Cluster 2 Fields Development, Block KG-DWN-98/2, Bay of Bengal, India
The KG-DWN-98/2 Block is located offshore Godavari Delta on the east coast of India covering an area of 7294.6km² of the Krishna-Godavari basin. Oil and Natural Gas Corporation (ONGC) is the current block operator, but Cairn Energy India operated it until March 2005.
The project proposes to develop the fields lying in Cluster 2 of the deepwater block after its field development plan was approved by the ONGC board of directors. A total investment of Rs340.12bn ($5.07bn) will be required for developing the fields, which lie in water depths ranging from 300m to 3,200m.
Cluster 2 is comprised of both oil and gas fields with oil fields grouped in Cluster 2A and gas fields in Cluster 2B. The oil fields are identified as A2, P1, M3, M1 and G-2-2, whereas the gas fields are named R1, U3, U1, and A1.
First gas production from the project is expected in June 2019 followed by oil production in March 2020. The Cluster 2 development is scheduled to be completed by June 2020.
Geology of the KG-DWN-98/2 block
The stratigraphy of the KG-DWN-98/2 block consists of both slope depositional and deepwater depositional systems. The Pliocene section is mainly formed of clay and contains certain deepwater channel and fan deposits.
The basin is composed of Achaean and Proterozoic rocks with its sediments ranging from lower-Permian to recent age. The western part of the basin is formed by Permo-Triassic, late Jurassic-Cretaceous and Tertiary rocks.
Oil and gar reserves
The oil deposits in Cluster 2A hold estimated in-place reserves of 94.26 million metric tonnes (mmt) of crude oil and 21.75 billion cubic metres (bcm) of associated gas, while Cluster 2B has estimated in-place reserves of free gas of 51.98bcm.
Total oil and gas production estimated from the project is 23.52mmt and 50.706bcm, respectively. Cluster 2A fields will produce oil at a peak rate of 77,305 barrels a day (bopd) and associated gas at a rate of 3.81 million metric standard cubic metre a day (mmscmd) with a peak water injection rate of 9,400m³/d.
Gas from Cluster 2B will be yielded at a peak production rate of 12.75mmscmd. The peak daily production rates of crude oil and natural gas from the project will be 16.89% and 27.60% of ONGC's current production rate.
Field development plan
The field development comprises of drilling and completing 35 wells including 15 oil producing wells, 12 water injection wells, and eight gas producing wells.
The field infrastructure will include a gas processing platform connected to a living quarter platform via a bridge, a floating production storage and offloading (FPSO) vessel, and ten manifolds along with riser base manifolds. Subsea pipelines approximately 430km-long with diameters varying from 6in to 22in as well 151km of umbilicals will also be required.
A 21.5km-long dual pipeline with an 18in diameter will be used for transporting oil from the fields to the anchored FPSO. Oil along with associated gas will be processed at the FPSO with the oil being transported to onshore terminal for custody transfer to Gas Authority of India (GAIL) located 35km away.
A 20in subsea pipeline will transfer the hydrocarbons from the fixed platform, while a 22in diameter pipeline will transfer the hydrocarbons from the FPSO to the landfall point. The hydrocarbons will further be transported to the Odalarevu onshore terminal. The wellheads will be secured to the manifolds via 8in diameter infield pipelines.
Key players involved
A geotechnical site investigation contract valued at $26m was awarded to Fugro. The scope of work will include collecting geotechnical and geohazard data required for the design and installation of wellheads, manifolds, platforms, FPSO anchors, umbilicals, pipelines and flow lines within the field.
The contractual work will be performed using a deepwater geotechnical vessel named Fugro Voyager and will begin towards the end of the third quarter of 2016. Data collection will be followed by in-depth laboratory testing, data analysis, interpretation and integration with previously gathered autonomous underwater vehicle (AUV) geophysical and metocean survey data.