Download Conversion of Drilling Rig to Hybrid Rig for clean environment

Conversion of Drilling Rig to Hybrid Rig for clean environment
Author: Keshab Chandra Paul, DGM(Elect.)
e-mail id: [email protected]
+91 9402141044
Co-Author: Sushil Kumar, SE(Elect.)
e-mail id: [email protected]
+91 9436501050
Abstract
Brief about the project and aim
Present Drilling Rigs are running on Four (04) numbers DG (Diesel Generator) sets of 1430
KVA each consuming approximately 82.91 Kiloliters of Diesel and 596 Liters of Lube oil per
Month, generating approximately 324274 kWh of Electrical energy (as per historical data of
Drilling Rigs of ONGC, Tripura asset, Agartala). The total running cost of these DG sets
calculated as per last three years records, comes at a whopping ₹58,35,780.00 per Month
(all data’s and calculations would be provided along with the full technical paper) .
ONGC owns significant natural gas reserves in the North Eastern state of Tripura. The
complexities of logistics and attendant costs limit the economic viability of transportation of
gas to other parts of the country. In order to optimally utilise the gas available in Tripura,
ONGC has developed (with 50% stake) a 726.6 MW Combined Cycle Gas Turbine (CCGT)
thermal power plant (ONGC Tripura Power Company Ltd - OTPC) close to its gas fields in
the state of Tripura. OTPC produces surplus power and feeds it to Tripura State Electricity
Corporation Limited (TSECL), which is further supplied to the deficit areas of North Eastern
States of India.
This project aims at giving the option of running the Drilling rigs on external power supply
fed from state electricity board in addition to present DG sets.
Recently, India has signed Paris agreement for climate change for reduction of
consumption of fossil fuel for clean environment. This project for conversion of Drilling Rig to
Hybrid Rig is for clean environment in support of the Paris agreement. This project not only
contributes towards clean environment and carbon credit but also gives huge monetary
benefits to the three Government Enterprises viz. ONGC, BHEL & TSECL. Details of the
project are mentioned below.
Detailed conversion process
The conversion would be done by installation of movable substation, comprising of one
step-down transformer of rating 4 to 5 MVA, 3 phase, 11 KV / 600 Volt / 440 Volt, 50 Hz.
This sub-station would be fed electrical power from Tripura State Electricity Corporation
Limited (TSECL) through 11 KV transmission lines and the output of the substation would be
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hooked to AC-PCR & DC-PCR through bus tie or bus coupler. The incoming transmission
lines would be laid very rapidly by TSECL, exclusively for the Drilling rig, for which plan
would be made in advance.
Technical discussion was held with BHEL (OEM of the drilling rig) representatives regarding
the project and BHEL has agreed to develop suitable customized movable sub-station with
safety arrangements as per IE rules and DGMS guidelines. Installation and commissioning
part would also be in BHEL’s purview.
Technical discussion was also held with Director (Technical) of TSECL. Director (Technical)
of TSECL has appreciated the proposal and agreed for full support & corporation for
providing 11 KV power from available nearby substation to the drill-site locations of drilling
rig. This would be the best way to monetize the surplus power generated from OTPC.
The layout & circuit diagrams after conversion of rigs are as below,
External power supply
Modified Layout Diagram of E-1400 series Rigs
Modified Circuit Diagram of E-1400 series Rigs
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Cost implications of the project
Cost implications of the project are not yet calculated, but BHEL has agreed to give
technical support and required material for this pilot project. However roughly the project
cost is estimated to be below ₹ One Crores per drilling rig.
Benefits of the project
This project would be beneficial in many ways such as,
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Reducing carbon emission.
Reduction in global warming.
Earning of carbon credits.
Noiseless operation at the Rig. Relief to nearby habitations.
Adherence to Paris agreement of climate change.
Huge monetary benefit. Cost benefit analysis is calculated as under,
Cost benefits analysis:
Cost of running 4 no’s of DG sets per Month per drilling rig = ₹58,35,780.00 (considering
costs of High Speed Diesel burned, Preventive maintenance cost, breakdown maintenance
cost and depreciation of capital cost of DG sets).
Total cost per Month for getting 324274 kWh of Electrical energy considering per unit rate of
₹7.00 (1 unit = 1 kWh) from external power source plus depreciation of capital cost of the
project = ₹22,69,918.00 + ₹2,08,333.00 = ₹23,74,084.00 (approximately 40.68 % of existing
setup)
I.e. a saving of approximately ₹34,61,696.00 per Month per Rig. Which when
implemented in all three Drilling Rigs of ONGC, Tripura asset would be a mammoth
₹12.46 Crores (approx.) per year.
The above cost benefit calculation is on the basis of 100% utilization i.e. consumption of
electrical power from the external source. The actual calculation would be on pro-rata basis
i.e. if 50% power is self-generated at the Rig & 50% is taken externally, cost benefit would
be approximately ₹17,30,848.00 per Month per Rig.
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