US 2855051 A
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Description (OCR text may contain errors)
Oct. 7, 1958 R. L. HOLLOWAY WELL PACKERS 2 Sheets-Sheet 1 Filed Jan. 15, 1957 INVENTOR.
A ITOR/VE VJ Oct. 7, 1958 R. L. HOLLOWAY WELL PACKERS 2 Sheets-Sheet 2 Fi led Jan. 15, 195'? Aria/aver United States Patent WELL PAUKERS Robert L. Holloway, Snyder, N. Y., assignor to American Iron 8.; Machine Works Company, Inc, Qldahoma fiity, Ulrla, a corporation of Delaware Application January 15, 1957, erial No. 634,269
3 Claims. (Cl. 166 118) a This invention pertains to well packers.
1. The principal object of the invention is to provide a well packer which can easily be released or unset fol- I lowing setting of the packer.
The invention may be used both with sleeve type packers and cup type packers but is particularly applicable to the latter.
For a description of a preferred embodiment of the invention reference will be made to the accompanying drawings wherein:
Figure 1 is an elevation, partly in section, showing a well packer in a well casing, the packer being unset;
Figure 2 is a view similar to Figure 1 showing the packer in set condition; and
Figure 3 is a view similar to Figure 1 showing a modification.
Referring to Figure 1, there is shown a well casing in which is disposed a well packer including a tubular mandrel 11 having a conical downwardly tapering packer expander cone 12 thereon. The mandrel 11 is made of steel or other similar metal, as is the cone 12 thereon. However, the cone 12 is coated with a thin layer 13 of Teflon, i. e., tetrafiuorethylene. The Teflon coating may have a thickness preferably of 0.005 to i 0.010 inch. I
Axially slidably mounted on the packer mandrel 11 is a support 20, to the upper end of which is screwed a I collar 21 to retain thereon a packer cup 22. The packer cup is preferably made of oil resistant natural or syn- 1 thetic rubber compound which may be reinforced with fabric or other flexible material. The lower end of the 1 cup is supported on the inside by a steel ring or sleeve 23. The upper end of the cup is supported on the outside by a steel ring 24. Support is provided on its lower end with a slip expander cone 30 to engageslips 31 forming parts of a conventional hook wall means for engaging the casing 10 to support the packer. As shown, the slips are piv otally connected to links 32 which in turn are pivotally connected to slip control ring 33. Slip control ring 33 normally rests on stop ring 33A secured to the mandrel 11 and is connected to bow springs 34 to frictionally engage the casing 10. The lower ends of the springs are connected to a ring 35 which normally is prevented from sliding upwardly relative to mandrel M by a key 36.
Upon slight upward movement of the mandrel (the springs 34 holding ring 35 stationary) followed by a quarter turn to the left, the key 36 engages stop 37 and is thus aligned with a slot 38 in ring 35 whereupon downward movement of the key 36 through ring 35 is possible. Downward movement of the mandrel causes cone 12 to engage cup 22 and drive cone 30 into slips 31 which are held stationary in the casing by springs 34. i The cone forces the slips to move radially into engagement with the casing.
2,855,051 Patented Got. 7, 1958 After the slips have set, that is, gripped the casing with their teeth 40 to prevent axial movement of the slips relative to the casing, further downward motion of the mandrel 11 forces cone 12 into packer cup 22 to expand it radially into sealing engagement with the casing, the position shown in Figure 2. The preferred particular shape of the packer cup, part tapered and part straight, is more fully described in United States Patent 2,356,232 to Fitzpatrick. I
The force required to set the packer, that is, to expand cup 22 into sealing engagement with the casing and to retain the packer in position against well pressure therebelow, may be of order of ten thousand pounds, this force being obtained by placing on the mandrel all or a part of the weight of the well tubing connected to the upper end of the packer mandrel. Normally after a packer has been once set considerable difficulty is experienced if it is ever desired to unset it to retrieve it from the well or reset it in a different position. A considerable part of this difficulty arises because the packer cup sticks to the packer expander cone. By virtue of the Teflon coating on the packer expander cone in accordance with the invention, this difliculty is overcome.
As previously stated, the invention may also be used with a conventional sleeve type packe in which the packer sleeve is compressed between a stop on the packer mandrel and a support such as the hook wall means herein described. In such case the Teflon coating would be disposed on the mandrel inside the sealing member of the packer as in the above described embodiment, the difference being that in this case the sealing member is a sleeve rather than a cup and the mandrel does not have a conical packer expander portion. Such a construction is shown in Figure 3.
While a preferred embodiment of the invention has been shown and described, many modifications of the invention can be made by one skilled in the art without departing from the spirit thereof and it is desired to cover by Letters Patent all forms of the invention falling within the scope of the following claims.
What is claimed is:
l. A well packer including a tubular mandrel, a rubber sealing means therearound, and means to expand said member to seal between the mandrel and a well casig, said madrel having an outer surface composed of Teflon releasably engaging said sealing means when the packer is set.
2. A well packer comprising a tubular mandrel having a packer expander cone thereon, a packer cup of oil resistant rubber compound disposed on said mandrel, means to support said cup in a well casing whereby axial motion of said cone into said cup radially expands said cup, said cone having a Teflon coating thereon where it engages said cup, whereby withdrawal of said cone from said cup is facilitated.
3. A well packer comprising a mandrel, annular rubber sealing means on the mandrel, and means between the sealing means and the mandrel to prevent the sealing means from sticking to the mandrel when the sealing means is placed under pressure between the mandrel and a well pipe in which the packer is disposed and subjected to the temperature conditions existent in a well.
References Cited in the file of this patent UNITED STATES PATENTS 2,356,232 Fitzpatrick Aug. 22, 1944 FOREIGN PATENTS 2,488,446 Switzerland Nov. 15, 1949