Mud Pulse Telemetry Time Delay Correction

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Solution Overview

Problem

Current mud-pulse telemetry systems in borehole operations face delays due to the limited speed of pressure waves through drilling fluids, leading to inaccuracies in data transmission timing and synchronization between downhole and surface systems.

Innovation Solution

A downhole system that generates and detects pressure variations using a pulse generation member and pressure sensors, allowing for the estimation of transmit time by correlating signals within the borehole fluid, enabling accurate synchronization and correction of data transmission delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If mud-pulse telemetry is used for data transmission, then data can be transmitted from downhole to surface, but time delay occurs due to limited pressure wave speed

Engineering Contradiction:

Improvedata transmission accuracyVSAvoidtransmission delay

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent replaces the mechanical estimation method (calculating delay based on assumed pressure wave speed) with an acoustic measurement system. Pressure sensors detect actual pressure wave arrivals, and cross-correlation analysis determines the true transmission delay, substituting mechanical calculation with acoustic field measurement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements feedback by measuring the actual pressure wave transmission time through sensors and using this measured delay to correct the timing of downhole data. The cross-correlation of pressure signals provides feedback on the true propagation time, which is then used to synchronize downhole and surface operations.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If estimated transmit time is used based on pressure wave speed assumptions, then synchronization can be attempted, but measurement precision is insufficient

Engineering Contradiction:

Improvesynchronization capabilityVSAvoidtime delay measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent substitutes mechanical estimation (based on assumed wave speed and distance) with acoustic measurement using pressure sensors. The actual pressure wave arrival times are measured and processed through cross-correlation to determine precise transmit time, achieving measurement precision unattainable by mechanical calculation alone.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system utilizes the vibrational/acoustic properties of pressure waves in the drilling fluid. By detecting the actual pressure wave arrivals and analyzing their correlation, the system extracts precise timing information from the acoustic field, converting mechanical vibration measurement into accurate time delay determination.

Inventive Principle:

Principle #18Mechanical vibration

3Device complexity

If downhole and surface systems operate independently, then system complexity is reduced, but synchronization between systems deteriorates

Engineering Contradiction:

Improvesystem integration complexityVSAvoiddata synchronization reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements feedback by measuring actual pressure wave transmission time and using this information to correct timing offsets between downhole and surface systems. The cross-correlation analysis provides continuous feedback on synchronization status, enabling dynamic timing adjustment to maintain reliable data correlation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The pressure wave itself serves as an intermediary that carries timing information from downhole to surface. By measuring the pressure wave arrival and using it as a reference signal, the system establishes a common time reference between independently operating downhole and surface systems without requiring complex integrated control.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 provides precise time synchronization and correction of data transmission delays, improving the accuracy of downhole operations by directly measuring the two-way travel time of pressure pulses, thus enhancing the reliability of data synchronization and depth correlation in borehole operations.

Implementation Method 1

a pulser is employed to generate a pressure wave that travels through the drilling fluid

Methodology Applied

Scientific EffectPressure wave propagation: Sound

Implementation Method 2

a pressure sensor arranged on the downhole assembly and configured to detect a first signal that correlates to the information signal at a first time and a second signal that correlates to the information signal at a second time

Methodology Applied

Scientific EffectPressure detection: Pressure Gradient

Data Source

PatentUS11459879B2Mud pulse transmission time delay correction

Publication Date: 2022.10.04 BAKER HUGHES OILFIELD OPERATIONS LLC

AI summary

Methods and systems for performing borehole operations are described. The methods include generating an information signal in a borehole using a pulse generation member, wherein the information signal comprises a pressure variation within a borehole fluid, detecting, in the borehole, a first signal that correlates to the information signal at a first time, detecting, in the borehole, a second signal that correlates to the information signal at a second time, and performing a borehole operation using the first signal and the second signal.