US 3131767 A
Description (OCR text may contain errors)
May 5, 1964 F. E. CHANCELLOR ETAL 3,131,767
STAGE COLLAR Filed April 24, 1962 2 Sheets-Sheet 2 RUGEQI' 0; fi m/65am INVENTORS.
United States Patent 3,131,767 STAGE COLLAR Forrest E. Chancellor and Robert O. Chancellor, both of 2917 Pierce Road, Bakersfield, Calif. Filed Apr. 24, 1962, Ser. No. 190,2fi8 Claims. (Cl. 166154) This invention relates to the art of completing oil wells to prepare these for production and particularly to stage collars employed for releasing cement through the wall of a well casing to accomplish a casing cementing operation.
A difiiculty commonly experienced in the use of stage collars heretofore provided for the oil industry has been in effecting the removal of the parts within the stage collar following a cementing operation.
It is an object of the present invention to provide a stage collar, the internal elements of which may be readily removed by a boring tool after the cement charge has set, leaving the collar with the same internal diameter as the casing in which it is assembled.
Another object of the invention is to provide such a stage collar having a novel valve mechanism for controlling the operation thereof, the main portion of which is disposed outside the collar and therefore does not have to be removed following the cementing operation.
Still another object of the invention is to provide a stage collar as aforesaid having a novel opening control means for a cement basket when said collar is used in conjunction with such a basket. I Yet another object of the invention is to provide a stage collar a series of which may be assembled in the same string of casing and actuated simultaneously by a corresponding series of cement plugs propelled by spaced charges of cement flowing down said casing.
The manner of accomplishing the foregoing objects as Well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which FIG. 1 diagrammatically illustrates in section a deep well bore into which a string of casing has been introduced, said casing having assembled therein a cementing tool known as a stage collar and comprising a preferred embodiment of the present invention. This view shows said tool prior to its actuation in order to effect a cementing operation in which said casing is cemented in said bore.
FIG. 2 is a view similar to FIG. 1 and illustrates the manner in which said tool functions when actuated to perfonn a cementing operation as aforesaid.
FIG. 3 is an enlarged vertical sectional view taken on the line 3-3 of FIG. 1 and illustrating the invention as it is shown in FIG. 1 and prior to the invention being actuated.
FIG. 4 is a view similar to FIG. 3 and is taken on the line 44 of FIG. 2, thus showing the parts of the invention disposed as they are following the actuation thereof and while the cementing operation aforesaid is taking place.
FIG. 5 is a view similar to FIG. 4 illustrating the appearance of the invention after the cementing operation has been completed, the cement is hardened, and the debris and portions of the tool extending inwardly within the tubular body member thereof have been bored out 3,131,767 Patented May 5, 1964 so as to leave said member with an inside diameter equal to that of the casing string in which said tool is assembled.
FIG. 6 is a horizontal sectional view taken on the line 66 of FIG. 3 and illustrates the novel means of the present invention by which a cement basket embodied with the invention is confined tightly wrapped around the tool pending the actuation of the latter in a cementing operation.
Referring specifically to the drawings, the invention is there shown as embodied in a stage collar 10 which is assembled in a casing string 11 prior to introduction of the latter into a well bore 12 for the purpose of conducting a cementing operation in which said casing will be cemented in said bore.
The stage collar 10 includes a tubular body member 13 which comprises a relatively short length of the same kind and size of pipe from which the casing string 11 is made. The member 13 is externally threaded at its opposite ends to receive upper and lower couplings 14 and 15, which may be standard couplings such as are used in the assembly of the casing string 11. The external cylindrical surface 16 of the member 13 is turned down smooth for a purpose which will be made clear hereinafter. The member 13 is also provided with aperture means including a series of cement discharge ports 17, which are disposed at a level near the upper end of the member 13, and a series of vertical slots 18 equally spaced circumferentially from each other and disposed below the discharge ports 17.
Slidably fitting the smooth cylindrical external surface 16 of the member 13 is a tubular valve sleeve 19, said sleeve having annular internal grooves just inwardly from each of its upper and lower ends to accommodate upper O-ring 20 and lower O-ring 21. The sleeve 19 is also provided with radial holes 25, equal in number to the vertical slots 18 and equally spaced circumferentially therewith, said holes snugly receiving heavy cast iron bar pins 26 which extend inwardly through the slots 18 and substantial distances into the tubular body member 13 as shown in FIG. 3. The pins 26 are welded in the holes 25 so as to close said holes and be permanently mounted on the sleeve 19.
The sleeve 19 is sufficiently shorter than the tubular body member 13 to have freedom for vertical sliding movement on the latter after the actuation of the tool described hereinafter. When thus free to slide vertically, the sleeve 19 may be shifted downwardly so as to expose the cement discharge ports 17 as shown in FIG. 4. Prior to actuation of the tool however, the sleeve 19 is elevated into the position in which it is shown in FIG. 3 and secured therein by the insertion of a brass shear pin 27 through a pair of aligned holes drilled in the sleeve 19 and tubular body member 13, as shown in FIG. 3. When the tool 10 is thus assembled, a flat aluminum ring 28 is inserted into the member 13 so as to come to rest on inwardly extending portions of the pins 26.
The tool 10 may be optionally provided with a cement basket 29 having a base band 30 which encircles and is welded to a lower portion of the tubular body member 13 as shown in FIG. 3. Yieldably secured to the base band 30 as by tack welding thereto are light straplike ribs 31, a circumferential series of which are provided so that these extend upwardly from the band 30 in close spaced relation entirely around the tool 10. Secured, as
by spot welding, to each of the ribs 31 is a thin metal blade 32 these blades extending from each of the ribs to which they are attached in a given direction circumferentially so as to underlie the ribs and blades adjacent thereto in feathering relation therewith and so as to enclose the sleeve 19 when the tool is assembled as shown in FIGS. 3 and 6. N
The present invention includes a novel releasing means for the basket 29 which includes a pair of metal eyes 33 and 34 which are welded to the upper coupling 14 with said eyes in vertical alignment, and a vertically disposed basket release pin 35 WhlChlS welded at its lower end on the upper edge of the sleeve 19 and extends vertically upwardly through the metal eyes 33 and 34. As shown in FIG. 3, these eyes are spaced vertically so as to provide room for opposite ends of a metal strap 40 being bent around the pin 35 after said strap has been drawn tightly around the upper end portions of the basket ribs 31.
OPERATION As above noted, the stage collar 10, assembled as shown in FIGS. 3 and 6, is incorporated in a casing string 11 prior to the latter being introduced into a well bore 12 as shown in FIG. 1 preparatory to conducting a cementing operation as shown in FIG. 2.
At the time of introduction of the casing 11. into the bore 12 as shown in FIG. 1 this bore is filled with rotary mud and the casing 11 is likewise filled with this mud. A circulation of mud is then set up through the casing string 11, this mud being pumped into the upper end of the casing string and flowing out of the lower end thereof and upwardly between the casing and the bore. As shown in FIGS. 1 and 2, the well bore 12 passes through a Water zone 41 and an oil producing zone 42. It being desirable to cement oh? the Water zone 41 in preparation for producing oil from the zone 42, the casing string 11 is low- 13 to be thus bored out in the cleaning up step which concludes the cementing operation. One of the main reasons for this is that the major portion of the sealing means in the tool 10, which is the sleeve 19, is located outside of the tubular body member 13 of the tool.
Another advantage of the invention is the simplicity and certainty of operation of the means provided on the tool 10 for releasing the cement basket 29. It is to be understood, however, that equipping stage collar 10 with a cement basket 29 is optional, and that use of such a basket is generally limited to when-the formation of the well is soft.
A further meritorious feature of the present invention is that a plurality of cementing operations may be performed in the same casing string by assembling an equal number of stage collars 10 in that string at difierent levels therein and providing rings 28 with internal openings of different diameters, these internal diameters decreasing progressivelydownwardly, and then employing cement plugs 44 of varying diameters so that the first plug inserted in the casing string 11 will pass downwardly through all of the tools 10 in the string excepting the lowermost tool where this plug will be intercepted by the ring 28 of that tool and in a similar manner plugs of successively larger diameter will be intercepted simultaneously by the other tools 10 provided inthe casing string so that all of the cementing operations at the different levels where the tools 10 are positioned in the ered into the well bore 12 until the tool 10 is positioned as shown in FIG. 1 just below the lower level of the water zone 41. A charge of cement 43 is now pumped down the casing string 11 preceded by a cement plug 44, the latter being of an outside diameter too large to pass through the ring 28. When the cement plug 44 reaches the tool 10 and contacts the ring 28 therein, the hole in said ring is closed and the downward pressure of the descending column of liquid in the casing string 11 is imposed on the ring 28 and the heavy cast iron bar pins 26 on which this rests. unable to resist this pressure, is sheared in two, allowing the pressure applied to the pins 26 and sleeve 19 to slide the latter downwardly to its lowermost position in which it is shown in FIG. 4. This simultaneously opens the cement discharge ports 17 permitting the cement 43 to flow outwardly therethrough and also withdraws the basket release pin 35 downwardly from the eyes 33 and '34 and from the metal strap 40, hooked around this pin, thereby allowing the cement basket 29 to expand outwardly against the well bore 12 as shown in FIG. 2 causing the cement 43 to flow upwardly from the tool 10, filling the space between the well bore 12 and easing string 11 as far as the cement flows.
When practically the entire charge of cement 43 has thus been discharged outwardly through the ports 17, the operator halts the pumping of liquid downwardly into the casing string 11 until the cement charge 43 has set. A drill string with a boring tool on the lower end is then inserted downwardly into the casing 11 with a diameter smoothly fitting the inner diameter of this casing. By the rotation of this tool, all of the cement 43 remaining within the casing string 11 and the tool 1! and as well as the aluminum ring 28 and inwardly extending portions of the bar pins 26 are bored out leaving the inside diameter of the tool 10 equal to that of the casing string 11 as shown in FIG. 5.
A comparison of FIGS. 4 and 5 readily shows what a The brass shear pin 27, being casing string 11 will concur in point of time.
1. In a cementing tool comprising a connecting link in a string of well casing, the combination of a tubular body member comprising a relatively short length of said casing, said member having a smooth cylindrical outer surface, aperture means being formed in said member including a plurality of equally circumferentially spaced vertical slots; a tubular valve sleeve slidably fitting said outer surface of said member, said sleeve being enough shorter than said member to be axially shiftable downward thereon to expose an upper portion of said aperture means, but long enough to cover all of said aperture means when disposed upwardly over said exposable upper portion of said aperture means; shear pin means temporarily uniting said member and said sleeve, with the latter lifted to cover all of said aperture means; and plug responsive means supported on said sleeve and extending inwardly through upper portions of said slots and cooperating with a cement plug propelled hydraulically downward in said casing when said plug comes in contact therewith, to transmit hydraulic pressure downwardly to said sleeve, thereby shearing said shear pin means, and shifting said sleeve downward to expose said upper portion of said aperture means and allow a charge of liquid cement following said plug to pass outwardly through said exposed upper portion of said aperture means.
2. A combination as recited in claim 1 wherein said plug responsive means comprise cast iron cylindrical bars mounted in radial holes provided in said sleeve and welded in place, said bars extending substantial distances inwardly through said slots and into said tubular member; and annular means fitting close within said member and supported on said bars for engagement by said cement plug and the transmission of downward pressure from the latter to said bars.
3. A combination as recited in claim 1 wherein O-ring seals are provided between said sleeve and said member at levels above and below said aperture means when said sleeve is in its elevated position and secured to said said sleeve; two eyes mounted on an upper portion of said member, said eyes being vertically aligned; a basket release pin welded on said sleeve and extending vertically upward therefrom through said eyes; and a steel strap encircling upper end portions of said ribs and with its ends hooked around said basket release pin between said eyes, whereby actuation of said tool by a cement plug withdraws said release pin from said eyes and said strap, releasing said ribs and allowing said basket to expand against the wall of a well bore in which a cementing operation is being conducted.
5. A combination as recited in claim 1 wherein said aperture means includes a series of circumferentially spaced cement discharge ports separate from and disposed upwardly from said vertical slots.
References Cited in the file of this patent UNITED STATES PATENTS 2,644,526 Lee July 7, 1953