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PETE 411 Well Drilling

PETE 411 Well Drilling. Lesson 13 Pressure Drop Calculations API Recommended Practice 13D Third Edition, June 1, 1995. Homework. HW #7. Pressure Drop Calculations Due Oct. 9, 2002 The API Power Law Model. Contents. The Power Law Model The Rotational Viscometer

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PETE 411 Well Drilling

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  1. PETE 411Well Drilling Lesson 13 Pressure Drop Calculations API Recommended Practice 13D Third Edition, June 1, 1995

  2. Homework • HW #7. Pressure Drop Calculations • Due Oct. 9, 2002 • The API Power Law Model

  3. Contents • The Power Law Model • The Rotational Viscometer • A detailed Example - Pump Pressure • Pressure Drop in the Drillpipe • Pressure Drop in the Bit Nozzles • Pressure Drop in the Annulus • Wellbore Pressure Profiles

  4. Power Law Model K = consistency index n = flow behaviour index 0

  5. Fluid Flow in Pipes and Annuli

  6. Fluid Flow in Pipes and Annuli Laminar Flow Turbulent LOG (SHEAR STRESS) (psi) n 1

  7. RotatingSleeveViscometer

  8. Rotating Sleeve Viscometer (RPM * 1.703) SHEAR RATE sec -1 5.11 170.3 511 1022 VISCOMETER RPM 3 100 300 600 ANNULUS BOB DRILLSTRING SLEEVE API RP 13D

  9. API RP 13D, June 1995for Oil-Well Drilling Fluids • API RP 13D recommends using only FOUR of the six usual viscometer readings: • Use 3, 100, 300, 600 RPM Readings. • The 3 and 100 RPM reading are used for pressure drop calculations in the annulus, where shear rates are, generally, not very high. • The 300 and 600 RPM reading are used for pressure drop calculations inside drillpipe, where shear rates are, generally, quite high.

  10. Example: Pressure Drop Calculations • ExampleCalculate the pump pressure in the wellbore shown on the next page, using the API method. • The relevant rotational viscometer readings are as follows: • R3 = 3 (at 3 RPM) • R100 = 20 (at 100 RPM) • R300 = 39 (at 300 RPM) • R600 = 65 (at 600 RPM)

  11. PPUMP Pressure DropCalculations Q = 280 gal/min r = 12.5 lb/gal PPUMP = DPDP + DPDC + DPBIT NOZZLES + DPDC/ANN + DPDP/ANN + DPHYD

  12. Pressure Drop In Drill Pipe OD = 4.5 in ID = 3.78 in L = 11,400 ft Power-Law Constant (n): Fluid Consistency Index (K): Average Bulk Velocity in Pipe (Vp):

  13. Pressure Drop In Drill Pipe OD = 4.5 in ID = 3.78 in L = 11,400 ft Effective Viscosity in Pipe (mep): Reynolds Number in Pipe (NRep):

  14. Pressure Drop In Drill Pipe OD = 4.5 in ID = 3.78 in L = 11,400 ft NOTE: NRe > 2,100, so Friction Factor in Pipe (fp): So,

  15. Pressure Drop In Drill Pipe OD = 4.5 in ID = 3.78 in L = 11,400 ft Friction Pressure Gradient (dP/dL)p : Friction Pressure Drop in Drill Pipe: DPdp = 665 psi

  16. Pressure Drop In Drill Collars OD = 6.5 in ID = 2.5 in L = 600 ft Power-Law Constant (n): Fluid Consistency Index (K): Average Bulk Velocity inside Drill Collars (Vdc):

  17. OD = 6.5 in ID = 2.5 in L = 600 ft Pressure Drop In Drill Collars Effective Viscosity in Collars(mec): Reynolds Number in Collars (NRec):

  18. OD = 6.5 in ID = 2.5 in L = 600 ft Pressure Drop In Drill Collars NOTE: NRe > 2,100, so Friction Factor in DC (fdc): So,

  19. OD = 6.5 in ID = 2.5 in L = 600 ft Pressure Drop In Drill Collars Friction Pressure Gradient (dP/dL)dc : Friction Pressure Drop in Drill Collars: DPdc = 227 psi

  20. Pressure Drop across Nozzles DN1 = 11 32nds (in) DN2 = 11 32nds (in) DN3 = 12 32nds (in) DPNozzles = 1,026 psi

  21. Pressure Dropin DC/HOLE Annulus Q = 280 gal/min r = 12.5 lb/gal 8.5 in DHOLE = 8.5 in ODDC = 6.5 in L = 600 ft

  22. Pressure Dropin DC/HOLE Annulus DHOLE = 8.5 in ODDC = 6.5 in L = 600 ft Power-Law Constant (n): Fluid Consistency Index (K): Average Bulk Velocity in DC/HOLE Annulus (Va):

  23. Pressure Dropin DC/HOLE Annulus DHOLE = 8.5 in ODDC = 6.5 in L = 600 ft Effective Viscosity in Annulus (mea): Reynolds Number in Annulus (NRea):

  24. Pressure Dropin DC/HOLE Annulus DHOLE = 8.5 in ODDC = 6.5 in L = 600 ft NOTE: NRe < 2,100 Friction Factor in Annulus (fa): DPdc/hole = 31.6 psi So,

  25. Pressure Dropin DP/HOLE Annulus q = 280 gal/min r = 12.5 lb/gal DHOLE = 8.5 in ODDP = 4.5 in L = 11,400 ft

  26. Pressure Dropin DP/HOLE Annulus DHOLE = 8.5 in ODDP = 4.5 in L = 11,400 ft Power-Law Constant (n): Fluid Consistency Index (K): Average Bulk Velocity in Annulus (Va):

  27. Pressure Dropin DP/HOLE Annulus Effective Viscosity in Annulus (mea): Reynolds Number in Annulus (NRea):

  28. Pressure Dropin DP/HOLE Annulus NOTE: NRe < 2,100 Friction Factor in Annulus (fa): DPdp/hole = 153.2 psi So, psi

  29. Pressure DropCalculations- SUMMARY - PPUMP = DPDP + DPDC + DPBIT NOZZLES + DPDC/ANN + DPDP/ANN + DPHYD PPUMP = 665+ 227+ 1,026 + 32+ 153+ 0 PPUMP = 1,918 + 185 = 2,103 psi

  30. 2,103 psi PPUMP = DPDS + DPANN + DPHYD DPDS = DPDP + DPDC + DPBIT NOZZLES = 665+ 227+ 1,026 = 1,918 psi P = 0 DPANN = DPDC/ANN + DPDP/ANN = 32 + 153 = 185 DPHYD= 0 PPUMP = 1,918 + 185 = 2,103 psi

  31. 2,103 psi What is the BHP? P = 0 BHP = DPFRICTION/ANN + DPHYD/ANN BHP = DPDC/ANN + DPDP/ANN + 0.052 * 12.5 * 12,000 = 32 + 153 + 7,800 = 7,985 psig BHP = 185 + 7,800 BHP = 7,985 psig

  32. DRILLPIPE 2103 DRILL COLLARS BIT NOZZLES ANNULUS

  33. BHP DRILLSTRING ANNULUS

  34. CIRCULATING 2103 STATIC

  35. 2103 DRILLSTRING ANNULUS (Static) BIT

  36. Pipe Flow - Laminar In the above example the flow down the drillpipe was turbulent. Under conditions of very high viscosity, the flow may very well be laminar. NOTE: if NRe < 2,100, then Friction Factor in Pipe (fp): Then and

  37. Annular Flow - Turbulent In the above example the flow up the annulus was laminar. Under conditions of low viscosity and/or high flow rate, the flow may very well be turbulent. NOTE: if NRe > 2,100, thenFriction Factor in the Annulus: Then and

  38. Critical Circulation Rate Example The above fluid is flowing in the annulus between a 4.5” OD string of drill pipe and an 8.5 in hole. The fluid density is 12.5 lb/gal. What is the minimum circulation rate that will ensure turbulent flow? (why is this of interest?)

  39. Critical Circulation Rate In the Drillpipe/Hole Annulus: Q, gal/min V, ft/sec Nre 280 2.197 1,044 300 2.354 1,154 350 2.746 1,446 400 3.138 1,756 450 3.531 2,086 452 3.546 2,099 452.1 3.547 2,100

  40. Optimum Bit Hydraulics • Under what conditions do we get the best hydraulic cleaning at the bit? • maximum hydraulic horsepower? • maximum impact force? Both these items increase when the circulation rate increases. However, when the circulation rate increases, so does the frictional pressure drop.

  41. n = 1.0

  42. Importance of Pipe Size Eq. 4.66e or, *Note that a small change in the pipe diameter results in large change in the pressure drop! (q = const.) Decreasing the pipe ID 10% from 5.0” to 4.5” would result in an increase of frictional pressure drop by about 65% !!

  43. Dpf = 11.41 v 1.75 turbulent flow Dpf = 9.11 v laminar flow Use max. Dpf value

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