Downhole Tool Radial Projection via Hydraulic Piston
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Solution Overview
Problem
Existing downhole tools face limitations in radial projection due to the size of springs used for anchoring, which restricts their reach and requires additional pressure compensation, leading to increased complexity and space constraints.
Innovation Solution
A downhole tool design featuring a projectable element with a radial bore and a hollow base part, utilizing a pump to fill an annular cavity with fluid, allowing the projectable element to extend further radially by minimizing the annular cavity and eliminating the need for an extra-strong spring, while maintaining pressure compensation through fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a strong spring is used to hold anchor parts under high pressure, then the anchor parts can be retained during submersion, but the radial projection distance is restricted due to spring size
Solution Approach 1:
The patent replaces the spring-based mechanical system with a hydraulic system. A piston is moved by hydraulic pressure differential between a first chamber and a second chamber, enabling the anchor element to project radially outward without being constrained by spring size or strength limitations.
Solution Approach 2:
The patent changes the physical state and pressure parameters of the fluid in the chambers. By controlling the pressure differential between the first chamber (higher pressure) and second chamber (lower pressure), the system achieves controlled projection and retraction of the anchor element, overcoming the fixed limitations of spring-based systems.
2Stress or pressure
If pressure compensation is implemented to prevent tool housing collapse, then the tool can withstand high well pressure, but the internal pressure increases putting pressure on anchor parts
Solution Approach 1:
The patent uses hydraulic pressure differential to counteract the external well pressure. The first chamber is pressurized to match the external pressure, while the second chamber remains at lower pressure, creating a net force that projects the anchor element outward without requiring excessive internal pressure compensation.
Solution Approach 2:
The patent applies the concept of counterbalancing forces by using the pressurized fluid in the first chamber to counteract the external well pressure, while simultaneously using the pressure differential to drive the anchor projection mechanism.
3Length of moving object
If the annular cavity is minimized during projection, then longer radial projection is achieved, but fluid must be evacuated from the cavity
Solution Approach 1:
The patent uses the hydraulic system to evacuate fluid from the annular cavity. As the piston moves outward, it creates a vacuum effect that draws fluid out of the annular cavity through the second chamber, allowing the cavity to be minimized and the anchor element to achieve maximum radial projection.
Solution Approach 2:
The patent prepares the hydraulic system in advance by establishing the pressure differential between chambers before projection begins. This preliminary setup ensures that fluid can be rapidly evacuated from the annular cavity as the projection occurs, enabling smooth and complete extension.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables longer radial projection without the need for a strong spring, reducing space requirements and enhancing the tool's anchoring capabilities by pressure-equalizing the chamber, allowing for increased radial reach and improved operational efficiency.
Implementation Method 1
a pump configured to pump fluid into the chamber via a fluid channel to move the projectable element into the projected position
Implementation Method 2
at least one spring element arranged in the chamber and connected to the closed first end of the projectable element and to the closed end of the hollow base part for retraction of the projectable element
Data Source
Figure 1
Figure 2
Figure 3A~4B
AI summary
The present invention relates to a downhole tool for projecting a projectable element downhole in order for the tool to perform an operation in a well, comprising a tool body having a tool outer diameter and a longitudinal extension, a radial bore extending in a radial direction perpendicular to the longitudinal extension, the radial bore having a first bore part having a first inner diameter and a second bore part having a second inner diameter being larger than the first inner diameter, a projectable element arranged and forming a piston in the radial bore, the projectable element having an open first end and a closed second end, the projectable element having a retracted position and a projected position where the second end is projected from the first bore part, the projectable element comprising at the second end a first element part having a first outer diameter corresponding to the first inner diameter and a second element part having a second outer diameter corresponding to the second inner diameter, in the retracted position the projectable element and the second bore part define an annular cavity closed by the second element part, a hollow base part having an open end and a closed end, the open end extending into the open first end of the projectable element forming a chamber therebetween, the open end of the hollow base part having an outer diameter which corresponds to an inner diameter of the projectable element, at least one spring element arranged in the chamber and connected to the closed first end of the projectable element and to the closed end of the hollow base part for retraction of the projectable element, a pump configured to pump fluid into the chamber via a fluid channel to move the projectable element into the projected position, wherein the annular cavity is filled with fluid which leaves the annular cavity as the projectable element change to the projected position minimising the annular cavity. The present invention also relates to a downhole tool string comprising the downhole tool and a driving unit for propelling the tool string forward in the well.