Two Stage Cementing Collar

Abstract

A cementing collar having a valve sleeve therein releasably held in port closed pre-cementing position until actuated by a plug device to a port open position maintained by a latching structure until a second plug device actuating a port closing seat disengages the latching structure and moves the valve sleeve into a post-cementing port closed position.

Description

The present invention relates to a novel cementing collar of the type shown and described in U.S. Pat. No. 3,633,671 upon which device the structure of this invention is an improvement. The patented structure incorporates a snap ring as part of the latching structure and radially disposed short pins actuated by a conical surface on a port closing seat to disengage the snap ring by expanding it out of a latching groove. The device of the instant invention provides a port closing seat having spline portions directly engageable with a similar snap ring without the necessity for interposing radial pins as in the earlier device. Omitting the radial pins from the device of this invention increases the reliability of the apparatus by reducing the number of parts to be actuated and provides a larger area of contact with the snap ring giving a more regular expansion of the snap ring to assure that it is completely disengaged from the latching groove in which it is ordinarily seated.

These and other objects and advantages of this invention will become more readily apparent upon consideration of the following description and drawings in which:

FIG. 1 is an exploded fragmentary view of the port closing seat of this invention and an upper portion of the port sleeve with which it cooperates;

FIG. 2 is a cross sectional view of the port closing seat of this invention together with the related portion of the port closing sleeve and cementing collar body constructed according to the principles of this invention taken substantially on line 2--2 of FIG. 4 looking in the direction indicated by the arrows;

FIG. 3 is an enlarged fragmentary sectional view of the device of this invention taken substantially on line 3--3 of FIG. 2 looking in the direction indicated by the arrows;

FIG. 4 is a median sectional view of the apparatus of this invention incorporated into a pipe string with the elements of the cementing collar in the relationship used for running in the pipe string;

FIG. 5 shows the apparatus of FIG. 4 plus a valve opening bomb immediately after seating in the apparatus of this invention;

FIG. 6 is similar to FIG. 5 except that the apparatus is in the open condition produced by the action of the valve opening bomb of FIG. 5;

FIG. 7 shows the apparatus of FIGS. 4 through 6 plus a closing plug seated at the upper end of the port closing sleeve and with the beginning of the action of closing the ports;

FIG. 8 is similar to FIG. 7 except that the apparatus has now progressed to the closed position as of the end of the cementing action.

As seen in FIG. 4 the apparatus of this invention embodies a cementing collar generally indicated at 10 comprising a body member 12 connectable in a pipe string generally indicated at 14 and represented by a portion of the bottom pipe joint of a pipe string suited to be suspended in a known manner. At the top and bottom of the cementing collar body 12 there are adaptors 16 and 17 (upper and lower, respectively) properly threaded to connect the collar body 12 into such a pipe string.

Body 12 is an elongated hollow cylindrical member of approximately the same outside diameter as the pipe string into which it is to be incorporated and is provided with a plurality of centrally located, radial through bores 18 three of which are shown in FIGS. 4 through 8 but which can be any number suitable for the cementing process hereinafter described and which may also be of any convenient shape for distributing the cement in a known manner.

The body 12 is internally threaded at both ends to properly threadedly engage the adaptors 16 and 17, respectively, which adaptors, having a smaller inside diameter than the internal diameter 20 of the main portion of body 12, form shoulder surfaces at the ends thereof, namely, shoulder 22 at the bottom end of adaptor 16 and shoulder 23 at the upper end of adaptor 17 for purposes hereinafter made clear. The main portion internal diameter extends from the bottom threads of the body 12 to an upwardly facing shoulder 24 formed within the body 12 by a groove 26 in the interior surface of the body 12 terminating at its upward edge in a new internal diameter 28 of the body 12 slightly larger than the main internal diameter 20. The new internal diameter 28 continues upwardly in the body 12 to the internal threads connecting the body 12 with the upper adaptor 16.

Seated within the bottom portion of the body 12 in a slightly enlarged interior diameter is an internally notched collet ring 30, rigidly secured between the upper surface 23 of adaptor 17 and the shoulder formed by enlarging the interior diameter 20, and having internal notches 32 for purpose to be set forth.

Slidably, sealingly received within the internal diameter 20 of the body 12 is an elongated hollow cylindrical port sleeve 36 having a number of radial bores 38 therethrough of the same number and size as the bores 18 of the body 12 and axially positioned to mate with the bores 18 at an intermediate position of the sleeve 36 within the body 12. Between the body 12 and the sleeve 36 are suitable seals such as O-rings 40 above and below the bores 18 and above and below the bores 38 and internally spaced from but adjacent to the end portions of the sleeve 36 in a well known manner to prevent leakage of cement or other fluids from within the pipe string 14 to the well annulus thereabout (not shown) to provide for good control of the flow of fluid through the pipe string 14.

Within the upper end of the sleeve 36 is positioned a hollow cylindrical member or port closing seat 50 with an outside diameter substantially equal to but slightly less than the inside diameter of the sleeve 36 to be slidable therein. As best seen in FIGS. 1 and 2 the upper end of the sleeve 36 is provided with upwardly extending circumferentially spaced spline elements 42 slidably receivable between circumferentially spaced outwardly extending spline elements 52 of the port closing seat 50 with the outside diameter of the splines 52 of the port closing seat 50 having a slightly greater dimension than the outside diameter of the splines 42 of the sleeve 36 as best seen in FIG. 3. The outer surface of each of the splines 42 is also provided with a notch 44 to receive therein a springy metallic, ring shaped securing means or element, such as an inwardly prestressed snap ring 46 having a single suitable opening therein to provide for close engagement within the notch 44 and disengagement therefrom as will hereinafter be made plain.

The lower portion of the outer surface of each of the splines 52 is an oblique inwardly, downwardly slanting ramp surface 54, all of which surfaces 54 are portions of a common conical surface. As shown in FIG. 3 the surfaces 54 are designed for bearing against the inner surface of the snap ring 46 so that upon relative axial motion of the port closing seat 50 downwardly within the port sleeve 36 the snap ring 46 will be moved outwardly for a purpose to be described.

In the upper end portion of the sleeve 36 just below the bottom ends of the splines 42 there is to be seen a plurality of threaded radial bores 48 and in the lower end portion of the seat 50 a similar number of similarly placed threaded radial bores 56 matable with the bores 48 when the seat 50 is inserted within the upper end of the sleeve 36 so that securing means such as frangible threaded elements or headless set screws 58 are receivable therein to hold the seat 50 in proper axial relationship with the sleeve 36 on first assembling of the cementing collar of this invention.

As best seen in FIG. 4 near the bottom of the sleeve 36 there is a circumferential groove 60 radially extending inwardly from the outer surface of the sleeve 36 partly through the body of the sleeve 36. In the body 12 at circumferentially spaced points matable with the groove 60 is a plurality of threaded radial bores 61 positioned so that when the cementing collar 10 of this invention is originally assembled securing means comprising a plurality of frangible elements such as pins 63 extend from bores 61 into groove 60 and headless set screws 62 are screwed into the bores 61 to secure frangible pins 63 therein to anchor the sleeve 36 with respect to the body 12 in the position shown in FIG. 4 with the bores 38 completely out of register with the bores 18 so that the sleeve is in the closed condition.

The bottom end portion of the sleeve 36 has on its exterior surface a plurality of notches 34 engagable with the notches 32 of the collet ring 30 to hold the sleeve 36 in its downwardmost position as will hereinafter be made plain. Within the bottom end portion of the sleeve 36 there is a threadedly engaged port opening seat element 70 internally provided with a stepped bore 72 sized to receive and support the shouldered portion of a releasing means such as a port opening bomb 74 of a type well known in the art (best seen in FIG. 5).

The upper end of the port closing seat 50 has an inwardly sloping chamfer 51 for the seating of the bottom end of another releasing means such as a port closing plug 76, see FIGS. 7 and 8 of a type well known in the art.

OPERATION

The operation of the device of this invention begins with a pipe string incorporating the cementing collar of this invention suspended in a well and the apparatus in the condition shown in FIG. 4 as the running-in condition with the interior of the apparatus open and the ports closed so that normal flow of pipe string fluid can take place through the cementing collar 10 until such time as cementing action is desired.

When cementing action is desired the first operation is to drop the port opening bomb 74 which, being suitably shaped, will travel downwardly through the pipe string 14 and through the port closing seat 50 to come to rest within the port opening seat element 70 in suitable contact with the stepped bore 72 to close off the sleeve 36 at its bottom end. As soon as the bomb 74 comes to rest the pressure against the top end of the bomb 74, above the seat 72, begins to build up with the result that the pins 63 are sheared and the sleeve 36 begins to move downwardly within the body 12 as seen in FIG. 5 wherein the bores 38 and 18 are seen to be slightly overlapped with the beginning of the opening of such bores.

As best seen in FIG. 6 the sleeve 36, under the force of fluid against the bomb 74 has continued to move downwardly within the body 12 until the snap ring 46 comes into contact with the shoulder 24 of the body 12 and, with the snap ring seated in the notches 44 on the outer surfaces of spline elements 42 of the sleeve 36, downward motion is arrested at this point with the bores 18 and 38 matched in full open position. In this condition cement is pumped down through the pipe string 14 and out through the mated bores 18 and 38 into the annulus surrounding the cementing collar 10 to the amount desired.

When the desired amount of cementing has been accomplished a port closing bomb 76 of a well known type is sent down the pipe string 14 with fluid pressure behind it to assure that it seats on the upper end of the port closing seat 50 as seen in FIG. 7. In that figure it is to be seen that the port closing seat 50 has been pushed downwardly within the sleeve 36 far enough to shear the screws 58. The downward motion of the port closing seat 50 within the upper end of the sleeve 36 brings the slanting surfaces 54 into use as ramps to bias the snap ring 46 outwardly from the notches 44 of the splines 42 so that the ring 46 is now biased completely into the notch 26 in the upper surface of the inner diameter of the body 12 and the sleeve 36 is free to travel downwardly within the body 12 as seen in FIG. 7.

Still considering FIG. 7 it is to be seen that the bores 18 and 38 are now almost completely mismatched with only a very slight opening remaining for possible flow of cement outwardly from the inner diameter of the sleeve 36. With continued pressure from the port closing plug 76 the sleeve 36 is pushed downwardly within the body 12 until the notches 34 around the end of the sleeve 36 engage with the notches 32 within the collect ring 30 as seen in FIG. 8. With the sleeve 36 in the lower position as seen in FIG. 8 the bores 18 and 38 are completely mismatched and the cementing ports thus closed and the sleeve 36 latched in a closed position.

With such latching it would now be possible to drill out the port closing seat 76, the opening seat 70, and the port opening bomb 74 leaving the interior of the pipe string completely open with the ports completely closed if such a condition is desired.

With the above described construction according to the principles of this invention it is to be noted that the use of two separate sets of frangible pins or set screws 58 and 62 prevents a continuous path being developed from the interior of the sleeve 36 out through the exterior of the body 12 because of looseness of the thread as was possible with earlier designs, while at the same time presenting the opportunity of providing for independent variation of the respective forces required for initiating port opening and port closing by selecting the number and size of the frangible elements used in the two locations.

The use of the conical surface portions 54 directly as ramp surfaces against the slip ring 46 eliminates troublesome force transferring radial pins found in earlier designs and makes the present design more reliable. The same feature provides a much larger of area of contact between the snap ring and the force applying elements and provides much more reliable disconnecting of the snap ring 46 from the grooves 44 which is of course necessary for the proper operation of the device.

The use of a collet for holding the tool in the closed position reduces manufacturing costs over that of earlier designs and also provides a capability of cycling the tool (after removing the shear pins and collet) through a complete operational sequence and then reassembling the tool in its original running-in condition to provide for testing of all the seals before the tool is finally put into the well.

Besides the above mentioned advantages this tool incorporates all of the advantages of the tool set forth in the above cited U. S. patent on which this invention is an improvement.

Claims

1. In a cementing collar comprising an elongated vertically extending tubular body having a central bore extending longitudinally therethrough and means for connecting said body in a pipe string, at least one radially extending port communicating between the exterior and interior of said tubular body, an elongated tubular sleeve axially received within said bore of said tubular body, said sleeve having a central bore extending therethrough and with at least one radially extending orifice communicating between the exterior and interior of said sleeve, first securing means for releasably securing said sleeve in a closed upper position within said body, said upper position being such that said orifice and said port are completely out of register when in the upper position, first releasing means received within said body for releasing said first securing means such that said sleeve takes an intermediate position with said port and said orifice in overlapping registration for establishing communication between the interior of said sleeve and the exterior of said body, second securing means engaged with a first groove in the exterior of said sleeve and engagable with a circumferential groove within the interior of said body for maintaining said sleeve and said body in said intermediate position to maintain the open condition, second releasing means received within said body for releasing said second securing means, a hollow cylindrical member axially slidable within said sleeve and releasably secured in inoperative relationship with said second securing means by third securing means maintaining said inoperative relationship by relative positioning of said member and said sleeve, the improvement comprising: said member having a substantially cylindrical outer surface with a plurality of axially elongated radially outwardly extending elements thereon said elements having downwardly tapering ramp surfaces thereon which are parts of a conical surface extending upwardly and outwardly at least to the full diameter of said sleeve, said sleeve having upwardly extending a plurality of circumferentially spaced separate portions receivable between said outwardly extending elements of said member, said ramp surfaces being engageable with said second securing means by axial movement of said member to bias said second securing means radially outwardly from the said groove in said outer surface of said sleeve to release said sleeve for downward movement into a second closed position wherein said port and said orifice are completely out of

2. The improvement as specified in claim 1 wherein; said first securing means is a first plurality of frangible elements extending from bores in said body into a second groove in the outer surface of said sleeve and said third securing means is a second plurality of frangible elements engaged in mated radial bores in said sleeve and said member respectively.

3. The improvement as specified in claim 2 wherein said first plurality of frangible elements is independent of said second plurality of frangible

4. The improvement as specified in claim 1 wherein; said second securing means is an inwardly prestressed snap ring engaged in said first sleeve groove and disengageable from said first groove by outward biasing of said

5. The improvement as specified in claim 1 additionally comprising fourth securing means within said body engageable with fifth securing means on said sleeve by relative axial movement thereof to maintain said sleeve and

6. The improvement as specified in claim 5 wherein said fourth securing means is a removable ring shaped internally toothed collet member rigidly

7. The improvement as specified in claim 6 wherein said fifth securing means is an externally toothed lower end portion of said sleeve engageable

8. The improvement as specified in claim 1 wherein said outwardly extending elements on said member are circumferentially spaced about the exterior of

9. The improvement as specified in claim 8 wherein said elements cover more than half the external circumference of the upper portion of said member.

10. The improvement as specified in claim 9 wherein there are only four of said elements and four of said upwardly extending sleeve portions together occupying substantially the whole external circumference of the upper portion of said member.