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Techno-Economic Appraisal

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Techno-Economic Appraisal

  1. 1. Techno Economic appraisal of Prospects A Case Study on CB-ONN-2009/8 Block ( Cambay Basin ) Vedant Makwana ( 45 ) Shashank Pandey ( 36 ) Aditya Harsh ( 03 )
  2. 2. Background ▪ The concerned block CB-ONN-2009/8 measuring 136 sq. km was awarded to JPIL by Govt. of India under NELPVIII. ▪ Jay Polychem India Ltd. (JPIL) is an integrated Energy Company having interest in Oil and Gas Exploration. ▪ The Production Sharing Contract PSC between JPIL and GoI was signed on 30 June 2010. ▪ Block CB-ONN-2009/8 falls in DholkaTaluka ofAhmedabad and TarapurTaluka of Anand district of Gujarat State.
  3. 3. On site Location Source : S.S.Merh
  4. 4. The Project ▪ JPIL has identified 12 wells in Ahmedabad and one in Anand district. ▪ Proposed operation are covered under category 1B of EIA Notification 2006. ▪ JPIL plans to carry out accelerated development programmes on the basis of recent 3D seismic data acquired. ▪ JPIL intends to drill wells to a depth ranging 800 to 2500 metres. ▪ There is a possibility of drilling a number of wells from a single site which is termed as cluster well drilling. ▪ Some of the wells may be drilled horizontal to increase sweep efficiency.
  5. 5. Technical Aspects
  6. 6. The Sedimentary Basin ▪ The Cambay rift basin is a rich petroleum province majorly lying in the state of Gujarat, India ▪ It is a narrow elongated rift grabben extending North to south from Sanchore to Surat. ▪ In the North the basin narrows , tectonically continuing beyond Sanchore to pass into the Barmer Basin of Rajasthan ▪ On the southern side the basin merges with Bombay offshore basin in the Arabian Sea. ▪ Seismic and drilled well data indicate a thickness of about 8 km of tertiary sediments resting over DeccanVolcanic basalt
  7. 7. Geology ▪ Cambay Basin in the western Indian state of Gujarat is a fairly well explored productive basin ▪ The Broach sub block lies in the southern part of the basin. It is bounded on the north by the Mahisagar River and in the south by Narmada River. ▪ It is bounded by basin marginal faults in the east and west. Most of the discovered oil in this block is in Hazad sands of the Ankleshwar Formation, but oil is also produced from deeper pays in the Cambay Shale and Olpad Formation of Palaeocene to Early Eocene age. ▪ In a basin with geological history of deltaic sedimentation, entrapment conditions formed in time and space witnesses varying degree of structural and stratigraphic control over hydrocarbon accumulations.
  8. 8. Cont… ▪ Cambay Shale below Hazad base includes the following succession from top to bottom: – A monotonous fissile shaly interval, occasionally carbonaceous, 100 to 200 m thick deposited in low energy conditions. – A thickening upward silty interval often associated with a few meters thick coal seam. This interval is widely correlatable in the Jambusar-Broach block. – Another monotonous shale interval, often carbonaceous, thickening from 50 to 150 m in Nada Malpur area, to 700-800 m in Gandhar and Jambusar wells. – Deeper, the shales includes 9 to 12 layers of lithic dirty sands, 2 to 10 m thick. Source : GMRC
  9. 9. Petroleum Systems ▪ Source Rock – Thick Cambay Shale has been the main Hydrocarbon Source Rock for oil fields in the Cambay Basin. – The TOC ( Total Organic Carbon ) and maturation studies suggest that Olpad Formation Shale is organically rich and thermally mature. ▪ Reservoir Rock – The reservoir majorly consists of sand sized Basalt fragments although localised sandstone lenses occur in the Cambay Shale. ▪ Cap Rock – Transgressive Shale within the deltaic sequences provide a good cap rock.
  10. 10. Operations ▪ Drilling of well – Based on the drilling Methodology adopted by JPIL the size of the Drill bit and other equipment would vary. – However a schematic cross- section of proposed well is displayed alongside. – Detail of drilling programme is under finalization , but is expected to follow the general sequence outlined below
  11. 11. Cont… ▪ Spud and Drill 17.5 inch section ▪ Run and cement 13.36 inch casing ▪ Install and test BOP ▪ Drill 12.25 inch section ▪ Run and cement 9.62 inch casing ▪ Drill 8.5 inch section ▪ Record well logs ▪ Run and cement 5.5 inch casing ▪ Finally the well will either be completed as producer or plugged and abandoned.
  12. 12. Oil Characteristics ▪ Unlike other oil fields of Cambay Basin the oil from the concerned block is heavy and sour. ▪ The API gravity of oil as obtained from discovery samples is approximately 14.0 ( SPGR = 0.95 ) ▪ The sulphur content ranges form 1.6 % to 2.2 %. ▪ This oil is waxy with pour points ranging from -8 to -3 °C.
  13. 13. Well Testing ▪ While Drilling rock core samples will be taken from the strata. ▪ Well log data will be recorded simultaneously. ▪ If Hydrocarbons are encountered , composition and reservoir permeability would be warranted. ▪ A production test might proceed through the final completion valves in place
  14. 14. Economic Aspects
  15. 15. Drilling Requirements ▪ Drilling Facilities – Drill Bit – Drill String – Drill Collars – Kelly – Top Drive Mechanism – Swivel with high pressure drilling hose – Diesel Engines – Blow Out Preventer – Storage tanks for Drilling Mud
  16. 16. Raw Materials For Slurries ▪ The main component of Drilling fluid is slurry of inert solids suspended in a liquid phase which will be made up of water. ▪ The anticipated chemicals used in the mud preparation of each well is given in table along side. ▪ JPIL may also explore use of synthetic based mud to achieve higher drilling efficiency. ▪ Schlumberger and Halliburton would be the consultants in case this option is tried. ▪ Another important raw material is cement slurry. On an average 200-250 thousand tonnes of cement is likely to be used for each well. Sr.No Chemical Quantity (Tonnes ) 1 Bentonite 0.7 2 Caustic Soda 0.4 3 Soda Ash 0.05 4 Lignite 5.05 5 Barites 120.75 6 PAC UL 0.6 7 PAC R 0.5 8 Spersene 0.9 9 Aluminium Stearate 0.03 10 Chrome Lignite 2.875 11 SulphonatedAsphalt 0.5
  17. 17. Economic Aspects ▪ WorkforceArrangement – During the drilling operations and pilot assessment phase about 20-30 people may be working in three shifts of 8 hours each. – 8-10 technical personnel will be present at the site during drilling period. – Once drilling is over no person is required at site except security cover through contractor. ▪ Power Requirement – Diesel Engines shall be utilized as prime movers – Capacity of the engines that shall be used for operating the rig and the circulation system should be in the range of 440 KVA ( 2 in number , 1 standby ).The Engines would consume high speed diesel at the rate of 20 litre per hour. – A power generator shall be installed for lighting – The generator shall consume approximately 150 litres per hour.
  18. 18. Cont… ▪ Water Requirement – Water is required for mud preparation , cement preparation , engine cooling , floor / equipment washing , sanitation , fire fighting storage , and personal uses of crew. – The emergency fire fighting provision water facility would be initially 150,000 litres. – According to CGWA ( Central Ground Water Authority ) , Tarapur of Anand District is decided as safe area. Sr.No Purpose Water Requirement 1 Construction and Site Preparation 4.7 Kl 2 Mud Preparation 10 Kl 3 EngineCooling 0.8 Kl 4 Washing 5 Kl 5 Fire Fighting Make-up 0.8 Kl 6 Domestic Requirements 2.55 Kl Total 19.5 Kl
  19. 19. Bottom Line Pros Cons
  20. 20. Conclusion ▪ The decision of putting in full investment for complete development of the oil fields of the Block CB-ONN-2009/8 depends heavily on the IOIP ( Initial Oil in Place ) assessment ▪ As concluded from the technical aspects the oil is difficult to produce because of low API gravity and supposed to be low flow rate ( No Primary permeability as reservoir rock is basalt ) ▪ Hence a lot will depend on the commercial quantities of oil that can be produced.
  21. 21. Reference 1) "Geology of Gujarat" by S.S.Merh published by Geological Society of India 2) "Geology of Gujarat" byV.N.Kulkarni (1985) published by Irrigation, R&B Deptt. Gujarat State in Journal "NAVNIRMAN" Vol. No.XXVII No.2 3) "Geology and Mineral Resources of Gujarat, Daman and Diu published by Geological Survey of India. Publication No.30 Part XIV-2001
  22. 22. Thank You

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