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E P T Recent Advances in Complex Well Design Phil Pattillo, BP EPTG - Houston
Overview New loads and limitations Thermal effects annular pressure build-up Designing with limited casing bore Extreme landing tools Beyond API designs Probabilistic design considerations ISO 10400 3
Annular Pressure Build-up (APB)
Annular Pressure Buildup (APB) Origin of APB loads Mitigating APB Principles and solution categories Specific well construction tools 16 in. casing collapse from APB during circulation 5
The origin of APB Mud Line What do we do about this hydrocarbon bearing zone? 20" 16" TOC? 6
APB depends on Mechanical and thermal properties of fluid Flexibility of the confining boundary Temperature increase Considering the fluid component, ΔV f = V f 1 α f ΔT C f Δp 7
8 Mitigating APB Brute Force Thick-walled casing Fluid Properties Foam spacer Fluids with low psi/f Cement entire annulus Control the Load Vacuum Insulated Tubing (VIT) Nitrogen blanket Gelled brine Connection leak integrity Initial annulus pressure Container Flexibility Vent the annulus Active path to surface Relief mechanism Formation fracture/toc Rupture disks Grooved casing Annulus communication Syntactic foam Avoid trapped pressures external to annulus
Mitigating APB Fluid Properties Foam spacer Fluids with low psi/f Cement entire annulus 9
01 Mitigating APB Container Flexibility Vent the annulus Active path to surface Relief mechanism Formation fracture/toc Rupture disks Grooved casing Annulus communication Syntactic foam Avoid trapped pressures external to annulus
1 Mitigating APB Container Flexibility Vent the annulus Active path to surface Relief mechanism Formation fracture/toc Rupture disks Grooved casing Annulus communication Syntactic foam Avoid trapped pressures external to annulus
21 Mitigating APB Outer Tube Inner Tube Connection Weld Vacuum Annulus Tubing A Annulus Control the Load Vacuum Insulated Tubing Nitrogen blanket Gelled brine Connection o leak integrity ty Initial annulus pressure th, ft. Measured Dept 5100 5150 5200 5250 5300 5350 5400 5450 5500 5550 5600 Temperature, Deg F 80 90 100 110 120 130 140 Gelled Brine 2 Gelled Brine 1
31 Mitigating APB Vacuum Insulated Tubing (VIT) 5100 Temperature, Deg F 80 90 100 110 120 130 5150 Gelled Brine 2 Me easured Dep pth, ft. 5200 5250 5300 5350 5400 5450 Weld Outer Tube Inner Tube Connection Vacuum Annulus Tubing A Annulus 5500 5550 5600 Gelled Brine 1
Designing within wellbore limitations
51 Deepwater HPHT wells, maintaining hole size Geometric constraints RISK Minimum production tubulars, SSSV 36" 28" 36" 28" Maximum 18-3/4 in. bore Possible solutions 18", 16" (Drilling Liners) 22" (Surface Casing) 22" (224.0 ppf X-8 18" (117.0 ppf N-8 Riserless drilling 16" (97.0 ppf P-11 Managed pressure drilling Designer muds Revisit casing risk profile DEPTH 11-7/8" (Drilling Liners) 13-5/8" (Deep Protective Casing) 13-5/8" (88.20 pp 11-7/8" (71.80 pp Probability x consequence Recovery Empirical validation 7" (Production Liners) 9-7/8" (Production casing or tiebacks) 9-7/8" (62.8 ppf C 7" (38.0 ppf C-110 Solid expandable liners
61 Maintaining hole size - example 8-1/2 in. hole on bottom Production tubulars with 18,000+ psi internal yield 5-1/2 in. tubing 9-3/8 in. upper tieback drift (subsurface safety valve) Clearance outside tieback for APB mitigation (syntactic foam) 36 28 2 18 16 1358 178 36 28 2 18 T 16 O SET 1334 1214 978 1034 7 7
Extreme landing loads
Landing strings and slip crushing Landing string static loads approaching 1.5 mm lbs Impulse load during tripping Heave induced excitation Applicability of Reinhold- Spiri To current systems? To other slip problems? 81
91 Understanding slip systems Strain gauged samples indicate Non-uniform loading Worst loading may be between inserts p L, lb/in 24000 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 A S M L L AXIAL TENSILE LOAD = 100,000 lb AXIAL TENSILE LOAD = 300,000 lb AXIAL TENSILE LOAD = 900,000 lb AXIAL TENSILE LOAD = 500,000 lb AXIAL TENSILE LOAD = 700,000 lb NUMBER OF LINE LOADS = 3 YOUNG'S MODULUS = 30x10 6 psi POISSON'S RATIO = 0.3 YIELD POINT = 100,000 psi WALL THICKNESS = 0.5 in MEAN RADIUS = 3.0 in AXIAL TENSILE LOAD FOR PIPE YIELD (WITH p L = 0) = 942,500 lb 0 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 w 0, in.
Probabilistic design considerations
Detailed inspection data 12
Application calculation of cross-sectional area 2
32 Application detailed collapse prediction Line pipe samples X65, D/t 16-18+ Detailed input Wall, diameter Axial, hoop σ-ε coupons Residual stress Full scale tests Pressure with bending Collapse, propagation Excellent results (<3% no bending, 0-9% with bending)
42 Probabilistic advantage using rupture disks Disk pressures have tight, controlled tolerances (± 5% on rupture pressure) Contrast with 12.5% wall tolerance and 10-30 ksi tensile strength variation for casing body Wide uncertainty of casing rupture and collapse pressures Cannot count on outer string failing first F 16" MIYP Rating C B 7 Production Liner Pipe Performance Uncertainty API API D 9-7/8" Colllapse Rating A 9-7/8" High Collapse Rating A Consider if shoe plugs 16" B Barlow 16" Rupture 9-7/8" C API Collapse 9-7/8" Tamano Collapse 7,500 10,000 12,500 15,000 17,500 P Pressure (psi)
52 ISO 10400 (New API 5C3) Clause Subject Comments 1-5 Introduction, symbols 6 Triaxial yield von Mises yield Axial yield, internal yield pressure as special cases 7 Ductile rupture All new 8-17 Annexes Collapse, connections, mass, elongation, etc. Details, derivations, performance property tables Identical to existing formulas Probabilistic properties (from performance or production data)
Conclusions No lack of challenging problems Continuing research on annular pressure mitigation Rethinking old solutions Design stretch via probability Increasing support from standards 62