Abstract 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the bolts shear releasing the collar (8) which drops out of engagement the catcher (7) allowing the retriever to be withdrawn from the packer.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.
An oil well packer retriever comprising a packer miller 6 for milling the packer to release same from the well casing and a packer catcher 7 for engaging the released packer enabling removal from the well characterised in that engagement between packer and catcher is maintained by retaining means 8 releasable in the event that the stress on said means exceeds a preselected value.
Claim 2
Dependent Claim
64 words
An oil well packer retriever comprising a packer miller 6 for milling the packer to release same from the well casing and a packer catcher 7 for engaging the released packer enabling removal from the well characterised in that engagement between packer and catcher is maintained by retaining means 8 releasable in the event that the stress on said means exceeds a preselected value.
Claim 3
Dependent Claim
34 words
A packer retriever as claimed in claim 1, in which the packer catcher 7 bears on a shear collar 8 the shear strength of which is set by preselection of fastening bolts or pins.
Claim 4
Dependent Claim
65 words
A packer retriever as claimed in claim 1 or claim 2, comprising an elongate tube 2 having an end to end through passage in which the packer catcher 7 is a series of sprung fingers extending round the tube 2 and bearing on an annular shear collar 8 fastened to the tube 2 by one or more shear bolts or pins of preselected shear strength.
Claim 5
Dependent Claim
31 words
A packer retriever as claimed in any preceding claim, in which the packer miller 6 comprises one or more radially extending fin-like blades the or each blade having a cutting face.
Claim 6
Dependent Claim
22 words
A packer retriever as claimed in claim 4, including also means 11 for delivering a jet of liquid proximate the blades 6.
Claim 7
Dependent Claim
23 words
A packer retriever as claimed in any preceding claim including also a milling head 10 dimensioned to penetrate the bore of a packer.
Claim 8
Dependent Claim
23 words
A packer retriever as claimed in claim 6, including also means 12 for delivering a jet of liquid proximate the milling head lO.