Drilling Fluid Viscosity Control via Centrifugal Feedback

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Solution Overview

Problem

Drilling fluids used in wellbore construction often experience fluctuations in viscosity and gel strength due to hydration of clays, leading to undesirable saw-tooth effects in mud properties, requiring manual adjustments and compromising drilling performance.

Innovation Solution

A centrifuge system controlled by computer-executable instructions adjusts the speed and feed rate to maintain optimal viscosity and density of drilling fluids, using sensors to compare actual values against set points, reducing operator intervention and maintaining consistent mud properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual adjustment of centrifuge pump speeds is used to optimize centrifuge treating performance, then viscosity control can be achieved, but operator intervention is required frequently and saw-tooth effects occur in mud properties

Engineering Contradiction:
Improvemud viscosity consistencyVSAvoidoperator intervention frequency
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system enables self-service operation through automatic centrifuge control. The computer-executable instructions continuously monitor mud density and viscosity, automatically adjusting centrifuge pump speeds to maintain optimal mud properties without operator intervention, eliminating the saw-tooth effects caused by manual adjustments

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements continuous feedback control by monitoring mud density and viscosity parameters and using this information to automatically adjust centrifuge operating parameters. This closed-loop control ensures consistent mud properties while eliminating the need for frequent manual interventions

Inventive Principle:
Principle #23Feedback

2Reliability

If centrifuge operates at high speed to remove solids and control viscosity, then mud viscosity can be reduced, but equipment wear increases and maintenance frequency increases

Engineering Contradiction:
Improvemud viscosity controlVSAvoidequipment maintenance interval
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system dynamically adjusts centrifuge pump speeds based on real-time mud density and viscosity measurements. Rather than operating at constant high speed, the centrifuge speed is optimized to match actual mud conditions, reducing unnecessary equipment wear while maintaining effective viscosity control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes centrifuge operating parameters (speed, feed rate) based on measured mud properties. By adjusting these parameters dynamically rather than maintaining fixed high-speed operation, the system achieves effective solids removal and viscosity control while extending equipment maintenance intervals

Inventive Principle:
Principle #35Parameter changes

3Reliability

If clay constituents are hydrated to increase viscosity and gel strength, then mud can suspend drill cuttings effectively, but viscosity becomes too high and drilling performance deteriorates

Engineering Contradiction:
Improvecutting suspension capabilityVSAvoiddrilling performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system extracts excess solids and clay constituents from the mud using the centrifuge. By removing these viscosity-contributing materials, the system maintains optimal viscosity and gel strength for cutting suspension while preventing the mud from becoming too thick and deteriorating drilling performance

Inventive Principle:
Principle #2Taking out (Extraction)

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

The system automatically controls viscosity and density, ensuring consistent mud properties and reducing the need for manual adjustments, thereby improving drilling performance and extending equipment maintenance intervals.

Implementation Method 1

a centrifuge for removing solids from the drilling fluid material

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

a viscosity sensor for sensing viscosity of the drilling fluid material in the container

Methodology Applied
Scientific EffectViscosity measurement: Viscometer

Data Source

PatentEP1937934B9Apparatus and method for controlling the viscosity of a drilling fluid
Publication Date: 2017.11.08 NAT OILWELL VARCO LP
  • EP1937934B9 patent drawingFigure 1
  • EP1937934B9 patent drawingFigure 2~3
  • EP1937934B9 patent drawingFigure 4

AI summary

A method for controlling viscosity (or density) of drilling fluid containing solids, said drilling fluid circulating in a drilling fluid system, which method comprises the steps of: (a) feeding drilling fluid into a container (16); (b) sensing with a viscosity (or density) sensor (19) a viscosity (or density) of drilling fluid in said container (16) and providing a viscosity (or density) signal representative thereof; (c) in response to said viscosity (or density) signal pumping a portion of said drilling fluid to a solids separation apparatus (40); (d) separating with said solids separation apparatus (40) at least some of the solids from said portion of drilling fluid; and (e) returning to said drilling fluid system drilling fluid and/or solids separated in step (d) to adjust the viscosity (or density) of said drilling fluid in said container (16).