Self-Powered Downhole Speed and Vibration Sensing From Drill String Motion
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Solution Overview
Problem
Current downhole drilling technologies face challenges with expensive and environmentally impactful lithium batteries, mechanical failures, and inefficient power generation in harsh drilling environments, limiting real-time data collection and increasing drilling costs.
Innovation Solution
A self-powered active sensing system (SASS) comprising a rotational speed sensor and a three-axis vibration sensor, which harnesses the rotation and vibration of the drill string to generate electrical signals, eliminating the need for external power sources and enabling real-time data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium batteries are used to power MWD and LWD tools, then the tools can operate downhole and collect logging data, but the cost increases significantly and environmental impact worsens due to manufacturing and disposal
Solution Approach 1:
The patent applies the self-service principle by enabling the drill string itself to generate electrical energy through its rotational motion during drilling operations. The drill string acts as both the workpiece and the power source, eliminating the need for separate battery systems. This is achieved through electromagnetic generators or piezoelectric elements integrated into the drill string that convert mechanical rotation into electrical power for sensors and electronics.
Solution Approach 2:
The patent replaces the chemical energy storage system (lithium batteries) with a mechanical energy conversion system. Instead of storing chemical energy in batteries, the system converts the mechanical kinetic energy of the rotating drill string directly into electrical energy through electromagnetic induction or piezoelectric effects, thereby eliminating battery manufacturing and disposal concerns.
2Power
If turbines or alternators are used to generate electricity downhole, then kinetic energy is harnessed, but power generation stops when fluid flow is blocked or reduced
Solution Approach 1:
The drill string serves multiple functions simultaneously: it performs the primary drilling function while also serving as the rotor for electromagnetic generators or piezoelectric elements. This multi-functionality ensures that power generation continues regardless of fluid flow conditions, as the drill string rotates due to the drilling operation itself rather than relying on fluid flow.
Solution Approach 2:
The patent extracts the power generation mechanism from fluid-flow-dependent turbines and replaces it with a system that uses the drill string's rotational motion directly. This eliminates the dependency on fluid flow for power generation, allowing continuous operation under varying downhole fluid conditions.
3Loss of information
If LWD/MWD sensors are run again to obtain updated logging data, then real-time parameters can be measured, but the cost increases significantly
Solution Approach 1:
The patent enables continuous power generation throughout the drilling operation by integrating electromagnetic or piezoelectric elements into the rotating drill string. This continuous power supply allows sensors to operate continuously and transmit data in real-time without interruption, eliminating the need for repeated tool runs to update logging data.
Solution Approach 2:
The drill string generates its own electrical power during rotation, providing continuous energy to sensors and electronics throughout the drilling operation. This self-powered capability enables uninterrupted real-time data collection and transmission, eliminating the need for costly repeated operations to update geological information.
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 SASS system provides continuous, cost-effective, and reliable real-time data on drilling parameters, reducing equipment wear and optimizing drilling operations by using the drill string's kinetic energy to power sensors and instrumentation.
Implementation Method 1
the spherical bearing is configured to contact the screen... the screen is configured to generate an electrical signal as a function of the movement of the spherical bearing across the screen
Implementation Method 2
the bearing is configured to contact the movable member and the movable member is configured to generate an electrical signal as a function of contact between the bearing and the movable member
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3
AI summary
Self-powered active sensing systems (SASS) for use in downhole drilling environments are disclosed. Sensor devices of the SASS can include a self-powered rotational speed sensor including a ring structure attached around a drill string. The ring rotates within a groove formed in an outer housing. Bearings on the ring are arranged to contact moveable members extending from the housing into the groove thereby causing the moveable member to generate an electrical signal representing rotational speed. The SASS can include a vibration sensor having a ring spring mounted within a housing. Spherical bearings on the outer surface of the ring are configured to contact screens that are mounted to the housing and that generate a signal representing movement of the bearing/ring from vibration. Multiple SASS units configured to wirelessly transmit sensor data can be placed along a drill string providing a distributed self-powered system for measuring downhole parameters.