Mud-Operated Pulser Power Generation for Downhole Tools
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Solution Overview
Problem
Existing methods for powering downhole well tools, such as batteries and electrical lines, face challenges like short operational times at high temperatures and interference with drilling operations, and mud-driven generators struggle with high flow rates leading to excessive power production and heat issues.
Innovation Solution
A mud-operated pulser system that uses a piston assembly with magnets and coils to generate electricity through the oscillation of drilling mud, allowing for efficient power production without relying on mud flow rates and enabling excess power storage or use by other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a mud-driven generator is used to generate electricity downhole, then electrical power can be produced using circulating drilling fluid, but at high flow rates the increased rotational rate produces high torques and generates more power than necessary leading to heat production
Solution Approach 1:
The patent employs a pulsed mud flow system where the mud flow is periodically interrupted through a valve mechanism. This creates discrete pulses of fluid that drive the turbine at controlled intervals rather than continuous high-speed rotation. The periodic action allows the system to generate necessary electrical power while avoiding sustained high torques that would otherwise produce excessive heat during high flow rates.
Solution Approach 2:
The system dynamically adjusts the mud flow characteristics by using a controllable valve to modulate the flow rate and create pressure pulses. This dynamic control allows the turbine to operate at optimal speeds matching the actual power requirements of downhole tools, rather than running at maximum speed dictated by high mud flow rates, thereby preventing overheating.
2Power
If electrical lines are used to supply power to well tools, then continuous electrical power can be delivered, but electrical lines can interfere with flow or access if positioned within tubing string and can be damaged if positioned inside or outside tubing string
Solution Approach 1:
The patent extracts the power delivery function from the mud flow control system by using the mud pulses solely for energy generation through the turbine, while electrical power is then transmitted through insulated conductors that are integrated into the tool string architecture. This separation allows electrical lines to be properly protected and routed without interfering with mud flow or access operations.
Solution Approach 2:
The electrical conductors are nested within the protective structure of the tool string and tubing, with proper insulation and positioning that allows them to coexist with the mud flow path. The electrical power transmission components are nested within the mechanical tool assembly, enabling both functions to operate simultaneously without interference.
3Device complexity
If batteries are used to power well tools, then portability and simplicity are achieved, but batteries cannot operate for extended periods at downhole temperatures and must be replaced periodically
Solution Approach 1:
The system uses the naturally occurring circulating drilling mud as the energy source, eliminating the need for external battery replacement. The mud flow is already present in the drilling operation, and the turbine converts this kinetic energy directly into electrical power, providing continuous operation as long as the drilling mud circulation continues. This self-service approach uses the existing operational environment to power the tools.
Solution Approach 2:
The patent replaces the chemical energy storage system (batteries) with a mechanical energy conversion system (turbine-generator). Instead of relying on chemical reactions that are limited by temperature and capacity, the system uses mechanical energy from the mud flow to generate electricity, which can operate continuously under downhole conditions without degradation from heat.
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
This solution provides reliable and efficient electrical power to downhole tools without mechanical regulation, addressing issues of power excess and heat production, and ensures consistent power delivery across varying mud flow rates.
Implementation Method 1
A magnet is arranged on one of the housing or piston assembly and a coil is arranged on one of the housing or piston assembly. The magnet is configured to displace relative to the coil such that electricity is generated
Data Source
AI summary
The present disclosure relates to generating electricity downhole using a mud-operated pulser. A disclosed example embodiment of a mud pulser system includes a piston assembly movably disposed within a housing, comprising a power piston, and configured to move in response to a pressure from a fluid flow, a control valve having an open state, in which the power piston receives the fluid flow, and a closed state, in which the power piston does not receive the fluid flow, a magnet disposed on the housing or the piston assembly, and a coil disposed on the housing or the piston assembly, wherein the magnet is configured to displace relative to the coil in response to movement of the piston assembly within the housing, such that relative movement of the magnet and the coil generates electrical energy.