Cairn Moving Ahead with Rajasthan Development
Rajasthan (Block RJ-ON-90/1)
Cairn is pursuing its goal of adding to the Rajasthan resource base through its active exploration and appraisal campaign. The company continues to evaluate and develop its existing discoveries to bring them onto production as soon as reasonably possible. The Field Development Plans for Mangala, Aishwariya, Raageshwari oil and Saraswati have been completed and were submitted to the Government of India in October 2005.
Discussions are on-going with Mangalore Refinery and Petrochemicals Limited, an ONGC subsidiary, which is the appointed nominee to take delivery of the Rajasthan crude, with regard to a detailed Crude Oil Sales Agreement. Studies for the Front End Engineering Design for Mangala are complete and the tendering process for the detailed work is almost concluded.
Mangala, Bhagyam and Aishwariya
The evaluation of the northern fields, Mangala, Bhagyam and Aishwariya, is now moving to a phase of detailed analysis of the potential for any additions to the volumetric and reserve base. In particular:
- pre-stack time migration work on the 3D seismic indicates the potential for the main field bounding faults to be positioned further up-dip. A dedicated well program designed to test the crestal fault locations in these fields is currently being planned.
- A re-appraisal of petrophysical parameters in these main fields suggests that the current evaluation may have been conservative when compared with analogous fields and crudes. A focused special core analysis program, involving new core material, is planned to evaluate the water saturation parameters to address this issue. The results of this study are expected in Q1 2006.
Greater Vijaya and Vandana area - N-R-4 Discovery
The N-R-4 discovery well, drilled six and a half kilometers (km) west of the Vijaya and Vandana fields, was drilled to a true vertical depth of 2741 meters (m) in pre-rift formation. The well encountered a number of oil bearing horizons, in similar units to those seen at Vijaya and Vandana, and has a log evaluated 38 m of oil bearing reservoir.
Oil was recovered from MDT samples at three reservoir horizons prior to three open-hole DST tests being carried out. The middle zone flowed oil into the tubing at an estimated rate of 40 barrels of oil per day (bopd) but did not flow naturally to the surface. The other two zones did not flow. It is anticipated that artificial lift, with or without stimulation will be required in future operations.
Based on this well and an appraisal well (N-R-5) together with 3D seismic mapping, the oil in place for the N-R-4 discovery is initially estimated at 100 - 400 million barrels (mmbbls) gross. In this type of stratigraphic trap, recoveries are anticipated to be low.
The N-R-4 discovery further extends westwards the stratigraphic trap potential seen at the Vijaya and Vandana fields.
GS-V-1 Gas and Condensate Discovery - Greater Saraswati area
The GS-V-1 Well was drilled to a separate structure nine km to the North West of the Saraswati field in the East-Central area of the Rajasthan contract area. The well reached a total depth (TD) of 2190 m in a fractured pre-rift formation where it encountered 12 m of net gas pay. An open-hole DST conducted over a 30 m interval of fractured sediments produced at a maximum stabilized rate of 3.2 million standard cubic feet per day and 70 bopd of 47.5 degree API condensate on a 32/64" choke.
While appraisal drilling will be required, the initial gas in place estimates for the GS-V-1 discovery are in the 20-30 billion cubic feet gross range.
A number of exploration prospects around the GS-V-1 discovery highlight further gas potential which will be targeted by an exploration drilling program.
Exploration 3D Seismic
A 300 square km exploration 3D seismic survey has been acquired over the area to the south of Bhagyam and to the west of Mangala. Interpretation of this survey is now underway and the first exploration well based on this data is expected to spud before the end of the year.
Kameshwari–West-1 – North-Central area
The Kameshwari-West-1 well was drilled to a TD of 1500 m in pre-rift formation. Strong residual oil shows were observed in good reservoir sands in the Barmer Hill and Fatehgarh levels in this separate structure, which lies some 16 km NW of the Kameshwari discovery.
The Kameshwari-West-1 well, although essentially a dry hole, gives positive evidence for the presence of good reservoir and hydrocarbon migration through the, as yet, poorly explored west-central part of the contract area.
Vijaya and Vandana appraisal well
The N-R-3 appraisal well, drilled four km south from Vijaya -1 and two km from Vandana-1, encountered 55 m of log evaluated oil bearing reservoir.
Based on the four wells drilled to date and the 3D seismic mapping, the oil in place for the Vijaya & Vandana discoveries is estimated at 200 – 900 mmbbls. In this type of stratigraphic trap, recoveries are anticipated to be low.
Greater Vijaya and Vandana area appraisal of N-R-4 discovery
The N-R-5 appraisal well 8 km to the north of the N-R-4 discovery well encountered 37 m of log evaluated oil bearing reservoir.
Raageshwari 3ST appraisal well
The Raageshwari–3ST appraisal well was drilled into a structural compartment on the NE flank of the Raageshwari field. The well encountered 15 m of oil bearing reservoir in the Thumbli formation.
The additional oil in place established by the Raageshwari –3ST well is estimated to be 5-15 mmbbls gross.
Bhagyam Gas Well
Following the discovery of a gas cap in the nearby N-I accumulation, a well is being planned at the crest of the Bhagyam field, to test the potential for additional gas cap volumes in both the Fatehgarh and Barmer Hill formations, as well as to gather information on the main bounding fault and the Fatehgarh oil reservoir at the field crest.
Gas cap volumes are potentially valuable as a future fuel source to power the energy demands of the nearby major fields as an addition to the considerable gas volumes discovered further south in the block.
Cambay Basin CB/OS-2 - Gauri Oil
The G-A-3 Gauri oil well has been commissioned and has produced first oil. Oil is evacuated through the gas system at the Suvali plant in Gujarat. The future performance of this well under depletion will be important in assessing the recoverable potential in similar more extensive channel reservoirs at Lakshmi.
Cambay Basin CB-ONN-2001/1 - Vanthvali -1
The ONGC operated Vanthvali -1 exploration well is currently operating.
KG Basin KG-DWN-98/2
Following the drilling of the "D" discovery well in August 2005, drilling has yet to recommence on this ONGC-operated, deep water block. A Padmavati appraisal well is expected to spud before the end of the year after which an exploration well on the "U" prospect is planned.
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