Control drilling solves surface hole problems
Drilling surface hole offshore is one aspect of drilling practice that should command greater planning and design. Surface hole could be crucial if the well is in an area with a chance of shallow gas, or if it is required to run a 30-in. pin corrector and a long string of riser back to surface. The problem grows more critical with deeper water and a longer riser which in turn gives a longer column of drilling fluid. Consequently, the hydrostatic pressure is much higher at the 30-in. casing shoe. Higher pressure increases the chance of exceeding the fracture gradient and may result in the loss of returns around the 30-in. shoe. This article describes a simple practice which can eliminate some surface hole problems. A control-drilling equation sets the maximum drilling rate (MDR) based on maximum permitted pressures at the casing shoe. Eliminating lost circulation will ultimately save rig downtime due to retrieving the conductor pipe and base plate, relocating the rig, and respudding the hole after suffering losses. This technique also has been successful while drilling out below drive pipe on jack ups and platform wells. Control drilling is most effectively used on these types of wells because only a friction seal (instead of cement coverage) exists around the bottom of the drive pipe.
- Research Organization:
- Jotco and Associates, Abilene, TX
- OSTI ID:
- 5213259
- Journal Information:
- Oil Gas J.; (United States), Vol. 84:32
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
03 NATURAL GAS
42 ENGINEERING
DRILLING FLUIDS
LOST CIRCULATION
OFFSHORE DRILLING
DEPTH
DRILL PIPES
DRILLING RIGS
EQUATIONS
FRACTURE MECHANICS
FRICTION
HYDROSTATICS
MARINE RISERS
MECHANICAL EFFICIENCY
NATURAL GAS WELLS
OIL WELLS
PLANNING
PRESSURE EFFECTS
SEALS
DIMENSIONS
DRILLING
DRILLING EQUIPMENT
EFFICIENCY
EQUIPMENT
FLUIDS
MECHANICS
PIPES
WELLS
020300* - Petroleum- Drilling & Production
030300 - Natural Gas- Drilling
Production
& Processing
420206 - Engineering- Mining & Drilling Equipment & Facilities- (1980-1989)
423000 - Engineering- Marine Engineering- (1980-)