Method for actuating a tool in a well at a given depth and tool allowing the method to be implemented
AssigneeSchlumberger Technology Corporation
InventorGerard Boisson
Life of this patent
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Abstract
A downhole tool is actuated at chosen well depth by selection of a control element that melts at the chosen depth well temperature. In one form of tool, a fusible pin melts to release spring-loaded jaws which move against an expansion cone to anchor the tool in the well. In another form, a fusible receptacle cover melts to release a quantity of dense fluid under action of gravity. Suitable control elements are formed of bismuth, with lead and zinc.
Claims11
A method for actuating a tool in a well at a chosen depth, comprising the following steps:
- determining the temperature of the well at the chosen depth;
- equipping the tool with a central element comprising a material capable of melting at a temperature near the temperature thus determined;
- lowering the tool into the well to the chosen depth;
- and
- maintaining the tool in the well at the chosen depth until actuation of the tool by the melting of the control element material.
A downhole tool designed to be actuated in response to the temperature of a well at a chosen well depth, comprising:
- a body member adapted to be lowered into a well at the end of a cable;
- energy storage means associated with said body member for storing energy in said tool prior to lowering said body member into said well;
- and
- control means comprising a material that melts at a temperature near the temperature of said well at said chosen depth and cooperable with said energy storage means for releasing said stored energy to cause actuation of said tool.
A tool as defined in claim 11, wherein said alloy comprises mainly bismuth, as well as at least one of the elements lead and zinc.
Dependencies are inferred from the claim text.