Following a comprehensive review, the Rajasthan block’s resource potential was estimated at 7.3 bn boe gross in-place.
There have been exploration upsides with the prospective resource base rising from an earlier estimate of 2.5 bn boe gross in-place to 3.1 bn boe gross in-place
The Rajasthan Block
- Cairn India is the operator with 70% participating interest. Its joint venture (JV) partner, ONGC, has a 30% participating interest.
- The block consists of three contiguous development areas: (i) Development Area (DA) 1, which comprises the Mangala, Aishwariya, Raageshwari and Saraswati (MARS) ; (ii) DA 2, consisting of the Bhagyam and Shakti ; and (iii) DA 3, having the Kaameshwari West.
- At present, the block is producing 175,000 bopd, thanks to GoI approval for higher Mangala offtake of 150,000 bopd.
- Some other within the block have also commenced production. The Bhagyam field started production on 19 January, 2012 and is currently producing at around 25,000 bopd. Saraswati began production on 27 May, 2011 and has produced over 75,000 barrels of oil till date. Raageshwari, which is primarily a gas field with marginal oil, also commenced production on 8 March, 2012 and is currently producing in excess of 250 bopd.
The Rajasthan project is crucial for the nation. Oil production from the project helps the country to reduce significant quantities of oil imports.
The Mangala, Bhagyam and Aishwariya (MBA) fields, among others, constitute Cairn India’s key assets in Rajasthan. The MBA are the three largest finds in Rajasthan. The Mangala field — considered to be the largest onshore hydrocarbon find in India in last two decades — was discovered in January 2004. This was followed by discoveries at the Bhagyam and Aishwariya fields. To date, 25 discoveries have been made in the Rajasthan block. Studies indicate that it has further potential for growth. The Production Sharing Contract (PSC) for the project was signed on 15 May, 1995. In 1997, Cairn acquired an interest in the block. In 2002, Cairn acquired 100% of the exploration interest and assumed the role of operator.
Rajasthan Hydrocarbon Resources
As mentioned earlier, during FY2012 Cairn India carried out a comprehensive review of the resource potential of the Rajasthan block. This was done using detailed studies involving innovative technologies and advanced geoscience. In addition, a specialist agency, DeGolyer and MacNaughton (D&M), has conducted a study to arrive at an independent estimate of reserves and contingent resources; it also reviewed the majority of the leads and prospects. D&M also undertook a separate reserves certification exercise on behalf of the RJ-ON- 90/1 joint venture (JV).
- Based on the Company’s assessment, the potential resource for the Rajasthan block is now estimated at 7.3 bn boe gross in-place. This is primarily due to an increase in the exploration upside with the prospective resource base now estimated at 3.1 bn boe gross in-place, versus an earlier estimate of 2.5 bn boe gross in-place. (See graph )
- The Rajasthan recoverable risked prospective resource has increased from 250 mm boe gross to 530 mm boe gross primarily due to generation of additional leads and prospects.
- The Company with ONGC, its JV partner, is working with GoI to obtain the necessary approvals required to carry out further exploration and appraisal activity in the block.
- The discovered resource base has increased from 4.0 bn boe gross in-place to 4.2 bn boe gross in place. This is due to an increase in the Stock Tank Oil Initially in Place (STOIIP) from Mangala and other Rajasthan.
- The Rajasthan block’s Expected Ultimate Recovery (EUR) has increased from 1.4 bn boe gross to 1.7 bn boe gross on account of increased recoverable risked prospective resource estimates.
- Given these new evaluations, the total resource base now provides a basin potential to produce 300,000 bopd, subject to further investments and regulatory approvals. This is equivalent to approximately 40% of India’s current crude oil production
Mangala, Bhagyam, Aishwariya and Other Rajasthan
The Mangala, Bhagyam and Aishwariya (MBA) fields have gross recoverable oil reserves and resources of over one bn boe. This includes proven plus probable (2P) gross reserves and resources of 636 mm boe with a further 308 mm boe or more of EOR resource potential. Today, Mangala and Bhagyam are cumulatively contributing more than 20% of India’s current domestic crude oil production.
At Mangala, a total of 148 development wells have been drilled and completed with 96 producers and 33 injectors operationalised. The Company has successfully drilled and completed 11 horizontal wells at Mangala. Going forward, the Company intends to bring other wells on stream in a staged manner.
Bhagyam is the second largest field in the Rajasthan block, with an approved production plateau of 40,000 bopd. A total of 62 development wells have been drilled till date with 21 producers and four injectors operational; 12 producer wells are yet to be drilled. Both Mangala and Bhagyam are connected to the Mangala Processing Terminal (MPT), which processes the crude oil from the Rajasthan.
The Aishwariya field is the third largest discovery in the Rajasthan block. Following an assessment of higher production potential and design optimisation due to increased reserves and resources, Cairn India
has commenced development work in the field.
The development will include nine well pads, 36 producer and 15 injector wells. Well fluids from Aishwariya will be collected at a Cluster Well Pad and the carbon dioxide rich associated gas will be separated before transporting the well fluid to MPT.
The Company received JV approval in December 2011 to start work on the field. Hence, it has awarded key contracts including the main EPC; and the contractor has been mobilised onsite. Crude oil production is expected
to commence towards end CY2012,subject to JV and GoI approval.
Raageshwari Deep Gas Field
The Raageshwari Deep Gas field is meant to supply gas to meet the energy requirements at the MPT and the Mangala Development Pipeline, which runs approximately 670 km from Barmer to Viramgam to Salaya and then on to Bhogat, near Jamnagar, on the Arabian Sea coast. During FY2012, the Company carried out drilling and completion of additional wells to augment gas production from the field as well as water production from the nearby Thumbli saline aquifer water field. Application of new fracture stimulation and completion technology has proven to be successful in the field.
Saraswati and Raageshwari
The Saraswati Field, which commenced production in May 2011, is currently producing at a rate of 250 bopd. Till date, it has produced over 75,000 barrels of oil. This oil is processed at the MPT, and blended with the Mangala oil which is sold through the pipeline. The marginal oil field at Raageshwari also commenced production in March 2012.
In Rajasthan, there are 19 other discoveries beyond MBARS and Barmer Hill — referred to as the satellite fields. These have been tested for hydrocarbons and have prospect for commercial development. In fact, Cairn India’s recent technical work indicates a higher potential for these fields than what was earlier envisaged. The Company has carried the resource potential in books as contingent resources. Field Development Plans (FDPs) for four fields have been submitted; and FDPs for remaining fields are under various stages of preparation.
Barmer Hill and other
Evaluation of other discoveries with the objective of optimising the Rajasthan development is currently under way. To test the potential of the Barmer Hill formation, Cairn India has planned a pilot hydraulic fracturing programme, subject to GoI approval. A declaration of commerciality for the Barmer Hill was submitted to the GoI in March 2010, and an FDP is under preparation. A staged development is being planned to monetise the reservoir.