Traditionally, selective injection equipment (SIE) has been manufactured from different kinds of metal alloys. SIE equipment, such as packers, sidepocket mandrels, and seating nipples, has been costly but the cost of retrieving or removing old equipment has been even more expensive.
Recently, drillable selective injection equipment has been developed for trial use in the Rangely Weber Sand Unit in Rangely, Colorado. The installations have been manufactured almost entirely of filament wound fiberglass and are almost metal free. Fiberglass cup-type packers have been developed and manufactured. Sidepocket
mandrels have also been developed and manufactured with a stainless steel pocket and the rest of the mandrel being made of fiberglass.
The only metal in the fiberglass or drillable part of the installations is some wire reinforcement in the rubber elements of the packers and the pockets in the sidepocket mandrels which are made of stainless steel (19" long each).
This concept will result in substantial savings in fishing operations when the installations need to be replaced. The top metal packers will be retrieved in the conventional manner. If the rest of the installations cannot be pulled out of the well easily, they can be drilled into small pieces with the small amount of metal either being retrieved in some kind of catch or driven to bottom. This will reduce workover rig time from weeks or even months to days.
Improvements in the next generation of drillable SIE are being pursued in an effort to address some specific concerns with the initial installation, such as packer wear going in the well, and drillable problems caused by the few metal parts. Fiberglass inflatable packers are also being developed to offer a choice in packer types available.