Method and apparatus for repair of wells utilizing meltable repair materials and exothermic reactants as heating agents

Abstract

A method and apparatus are described for creating a fluid seal in a subterranean well structure having a fluid seal defect. The method comprises introducing a meltable repair material proximate a structure in a subterranean well which has a fluid seal defect or enhanced seal capacity is required or it is desired to temporarily or permanently hydraulically isolate a portion the well or strengthen the structural integrity of well tubulars or tubular hangers. Exothermic reactant materials are located proximate the meltable repair material. The exothermic reactant material is ignited or an exothermic reaction otherwise initiated which supplies heat to and melts the meltable repair material into a molten mass. The molten mass flows and solidifies across the structure and the fluid seal defect to effect a fluid seal in the subterranean well structure or the structural integrity is enhanced. Examples of preferred exothermic reactant materials include thermite, thermate, fusible chemical reactants such as ammonium chloride and sodium nitrate, and oxidizers and accompanying hydrocarbon based fuels. Examples of preferred meltable repair materials include solder or brazing materials and eutectic metals which expand upon cooling and solidifying from a molten state.

Description

TECHNICAL FIELD [0001] The present invention relates generally to the repair of gas and oil wells, and more particularly, to those repairs which utilize eutectic metal plugs to seal existing leaks or to form temporary or permanent plugs for the purpose of isolating pressure within a portion of a well. BACKGROUND OF THE INVENTION [0002] During the life of a well, it is often necessary to isolate parts for the well to 1) shut off unwanted production of water or gas, 2) prevent communication of pressure to surface through annular communication, or 3) isolate portions of the well from acid or hydraulic stimulation to facilitate selective stimulation. Examples of structures having fluid seal defects needing repair may include leaking cemented annuli, leaking plugs such as cement and mechanical plugs, leaking abandoned or unwanted water or gas producing perforations, high pressure intervals which are to be temporarily or permanently isolated and gravel-packed production intervals which ar...

AI Technical Summary

Benefits of technology

[0007] A method and apparatus are described for effecting a fluid seal in a subterranean well structure. The method comprises introducing a meltable repair material proximate a structure in a subterranean well where a fluid seal is desired. Exothermic reactant materials are located proximate the meltable repair material. The exothermic reactant is ignited or otherwise initiated to create an exothermic reaction which supplies heat to and melts the meltable repair material into a molten mass. The molten mass flows and solidifies across the structure and the fluid seal defect to effect a fluid seal in the subterranean well structure. Examples of preferred exothermic reactant materials include thermite, thermate and highly exothermic chemical reactions such as the reaction between ammonium chloride and sodium nitrite. Examples of preferred meltable repair materials include solder and eutectic metals which expand upon cooling and solidifying from a molten state Also, the exothermic reactant materials may include oxidizers and separate fuels which can be combined and ignited to pro

Problems solved by technology

The repair tool may be introduced into a well and

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