US 3842906 A
Description (OCR text may contain errors)
linited' States Patent 1191 Paramore et a1.
WELL BORE CLEANER CONSTRUCTION Inventors: Edwin L. Paramore; Tom W. Howe,
both of Duncan, Okla.
Assignee: Halliburton Company, Duncan,
Filed: Oct. 31, 1972 Appl. No.: 302,434
US. Cl 166/172, '166/173, 403/194, 1 403/199 Int. Cl E2lb 37/02 Field of Search 166/172, 173, 241, 177; 403/193, 194, 199, 274; 24/73 ES References Cited UNITED STATES PATENTS 3/1942 Andren et a1 403/193 X PrimaryExaminerH. Hampton Hunter Attorney, Agent, or Firm-John H. Tregoning 5'7] ABSTRACT In the construction of an oil well bore scraping device, a plurality of braided cables each receive cylindrical spooled ends which are swaged onto one or both ends of the cable and then inserted into the cylindrical wiper body and bradded over, leaving the cables extending outwardly from the wiper body.
11 Claims, 8 Drawing Figures 1 I WELL BORE CLEANER CONSTRUCTION BACKGROUND OF THE INVENTION In completing an oil well for production a most critical step involves primary cementing of the well. To simplify the description of this often complex process, an aqueous cement slurry is placed between the casing and borehole and allowed to harden to bond the casing to the borehole and provide lateral support for the easing against the underground formation. It also provides a permeable annular seal against loss of high pressure gas and/or formation fluids from the underground formation to the surface via the annular area between the casing and the borehole wall.
In order for this bonding, sealing, and supporting function to be performed successfully, good contact must be obtained between the cement slurry and the borehole wall. Thisis often difficult because of the semi-dry filtercake deposited on the borehole wall from thedrilling mud, which filtercake is not removed when the cement slurry displaces the drilling mud, and which filtercake undesirably serves to insulate the cement slurry from the borehole wall.
In order to remove this filtercake from the formation, it is known that placing abrasive devices on the casing to scratch or scrape the borehole wall as the casing is lowered into the hole will serve to remove the undesirable filtercake.
A common type of wall cleaner has been the cable type such as those revealed in U.S. Pat. No. 2,826,253 and US. Pat. No. 3,213,943. These devices consist of a sleeve to be inserted over the casing as it enters the well. To the sleeve are attached a plurality of looped cables. The sleeve is fixedly attached to the casing and the cables are arranged to provide abrasive contact with the bore wall as the casing enters the well. The casing can be reciprocated while in the well to provide even further cleaning.
The difficulty which arises with the prior art devices is that the method of attaching the cables or cable loops to the cable sleeve leaves much to be desired. Some means of attaching, such as by clamping the cables down on the external surface, results in the cables subsequently pulling free from the clamps or else they are clamped so tightly that they are pinched, and through bending and fatigue will shear and break loose.
Other means of attaching the cable allow them too much movement such that they are not held stiffly against the bore wall surface and, therefore, do not provide adequate scraping and cleaning.
The wall cleaner of the present invention provides a sleeve having stiff durable cables rigidly and firmly secured in the sleeve and projecting outward at the optimum angle for maximum cleaning results.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross sectional view of the cable and cylindrical spoolprior to their attachment to each other;
F IG. 2 is a cross sectional view of the socket assembly and cable after attachment;
FIG. 3 is a cross sectional view of the socket assembly and cable installed in the sleeve;
FIG. 4 is an isometric view of the cable wall cleaner having staggered overlapping cable loops;
FIG. 5 illustrates the apparatus of FIG. 4 in place on a casing string in a borehole;
FIG. 6 illustrates a second embodiment of the apparatus;
FIG. 7 illustrates a third embodiment of the invention; and
FIG. 7a illustrates the apparatus of FIG. 7 in a collapsed position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention is disclosed in FIG. 4 in which a cylindrical cable sleeve 10 has openings 11 through the wall thereof capable of receiving socket assemblies 12 on the ends of cables 13. Preferably, for simplicity of manufacture and optimum efficiency, sleeve 10 is formed with two horizontal rows of apertures 11 and each cable loop has one end in the lower row 210 and one end in the upper row 110. In this embodiment each cable loop spans two apertures and is staggered to overlap the adjacent cables on each side by one aperture space. Thus, by this spacing arrangement a complete circumference of cable loops extend outward around the sleeve 10 while there is maintained sufficient space between the cables 13 and sleeve 10 and between each of the cables to allow proper flow of the removed filter-cake away from the apparatus and up the annulus. The staggered spacing between the cable 13 also prevents wear and entanglement between the cables and further provides optimum cement reinforcing qualities when the casing string is cemented.
Referring now to FIGS. 1, 2, and 3, the method of attaching cables 13 into sleeve 10 to obtain optimum strength, stiffness, and cable angle with a minimum of operations is shown.
In assembling the cable loops 13 for attachment into sleeve 10, a cylindrical tubular spool 12 is slipped over the end of the braided metal cable as shown in FIG. 1 and swaged down tightly as shown in FIG. 2 to provide a slip-proof attachment of the end 12 to the cable. This results in the cable socket assembly shown in FIG. 2 This assembly procedure is performed on each end of each cable 13.
The remaining cylindrical portion of the socket assembly 12 comprises the outermost extended portion of each cable end after it is swaged thereon. This cylindrical portion is then inserted through the appropriate circular aperture 11 in sleeve 10, which apertures are of a size sufficient to allow a relatively snug fit of the socket assembly therein.
The final step of assembly is the bradding over of the cylindrical end 120 protruding inward in sleeve 10 to obtain a permanent, stable attachment to sleeve 10 of the cable and socket assembly.
The bradding over of cylindrical end 120 on the interior surface 150 of sleeve 10 results in a pulling tight of belled end of socket assembly 12 against the outer surface of sleeve 10 and results in the longitudinal axis of the cable and socket assembly being rigidly held in a postion normal or perpendicular to the surface of sleeve 10 at that point. This results in the optimum cable angle for scraping the borehole wall while providing a strong, wearable connection between the sleeve and the cable.
The cable loop is urged directly out from sleeve 10 in a non-movable position to provide maximum cable contact with the borehole wall. The rigid non-rotatable connection of the cable in the sleeve helps resist upward or downward movement of the cable and allows greater maneuverability in reciprocating the casing to obtain more extensive wall cleaning.
The efficient overlapped and staggered placement of the cables 13 on sleeve allows optimum cleaning action with fewer number of cable loops needed.
Sleeve 10 is attached to the casing by means such as threaded studs 15 extending through sleeve 10 and tightly abutting the casing. While one such stud may be used, better attachment can be achieved by using two or more studs. Alternatively, circumferential casing clamps can be used above and below the apparatus to hold it in place on the casing.
FIG. 6 illustrates an alternative method of emplacement of cables on the casing to obtain a cleaning and scouring effect on the borehole wall. In this embodiment instead of using cable loops, short stiff sections of cable 113 are attached to vertical runners 114 which are in turn held by clamps 115 to the casing in a vertical orientation. One or more of the runners 114 may be positioned on the casing, and cleaning is accomplished by vertical reciprocation and/or rotation of the casing in the hole.
It is clear that the looped cable orientation may be used on the vertical runners in place of or in conjunction with the bristle type of cleaner. This is illustrated in FIG. 6 with vertical runner 214 having looped cables 213 attached thereto.
The looped cable configuration is generally preferable for removing the softer, bulkier filtercake, while the bristle configuration is advantageous for removing the harder, drier filtercake. Thus, a combination of the two embodiments would be advantageous as a general allpurpose scraper. The looped and bristled cable cleaners could be placed in a staggered relationship for optimum effect.
FIG. 7 illustrates a third embodiment utilizing a helical mounting strip 314 passing helically around the casing and held in place by easing clamps 315. In this embodiment the stiff bristle type cables 323 or the looped cables 313 can be attached to the mounting strip by the socket assembly as illustrated in FIGS. 1 through 3. The bristles and loops may be alternated to obtain a compound scouring action.
FIG. 7a illustrates how the helical cleaner of FIG. 7 can be collapsed for shipment or storage when not installed on the casing. Another distinct advantage of the helical configuration is the wide range in casing sizes that one such wall cleaner will fit upon and operate effectively.
Although specific preferred embodiments of the present invention have been described in the detailed description above, the description is not intended to limit the invention to the particular forms or embodiments disclosed herein since they are to be recognized as illustrative rather than restrictive and it will be obvious to those skilled in the art that the invention is not so limited. For example, any number of cables or rows of apertures could be utilized with the apparatus of this invention. It is also clear that the sleeve can be of any desired diameter and the length of the cables can be tailored to match both the sleeve size and borehole size. The extension distance of the cables from the sleeve can be altered by altering the cables length or by altering the spacing between the apertures in the sleeve. Thus, the invention is declared to cover all changes and modifications of the specific example of the invention herein disclosed for purposes of illustration, which do not constitute departures from the spirit and scope of the invention.
What is claimed is:
1. Apparatus for cleaning well bores of drilling mud filtercake buildup comprising:
a cylindrical sleeve of generally larger inner diameter than the outer diameter of casing in the well bore;
said cylindrical sleeve having a plurality of apertures through the wall thereof around the periphery of said sleeve;
a plurality of braided cables;
each end of said braided cable having a bell-ended socket assembly swaged thereto, and each said bell-ended socket assembly having an initially cylindrically extending portion extending into one of said apertures in said sleeve and bradded over on the inside of said sleeve, thereby permanently attaching said cables to said sleeve;
each said cable being of sufficiently greater length than the distance between said apertures to which it is connected, thereby forming a stiff outwardly extending cable loop on the outer surface of said sleeve; and
means for securing said sleeve fixedly to a section of well casing.
2. The apparatus of claim 1 wherein said sleeve has two horizontal, parallel rows of apertures therethrough and each said cable loop has one end secured through an aperture in one row and the other end secured to an aperture in the other row, with said cable spanning two or more apertures which are not occupied by that particular cable loop, and with said cable loops arranged in a staggered, overlapping arrangement to provide a full 360' of bore wall contact cable area.
3. A method of constructing a well bore cleaning apparatus comprising the steps of:
drilling a plurality of apertures through the wall of a cylindrical sleeve which is adapted to slide over a well casing;
providing a plurality of stiff braided metallic cable lengths; swaging upon each end of each cable length a socket assembly having a flared midsection and a cylindrical longitudinally extending end, with said cylindrical end pointing away from said cable length;
inserting said cylindrical ends of said socket assemblies through appropriate apertures in said sleeves so as to result in a staggered, over-lapping plurality of looped cables extending outward from said sleeve; and
bradding said cylindrical ends of said socket assemblies over on the inside surface of said sleeve so as to secure said assemblies permanently in said apertures.
4. A method of attaching generally cylindrical cables to a relatively wide, thin sheet comprising:
forming openings in said sheet to receive said cables;
inserting the end of said cable to be attached to said sheet into a tubular sleeve;
swaging said sleeve down on said cable thereby clamping said cable securely within said sleeve;
simultaneously forming a belled rib on said sleeve while retaining a cylindrical extended end on said sleeve;
inserting said cylindricalend into one of said openings until said belled end abuts a surface of said sheet; and
bradding said cylindrical end over on the surface of said sheet opposite from the surface abutting said belled end. 5. A wellbore cleaning device comprising: means for encircling a casing string in relatively close fitting relationship, said encircling means having a plurality of holes through the wall thereof;
attachment means for securing said encircling means to the casing string;
a plurality of stiff cable means projecting outwardly from said encircling means; and
means for securing said stiff cable means fixedly to said encircling means, said securing means comprising a plurality of initially cylindrical sleeves each having a belled end formed by swaging said sleeve onto said cable means, and each said sleeve passing through one of said holes and being bradded over on the inside of said encircling means thereby securing each said sleeve to said encircling means in relatively normal orientation to the surface thereof.
6. The apparatus of claim 5 wherein said encircling means comprises a plurality of vertical bars arranged around the circumference of the casing and said attachment means comprises one or more circle clamps passing around said vertical bars and said casing and tightly securing said bars to said casing. I d
7. The apparatus of claim 5 wherein said encircling means comprises a helical strip passing helically around the casing and said attachment means comprises one or more circle clamps passing around said helical strip and the casing and tightly securing said strip to the casing.
8. The apparatus of claim 5 wherein said encircling means comprises a cylindrical sleeve adapted to slide over said casing and said attachment means comprises one or more threaded members passing through said sleeve in threaded relationship therewith and arranged to abut the casing and prevent movement of said sleeve with respect to said casing.
9. The apparatus of claim 5 wherein said cable means project straight outward radially from said encircling means and have one end attached to said encircling means, and one end free.
10. The apparatus of claim 5 wherein said cable means comprises a plurality of looped cables having each end thereof secured to said encircling means and being of sufficient length to form outwardly extending loops of cable on said encircling means.
11. The apparatus of claim 5 wherein said cable means comprises a plurality of looped cables and a plurality of outwardly straight cables both attached tosaid encircling means.