Arctic caisson
AssigneeExxon Production Research Company
InventorBen G. Gerwick, Jr.
Life of this patent
Estimating the term…
Abstract
An offshore structure, adapted for operation in an ice infested arctic environment, includes a floating caisson that can be actively heaved in the water to break ice. The caisson comprises a radially tapered upper portion, preferably conically shaped. Means for vertically moving the caisson are provided so that the upper portion of the caisson can obliquely contact ice sheets and other ice masses with sufficient dynamic force to pierce and break the ice. A plurality of mooring lines anchored to the sea floor are attached to the caisson to secure its position in the water.
Claims19
An offshore structure which is adapted for operation in an arctic sea containing floating ice masses comprising:
- a floating caisson, said caisson having a radially downwardly tapered upper ice-breaking portion;
- a plurality of mooring lines secured at a first end to said caisson and at a second end to the sea floor;
- and
- means for vertically moving said caisson a sufficient distance and with sufficient dynamic force so that said upper portion of said caisson obliquely contacts and breaks said ice masses.
An offshore structure which is adapted for drilling operations in an ice infested arctic sea comprising:
- a floating caisson, said caisson having an upper portion which is radially downwardly tapered at an angle of between about 30.degree. and 60.degree. from the vertical;
- a plurality of mooring lines secured at a first end to said caisson and at a second end to the sea floor;
- and
- means for tensioning and untensioning said mooring lines so that said caisson can be moved vertically a sufficient distance and with sufficient dynamic force to permit said upper portion of said caisson to obliquely contact and break floating ice masses which impinge upon said caisson.
In a method conducting drilling operations from a floating caisson in an arctic sea containing floating ice masses, said caisson having a radially downwardly tapered upper ice-breaking portion, the improvement comprising vertically moving said caisson a sufficient distance and with sufficient dynamic force so that the upper portion of said caisson obliquely contacts and breaks said ice masses.
In a method of conducting drilling operations from a floating caisson in an arctic sea containing floating ice masses, said caisson having a radially downwardly tapered upper ice-breaking portion and being secured to the sea floor by a plurality of mooring lines attached to said caisson, the improvement comprising:
- sequentially tensioning and untensioning said mooring lines to vertically move said caisson a sufficient distance and with sufficient dynamic force so that the upper portion of said caisson obliquely contacts and breaks said ice masses.
Dependencies are inferred from the claim text.