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Casing Drilling with Retrievable Drilling Assemblies OTC 2004 May 3-6, 2004 T. M. Warren, R. M. Tessari, B. Houtchens - Tesco Corp. Overview of Talk Casing Drilling system Example Applications Lobo (85 wells) Stratton (15 wells) Where to next? Directional Drilling
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Casing Drilling with Retrievable Drilling Assemblies OTC 2004 May 3-6, 2004 T. M. Warren, R. M. Tessari, B. Houtchens - Tesco Corp.
Overview of Talk • Casing Drilling system • Example Applications • Lobo (85 wells) • Stratton (15 wells) • Where to next? • Directional Drilling • Casing Running Casing Drillingtm is a trade name of Tesco Corp.
What is CASING DRILLINGtm? “Process to simultaneously drill and case wells by using the casing as the drill string.” • Casing is rotated to drill. • Casing is near bottom at all times. • Casing cemented in the well without tripping it out. • Two Types • Retrievable & re-runable BHA • “Bit” attached to casing
Lost circulation Stuck Pipe Kick Other Sloughing Shale 24% of time from spud to TD (Jan 2004 Offshore magazine) Casing Drilling Justification • Faster process • Reduces trouble time • Increased reserves • More wells • Better production rate • Integrated rig solution
Handling the Casing • Interface to top drive • Protect threads • Fast connections • Safe pipe handling Casing Drive System
Connections for Adequate Torque • Buttress with MLT ring • Premium Casing Drilling connections • Must balance fatigue, torque rating & cost MLT Ring
Casing Protection Casing coupling Crimping area Wear Band Installation Tool TC hardfacing
Casing Retrievable Drilling Assembly Profile Nipple DLA • Top of assembly locked in profile nipple. • Drilling assembly extends below casing shoe. • Capable of multiple runs . • Normally retrieved with 9/16” braided cable. • Must be reliable. Stabilizer Shoe Underreamer Bit
Tesco Casing Drilling Experience • Drilled 31,000 ft in test wells • Drilled 130+ commercial wells • 4-1/2” – 13/3/8” casing • 700,000 ft with retrievable BHA • 300,000 ft with non-retrievable BHA • 300+ string of casing drilled • 9 strings drilled directionally • Commercial foothold established
After 85 Wells at Lobo • Significant learning curve • Learned drilling techniques • Developed casing accessories • Improved equipment reliability • Built three rigs & trained crews • Benefits defined • Minimized lost circulation • High well control tolerance • Ability to save well under adverse conditions • Faster in-field moves • Field drilling cost reduced Improved hole quality. Reduced casing strings
Casing Drilled Offset 1 Offset 2 Offset 3 9 5/8” Csg. 9 5/8” Csg. 9 5/8” Csg. 9 5/8” Csg. 7” Csg. 7” Csg. 7” Csg. 7” Csg. 5,145’ 5,272’ 6,917’ 5 1/2” Liner 5 1/2” Liner 8,103’ 7,985’ 8,185’ 8,162’ 9,400’ 3 1/2” Csg. 4 1/2” Csg. 3 1/2” Csg. 4 1/2” Csg. 19 days 10 days Spud to Cementing of Intermediate (Well 14) 200 - 300 sack balanced cement plug Controls Lost Circulation
Saves Wells • First Conventional Attempt • 7” casing set at 7,500 ft • Kick at 11,215 - loosing mud at kill wt • Drilled to TD 11,550 ft • Cement DP in well to control flow • Second Conventional Attempt • Lost circ on trip at 5,971 ft • Spot 2 cement plugs • Set 7” at 6,240 could get no deeper • Set 5-1/2” liner at 7,600 • Drill to TD 11,600 ft • Lost returns, took kick, pipe stuck • Cement DP in well to control flow • Casing Drillingtm • Slight losses • Set 7” at 8,085 ft • Set 4-1/2” at 11,574 ft Lost Circulation 7” Csg Pt 5-1/2” Liner
Rejuvenates Old Field • Stratton Field • Objective – Low pressure sands • Focus on production enhancement • 9-5/8” and 7” casing to 7,000 ft • Conventional wells uneconomical • Casing Drilled with no difficulty • Fluid loss reduced from several 1000 bbls to <100 bbls. • Multi-well program in progress • Drilling time cut in half • Production more than doubled Conventional Average Well Number
Directional Drilling with Casing Non-Mag Non-Mag MWD Motor Rotary Steerable • Requires retrievable system • In its infancy. (9 strings drilled) • Practical for a wide range of build rates. • Is more effective with larger sizes of casing (>7”) • Potential to captures time savings and trouble avoidance benefits Steerable Motor
TESCO CASING RUNNING SYSTEM • Casing is run on every well • 12 - 21% of time on the well is spent in casing installation • Process same since mid–1950’s • Potentially hazardous operations - Falls from elevations - Pinch points (from power tongs) - Slips/trips & sprains from handling tongs and casing - Struck by (elevators) • May have difficulty running casing
New Casing Running System • Developed from Casing Drilling™ technology • Top drive with CDA provides - Rotation - Tension - Circulation • Benefits of top drive drilling with casing running. • Active commercial service • 150 + jobs completed • 1,000,000+ ft of casing run • Jobs for 31 operators
Summary • Sufficient Casing Drilled wells completed to establish foothold in industry. • Lost circulation & well control incidents reduced in frequency and severity. • More wells are economical – Added reserves. • Directional applications are practical. • Casing running service saves time, improves safety, and adds capability .