Inflatable Bridge Plugs are inflatable packers which are typically used to permanently or temporarily abandon a complete or lower section of the hole. Various designs of the bridge plug have been developed over the years as can be seen below.
Permanent bridge plus or otherwise known as abandonment packers are lowered down hole to the desired setting depth at which point the drill string can be filled with water and pressurised to inflate the packer.
Once the drill string is vented at surface the drill string can be disconnected from the packer by applying either a clockwise rotation to disconnect from a left hand threaded sub or an over pull to shear pins within a shear-off sub.
Dependent on down hole conditions they can be used alone or can be used to support a cement plug above the packer element.
Typically used to temporarily isolate underground mine breakthrough pilot holes. Once inflated the packer allows for drilling returns to surface whilst the hole is reamed to a larger diameter.
Utilising the same inflation procedure as permanent bridge plugs except the top sub is constructed of drillable materials. Top sub can be effectively drilled out to deflate the packer.
Retrievable Bridge Plugs are lowered down hole to the desired setting depth at which point the drill string can be filled with water and pressurised to inflate the packer.
Once the drill string is vented at surface a clockwise rotation is applied to disconnect from the left handed sub on top of the packer.
The retrievable aspect is typically common to allow for isolation of lower screen sections for water quality testing.
Once testing is completed a latching sub is run in and located within the plug, an over pull is then applied to shear pins to deflate the packer. Once deflated the plug is retrieved via the latching sub.
The typical sizes available can be split into low pressure and high pressure options.
Low Pressure – 114mm, 141mm, 168mm, 219mm, 273mm and 323mm
High Pressure – 9 5/8″, 13 3/8″, 20″ and 30″
High Pressure (Moving End Packers) – 12″/20″, 15″/25″ and 17″/30″
Custom sizes are available at short notice upon request.