Ice slot maintenance
AssigneeShell Oil Company
InventorDean P. Hemphill
Life of this patent
Estimating the term…
Abstract
During winter construction of offshore Arctic pipelines, it is frequently necessary to cut an ice slot in order to lay a pipeline on the sea bottom. Once such slots are cut, they rapidly freeze over, so that it is necessary to remove ice from the slot during the pipelaying time span. The present invention provides a method and apparatus for removing the newly formed ice from the ice slot. An inclined plane, sized to fit within the ice slot width to be maintained, penetrates below the surface of the water within the slot and to a depth at or below the underside of the newly formed ice on the water's surface. By moving the plane along the surface, the ice is raised, broken, and then conveyed upward and then to one side out of the ice slot as spoil.
Claims20
A method for laying a pipeline beneath ice covering water comprising:
- cutting an elongated slot in the ice;
- removing newly formed ice from the ice slot until the pipeline can be laid through the ice slot by
- positioning an inclined plane in the ice slot to a depth no less than the interface of the newly formed ice and underlying water, the inclined plane being at least partly supported by means located adjacent to the ice slot;
- moving the inclined plane laterally along the length of the ice slot;
- sliding the newly formed ice up the inclined plane and out of the water;
- and
- laying the pipeline through the ice slot.
An apparatus for laying a pipeline beneath ice covering water comprising:
- means for removing newly formed ice from the ice slot until the pipeline can be laid through the ice slot, comprising
- an inclined plane;
- means for positioning the inclined plane in the ice slot to a depth no less than the interface of the newly formed ice and underlying water, the inclined plane being at least partly supported by means adjacent to the ice slot;
- means for moving the inclined plane laterally along the length of the ice slot, thereby sliding the newly formed ice up the inclined plane and out of the water ;
- and
- means for laying the pipeline through the ice slot.
Dependencies are inferred from the claim text.