US 3129759 A
Description (Le texte OCR peut contenir des erreurs.)
April 2l, 1964 B. J. TxLLMAN CASING ALIGNMENT AND CEMENTING TOOL AND METHOD B. J. TILLMAN April Z1, 1964 CASING ALIGNMENT AND CEMENTING TOOI.l AND METHOD Filed April 5. 1961 2 Sheets-Sheet 2 RNEY United States Patent O 3,129,759 CASING ALIGNMENT AND CEMENTING TOL AND METHOD Bill J. Tillman, Midland, Tex., assigner to Halliburton Company, Duncan, Giua., a corporation of Delaware Filed Apr. 5, 196i, Ser. No. 160,980 2 Claims. ((11. 16d-14) This invention relates to a method and apparatus for aligning parted sections of a casing string in a well bore.,
Wells utilized in the production of sub-surface fluids are normally lined with a sectional length of casing commonly referred to as a string. Infrequently, because of corrosion or imposed mechanical stress, a break will occur in the casing string deep within the well bore. When this contingency occurs, the lower parted section of the string may drop and thus separate a short distance from the upper section. As there is normally an annular space between the casing and the wall of the well bore, the parted end thus freed may become inclined or axially disoriented with respect to the upper parted section.
A parted casing requires immediate attention to prevent the occurrence of further and more extensive damage to a well bore. In the parted condition, the casing will permit the ingress of undesirable formation lluids and debris through the exposed ends of the break. Additionally, of course, where the parted section has become inclined, it will interfere with tubing or pumping apparatus which may be in the well and will prevent the lowering of apparatus into the well.
Several attempts have been made to provide a satisfactory technique for repairing broken casing in well bores. In one technique, the upper section of the parted casing string is removed from the well bore, a tubular section of large diameter is aixed to its lower end, and it is then lowered back into the well bore to position the large diameter section over the upper end of the lower parted casing section. Cement is then forced down through the upper section and into the space between the upper end of the lower casing section and the enlarged section on the lower end of the upper casing section as well as between this enlarged section and the formation wall. The cement is allowed to rigidify and the interior of the casing string is then drilled out. As is readily apparent, however, this technique suffers from two principal disadvantages. It is necessary to remove the upper portion of the parted casing string which is time consuming and extensive equipment and personnel are required. Additionally, there would be a distinct likelihood of encountering difliculty in lowering the upper casing section with the enlarged lower end portion due to interference presented by the well bore irregularities.
A more recent concept of casing repairing avoids the removal of the upper parted casing section. In this technique, a uid expandable tubular member having a lower end tapering downwardly to one side to form a wedge is lowered on the end of a tubing string through the upper casing section. When the casing break is reached, the tool is oriented to allow the wedge to enter the lower casing section. The tool is positioned with the lluid expandable portion extending into adjacent ends of the parted casing sections. By means of pressurized fluid introduced through the tubing string, the tool is radially enlarged and forced against the walls of the adjacent casing ends to effect absolute casing alignment. A perforating gun is then lowered into the tool and detonated to provide radially extending outlets passing through the wall of the tool and the casing. The perforating gun is then withdrawn, after which cement is forced down the tubing string into the tool, through the radial outlets and into the annular space between the parted casing ends and the well bore. After the cement has been allowed to harden, the tubing ICC string is disengaged from the tool and withdrawn from the casing and the tool then drilled out.
While this technique is advantageous in that it does not require removal of the casing, it presents serious operational problems. In being liuid expanded, the tool is likely to impose a severe radial stress on the already weakened ends of the parted casing sections. This hydraulically created stress is aggravated by the subsequent explosive shock resulting from the gun perforation. Such manipulative steps are likely to effect material weakening of the casing and occasion further breaks. Additionally, the steps involved provide for an unduly protracted repairing operation and require the use of highly specialized equipment and personnel which may not be readily available.
Recognizing the need for an improved technique for repairing parted casing, it is an object of this invention to provide a method and apparatus for aligning parted sections of a casing string in which repair is effected without imposing excessive stress on the parted casing sections.
It is a further object of this invention to provide such a method and apparatus in which inexpensive equipment is utilized which is readily available at field locations.
It is an additional object of this invention to provide such a method and apparatus in which manipulative steps are maintained at a minimum level so as to achieve maximum speed and efficiency in the repairing operation.
In the technique contemplated in this invention, an aligning tool is assembled beneath an expandible packer on the lower end of, and in axial alignment with, a pipe string. This aligning tool has a lower end of generally conical configuration so as to provide a central guide point. Extending axially upward from the conical end of the tool are a tubular alignment wall of less diameter than the casing to be repaired; and within this aligning wall, an axially extending passage. A plurality of radially extending openings passing through the aligning wall provide liuid communication between the passage and the exterior of the tool.
The aligning tool is vlowered into the casing string to allow the conical end to guide the tool into the lower parted casing section. The tool is then positioned so that the aligning wall extends into and aligns adjacent ends of the parted sections. The packer is then expanded into sealing engagement with the inner wall of the upper parted section of the casing string and fluid cement then forced downwardly under pressure through the pipe string into the passage of the aligning tool. From this passage the cement passes outwardly through the radially extending opening to the exterior of the tool and from there passes between the adjacent ends of the parted casing sections into the annular space between the parted sections and the adjacent well bore. After the cement has rigidified in this annular space to support the parted casing sections in aligned relationship, the pipe string is disconnected from the packer and tool and withdrawn from the casing string, after which the packer and tool are drilled out.
ln describing the invention, reference will be made to a preferred apparatus embodiment illustrated in the accompanying drawings in which:
FIGURE 1 is a longitudinal sectional view through a well bore showing a repair apparatus being lowered into a parted casing string, Y
FIGURE 2 illustrates the apparatus positioned to align parted casing sections,
FIGURE 3 illustrates the apparatus during the cementing phase of the repairing operation,
FIGURE 4 represents the repaired casing string, and
FIGURE 5 is an enlarged longitudinal sectional view of the aligning tool of the apparatus.
In FIGURE l, a casing string in well bore 1 is shown which has parted so as to leave lower section 2 separate from and inclined relative to upper section 3.
To effect the alignment and repair of the casing, an apparatus is assembled as shown in FIGURES l and 2 to include a radially expansible squeeze packer d and an aligning tool 5. Packer 4 and tool 5 are carried on the lower end of a pipe string 6.
Aligning tool 5, shown in an enlarged section in FIG- URE 5, is elongate in character and includes a generally conical end 7, a tubular central conduit or uid passage 8, and a thin tubular aligning wall 9. Conduit 8 and aligning wall 9 extend coaxially upward from conical end 7. Conduit S is fabricated from tubing of the type included in pipe string 6 so as to deiine a continuation of the conduit provided by this string and be readily connectable to the string. Aligning wall 9 is of slightly less diameter than the casing so as to be freely slidable therethrough. In fabricating the tool, the tubular aligning wall 9 is positioned over the central conduit 8 and its ends are beveled to provide the lower conical end 7 and upper neck 1t) which joins with the exterior of the upper end of the conduit 8.
Tubular aligning wall 9 is formed of easily worked material such as thin aluminum. To provide support for this thin and structurally weak wall, the annular space between central conduit 8 and aligning wall 9 is lled with cementitious material 11.
A plurality of radially extending openings 12 are bored in the tool so as to extend through the aligning wall 9, cementitious material 11, and central conduit S and thus provide uid communication passages between the interior and exterior of the tool.
Aligning tool is secured below radially expansible packer 4 at coupling 13. Packer 4 is a conventional squeeze packer of the type disclosed in United States Morrisett Patent 2,589,506. This packer has a fluid passage extending centrally and longitudinally therethrough and carries radially expansible packer elements 14 and slips 15. A conventional pipe operated setting tool 16 is associated with the packer 4. This tool includes a setting sleeve 17 engageable with the upper end of the packer and drag springs 1S frictionally engaging the inner wall of the casing string as is also shown in the Morrisett patent. Setting tool 16 is threadably mounted on the tubing string 6. With the setting tool 16 restrained against rotational movement by drag springs 18, rotation of tubing string 6 is elective to cause relative longitudinal movement between the string and the tool 16. Such movement causes sleeve 17 to advance downwardly relative to packer 4 to eiect longitudinal compression and consequential radial expansion of packer elements 14 into sealing engagement with the inner wall of the casing. To enable release of the pipe string 6 from the packer and aligning tool, a coupling 19 is employed. This coupling conventionally includes a left hand back-off thread as opposed to the right hand threads in the other pipe string couplings. With this arrangement, by imparting a right hand rotation and a lifting force to the pipe string 6, the string will be disconnected from the packer and aligning tool at the coupling 19.
With the apparatus assembled as shown, it is lowered by pipe string 6 into upper section 3 of the casing string. As the aligning tool 5 approaches the casing break 20, the conical end 7 on the lower end of the tool guides the tool into the lower, parted casing section 2. As the aligning wall 9 is of only slightly less diameter than the casing, it will be effective to substantially align sections 2 and 3 when positioned so as to extend into their adjacent ends. Through eld testing, it has been found that where a 7 inch casing has parted, satisfactory results are achieved by employing a tubular aligning wall having a 6 inch outer diameter.
With the tool 5 thus positioned to align the ends of casing sections 2 and 3, the setting tool 16 is operated by rotating the pipe string 6 so as to radially expand packer elements 4 into sealing engagement with the inner wall of the casing section 3 as illustrated in FIGURE 2. In this manner, the portion of casing string 3 above the repair apparatus is edectively segregated fromthe break zone. Cement is then pumped under pressure downwardly through pipe string 6 and packer 4 into the central conduit 8 of the aligning tool 5. Cement in this axially extending passage then moves radially outward through openings 12 to the exterior of the tool 5. The cement then passes through the casing break 2t) into the 4annular space between the ends of casing sections 2 and 3 and the well bore in the manner shown in FIGURE 3. The cement thus positioned, as shown in FIGURE 3, is allowed to harden. The tubing string is then raised and rotated to the right to break the coupling 19, following which the pipe string 6 may be raised and removed from the casing. The interior of the casing string may then be cleared by drilling out the packer, its associated setting tool, and the aligning tool to leave the fully repaired casing as shown in FIGURE 4t l I Having described the method and apparatus employed in this invention, the advantages inuring to their characteristics are apparent. The conical end of the aligning tool provides a central guide nose which will guide the tool into the lower parted casing section notwithstanding the rotational orientation of the tool. With the align= ing tool of a diameter only slightly less than that of the interior of the casing to be repaired, it may merely be lowered into position to effect the desired alignment. AIn operating the tool, there is no mechanical or explosive force imposed by the tool upon the ends of the parted and weakened casing sections which might inflict further damage, weakening, or breaking. The use of the packer above the apparatus effectively contines the cementing operation to the repair Zone and avoids unnecessary contamination of the interior of the upper casing section.
The aligning tool is particularly unique with respect to its ease of fabrication. The components employed, i.e. the tubular central conduit 8 and the thin aligning wall 9 are merely conventional tubular stock readily available in the field. The bulk of the tool is formed by cementitious material 11 making it easy to drill out.
A particularly significant advantage resides in the minimum manipulative steps which are required during the repair operation. In eiect, it is merely necessary to lower the tool into aligning position, force cement into the break zone, remove the tubingstring, and drill out the casing. These operations may be performed with readily available field equipment with minimum personnel in a short period of time. This expeditious and etticient technique effects a substantial saving in repair costs and reduces considerably the shut down time required for repair.
While the invention has been described in connection with a preferred embodiment of the apparatus, certain minor modiiications will readily occur to those skilled in the art which are well within the scope of the invention as deiined in the appended claims.
l. In a method of aligning parted sections of a casing string in a weil bore, the steps comprising: assembling an aligning tool beneath an expandable packer on the lower end of and in axial alignment with a pipe string, said aligning tool having a lower end of generally conical coniiguration, a tubular aligning wall of less diameter than said casing extending axially upward from said lower end, an axially extending passage communicating with the interior of said pipe string, and a plurality of radially extending openings providing uid communication between said passage and the exterior of said tool; lowering said aligning tool into said casing string to allow said conical end to guide said tool into the lower parted section of said casing string; positioning said aligning tool so that the aligning wall extends into and substantially aligns adjacent ends of said parted sections; expanding said packer into sealing engagement with the inner wall of tne upper parted section of said casing string; forcing uid cement under pressure downwardly through said pipe string into said passage of said aligning tool whereby it may pass through said radially extending openings, between adjacent ends or" said parted sections, and into the annular space between said parted sections and the adjacent well bore wall; allowing said cement to rigidify in said annular space; disconnecting said pipe string from said packer and tool and withdrawing it from said casing string; and thereafter drilling out said packer and tool.
2. An apparatus for aligning parted sections of a casing string in a well bore comprising: an elongate aligning tool including a generally conical guide end, a tubular central conduit coaxial with said guide end and extending upwardly therefrom, a thin, tubular aligning wall comprising the outermost peripheral surface of said tool, said aligning wall being coaxial with said guide end and dening an integral, upwardly projecting, extension thereof, said aligning wall being of greater diameter than said central conduit and less diameter than said casing string, but of sufficient diameter to substantially align the parted sections of a casing string when extending therebetween, the space between said central conduit and said aligning wall being lled with cementitious material to support said aligning wall, and a plurality of openings extending radially of said tool through said central conduit, cementitious material, and aligning wall; conduit means connected to said central conduit of said tool and extending upwardly therefrom, said conduit means including disconnectable coupling means at its upper end for connection with the lower end of a pipe string of substantially the same diameter as said tubular central conduit of said aligning tool; and radially expansible packer means operably independent of said aligning tool and carried by said conduit means.
References Cited in the le of this patent UNITED STATES PATENTS 2,092,041 Armentrout et al. Sept. 7, 1937 2,644,523 Brown July 7, 1953 2,734,580 Layne Feb. 14, 1956 2,751,022 Baker et al. June 19, 1956
Citations de brevets