PURPOSES
OF OIL WELL CEMENTING
Oil well cementing falls into three
main categories: primary cement jobs on
casing strings / squeeze cementing / cement plugs.
Primary
casing job: among the main objectives
- to provide a solid “anchoring” of the casing
string on the formation,
- to provide a seal in the annulus casing x
formation or casing x casing
- to
provide isolation of formation to each other behind the casing
Squeeze
cementing: major applications are as follows
- supplement a faulty primary casing cement
job; repair casing leaks
- isolation ….: to reduce water-oil, water-gas or gas-oil
ratio; abandon a productive zone
- isolate a zone before perforations for
production (block squeeze) or before fracturing
- stop losses; bring a well under control
Plugs:
major applications are: when recompletion above a depleted producing
zone is necessary,
when a solid seat is necessary (set a whipstock,
side-tracks, …), plug lost circulation zones, at the time of well P&A operations.
