-54 SECOND EDITION with NEW & UPDATED MATERIAL 11 L Formulas Calculations for Drilling, Production, Workover and and Second Edition [...]... Drill Pipe/Drill Collar Calculations - Capacities, bbyft, displacement, bbuft, and weight, lblft, can be calculated from the following formulas: ID, in.' Capacity, bbVft = _ 1029.4 Displacement, bbVft = OD, - ID, in.' 1029.4 Weight, Ib/ft = displacement, bbl/ft x 2747Ibbbl 26 Formulas and Calculations Example: Determine the capacity, bbl/ft, displacement, bbllft, and weight, lblft, for the following: Drill...2 Formulas and Calculations Metric calculations Pressure gradient, barlm = drilling fluid density kg/l x 0.0981 Pressure gradient,bar/lOm = drilling fluid density kg4 x 0.981 S.I units calculations Pressure gradient, kPa/m = drilling fluid density, kg/m3 t 102 Convert pressure gradient, psilft, to mud weight, ppg... 0.052 x TVD, m x 3.281 Example: mud weight = 12.2ppg true vertical depth = 3700 meters 3 4 Formulas and Calculations HP = 12.2ppg x 0.052 x 3700 x 3.281 H P = 7701psi Metric calculations Hydrostatic - drilling fluid pressure, bar density, kg/l 0'0981 true vertical depth, m S.I units calculations Hydrostatic - drilling fluid density, kg/m3 x true vertical depth, m pressure, kPa 102 Converting Pressure... Pump Formula 1 PO, bbl/stk = 0.000243 x (:Eieter, in.y x (, E :; ;: in) E.xample: Determine the pump output, bbllstk, at 100% efficiency for a 7-in by 12-in triplex pump: PO @ loo'%, = 0.000243 x 7' x 12 PO @ 100% = 0.142884bbVstk Adjust the pump output for 95% efficiency: 8 Formulas and Calculations Decimal equivalent = 95 + 100 = 0.95 PO @ 95% = 0.142884bbVstk x 0.95 PO @ 95% = 0.13574bbllstk Formula... 0.433 p d f t SG = 0.433pdft SG = 1.0 + 0.433 Metric calculations Drilling fluid density, kg/l = pressure gradient, badm 0.0981 Drilling fluid density, kg/l = pressure gradient, bar/l0m + 0.981 Basic Formulas S.I units calculations Drilling fluid density kg/m3 = pressure gradient, kPa/m x 102 Hydrostatic Pressure (HP) - -_ Hydrostatic pressure using ppg and feet as the units of measure HP = mud weight,... 0.0075bbVft) Feet = 150 psi x 0.05204 11.5 ppg x 0.052 x 0.02526 Feet = 7.806 0.01 51054 Feet = 516.8 Metric calculations drilling fluid metal displacement, o.0981 Pressure drop per density, k f l Vm meter tripping = casing capacity, - metal displacement, dry pipe, bar/m V m l/m 24 Formulas and Calculations drilling fluid metal displacement, o.0981 Pressure drop per density, bar/m V m = meter tripping casing... bbVft weight,ppg pipe cap., bbl/ft Formulas and Calculations 22 Example: Determine the hydrostatic pressure decrease when pulling WET pipe out of the hole: Number of stands pulled Average length per stand Pipe displacement Pipe capacity Casing capacity Mud weight =5 = 92ft 0.0075 bbl/ft 0.01776bbVft = 0.0773bbl/ft = 11.5ppg = = Step 1 0.0075 bbVft displaced displaced = 5 stands x 92ft/std x 0.01776 bbl/ft... Capacity = 0.3392ftlgal ID2 e) Capacity, ft3/Iinft = 183.35 E.xarnple; Determine the capacity, ft3/linft, for a 6.0in hole: 6.0’ Capacity ft3/Iinft = 183.35 17 18 Formulas and Calculations Capacity = 0 1963ft3/linft f ) Capacity, Iinft/ft3 = ~ 183.35 ID, in.2 Example: Determine the capacity, linft/ft3, for a 6.0in hole: 183.35 Capacity, linft/ft3 = 6.02 Capacity = 5.093051inft/ft3 Amount of cuttings drilled... MDR, ftkr = 306.25 MDR = 81.16ft/hr 20 Formulas and Calculations Buoyancy Factor (BF) Buoyancy factor using mud weight, ppg 65.5 - mud weight, ppg 65.5 BF = Example: Determine the buoyancy factor for a 15.Oppg fluid: BF = 65.5 - 15.0 65.5 BF = 0.77099 Buoyancy factor using mud weight, lblft? BF = 489 - mud weight, Ib/ft3 489 Example: Determine the buoyancy factor for a 1201b/ft3fluid: 489 - 120 489 BF... pulling DRY pipe Step 1 number displaced average pipe = of stands x length per x displacement pulled stand, ft bbVft Step 2 HP,psi - barrels displaced bbVft bbVft o.052 mud weight, PPg Basic Formulas 21 Example: Determine the hydrostatic pressure decrease when pulling DRY pipe out of the hole: Number of stands pulled Average length per stand Pipe displacement Casing capacity Mud weight = 5 = 92ft = . Formulas Calculations for Drilling, Production, Workover and and Second Edition