Cement Plug Detection Using Sequential Pressure Drops

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Solution Overview

Problem

Existing methods for detecting the launch of a cement plug during casing operations in well drilling are inefficient, as they rely on magnets that can interfere with drilling rig components and lack visibility of the plug's position, making it difficult to confirm proper placement and launch.

Innovation Solution

A system utilizing a first and second pressure sensor positioned within the casing string to detect pressure drops as the plug travels past them, with a controller determining the plug's launch based on sequential pressure drops within a predetermined elapsed time range, ensuring accurate detection without magnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If magnets are used to detect the cement plug, then the plug position can be detected, but magnetic interference with drilling rig components occurs

Engineering Contradiction:

Improveplug position detectionVSAvoidmagnetic interference

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The patent replaces magnetic detection systems with a pressure-based detection system. Pressure sensors monitor fluid pressure changes within the casing to detect the cement plug's position and launch, eliminating magnetic fields and their interfering effects on drilling rig components while maintaining effective detection capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces fluid pressure as an intermediary medium to detect the cement plug's position. Instead of directly detecting the plug with magnets, the system uses pressure changes in the surrounding fluid as an indirect indicator of the plug's location and movement, thereby avoiding direct interaction and magnetic interference

Inventive Principle:

Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If conventional detection methods are used, then plug detection is possible, but visibility of plug position and confirmation of proper placement is difficult

Engineering Contradiction:

Improveplug detection capabilityVSAvoidplug position visibility

Core Design Contradiction:

Difficulty of detecting and measuringVSLoss of information

Solution Approach 1:

The patent implements a feedback system where pressure sensors continuously monitor pressure changes and provide real-time information about the cement plug's position and launch status. The controller receives this feedback data and can confirm proper plug placement and launch, eliminating the visibility and confirmation problems of conventional methods

Inventive Principle:

Principle #23Feedback

3Reliability

If pressure sensors are used to detect plug launch, then accurate detection without magnetic interference is achieved, but system complexity increases

Engineering Contradiction:

Improvedetection accuracyVSAvoidsensor system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses pressure sensors that serve multiple functions: detecting the cement plug's position, confirming proper placement, and verifying successful launch. This multi-functionality reduces the need for multiple separate detection systems, thereby limiting the increase in overall system complexity while maintaining high detection accuracy and reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 method provides reliable and non-invasive detection of the cement plug's launch, ensuring its proper positioning and movement within the casing, enhancing operational efficiency and safety by eliminating magnetic interference issues.

Implementation Method 1

a first sensor disposed within a tubular and configured to monitor a pressure within the tubular, a second sensor disposed within the tubular downstream of the first sensor with respect to a flow of fluid through the tubular, where the second sensor is configured to monitor the pressure within the tubular

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Data Source

PatentUS10472950B2Plug detection system and method

Publication Date: 2019.11.12 NABORS DRILLING TECHNOLOGIES USA INC

AI summary

A system that can include a first sensor disposed within a tubular and configured to monitor a pressure within the tubular, a second sensor disposed within the tubular downstream of the first sensor and configured to monitor the pressure within the tubular, and a controller. The controller being configured to detect a launch of the cement plug when the first sensor detects a first pressure drop and when the second sensor detects a second pressure drop, where the second pressure drop occurs after the first pressure drop within a predetermined elapsed time range.