Abandoning offshore well

Patent · Tue Aug 25 00:00:00 EDT 1987

OSTI ID:6109883

Prichard, Jr, J J

This patent describes a method for abandoning an offshore oil or gas well drilled into the ocean floor and having concentric strings or pipe having throughbores and being arranged in spaced relationship so as to form an annular space between adjacent pipe strings, with a wellhead being secured to the upper ends of the pipe strings which are substantially filled with a well fluid. The steps consist of: (a) establishing fluid flow communication through the wall of the innermost pipe string only between the bore thereof and the annular space outside at a selected depth in the well below the ocean floor, (b) determining the presence of gas under pressure in the annular space outside the innermost pipe string, (c) releasing any gas under pressure from the annular space outside the innermost pipe string, (d) cutting of the upper portion of the innermost pipe string at a selected level if no gas under pressure has been found under second step above, (e) removing the cutoff upper portion of the pipe string from the well, (f) spotting a volume of cement slurry in the well above the cutoff end of the innermost pipe string to close the cutoff end with a concrete plug of selected height, and (g) repeating at a level above the concrete plug the above steps (a) through (f) for the pipe string immediately outside of the concrete plug, which pipe string formerly surrounded the cutoff section of the innermost pipe string.

• Assignee: Shell Offshore, Inc., Houston, TX
• Patent Number(s): US 4688640
• OSTI ID: 6109883
• 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
423000 -- Engineering-- Marine Engineering-- (1980-)
ABANDONED WELLS
ANNULAR SPACE
BUILDING MATERIALS
CEMENTS
CLOSURES
CONCRETES
CONFIGURATION
CONTROL
CUTTING
DEGASSING
DEPTH
DIMENSIONS
DISPERSIONS
DRILL BITS
DRILL PIPES
DRILLING
DRILLING EQUIPMENT
EQUIPMENT
MACHINING
MATERIALS
MIXTURES
NATURAL GAS WELLS
OFFSHORE DRILLING
OFFSHORE OPERATIONS
OIL WELLS
PIPES
PRESSURE CONTROL
REMOVAL
SEA BED
SLURRIES
SPACE
SUSPENSIONS
WELLHEADS
WELLS