ONGC Ltd. is preparing to develop the Ratna and R-Series (R&RS) fields, located in the shallow waters of the Arabian Sea’s Mumbai Basin, which it won back after the Indian government canceled the award to a consortium-led by Essar Oil.

“We have floated the tenders for drilling wells, construction of platforms and associated subsea structures in the R-Series fields,” an ONGC official said.

The Indian company is focusing on development of seven new fields (R-7, 7A, 8, 9, 10, 13 and 71) and redevelopment of the Ratna Field (R-12), where it suspended the operations before surrendering the Ratnagiri concession to the Indian government in 1994.

The development plan, according to the official, envisages drilling and completion of 31 wells (22 producers and nine water injectors), installation of five new well platforms (R-7A, R-9A, R-10A, E-12B, R-13A) including 1 riser-cum-wellhead platform with associated pipelines, revival of R-12A platform and hiring of jackup mobile offshore production unit (MOPU) with oil and gas processing facilities.

The operator said in a tender that it would hire an MOPU for a period of up to 18 years.

The work includes laying more than 140 km (87 miles) of subsea pipeline to evacuate oil from 22 producing wells to the existing Heera Processing Complex.

The peak production rate of 14,583 bbl/d is expected to be achieved in the 2019-2020 fiscal year, which ends March 31, 2020, with a cumulative production of 8.39 MMT of oil and 1.696 Bcm (60 Bcf) of gas during the project life.

The entire R-series project is estimated to cost more than $640 million.

The R&RS fields are located about 130 km (81 miles) southwest of Mumbai and about 41 km (25 miles) from Heera Field in the western offshore in water depths between 40 m and 50 m (131 ft and 164 ft). It has 37 structures, of which eight structures are found to be oil bearing.

The in-place reserves for these offshore fields are estimated at 87 MMbbl of oil and 1.2 Bcm (42 Bcf) of gas.

“ONGC has initiated necessary action for development of this field after cancellation of [the] letter of award to Essar Oil Ltd. and Premier Oil Ltd.,” the petroleum and natural gas ministry said in annual report for fiscal 2016-2017. “ONGC will be able to bring the field back to production in four years’ time and achieve a rate of production of 3,300 bbl/d.”

Regaining Control

ONGC had drilled 35 exploratory wells, nine development wells and installed one well-cum-production platform in the R-12 Field and a single-buoy mooring terminal in the R&RS fields before the exit. Small quantities of oil and gas were produced from the R-12 platform till 1994.

Despite the discovery of oil and gas reserves, state-run ONGC surrendered the R&RS fields in 1995 as part of the Indian government’s plan to encourage private investments in development of small- and medium-sized oil and gas prospects in the country.

R&RS is one of the 19 small and medium prospective oil and gas fields awarded to the private investors. Others include: Ravva (Krishna Godavari Offshore), Panna and Mukta (Mumbai Offshore), Mid and South Tapti (Mumbai Offshore) and Kharsang (Arunachal Pradesh).

The consortium of Essar Oil, Premier Oil and ONGC, with participating interest of 60% (operator), 10% and 40%, respectively, won the R&RS fields for exploration and development in 1996 but failed to finalize the production-sharing contract even after 20 years due to the differences in royalty rates and taxes.

The new Indian government, headed by Prime Minister Narendra Modi, canceled the award of the concession to Essar Oil-led consortium in March 1996 and decided to return it to ONGC.

—Ravi Prasad