Platform crane

• US 4,081,932 A
• Filed: 06/21/1976
• Issued: 04/04/1978
• Est. Priority Date: 08/11/1975
• Status: Expired due to Term

• Current Assignee: Pool Corporation
• Original Assignee: Pool Corporation
• Inventors: Armstrong, James Eubank
• Primary Examiner(s): Bell, J. Karl
• Application Number:
  US05/698,119
• Time in Patent Office: 652 Days
• Field of Search: 52/111, 52/114, 52/116, 52/118, 52/645, 52/646, 61/46, 61/46.5, 173/28, 173/1, 175/5-10
• US Class Current: 52/111
• CPC Class Codes: B66C 23/52 Floating cranes floating dredgers E02F

Abstract

A mobile crane for use on an offshore oil well platform, comprising parallel base beams adapted to span the capping beams of the platform, and a pedestal and a rotating upper works movably mounted on the base beams. A method is described for erecting a workover rig on the offshore platform by means of the crane, and for expeditiously erecting workover rigs on a plurality of platforms in succession.

Claims

1. A method for constructing a rig on an offshore platform having a pair of substantially parallel horizontal capping beams and a deck-mounted crane comprising

lifting a pair of base beams with said deck-mounted crane and placing them to span said capping beams,

removably attaching said base beams to said capping beams,

lifting a pedestal of a second crane with said deck-mounted crane and placing it on said base beams,

removably attaching said crane pedestal to said base beams,

lifting a second crane rotating upper works with said deck-mounted crane and placing said works on the pedestal,

fastening said works to said pedestal, and

lifting elements of such a rig with said second crane and placing them on said capping beams.

2. A method as defined by claim 1 wherein both the second crane and the rig are lifted from a vessel alongside the platform.

3. A method as defined by claim 1 wherein the second crane is skidded along the base beams and then the base beams are skidded along the capping beams to a desired location.

4. A method of performing workover operations at a plurality of offshore platforms comprising

erecting a first crane on a first platform,

erecting a rig on the first platform by means of said first crane.

erecting a second crane on a second platform while operations are being performed by the rig on the first platform,

removing the rig from the first platform by means of the first crane,

removing the first crane from the first platform, and

erecting the rig on the second platform by means of the second crane.

5. A method as defined by claim 4 and including

erecting the first crane on a third platform while operations are being performed by the rig on the second platform.

6. A method of performing workover operations at a plurality of offshore platforms comprising

carrying a workover rig and two portable cranes in a vessel,

erecting the first portable crane on a first platform,

erecting the rig on the first platform by means of the first portable crane,

transporting the second portable crane on the vessel to a second platform and erecting the second portable crane on the second platform,

performing workover operations on the first platform while the second portable crane is being erected,

removing the workover rig from the first platform by means of the first portable crane and returning it to the vessel,

removing the first portable crane from the first platform and returning it to the vessel,

transporting the workover rig on the vessel to the second platform,

erecting the rig on the second platform by means of the second portable crane,

transporting the first portable crane to a third platform,

erecting the first portable crane on the third platform, and

performing workover operations on the second platform while the first portable crane is being erected on the third platform.

7. A method for constructing a portable mobile crane on an offshore platform having a fixed crane mounted thereon and a pair of substantially parallel horizontal capping beams comprising,

lifting a pair of base beams from a transport vessel with said fixed crane,

placing said base beams on said capping beams whereby the base beams span the capping beams,

releasably attaching the base beams to the capping beams,

lifting a crane pedestal from said transport vessel with said fixed crane,

placing said crane pedestal on the base beams,

releasably attaching the crane pedestal to the base beams,

lifting a crane upper works from said transport vessel with said fixed crane,

placing said crane upper works on said crane pedestal, and attaching the crane upper works to the crane pedestal.