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Swage Well Repair for 6" to 21" Steel Casing
and the new
Slim-Hole Swage
Tool for 6-inch to 10-inch wells covered on another page. The standard swages are used
to repair damage to steel cased wells with inside diameters from 10-inches to 20-inches.
What is a swage?
A swage (shown to the right) is a repair device that acts like a circular wedge
to push back damaged casing and install liners. The lower end is tapered to fit into
reduced diameter pipe then hydraulic power is used to open the jaws of the swage and push
casing back to about the original diameter. The pressure exerted by the swage is greater
than 50 tons per square inch.
How is the swage run into a well?
The swage is run off a rig or crane with at least 5/8-inch cable or 2-inch pipe,
an electric wire is also connected to the swage to supply electrical power. The power sent
down the wire activates a motor and pump inside the tool for the hydraulic action. After
the casing is pushed as close to the original diameter as possible, a liner is usually
installed to cover the damaged area. A liner is attached to the end of the swage then
lowered to the proper depth and pressed into place.
How are damaged areas found in a well?
Wells start pumping sand which damages the pump. When the pump is pulled for
repair, a Video Survey is run to look for the problem. welenco
has Slim-Hole, Standard Color, and Side-Scan Cameras available for these well inspections.
What type of damage does a swage repair?
The most common problems are holes and compression breaks, an example of a
compression break taken from a video survey is shown below on the left. Ground subsidence
has caused the casing to collapse upon itself. On the right is an example of a less common
problem, the casing has bulged inward. Both of these areas were pushed out with the swage
and liners installed. Other problems that can be repaired using the swage are enlarged
perforations, short splits, perforations at incorrect depths, and water quality problems.
The metal to metal contact between the liner and casing does not totally seal off water
entry but can reduce the volume. Rubber strips can also be attached to the liners to try
to improve the seal.
Compression Break
Casing Bulge
Click here for a larger image of the Compression Break (121Kb)
What kind of liners are used?
The liners are usually made of mild steel that is annealed and corrugated (see
image to the left). Annealing is a heating process that softens the metal so it will not
spring back after stretching. The liners are corrugated (bent inward) to reduce the
diameter for installation. The liners are made in 5-foot lengths and various diameters.
Liners can either be overlapped to cover areas longer than five feet or up to four liners
can be welded together to make up to a 20-foot liner. Liners can also be made of stainless
steel, for areas with corrosion problems. A view of the lower section of a liner before it
has been fully pushed out is shown below on the left. On the right is the top of a liner
after installation. The liners are made of 12 gage steel and reduce the inside diameter
approximately 1/4". Hard liners often reduce the inside diameter 2-inches and make
repair below them very difficult.
Liner partially installed
Liner top after
repair
Left - five foot liner attached to swage
How do you know the casing size when there are reductions?
If there are good well records the size may be listed. But if no records are
available which is often the case, a Caliper Log can be run to measure the diameter. Our
policy is to run a Caliper Log at no charge when damage is found during a Video Survey on
individual wells. This helps us with the repairs and offers greater value for our service.
