A method for cementing a wellbore having a lost circulation zone includes installing a cement basket around a casing string having a casing diameter, and running and setting the casing string in the wellbore. The cement basket is set in proximity of and up hole from the lost circulation zone. The method includes pumping a cement slurry, through the casing string, to a first depth downhole from the cement basket, running a first tubing, having a tubing diameter, into an annulus between the casing string and the wellbore, and pumping the cement slurry, through the first tubing, to a second depth up hole from the cement basket. The tubing diameter is less than the casing diameter.

A method for cementing a wellbore having a lost circulation zone includes installing a cement basket around a casing string having a casing diameter, and running and setting the casing string in the wellbore. The cement basket is set in proximity of and up hole from the lost circulation zone. The method includes pumping a cement slurry, through the casing string, to a first depth downhole from the cement basket, running a first tubing, having a tubing diameter, into an annulus between the casing string and the wellbore, and pumping the cement slurry, through the first tubing, to a second depth up hole from the cement basket. The tubing diameter is less than the casing diameter.

A chemical reaction heat source for use in heaters used in down-hole application. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperature down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A chemical reaction heat source for use in heaters used in down-hole application. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperature down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A wellbore tool system for use within a wellbore includes a stage packer shoe, having a lower body extending from a first end to a second end; an upper body attached to the lower body at the second end; and circulation ports extending through a thickness of the upper body; a metal cup having a predetermined diameter as determined by a diameter of the wellbore; the metal cup secured around a periphery of the lower body of the stage packer shoe such that the metal cup extends away from the periphery; the metal cup is to engage with the wellbore enough to have differential pressure holding capability between the stage packer shoe and the wellbore; and the differential pressure of the metal cup is dependent on a strength of the cup and the wellbore with which the metal cup is engaged.

A chemical reaction heat source for use in heaters used in down-hole applications is provided. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperatures down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A chemical reaction heat source for use in heaters used in down-hole applications is provided. The heat source has a fuel composition that comprises thermite and a damping agent. The use of the thermite mix enables the heaters of the present invention to generate hotter temperatures down wells. This in turn allows the use of Bismuth/Germanium alloys, which have higher melting points, to enable the production of plugs for the abandonment of deeper wells where subterranean temperatures are higher.

A flow restrictor for restricting flow in an annulus, the flow restrictor comprising a body and a restrictor assembly mounted on the body, wherein the restrictor assembly is actuatable between a run-in configuration and a set configuration in which at least a portion of the restrictor assembly is radially splayed to thereby substantially restrict flow in the annulus, and wherein the flow restrictor is actuatable by fluid flow over the restrictor assembly above a threshold flow rate to actuate the restrictor assembly from the run-in configuration to the set configuration.

A flow restrictor for restricting flow in an annulus, the flow restrictor comprising a body and a restrictor assembly mounted on the body, wherein the restrictor assembly is actuatable between a run-in configuration and a set configuration in which at least a portion of the restrictor assembly is radially splayed to thereby substantially restrict flow in the annulus, and wherein the flow restrictor is actuatable by fluid flow over the restrictor assembly above a threshold flow rate to actuate the restrictor assembly from the run-in configuration to the set configuration.

A plug for plugging wells, and in particular oil and gas wells, is provided. The plug has a plug body formed from an outer metal tube of a reduced thickness. The plug also has reinforcement means, attached to an inner surface of the outer tube, that give the plug a cross-sectional structural strength that is at least equivalent to that of a thicker metal tube. The plug has a central heater receiving void located along the axis of the plug to enable a plug deployment heater to be received therein. Also provided is a plug assembly with a variable cross-sectional area in a plane perpendicular to the plane in which the assembly is deployed during the plugging of underground conduits.