Downhole Generator Using Progressive Cavity Pump
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Solution Overview
Problem
Existing downhole power generation methods face issues such as high wear in articulated joints and bearings due to high RPM, potential plugging from lost circulation, and low torque output in vane-type devices, which are not feasible in all scenarios and suffer from wear and efficiency problems.
Innovation Solution
A downhole generator assembly utilizing a progressive cavity pump that converts fluid energy into rotational power, with a tubular housing and rotary shaft, and a restriction mechanism to control fluid flow, which can generate either hydraulic or electrical power for downhole tools, minimizing the use of U-joints and addressing wear issues through a positive displacement motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a vane-type device is used to generate downhole power, then the device can convert fluid energy to rotational power, but the device experiences high wear in articulated joints and bearings due to high RPM
Solution Approach 1:
The patent replaces the traditional vane-type mechanical system with a progressive cavity pump system. The PCD device uses a progressive cavity rotor and stator configuration that eliminates articulated joints and universal joints, substituting the high-wear mechanical connection system with a positive displacement mechanism that operates at lower RPM with significantly reduced wear.
Solution Approach 2:
The invention changes the operational parameters by using a progressive cavity pump that operates at lower rotational speeds compared to vane-type devices. This parameter change from high RPM to lower RPM operation, combined with the positive displacement mechanism, reduces the wear on moving parts while maintaining power generation capability.
2Power
If a turbine-type device is used to generate downhole power, then the device can convert fluid energy to rotational power, but the device is susceptible to plugging and lost circulation
Solution Approach 1:
The patent substitutes the turbine mechanical system with a progressive cavity pump system. The PCD device uses a progressive cavity rotor and stator configuration that eliminates articulated joints and universal joints, substituting the high-wear mechanical connection system with a positive displacement mechanism that operates at lower RPM with significantly reduced wear.
Solution Approach 2:
The invention changes the operational parameters by using a progressive cavity pump that operates at lower rotational speeds compared to vane-type devices. This parameter change from high RPM to lower RPM operation, combined with the positive displacement mechanism, reduces the wear on moving parts while maintaining power generation capability.
3Speed
If a vane-type device is used to generate downhole power, then the device can convert fluid energy to rotational power, but the device produces low torque output despite high RPM
Solution Approach 1:
The invention changes the operational parameters by using a progressive cavity pump that operates at lower rotational speeds compared to vane-type devices. This parameter change from high RPM to lower RPM operation, combined with the positive displacement mechanism, reduces the wear on moving parts while maintaining power generation capability.
Solution Approach 2:
The patent replaces the traditional vane-type mechanical system with a progressive cavity pump system. The PCD device uses a progressive cavity rotor and stator configuration that eliminates articulated joints and universal joints, substituting the high-wear mechanical connection system with a positive displacement mechanism that operates at lower RPM with significantly reduced wear.
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
The solution effectively generates power with reduced wear and plugging risks, providing high torque at reasonable RPM and minimizing concerns related to lost circulation, while offering a reliable power source for downhole tools.
Implementation Method 1
A progressive cavity pump is also provided with the rotor rotating in response to fluid passing through the progressive cavity housing to rotate the shaft
Implementation Method 2
the rotary shaft rotates one of windings or magnets relative to the other of windings and magnets to generate electrical power for powering one or more tools
Data Source
AI summary
A generator (10) is provided for positioning downhole in a drill string (12) to generate power powering one or more downhole tools (16). The generator includes a progressive cavity housing (28) and a progressive cavity rotor (30) which rotates in response to fluid passing through the progressive cavity housing. A restriction (36) in the annulus downstream from the ports controls the fluid flow in the annulus and past the restriction, and thereby the fluid flow through the progressive cavity housing. The generator may provide either hydraulic or electrical power, or both, powering the one or more tools.