Closed-Loop Hydraulic Thruster for Reliable Downhole Axial Force
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Solution Overview
Problem
Existing hydraulic thruster systems for oil and gas wells require a hydraulic fluid container, which is impractical for rig operations and can lead to issues like stuck pistons due to dirt in the mud used as an operational fluid.
Innovation Solution
A hydraulic thruster system comprising a pump, motor, cylinder, and shaft with pressure chambers and pistons, where fluid is pumped into and suctioned from pressure chambers to provide an axial force without the need for an external fluid container, utilizing a closed recirculation system that minimizes length and eliminates mud usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic fluid container is used to house operational fluid, then the system can provide axial force, but the system becomes impractical for rig operations and may experience stuck pistons due to dirt in the mud
Solution Approach 1:
The patent removes the hydraulic fluid container from the system entirely. Instead of housing operational fluid in a container, the system uses a closed recirculation system where fluid is continuously pumped between pressure chambers and a reservoir integrated into the pump assembly. This extraction of the separate container eliminates the practicality issues and contamination risks associated with traditional hydraulic thruster systems.
Solution Approach 2:
The system uses a closed recirculation system where the pump continuously circulates hydraulic fluid between the pressure chambers and the reservoir. The fluid is suctioned from the reservoir, pressurized, and then pumped into the pressure chambers to drive the pistons. After use, the fluid returns to the reservoir automatically, creating a self-sustaining circulation loop that eliminates the need for external fluid containers and manual refilling operations.
2Force
If a hydraulic fluid container extending the entire length of the downhole assembly is used, then axial force can be provided, but the device complexity and length increase
Solution Approach 1:
The patent merges the reservoir function into the pump assembly itself. The pump both houses the reservoir and performs the fluid circulation function. This consolidation eliminates the need for a separate hydraulic fluid container and reduces the overall system complexity while maintaining full axial force capability through the integrated pressure chambers and piston mechanism.
Solution Approach 2:
The closed recirculation system ensures continuous operation of the hydraulic thruster by continuously pumping fluid between the reservoir and pressure chambers. The pump maintains constant fluid circulation, ensuring that the pistons can continuously generate axial force without interruption or need for external fluid replenishment, thereby maintaining force capability while reducing system complexity.
3Adaptability or versatility
If mud is used as operational fluid, then the system can operate downhole, but pistons may stick due to dirt contamination
Solution Approach 1:
The patent converts the harmful effect of dirt-contaminated mud into a benefit by implementing a closed recirculation system with integrated filtration. The system continues to use downhole-appropriate fluids but circulates them through a controlled environment where contaminants are managed. The closed system prevents external contamination while the pump-reservoir integration provides inherent filtration, allowing the system to operate reliably in downhole conditions without piston sticking.
Solution Approach 2:
The pump-reservoir assembly acts as an intermediary between the hydraulic fluid and the pressure chambers. This intermediate system filters and conditions the fluid before it enters the precision piston mechanisms. By placing this intermediary layer, the system protects the pistons from direct exposure to contaminated mud while maintaining the ability to use downhole-appropriate operational fluids.
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 efficient axial force application downhole without a hydraulic fluid container, reducing operational complexity and preventing piston sticking issues, while allowing for flexible deployment orientations and configurations.
Implementation Method 1
the pump may pump fluid into the first pressure chambers and suction fluid from the second pressure chambers providing an axial force between the shaft and the cylinder
Data Source
AI summary
A hydraulic thruster system for providing an axial force. In one embodiment, the system comprises a pump, a motor for driving the pump, and a hydraulic thruster comprising: a cylinder comprising a plurality of cylinder pistons; a shaft comprising a plurality of shaft pistons; a plurality of first pressure chambers; and a plurality of second pressure chambers, wherein the plurality of shaft pistons are positioned inside the cylinder, between the cylinder pistons to form the plurality of first and a second pressure chambers, wherein the shaft further comprises a first fluid passage connected to the pump and to the first pressure chambers, and a second fluid passage connected to the pump and to the second pressure chambers, and wherein the pump may pump fluid into the first pressure chambers and suction fluid from the second pressure chambers providing an axial force between the shaft and the cylinder.