as constructing production facilities such as an FPSO unit, fixed offshore platform as well as subsea equipment, a subsea pipeline and an inland terminal.

Hydrocarbon fluids produced from Cluster-II will be taken for treatment to an FPSO unit anchored nearby via an 18-in. 21.5-km (13-mile) dual subsea pipeline. The stabilized crude oil will be transported in sea tankers. Compressed and dehydrated gas will be taken to a fixed platform via pipeline, with an option of being taken from the FPSO unit to the existing Odalarevu Onshore Terminal through a 22-in. 34.3-km (21-mile) pipeline—placed 2 m (6.5 ft) below surface—for sale.

According to an internal report, ONGC expects a peak oil rate of 77,305 bbl/d and 3.81 MMscm/dof associated gas through the 15 producer wells and 12 water injection wells with a peak water injection rate of 9,400 sq m/d (101,181 sq ft/d) from Cluster-IIA fields. The peak production rate of gas is envisaged at 12.75 MMscm/d from eight wells from the Cluster-IIB free gas fields.

Total oil and gas production from all fields in Cluster-II is expected to be 23.5 million tons and 50.7 Bcm during the project life of 12 to 16 years.

Cluster-IIA has estimated in-place reserves of 94.26 million tons of crude oil and 21.75 Bcm of associated gas (solution gas plus gas cap gas). Cluster-IIB has estimated in-place reserves of free gas of 51.98 Bcm.

The developer has received clearance from the environment ministry to drill 45 development wells and to construct the Cluster-I and II production facilities. Produced gas from Cluster-I will be taken to a fixed platform in shallow-water depths through an 18-in. 16.1-km (10-mile) dual pipeline for processing and subsequently taken to the Odalarevu onshore terminal through a 20-in. 35.5-km (22-mile) pipeline for sale.

Development plans for the block’s Southern Discovery Area (SDA), located in ultradeep waters of up to 3,100 m (10,171 ft), remain in the air.

“Considering the water depth (2,400 m to 3,100 m) and the constrained techno-economic solutions, execution of this [SDA] is presently not being pursued for development,” the minister said. “Scouting for suitable technology/solution for field development is in progress.”

ONGC holds 100% participating interest in KG-DWN-98/2 Block, which sits next to the KG-D6 Block operated by Reliance Industries Ltd.

—Contributed by Ravi Prasad