Choke Control Using Flow Coefficient for Drilling Pressure

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Solution Overview

Problem

Existing controlled pressure drilling systems face challenges in accurately controlling choke positions due to non-linear responses, making it difficult to maintain desired flow rates and pressures, especially in dynamic environments where conditions change frequently.

Innovation Solution

A computerized control system that measures parameters such as pressure and flow rates, calculates errors, and adjusts choke positions using interpolated flow coefficient data to maintain optimal drilling conditions, reducing the need for manual tuning and improving adaptability to changing conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional choke control methods are used, then the system can operate with simple control mechanisms, but the control precision deteriorates due to non-linear choke response

Engineering Contradiction:

Improvecontrol mechanism simplicityVSAvoidchoke position control precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control system that continuously monitors actual flow rate and compares it to the desired flow rate. The controller adjusts the choke position based on the error signal to maintain the desired flow rate, compensating for the non-linear choke response characteristics.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the control parameter from direct choke position control to flow rate control. By measuring actual flow rate and using it as the feedback parameter, the system adapts to the non-linear choke characteristics and maintains precise control despite the non-linear response.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If manual tuning of choke positions is used, then the control system remains simple, but the adaptability to changing drilling conditions deteriorates

Engineering Contradiction:

Improvecontrol system complexityVSAvoidadaptability to changing conditions

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The automated feedback control system continuously monitors flow rate and automatically adjusts choke position in response to changing drilling conditions, eliminating the need for manual tuning while significantly improving adaptability to dynamic environments.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control system performs self-adjustment by automatically detecting flow rate deviations and correcting choke position without human intervention, enabling the system to adapt to changing conditions autonomously.

Inventive Principle:

Principle #25Self-service

3Speed

If automated choke response is implemented, then the response speed to kicks improves, but the device complexity increases

Engineering Contradiction:

Improveresponse speed to kicksVSAvoidcontrol system complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The automated feedback control system provides rapid response to kicks by continuously monitoring flow rate and immediately adjusting choke position when deviations are detected, achieving fast response through automation while managing complexity through systematic control architecture.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual mechanical adjustment with automated electronic control, using sensors and controllers to automatically adjust choke position, thereby achieving faster response speeds while the electronic control system manages the complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If flow coefficient interpolation is used, then the control precision improves, but the computational requirements increase

Engineering Contradiction:

Improvechoke position control precisionVSAvoidcomputational power requirements

Core Design Contradiction:

Manufacturing precisionVSPower

Solution Approach 1:

The patent pre-calculates and stores flow coefficient data in lookup tables before operation. During control operations, the system interpolates from these pre-computed tables rather than performing complex real-time calculations, achieving high precision while minimizing computational power requirements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system prepares flow coefficient data and interpolation tables in advance to cushion against the need for complex real-time computations, ensuring precise control is achieved without demanding high computational power during actual operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS9995098B2Choke control tuned by flow coefficient for controlled pressure drilling

Publication Date: 2018.06.12 WEATHERFORD TECHNOLOGY HOLDINGS LLC

AI summary

A computerized control is used in controlling a choke when drilling a wellbore with a drilling system. The computerized control obtains a measured value of a parameter in the drilling system and controls the parameter in the drilling system using the choke. The computerized control obtains indications of an error between a set point of the parameter and the measured value of the parameter in the drilling system, a flow coefficient character of the choke, and a current position of the choke. Based on these indications, the computerized control then determines a position adjustment for the choke and adjusting the parameter in the drilling system by applying the position adjustment to the choke.