Downhole Time Interlaced Communications for Multi-Tool Systems
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Solution Overview
Problem
Interference between two downhole communication systems connected to different tools in a well bore via a two-core cable occurs due to the close proximity of the cable cores, leading to communication errors and inefficiencies.
Innovation Solution
Implementing a method of downhole time interlaced communications by setting distinct command intervals with delays between consecutive commands, applying temporary shifts to synchronize the systems, and using configurable interface cards with registers to manage communication parameters, thereby minimizing interference and optimizing communication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two downhole communication systems operate simultaneously over a two-core cable, then communication coverage is expanded, but communication interference occurs due to close proximity of cable cores
Solution Approach 1:
The patent implements time-interlaced communication by dividing communication into periodic time slots. The first communication system transmits during first time slots, then both systems remain inactive for a second time slot, allowing the second communication system to transmit during third time slots. This periodic time-division multiplexing eliminates simultaneous transmission interference while maintaining expanded communication coverage.
2Reliability
If command intervals are increased to reduce interference, then communication reliability improves, but communication efficiency decreases
Solution Approach 1:
The patent applies partial action by introducing communication inactivity periods only during specific time slots when one system is transmitting, rather than maintaining continuous communication. The first communication system transmits during first time slots with inactivity during second time slots, and the second system transmits during third time slots. This partial temporal separation ensures reliability by eliminating interference while minimizing the impact on overall communication efficiency.
3Reliability
If time interlacing is implemented to eliminate interference, then communication reliability improves, but system complexity increases
Solution Approach 1:
The patent segments the communication timeline into distinct time slots (first, second, and third time slots) assigned to different communication systems. This temporal segmentation allows multiple systems to share the same cable without interference. The interface cards are configured with specific command intervals to automatically align with these time slots, implementing reliability through segmentation without requiring complex active coordination mechanisms.
4Object-affected harmful factors
If command intervals are set to define inactivity periods, then interference is reduced, but resynchronization time increases
Solution Approach 1:
The patent implements dynamic command interval configuration where the first interface card operates with a first command interval and the second interface card operates with a second command interval. These intervals are dynamically adjusted to account for drift effects while maintaining the time-interlaced structure. The configurable interface cards adapt their timing parameters to minimize resynchronization requirements while preserving interference reduction benefits.
Data Source
AI summary
A method, system, and apparatus of downhole time interlaced communications are provided. The method includes setting command intervals for first and second communications systems associated with downhole tools. Each command interval is a delay value between consecutive commands greater than an actual command duration to define periods of communications inactivity. The command interval of the second communications system is slightly greater than that of the first to overcome any drift. The method includes detecting communications interference between the systems and applying temporarily a positive command interval shift to the first communications system and a negative command interval shift to the second communications system so that a duration of a resynchronization is minimized. An apparatus for downhole time interlaced communications includes a configurable communications interface card to communicate with surface equipment, having a command interval register and a command interval shift register that is applied temporarily when communications interference is detected.