OIL WELL PACKER RETRIEVER

摘要

An oil well packer retriever has a packer miller (6) which has a series of fin-like blades radiating from a central tube string (2). The blades are faced with tungsten carbide and in use these mill away the packer allowing it to drop by gravity. A packer catcher (7) catches and retains the fallen packer for removal from the well. The weight of the packer held by the catcher (7) bears on a shear collar (8) which is secured to the central string (2) by one or more shear bolts the combined strength of which is known. Should the shear stress on the collar (8) exceed that which has been preselected by the number and/or material of the shear bolts, the bolts shear releasing the collar (8) which drops out of engagement the catcher (7) allowing the retriever to be withdrawn from the packer. The packer retriever can under normal conditions mill out and extract several packers without redressing the blades and replacing the catcher.