How to avoid casing collapse during inner string cementing

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Drilling-DCW; (United States)

OSTI ID:5968187

Lubitz, R

This article reports that in the Mobile Bay area offshore Alabama, inflatable surface packoffs are being used to seal the top of the 20-in. conductor casing-to-drill pipe annulus. With the seal in place, annular pressure is maintained during inner string cementing jobs to counter forces that tend to shorten the drill pipe inner string. Inside pressure also helps protect the casing from collapse due to the hydrostatic pressure of a long column of cement. Casing is less resistant than the bottom of the hole and the wellbore, (unless a weak formation breaks down) and can crush under the hydrostatic weight when fluid inside does not offer enough offsetting support. Casing collapse can cause cement to leak into the casing-to-drill pipe annulus, thereby cementing the drill string in the well or otherwise ruining the cement job. In a situation where casing does not have sufficient collapse resistance to withstand hydrostatic pressure loading, a surface packoff can be used to maintain pressure inside the casing throughout the cementing job.

• Research Organization: Halliburton Services, Duncan, OK
• OSTI ID: 5968187
• Journal Information: Drilling-DCW; (United States), Journal Name: Drilling-DCW; (United States) Vol. 48:2; ISSN DRDCD
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
03 NATURAL GAS
030300 -- Natural Gas-- Drilling
Production
& Processing
42 ENGINEERING
420206 -- Engineering-- Mining & Drilling Equipment & Facilities-- (1980-1989)
422000 -- Engineering-- Mining & Underground Engineering-- (1980-)
ACCIDENTS
ALABAMA
ATLANTIC OCEAN
BUILDING MATERIALS
CARIBBEAN SEA
CEMENTING
CEMENTS
DRILL PIPES
DRILLING EQUIPMENT
EQUIPMENT
FAILURES
FEDERAL REGION IV
GULF OF MEXICO
HYDROSTATICS
LEAKS
MATERIALS
NATURAL GAS WELLS
NORTH AMERICA
OFFSHORE PLATFORMS
OIL WELLS
PIPES
PRESSURE DEPENDENCE
SEALS
SEAS
SURFACE WATERS
USA
WELL CASINGS
WELL COMPLETION
WELLS