Coupling assembly for submarine casing sections

{
  "publication_number": "US4073511A",
  "country": "US",
  "kind": "A",
  "title": "Coupling assembly for submarine casing sections",
  "abstract": "This invention relates to a coupling assembly by which sections of well casing disposed beneath the floor of the sea or ocean can be detached from each other at a time when a well is to be cemented in, and it is desired to remove the wellhead structure and the sections of casing extending thereabove to a drilling platform. The coupling assembly comprises an upper casing section, a lower casing section, and an external coupling sleeve slidably telescoped over the lower end of the upper casing section and the upper end of the lower casing section. An internal collar is slidably positioned within the external sleeve at a location between the casing sections, and includes an annular ring projecting over and around an end portion of the lower casing section within the external coupling sleeve. An expandable locking element is positioned between said annular ring and the upper end portion of the lower casing section. The annular ring and the expandable locking element bear against an internal shoulder formed in the external coupling sleeve, and function to interlock the external coupling sleeve to the lower casing section. A frangible retaining element extends between and interengages the internal collar to the external coupling sleeve when the annular ring and expandable locking element are in their interlocking status, and is severable to permit the internal collar to be moved axially within the external coupling sleeve to facilitate disengagement of the coupling sleeve from the lower casing section.",
  "claims": [
    "1. A coupling assembly for coupling spaced aligned casing sections together comprising: an external coupling sleeve having a first open end adapted to telescopingly engage an open end of a first casing section, and having a second open end adapted to telescope over an open end portion of a second casing section, said coupling sleeve further including annular shoulder means spaced inwardly from the second open end thereof; an internal tubular collar slidably positioned in said external coupling sleeve and including: an annular locking ring forming an end of said tubular collar bearing against said annular shoulder and movable as a part of the tubular collar with the remainder of the tubular collar; and engaging means for engaging a tool extended through the first casing section into the internal collar to facilitate sliding said collar in said coupling sleeve away from said annular shoulder when said tool is pulled toward the first casing section; an expandable locking element constrictively positioned within said annular locking ring, bearing against said annular shoulder, and adapted to interlock with the outer surface of said second casing section; and a shearable element interconnecting said sleeve and internal tubular collar, and adapted to shear when said collar is slidably urged upwardly toward said first open end of said coupling sleeve to a position free of said locking element.",
    "2. A coupling assembly as defined in claim 1 wherein said expandable locking element comprises a split band having radially inwardly projecting teeth on the radially inner side thereof, and including an axially beveled radially outer surface extending between a first end of said band bearing against said shoulder and a second end of said band of lesser radial thickness than said first end of said band.",
    "3. A coupling assembly as defined in claim 1 wherein said coupling sleeve includes a diametric constriction in the bore thereof between said second open end thereof and said shoulder adapted for limiting the distance said sleeve can telescope over said second casing section.",
    "4. A coupling assembly as defined in claim 1 wherein said engaging means comprises an annular groove in the internal wall of said collar between the opposite ends thereof.",
    "5. A coupling assembly as defined in claim 1 wherein said shearable element comprises a shear pin extending into aligned pin holes in said collar and coupling sleeve.",
    "6. A coupling assembly as defined in claim 2 wherein said coupling sleeve includes a diametric constriction of the bore thereof between said second open end thereof and said shoulder adapted for limiting the distance said sleeve can telescope over said second casing section.",
    "7. A coupling assembly as defined in claim 6 wherein said engaging means comprises an annular groove in the internal wall of said collar between the opposite ends thereof.",
    "8. A coupling assembly as defined in claim 7 wherein said shearable element comprises a shear pin extending into aligned pin holes in said collar and said coupling sleeve.",
    "9. A coupling assembly as defined in claim 8 wherein: said first open end of the coupling sleeve passes outside of, and around, the open end of said first casing section; and said internal tubular collar has a beveled end opposite its end carrying said annular locking ring means for cooperating with said end of said first casing section for excluding accumulations of cement from therebetween when said collar is moved toward said first casing section.",
    "10. An oil and gas well comprising: a vertically extending casing string including an upper portion having a first casing section at the lower end thereof, and a lower portion having a second casing section at the upper end thereof, said second casing section having an enlargement around the outer side thereof; a tubular sleeve having an upper end telescoped over and secured around said first casing section, and depending from said first casing section and including an upset lower end of enlarged diameter secured over the open upper end of said second casing section, said tubular sleeve further including an axially facing, radially extending shoulder projecting radially outwardly from the external wall of said second casing; a radially expandable, annular locking element extending around, and engaging at the inner periphery thereof, the upper end of said second casing section; means around said locking element restricting it, by compression, to a relatively small diameter, and vertically movable in said tubular sleeve from said shoulder to the lower end of said first casing section to a position free of said locking element; and means releasably securing said locking element restricting means against said shoulder."
  ],
  "cpc": [
    "F16L 25/00",
    "E21B 33/038"
  ],
  "assignees": [
    "HAAS BILLIE G",
    "HAAS CAROL B"
  ],
  "filing_date": "1976-07-22",
  "publication_date": "1978-02-14",
  "grant_date": "1978-02-14",
  "priority_date": "1976-07-22",
  "application_number": "US-70783076-A",
  "family_id": "24843329",
  "citations": [
    "US2778433A",
    "US3321217A",
    "US3727948A",
    "US3926457A"
  ]
}