BHA Bus Sectioning Isolation for Downhole Reliability
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Solution Overview
Problem
Downhole tool strings in BHA are prone to single-point failures due to shared electrical paths, making failure detection and remediation challenging, as communication disruption leads to costly and time-consuming removal processes, and stress-activated failures are difficult to diagnose in harsh downhole environments.
Innovation Solution
The method involves isolating a bus section by disconnecting it at two nodes, creating separate sub-buses that can communicate wirelessly, allowing for continued operation and diagnosis without removing the tool string from the well, using transceivers that can transmit and receive electromagnetic, acoustic, or electric signals through the drill string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bus is used to connect all segments, then device complexity is reduced, but reliability deteriorates due to single point of failure
Solution Approach 1:
The patent divides the single bus into multiple independent sub-buses (first sub-bus and second sub-bus) that can operate separately. When a failure occurs in one sub-bus, the other remains functional, eliminating the single point of failure while maintaining relatively simple device architecture.
2Measurement precision
If the tool string is removed from downhole for failure diagnosis, then measurement precision improves, but loss of time increases due to removal and reinstallation
Solution Approach 1:
The patent performs failure diagnosis actions while the tool string remains in the downhole position. The isolation mechanism allows diagnostic equipment to access and test components in situ, eliminating the time-consuming removal and reinstallation process while maintaining accurate failure identification.
Solution Approach 2:
The patent introduces an isolation mechanism that acts as an intermediary, allowing the tool string to be divided into isolated sections. This enables diagnostic equipment to access specific failed components without removing the entire tool string, facilitating in-situ diagnosis while maintaining operational efficiency.
3Reliability
If stress-activated failures occur in downhole environment, then reliability deteriorates, but difficulty of detecting and measuring increases due to harsh conditions
Solution Approach 1:
The patent segments the tool string into isolated sections using the isolation mechanism. This allows failures to be contained within specific segments rather than affecting the entire system, making it easier to identify and diagnose stress-activated failures in harsh downhole conditions without overwhelming complexity.
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 approach enables failure isolation and communication maintenance without removing the tool string, reducing downtime and costs, and allows for real-time data transmission to the surface, improving diagnostic capabilities and operational efficiency.
Implementation Method 1
transceivers that can transmit and receive electromagnetic, acoustic, or electric signals through the drill string
Implementation Method 2
transceivers that can transmit and receive electromagnetic, acoustic, or electric signals through the drill string
Data Source
AI summary
A system for remediating a bus sectioning events, such as a bus failure or controlled sectioning, comprises a plurality of nodes coupled together by a bus in a tool string used in a bottom hole assembly (BHA). Each node comprises a bus switch configured to isolate the node from a section of the bus. Upon a bus sectioning event, a first sub-tool string and a second sub-tool string are created on either side of the bus section to be isolated, each of which independently operate in parallel. Communication between the first and second sub-tool buses is established through respective nodes connected to each sub-tool bus that comprise a wireless communication transceiver configured to convey signals along the tool string. Alternatively or additionally, each of the sub-tool buses has a node with telemetry for communicating with the surface. Accordingly, each of the sub-tool busses continues independently operating normally.