Abstract: The present invention provides an approach for drilling offshore arctic wells in areas covered by floating ice. A grounded spray ice drilling structure having an inner drilling platform portion and an outer barrier portion which are contiguous is constructed by withdrawing water from beneath the ice sheet and spraying the water through the air when the air is below the freezing temperature of the water. This causes the water to freeze into spray ice as it passes through the air. The resulting spray ice is deposited on the ice sheet to build up the grounded spray ice drilling structure. The outer barrier portion is built up to a greater freeboard than the inner drilling platform portion, and is adapted to laterally confine the inner drilling platform portion and to protect the inner drilling platform portion from natural ice forces.

Abstract: A method is provided for constructing spray ice barriers to protect offshore structures in a frigid body of water from mobile ice, waves and currents. Water is withdrawn from the body of water and is sprayed through ambient air which is below the freezing temperature of the water so that a substantial amount of the water freezes as it passes through the air. The sprayed water is directed to build up a mass of ice having a size and shape adapted to protect the offshore structure. Spray ice barriers can also be constructed for the containment of pollutant spills.

Abstract: A method and apparatus for mitigating or eliminating the frost heave of refrigerated pipelines buried in frost-susceptible soil are provided. A blanket of heat absorbent material is placed over the pipeline on the surface of the soil to increase the flow of heat into the region surrounding the pipeline. This technique may be used in combination with other frost heave mitigation techniques, such as insulating the pipeline and supporting the pipeline with a heave resistant bedding material.

Abstract: An improved offshore arctic structure is disclosed which controls the horizontal forces exerted by impinging ice masses. The structure includes lesser sloped wall sections near the sea floor and steeper sloped wall sections near the water surface. Thus, the deep pressure ridges contact the lesser sloped wall sections and the shallower ice sheets contact the steeper sloped wall section. The slope of all wall sections is chosen so as to keep all horizontal loads due to impinging ice masses below a preselected design maximum.

Abstract: The invention relates to a water navigable vessel having an ice-breaking bow and a rotatable screw mounted on the front on the bow for the purpose of advancing the vessel up onto an ice layer and failing the ice layer in flexural bending. The rotatable screw includes ice-cutting blades which form grooves within the top of said ice layer thus translating the rotational energy of said screw into a generally horizontal, (longitudinal) tractional force which pulls or drags the bow of said vessel forward and over said ice layer and, thereby, utilizes the mass of said bow to impart a downward gravitational force upon said layer of ice to cause it to fail flexurally.

Abstract: An artificial ice structure for use as, for example, a base for oilfield operations or a road, is constructed in an offshore frigid environment where the water is covered by a sheet of floating ice. A berm or dike enclosing a predetermined area is built on the ice sheet to contain flood water and a trench is cut through the ice sheet around the perimeter of the dike to separate the predetermined area from the parent ice sheet and thereby form an island. The island of predetermined area is flooded with water and the water is allowed to freeze and weight the island down until essentially the entire ice mass of the island is resting on the ground underlying the body of water. After the structure is grounded, flooding with water is continued until the island has sufficient mass, in combination with other defensive measures, to resist the forces imposed by movement of the surrounding fast ice.

Abstract: In order to prevent damage due to frost heaving of a refrigerated gas pipeline which traverses frost-susceptible soil resulting from horizontal ice lense formation beneath the pipeline, heat pipes are located in diametrically opposed pairs, one on either side of the pipeline. Frost bulbs are formed in the soil around each heat pipe adjacent to the pipeline, causing the horizontal ice lenses to be formed further below the pipeline. Heaving rate is reduced due to the lower temperature gradient in the vertical direction, a greater overburden above the horizontal ice lenses and a reduced water supply directly beneath the pipeline. Also, lateral expansion of the frost bulbs provides opposing horizontal forces to counteract the upward force of the horizontal ice lenses.

Abstract: A method and apparatus is disclosed for forming and maintaining an offshore ice structure in an Arctic environment. The structure is formed by a series of caissons oriented in a ring forming an enclosure capable of retaining a predetermined amount of water and thereby defining an ice island when frozen. The structure includes a passive heat extracting system which removes heat from the water within the enclosure and from the soil immediately below the enclosure and the caissons thereby advancing the freezing of the soil beneath the enclosure and water within the enclosure. In this manner, the lateral stability of the structure is improved by providing a single frozen mass of water and soil bonded in unitary construction increasing the foundational base of the structure. In addition, refrigeration means are provided to prevent surface melting of the ice within the enclosure and preserve the integrity of the ice structure during warmer months.

Abstract: An air convection pile for transferring heat from a medium surrounding the lower end of the pile is disclosed to the colder ambient air. A pipe of sufficient length to extend from the air-medium interface downward into the medium is adapted to be opened to the ambient air near its upper end. A flow dividing partition is placed longitudinally within the pipe. The partition has two longitudinal edges which contact the inner wall of the pipe to divide the interior volume of the pipe into two flow channels. The partition is adapted near the lower end of the pipe to allow the flow of air between the flow channels. Apparatus for controlling the flow of air through the pile is also disclosed. A hood encloses the open upper end of the pile. It is adapted to allow the flow of air between the ambient air and the flow channels. Within the hood, there is a temperature responsive, or manual, means for closing off the flow channels from the ambient air.

Abstract: An artificial ice structure for use as, for example, a base for oilfield operations or a road, is constructed in an offshore frigid environment where the water is covered by a sheet of floating ice. A berm or dike enclosing a predetermined area is built on the ice sheet to contain flood water and a trench is cut through the ice sheet around the perimeter of the dike to separate the predetermined area from the parent ice sheet and thereby form an island. The island of predetermined area is flooded with water and the water is allowed to freeze and weight the island down until essentially the entire ice mass of the island is resting on the ground underlying the body of water. After the structure is grounded, flooding with water is continued until the island has sufficient mass, in combination with other defensive measures, to resist the forces imposed by movement of the surrounding fast ice.