Benefits of Aluminum Drill Pipe FuchsRohr AluDrill in Deviated Wells OTTO FUCHS Drilling Solutions August, 2014 1
Outline of the presentation Problematic Torque & Drag Basics Friction & Contact Forces Weight / Buoyancy / SWR Stiffness Buckling Basics Conventional Theory Advanced Theory Aluminum DP - FuchsRohr AluDrill size & position Case Studies ERD 3D Shale Gas Conclusion
Objective Problematic Torque & Drag & Buckling is a concern in long deviated wells (ERD, Horizontal) because of cumulative Friction Forces that lead to Excessive Torque Compression & Buckling (poor WOB Transfer) Casing Wear Solution Reducing Friction Forces with light weight Aluminum DP FuchsRohr AluDrill
Torque & Drag Basics Friction & Contact Forces Normal Force = f (Weight, Stiffness, Inclination, Dog Legs ) Friction Force = µ. Normal Force µ = Coefficient of friction Reduction of Friction Forces with FuchsRohr AluDrill due to lighter weight
Torque & Drag Basics Weight / Buoyancy Pipe Density Weight in Air (lb/ft) Weight in 10 ppg Mud (lb/ft) 5 7/8 Aluminum DP (FuchsRohr AluDrill ) 2.8 17.2 9.8 5 ½ Steel DP 7.85 25.3 21.4 Difference -32 % - 54 % Reduced Weight & Higher Buoyancy
Torque & Drag Basics Weight / Buoyancy. Buoyancy Factor 1.0 0.9 0.8 0.7 0.6 0.5 0.4 Buoyancy Factor Less Weight 5.0 10.0 15.0 Mud Weight (ppg)
Torque & Drag Basics Strength to Weight Ratio Higher SWR than Steel: possibility to extend the drilling envelop
Torque & Drag Basics Stiffness As bending Stress is lower with FuchsRohr AluDrill, the contribution of stiffness to normal force is reduced, leading due a reduction of Torque & Drag Bending Stress
Torque & Drag Basics Reduced Stiffness + Lighter Material + Higher Buoyancy = Less Torque & Drag Better WOB transfer Less Casing Wear
Buckling Basics Conventional Theory Sinusoidal Idealized WellBore Helical Fc= 2 EIωsin(Inc) r Fc= λ EIωsin(Inc) r λ = 2 2 λ = 2(2 λ = 4 2 = 2.83... Chen & Cheatham 2 1) = 3.65... Dawson & Paslay = 5.65... Mitchell Actual WellBore Rotation, Friction and Dog Legs effects are not taken into account in conventional buckling theory
Buckling Basics Advanced Theory Effects of Rotation, Friction & Dog Legs No analytical solution exists for this complex buckling case (non linear problem) New Buckling Model: Numerical Approach Full-scale Validation (Ulrigg test in Norway) Publications: SPE 140211, 119861, 112571, 102850
Buckling Basics Advanced Theory Bending Stress level can be low in Helical Buckling (it depends mainly on the clearance between the pipe and the hole) Buckling Severity Index is based on: 1) Bending Stress 2) Contact Force 3) Von Mises Stress BSI applies for: Non-rotating Case Calculated by Torque & Drag Software (stiff-string models) Rotating Case (steady-state conditions based on Fatigue Limits) BSI if Bending Stress Buckling Severity Index Evaluates the Risk of lock-up or possible failure due to buckling
FuchsRohr AluDrill Size & Position The number of FuchsRohr AluDrill joints, size & position should be optimized with Torque & Drag & Buckling calculation Generaly speaking, the higher the number of FuchsRohr AluDrill joints, the higher the reduction in Torque & Drag However, risks have to be identified (trade-off between weight reduction & lower stiffness) Mixed string of Steel DP + FuchsRohr AluDrill is often the best solution
Case Studies Comparison between mixed SDP- FuchsRohr AluDrill string & SDP string Drag Reduction: up to 35% Torque Reduction: up to 25% Mean Side Force Reduction: 32% Mean Bending Stress Reduction: 42% Less Compression & Buckling 3D ERD 80 deg. Drag Reduction: up to 20% Torque Reduction: up to 23% Mean Side Force Reduction: 20% Mean Bending Stress Reduction: 33% Less Compression & Buckling 12 deg./100ft Shale Gas Drag Reduction: up to 27% Torque Reduction: up to 22% Mean Side Force Reduction: 43% Mean Bending Stress Reduction: 38% Less Compression & Buckling
Case Studies ERD 3D Shale Gas
Case Study: 3D 5 ½ in. SDP 25.3 ppf TJ OD=6 ¾ in. x300 jts 5 7/8 in. FuchsRohr AluDrill 17.2 ppf TJ OD=7 ¼ in. BHA 90 deg. 9 5/8 in. Casing Hole Size = 8 ½ in. BHA Schematics not to scale
Case Study: 3D Pull Out of Hole @ TD = Maximum Tension in the string Mixed SDP-FuchsRohr AluDrill String SDP String Margin of over pull Tensile Yield Tensile Yield Tension is reduced by up to 35% The margin of overpull is higher with FuchsRohr AluDrill (+100 klbs)
Case Study: 3D Run in Hole @ TD = Compression in the string Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Helical Buckling Limit Reduced Compression & Buckling For a friction factor = 0.3, the compression is reduced by 45% with FuchsRohr AluDrill For a friction factor = 0.4: SDP cannot be run in the hole (lock-up). Mixed SDP-FuchsRohr AluDrill can be run in the hole in slightly exceeding the Helical Buckling Load (BSI=1)
Case Study: 3D Drilling @ TD (WOB = 25 klbs): Maximum Torque at surface & on the string Mixed SDP-FuchsRohr AluDrill String SDP String Make Up Torque Make Up Torque WOB=25 klbs Torque is reduced by up to 25% Higher safety margin for the MUT Upgrading to High Torque Connection not necessarily required
Case Study: 3D Drilling @ TD (WOB = 25 klbs): Buckling Risk Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Helical Buckling Limit Compression is less than the Helical Buckling Load Buckling Severity Index = 1
Case Study: 3D Drilling @ TD (WOB=25 klbs): Contact Forces Mixed SDP-FuchsRohr AluDrill String SDP String Friction Factor = 0.3 Friction Factor = 0.3 Mean Contact Forces reduced by about 32% Possibly less Casing Wear
Case Study: 3D Drilling @ TD (WOB=25 klbs): Bending Stress Mixed SDP-FuchsRohr AluDrill String SDP String Friction Factor = 0.3 Friction Factor = 0.3 Mean Bending Stress reduced by about 32%
Case Study: ERD 5 7/8 in. SDP 27 ppf TJ OD=7 in. x300 jts 5 7/8 in. FuchsRohr AluDrill 17.2 ppf TJ OD = 7 ¼ in. BHA 9 5/8 in. Casing Hole Size = 8 ½ in. BHA Schematics not to scale
Case Study: ERD Pull Out of Hole @ TD = Maximum Tension in the string Mixed SDP-FuchsRohr AluDrill String SDP String Margin of over pull Tensile Yield Tensile Yield Tension is reduced by up to 20% The margin of overpull is higher with FuchsRohr AluDrill (+80 klbs)
Case Study: ERD Run in Hole @ TD = Compression in the string Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Helical Buckling Limit Reduced Compression & Buckling For a friction factor = 0.2, the compression is reduced by 45% with FuchsRohr AluDrill and SDP cannot be run in the hole (lock-up). Mixed SDP-FuchsRohr AluDrill string can be run in the hole without exceeding the Helical Buckling Load
Case Study: ERD Drilling @ TD (WOB=25 klbs): Maximum Torque at surface & on the string Mixed SDP-FuchsRohr AluDrill String SDP String Make Up Torque Make Up Torque Torque is reduced by up to 23% MUT exceeded for SDP if Friction Factor 0.4 FuchsRohr AluDrill enables to stay below MUT whatever the Friction Factor
Case Study: ERD Drilling @ TD (WOB = 25 klbs): Buckling Risk Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Helical Buckling Limit Compression is less than the Helical Buckling Load Buckling Severity Index = 1
Case Study: ERD Drilling @ TD (WOB=25 klbs): Contact Forces Mixed SDP-FuchsRohr AluDrill String SDP String Friction Factor = 0.3 Friction Factor = 0.3 Mean Contact Forces reduced by about 20% Possibly Less Casing Wear
Case Study: ERD Drilling @ TD (WOB=25klbs): Bending Stress Mixed SDP-FuchsRohr AluDrill String SDP String Friction Factor = 0.3 Friction Factor = 0.3 Mean Bending Stress reduced by about 33%
Case Study: Shale Gas 5 in. SDP 22.5 ppf TJ OD=6 5/8 in. 9 5/8 in. Casing x300 jts 5 1/2 in. FuchsRohr AluDrill 15.4 ppf TJ OD = 7 ¼ in. BHA Hole Size = 8 ½ in. BHA Schematics not to scale
Case Study: Shale Gas Pull Out of Hole @ TD = Maximum Tension in the string Mixed SDP-FuchsRohr AluDrill String SDP String Margin of over pull Tensile Yield Tensile Yield Tension is reduced by up to 27% The margin of overpull is higher with FuchsRohr AluDrill (+150 klbs)
Case Study: Shale Gas Run in Hole @ TD = Compression in the string Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Helical Buckling Limit Reduced Compression & Buckling For a friction factor = 0.2, the compression is reduced by 45% with FuchsRohr AluDrill (buckling reduced). For a friction factor = 0.3: SDP cannot be run in the hole (lock-up). Mixed SDP- FuchsRohr AluDrill string can be run in the hole in exceeding the Helical Buckling Load (BSI=1)
Case Study: Shale Gas Drilling @ TD (WOB=25 klbs): Maximum Torque at surface & on the string Mixed SDP-FuchsRohr AluDrill String SDP String Make Up Torque Make Up Torque Torque is reduced by up to 22% MUT exceeded for SDP if Friction Factor 0.4 FuchsRohr AluDrill enables to stay below MUT whatever the Friction Factor
Case Study: Shale Gas Drilling @ TD (WOB=25klbs): Contact Forces Mixed SDP-FuchsRohr AluDrill String SDP String Friction Factor = 0.3 Friction Factor = 0.3 Mean Contact Forces reduced by about 43% Possibly Less Casing Wear
Case Study: Shale Gas Drilling @ TD (WOB=25klbs): Bending Stress Mixed SDP-FuchsRohr AluDrill String SDP String Friction Factor = 0.3 Friction Factor = 0.3 Mean Bending Stress reduced by about 38%
Case Study: Shale Gas Drilling @ TD (WOB = 25 klbs) in Rotary Mode: Buckling Risk Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Helical Buckling Limit Helical Buckling Limit Compression is less than the Helical Buckling Load Buckling Severity Index = 1
Case Study: Shale Gas Drilling @ TD (WOB=10klbs): Sliding mode with a Steerable Mud Motor Mixed SDP-FuchsRohr AluDrill String SDP String Helical Buckling Limit Friction Factor = 0.3 Friction Factor = 0.3 Helical Buckling Limit Reduced Compression & Buckling The compression is reduced by 45% with FuchsRohr AluDrill (buckling reduced). Buckling Severity Index is reduced (BSI=3 instead of 4). Available Hook load at surface to run the string in the hole (lock up with SDP string). Better WOB transfer
Conclusion FuchsRohr AluDrill enables to reduce Torque & Drag by about 30% Reduced Stiffness Lighter Material Higher Buoyancy Less Torque & Drag means Extend the drilling envelop (longer ERD, Horizontal and 3D wells) No need to upgrade equipments (rig, steel grade or connections) Less Casing Wear (reduced contact forces) Increased overpull capacity Better WOB transfer while sliding Buckling Compression & risk of buckling is reduced with FuchsRohr AluDrill (sliding or run in hole operations) In rotary mode, FuchsRohr AluDrill should be operated below conventional helical buckling loads