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Trapped Volume Compensation using Fusible Materials

IP.com Disclosure Number: IPCOM000240203D
Publication Date: 2015-Jan-12
Document File: 3 page(s) / 59K

Publishing Venue

The IP.com Prior Art Database

Abstract

In industrial assemblies, such as in downhole oilfield tools, there can be regions within the tool where fluid can fill a volume and then become trapped due to devices such as a one-way check valve. Operating an oilfield tool such as this typically involves deploying the tool at surface on a tubing string. When the oilfield tool reaches the fluid level of the well the fluid can flow past the check valve and fill the interior volume. As the tool continues to be run into the well bore the temperature will increase. This increase in temperature generates a high pressure within the trapped volume that may damage the valves or the body of the tool. This paper presents a method to prevent fluid from entering a region of an assembly until the desired operating temperature is reached thus preventing the potential for damage to components from thermal expansion of the fluid. To prevent fluid from becoming trapped, the volume is displaced by a fusible metal that has a controlled melting temperature. The thermal expansion ratio of the fusible metal is similar to the components within the assembly so there is only a minimal increase in pressure from an increase in temperature. The melting point of the fusible metal is selected to be lower than the bottom-hole temperature so that it will melt during the installation into the well. Once the fusible metal material has melted, the valve assembly can operated as originally designed.

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Page 01 of 3

Trapped Volume Compensation using Fusible Materials

Abstract

In industrial assemblies, such as in downhole oilfield tools, there can be regions within the tool where fluid can fill a volume and then become trapped due to devices such as a one-way check valve. Operating an oilfield tool such as this typically involves deploying the tool at surface on a tubing string. When the oilfield tool reaches the fluid level of the well the fluid can flow past the check valve and fill the interior volume. As the tool continues to be run into the well bore the temperature will increase. This increase in temperature generates a high pressure within the trapped volume that may damage the valves or the body of the tool. This paper presents a method to prevent fluid from entering a region of an assembly until the desired operating temperature is reached thus preventing the potential for damage to components from thermal expansion of the fluid. To prevent fluid from becoming trapped, the volume is displaced by a fusible metal that has a controlled melting temperature. The thermal expansion ratio of the fusible metal is similar to the components within the assembly so there is only a minimal increase in pressure from an increase in temperature. The melting point of the fusible metal is selected to be lower than the bottom-hole temperature so that it will melt during the installation into the well. Once the fusible metal material has melted, the valve assembly can operated as originally designed.

In industrial assemblies, such as in downhole oilfield tools, there can be regions within the tool where fluid can fill a volume and then become trapped due to devices such as a one-way check valve, as shown in Figure 1. Operating an oilfield tool such as this typically involves deploying the tool at surface on a tubing string. When the oilfield tool reaches the fluid level of the well the fluid can flow past the check valve and fill the interior volume. As the tool continues to be run into the well bore the temperature will increase. This increase in temperature generates a high pressure within the trapped volume that may damage the valves or the body of the tool.

Sample Chamber

Annulus

Figure 1. Hydraulic schematic of sampling valve with tubing and annulus check valves.

Tubing


Page 02 of 3

This paper presents a method to prevent fluid from entering a region of an assembly until the desired operating temperature is reached thus preventing the potential for damage to components from thermal expansion of the fluid.

To prevent fluid from becoming trapped, the volume is displaced by a fusible metal that has a controlled melting temperature. The thermal expansion ratio of the fusible metal is similar to the components within the assembly so there is only a minimal increase in pressure from an increase in temperature. The melting point of the fusible metal is selected to be lower than the bottom- hole temperature so that it will melt during the installation into...