One trip system to set an alloy seal and mill through

Patent metadata

Field	Value
Publication number	US-12338713-B2
Application number	US-202318243463-A
Country	US
Kind code	B2
Filing date	Sep 7, 2023
Priority date	Sep 7, 2022
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

The present invention provides a tool assembly system for use in a single trip downhole operation in which an alloy plug/seal is set and then at least partially milled through. The system comprises a tubular chemical heater with a mill that has at least one flow port and a tubular mandrel arranged on the outside of the heater at up-hole and down-holes ends of the heater respectively and whereby the heater is removably retained within the mandrel so that the mill can be subsequently repositioned to work on the mandrel once the alloy plug/seal has been formed. The present invention also provides an associated method of forming an alloy plug/seal and milling it at least partially through in a single trip.

First claim

The invention claimed is:

1. A downhole tool assembly system for use in deploying alloy plugs and/or seals in oil and gas wells, said system comprising:
a tubular heater with an exothermic chemical reaction heat source, wherein the tubular heater is provided with a running tool at an up-hole end thereof;

a tubular mandrel in which a down-hole portion of the tubular heater is removably retained such that the tubular heater and the tubular mandrel are in thermal communication; and
a mill arranged on the outside on the tubular heater at a location proximal to the up-hole end thereof and separated from the tubular mandrel by a clearance space, wherein the mill comprises at least one flow port that by-passes the tubular heater and provides access to the clearance space from an up-hole location.

2. The system of claim 1 , wherein the tubular heater is retained in position within the tubular mandrel by one or more shear pins configured to fail under a predetermined load so that the tubular heater and the tubular mandrel can be detached from one another.

3. The system of claim 1 , further comprising a quantity of alloy mounted on the tubular mandrel at a location proximal to the tubular heater within the clearance space.

4. The system of claim 3 wherein the alloy is selected from a eutectic, bismuth based and/or low melting point alloy that melts at temperatures of 300° C.

5. The system of any one of claims 1 to 2 , wherein the tubular mandrel comprises a skirt provided on a down-hole end thereof.

6. The system of any one of claims 1 to 2 , wherein the mill is tapered at least one end thereof.

7. The system of any one of claims 1 to 2 , wherein each of said at least one flow port is provided with a rupture disc that is configured to block the flow port until it is ruptured; preferably when subject to a predetermined pressure.

8. The system of any one of claims 1 to 2 , wherein the mandrel is formed from aluminium.

9. A method of deploying an alloy plug and/or seal within a target region of an oil and/or gas well, said method comprising:
running a downhole tool assembly system downhole to said target region, wherein the system comprises a tubular chemical heater with a mill that has at least one flow port and a tubular mandrel arranged on the outside of the heater at up-hole and down-holes ends of the heater respectively and whereby the heater is removably retained within the mandrel;
providing alloy within a clearance space located between the mill and the mandrel and operating the chemical heater to melt the alloy so that it can flow within the target region before cooling and re-solidifying to form an alloy plug and/or seal within the target region that secures the mandrel in position within the well;
repositioning the mill and operating such to mill away at least a portion of the mandrel, and preferably also a portion of the alloy set within the target region.

10. The method of claim 9 , further comprising a pre-heating milling step in which the mill is operated to clear the target region of the well before the alloy is melted to form the alloy plug and/or seal.

11. The method of claim 9 or 10 , wherein said at least one flow port is used to extract milling waste from the target region.

12. The method of any one of claims 9 to 10 , wherein the step of providing the alloy comprises mounting the alloy on the outside of the mandrel or on the outside of both the mandrel and the heater.

13. The method of any one of claim 9 or 10 , wherein the step of providing the alloy comprised delivering the alloy downhole to the clearance space via said at least one flow port.

14. The method of any one of claims 9 to 10 , wherein the target region comprises a perforated or fractured well tubing or casing and the mill is operated to clear the entire mandrel and the majority of the alloy set within said well tubing or casing so as to render the well tubing or casing's internal diameter close to its original internal diameter within the target region.

Assignees

• Bisn Tec Ltd

Inventors

• Dearmon Jake
• Naylor Matt

Classifications

• E21B29/002

  Cutting, e.g. milling, a pipe with a cutter rotating along the circumference of the pipe · CPC title

• E21B33/1208

  characterised by the construction of the sealing or packing means (E21B33/1277 takes precedence) · CPC title

• E21B36/008 Primary

  using chemical heat generating means · CPC title

• E21B33/13

  Methods or devices for cementing, for plugging holes, crevices or the like · CPC title

• E21B33/12 Primary

  Packers; Plugs (used for cementing E21B33/134, E21B33/16) · CPC title