US3444929A - Cementing method and apparatus - Google Patents

Description

A May 20, 1969 BROWN ET AL 3,444,929

CEMENTING METHOD AND APPARATUS Sheei Z of 3 Filed Aug. 31, 1966 CARL CHWA INVE AFFOR. 8

Leaf

May 20, 1969 J. R. BROWN ET AL 3,444,929

CEMENTING METHOD AND APPARATUS sheetiors Filed Aug. 31, 1966 :JOE R. BROWN CARL M. SCHM AB I N VIZNTOR.

A T TORNE Y5 y 1969 J. R. BROWN ET AL 3,444,929

CEMENTING METHOD AND APPARATUS Sheet 3 of3 Filed Aug. 31. 1966 JOE R. BROWN United States Patent 3,444,929 CEMENTING METHOD AND APPARATUS Joe R. Brown and Carl M. Schwab, Houston, Tex.; said Schwab assignor to Brown Tools, Inc., Houston, Tex., a corporation of Texas Filed Aug. 31, 1966, Ser. No. 576,445 Int. Cl. E21b 37/02 US. Cl. 166-173 3 Claims ABSTRACT OF THE DISCLOSURE A method of and an apparatus for wiping the exterior of a well pipe in a Well bore clean by reciprocating the well pipe through a wiping surface which is in contact with the well pipe exterior and is held against movement in the well bore.

The present invention relates to a new and improved ered in the well bore to remove the wall cake from the 0 interior surface of the well bore to improve the bonding of the cement to the interior surface of the well bore. Additionally, the exterior surface of the well pipe has been treated before lowering it into the well bore in an attempt to obtain improved bonding of the cement to the well pipe. Such treating has been partially successful but one of the major causes of poor bonding of the cement to the well pipe results from the coating of the exterior of the well pipe by the drilling fluids and mud necessarily present in the well bore when the well pipe is lowered therein to the desired position.

-It is, therefore, an object of the present invention to provide an improved cementing method and apparatus to prepare the exterior surface of the well pipe during cementing to improve the cement bonding thereto.

Another object is to provide a new and improved device for wiping the exterior of a well pipe in a well bore during cementing operations without interfering with normal cementing operations.

Another object is to provide a new and improved wiper device adapted to be slidably mounted on a well pipe section which is to be cemented in a well bore in conjunc tion with other devices to wipe the exterior of the well pipe while removing wall cake from the wall of the well bore.

Still another object is to provide a new and improved wiper device in combination with another device commonly used on well pipes for cementing operations,

A further object is to provide a new and improved well pipe wiper device adapted to be actuated by wall scratchers and centralizers during a cementing operation to wipe drilling fluids from the exterior surface of the well pipe.

These and other objects and advantages of the present invention will be apparent from the claims and the following specification describing the preferred form of the present invention with reference to the drawings wherein:

FIGURE 1 is a partial longitudinal sectional view through a well bore and illustrates the preferred form of wiper device of the present invention on a well pipe with a centralizer;

FIGURE 2 is another partial longitudinal sectional 3,444,929 Patented May 20, 1969 view through a well bore illustrating another form of the wiper device of the present invention incorporated into a centralizer unit;

FIGURE 3 is another partial longitudinal sectional View through a well bore and shows another form of the wiper device of the present invention incorporated into a wall scratcher unit;

FIGURE 4 is a cross-sectional view taken along line 44 in FIGURE 1;

FIGURE 5 is a cross-sectional view taken along line 5-5 in FIGURE 1;

FIGURE 6 is a cross-sectional view taken along line 66 in FIGURE 2;

FIGURE 7 is a cross-sectional view taken along line 77 in FIGURE 3; and

FIGURES 8, 9 and are schematic views to illustrate the operation of the method of the present invention; FIGURE 8 showing the position of the components at the commencement of an up-stroke; FIGURE 9 showing the position of the components as wiping starts on the upstroke and FIGURE 10 showing the position of the components at the completion of wiping on the up-stroke.

The wiping device 10 of the present invention is illustrated in FIGURE I mounted around the well pipe P within the well bore B with the components shown as they are run into the well bore. The centralizer C is shown as providing the means for engaging the wiping device 10 to hold it relatively stationary so that raising and lowering of the well pipe P produces a relative movement between the wiper device 10 and the well pipe P, which movement causes the wiper 10 to wipe the exterior surface of the well pipe P in the presence of cement to improve the bond between the cement and the well pipe P. A scratcher S is also mounted on the well pipe P to prepare the well bore for cementing while the well pipe P is being cleaned.

As can be seen from FIGURES 1 and 5, the wiping device 10 includes a resilient sleeve 14 having integral, inwardly extending, annular ribs 16 and the split channelshaped collar 18. The sleeve 14 is split at 20 so that it can readily be mounted around a well pipe. The collar 18 is made in two sections which are joined together at the extremities by bolts 22 and 24 to form the support around the outer periphery of sleeve 14. Each of the collar sections is channel-shaped, having upper and lower inwardly extending flanges 26 and 28 which retain the sleeve 14 within the collar 18. If desired, a portion of the exterior of sleeve 14 may be suitably bonded to the interior of one of the sections of the collar 18. The collar 18 is of a predetermined size so that when it is mounted on a Well pipe with the sleeve 14 contained therein, the inner surfaces of the ribs 16 are in wiping contact with the exterior surface of the well pipe. Additionally, the collar 18 must have an outer diameter when mounted on a well pipe P to assure engagement by the centralizer collars 30 and 32.

The centralizer C illustrated in FIGURE 1 includes the two collars 30 and 32 spaced from each other and connected by a plurality of centralizer springs 36. As shown, the centralizer collars 30 and 32 are split collars for ease in mounting the centralizer C on the well pipe P. Thus, with the wiping device 10 mounted around the well pipe P, the centralizer C is mounted around the well pipe P with collar 30 positioned above wiping device 10 and collar 32 positioned below wiping device 10. The stops 37 and 38 are secured to the well pipe P by the set screws 40 and 42 to limit the relative longitudinal movement between the well pipe P and the centralizer C.

In operation, the well pipe P having wiping device 10, centralizer C, stops 37 and 38 and scratcher S mounted thereon is lowered into the well bore B to the level at which it is to be cemented. In lowering well pipe P into well bore B, the components mounted thereon assume the positions illustrated in FIGURE 1, i.e., the centralizer C is engaged by upper stop 37 and the wiping device is in engagement with the lower collar 32 of centralizer C. As in usual cementing procedures, the well pipe P is then reciprocated longitudinally to prepare the well bore B and the well pipe P for cementing. Such reciprocation functions to raise and lower wall scratcher S to remove the wall cake from the walls of the well bore which is generally necessary to provide an adequate bond of the cement to the wall of the well bore. With the present invention, this reciprocation also accomplishes during a portion of each stroke the preparation of a portion of the exterior of the well pipe P by the wiping action as hereinafter explained.

Referring to FIGURES 8, 9 and 10, the relative movement of the component parts of the present invention are shown during the upward stroke of the pipe reciprocation. Two centralizers C1 and C-2, two wiper devices W-l and W-Z are shown mounted on the well pipe P. Also included are the three stops A1, A-2 and A-3 and the well scratcher S.

In FIGURE 8, the position illustrated is taken at the end of a downward movement of the well pipe P. As also shown in FIGURE 1, the centralizers are engaging their upper stop and the wiper devices are in engagement with the lower collars of the centralizers.

The well pipe P, as shown in FIGURE 9, has moved upwardly a short distance. The wiper devices W-1 and W-2 have moved upwardly with the well pipe P to a position engaging the upper collars of the centralizers C1 and C2. The centralizers C-1 and C-2, because of their engagement with the well bore B, have remained stationary. The scratcher, being shown to be secured to the well pipe P, has moved upwardly and has scratched the wall of the well bore B.

The well pipe P has been moved upward an additional distance to reach the position shown in FIGURE 10. The

centralizers C-1 and C-2 being positioned between stops during such movement remain stationary. Also, the centralizers hold the wiper devices stationary and the well pipe P moves therethrough and a portion of its exterior has been wiped or cleaned thereby. The engagement of the stops A-2 and A-3 against the lower end of the centralizers C-1 and C-2 terminates the wiping action. Further upward movement of the well pipe P from the position shown in FIGURE 10 does not result in any relative movement of the pipe with respect to the wiper devices and the centralizers but only in a scratching action of the scratcher on the wall of the well bore B.

The downward stroke of the well pipe P is similar to the described upward stroke. During the first portion of the downward stroke, the well pipe P and the wiper devices move downwardly with respect to the centralizers. When the lower collars of the centralizers engage the wiper devices, the well pipe moves through the wiper devices and is cleaned or wiped by the wiping action resulting from such relative movement.

Generally such reciprocation of the well pipe for scratching the well bore and cleaning the well pipe is commenced immediately proceeding or during the placement of cement. However, whenever it becomes derisable to wipe or clean a portion of the exterior surface of a well pipe in a well bore, such cleaning may be accomplished by reciprocating the Well pipe having thereon suitable wiping devices and a means of retaining the wiping devices stationary during at least a portion of the pipe movement.

While the entire surface of the well pipe P between stops 37 and 38 is not wiped by the wiping device 10, a sufiicient portion of such surface is wiped to assure an adequate cement bond to the well pipe P.

In FIGURES 2 and 6, a modified form of the present invention is illustrated which includes two wiping devices 44 and 46 mounted in the upper and lower collars 48 and 50, respectively, of the centralizer 52. As shown,

, centralizer springs 62 connecting between the collars 48 and 50. The springs 62 are adapted to engage the wall of the well bore B when the centralizer 52 is mounted around the well pipe P and lowered into the Well bore B. Stops 64 and 66 are secured to the well pipe P by set screws 68 and 70 above and below the centralizer 52 to limit the relative longitudinal movement between the centralizer 52 and the well pipe P. When centralizer 52 is installed around well pipe P, the ribs 58 and 60 should be in wiping contact with the exterior surface of the well pipe P. To facilitate mounting, the sleeves 54 and 56 may be split, as at 72 (FIGURE 6), and may be partially bonded to one part of the collars 48 and 50.

In operation, the reciprocation of the well pipe P during cementing moves the Well pipe P in wiping contact through the wiping devices 44 and 46 to remove drilling fluids, mud and production fluids. This wiping of the exterior of the well pipe P allows the cement to come into direct contact and to set against the exterior of the well pipe P to provide an improved bonding of the cement to the well pipe.

In FIGURES 3 and 7, another form of wiping device is shown. In this form the resilient wiping sleeve 74 having integral, inwardly extending, annular ribs 76- is installed within the internal recess 78 of the body of the wall scratcher 80. The wall scratcher 80 is shown mounted around the well pipe P between the stops 82 and 84, which are suitably secured to the well pipe P by set screws 83 and 85, and includes a plurality of scratching fingers 86 adapted to engage the wall of the well bore B in the usual manner. The resilient sleeve 74 may be split, as at 88, and partially bonded in the recess 78 to facilitate installation of the unit on the well pipe P.

During a portion of the longitudinal reciprocation of the well pipe P for wall scratching, the well pipe moves through the wall scratcher until the scratcher is engaged by the stops 82 and 84. This relative movement accomplishes the wiping of drilling fluids, mud and production fluids from the exterior surface of the well pipe P by the movement of the well pipe relative to the wiping contact of the ribs 76. As previously described, this wiping of the exterior surface of the well pipe P results in an improved cement bond. It is contemplated that a wiping device having inwardly projecting, longitudinally extending ribs in wiping contact with a well pipe may be used with scratcher devices which require rotation to remove wall cake rather than reciprocation.

From the foregoing the various forms of the improved wiping device of the present invention and the improved method of cementing which improves the cement bond to a well pipe being cemented in a well bore have been described and explained. The wiping device of the present invention, when installed on a well pipe, together with means for engaging and retaining the device stationary, wipes the exterior surface of the well pipe in the presence of cement responsive to the normal raising and lowering for scratching the well bore, and such wiping assures an adequate bond of the cement to the well pipe.

The foregoing disclosures and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

5 What is claimed is: 1. A Wiper device for cleaning a well pipe in a well bore, comprising:

a resilient wiping sleeve, and

a centralizer having two collars connected by a plurality of centralizer springs mounted on a well pipe,

said sleeve being mounted in one of said collars of said centralizer to position said sleeve around the well pipe in wiping contact with the exterior surface of said well pipe,

said centralizer retaining said sleeve relatively stationary with respect to a well bore whereby movement of said well pipe produces a relative movement of said pipe with respect to said sleeve to clean a portion of the exterior surface of said well pipe.

2. A wiper device according to claim 1, including:

a second resilient wiper sleeve having inwardly extending ribs positioned in the other collar of said centralizer.

3. A wiper device for cleaning a well pipe in a well bore, comprising:

a resilient wiping sleeve,

a collar having a recess for receiving said resilient wiping sleeve,

said collar being mounted around a well pipe and being sized to retain the inner surface of said sleeve in wiping contact with the exterior of said Well pipe, and

a centralizer having two collars connected by a plurality of centralizer springs,

said centralizer mounted on said well pipe with said wiping sleeve collar between the centralizer collars for retaining said sleeve relatively stationary with respect to a well bore whereby movement of said well pipe produces a relative movement of said pipe with respect to said sleeve to clean a portion of the exterior surface of said well pipe.

References Cited UNITED STATES PATENTS JAMES A. LEPPINK, Primary Examiner.

U.S. Cl. X.R. 15-104.4

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