Capillary Rheometer Drilling Fluid Measurement Automation

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Solution Overview

Problem

Current methods for analyzing drilling fluid properties during oil and gas well drilling operations are prone to errors due to manual measurements and changes in fluid composition during testing, affecting accuracy in density, viscosity, and solids content assessments.

Innovation Solution

A system utilizing a capillary rheometer with pressure sensors and a control system to measure drilling fluid properties, including density through pressure differences and viscosity by converting pressure drop and flow rate measurements, while minimizing the impact of fluid composition changes and turbulence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual measurement methods (mud balance, Marsh funnel, rotating cylinder viscometer, mud retort) are used to measure drilling fluid properties, then the measurement process is simple and equipment is readily available, but measurement accuracy is compromised due to human error in reading indicators and recording data

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical measurement systems (mud balance with bubble level, Marsh funnel with stopwatch, rotating cylinder viscometer with manual indicators) with an automated electronic measurement system that uses pressure sensors, flow meters, and a computer to automatically collect and process data, eliminating human reading and recording errors while maintaining measurement functionality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The measurement system performs self-measurement by automatically collecting drilling fluid samples, measuring pressure differentials, calculating density and viscosity values, and generating reports without requiring technician intervention for reading indicators or recording data, thereby improving accuracy while keeping the system relatively simple

Inventive Principle:
Principle #25Self-service

2Reliability

If drilling fluid samples are collected and measured using traditional devices, then the measurement process can be completed, but fluid composition changes during testing alter the measured properties, reducing measurement reliability

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidfluid composition stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system performs preliminary stabilization by allowing the drilling fluid sample to reach equilibrium conditions before measurement begins, and by continuously monitoring pressure differentials to detect and compensate for any composition changes that occur during the measurement process, ensuring reliable measurements despite potential fluid instability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The measurement system incorporates feedback mechanisms where pressure sensors continuously monitor the drilling fluid properties during measurement, and the computer adjusts calculations based on real-time pressure differential data to compensate for composition changes, thereby maintaining measurement reliability

Inventive Principle:
Principle #23Feedback

3Productivity

If high flow rates are used in capillary rheometer measurements to reduce measurement time, then productivity increases, but turbulence develops in the capillary tube which compromises measurement accuracy

Engineering Contradiction:
Improvemeasurement speedVSAvoidviscosity measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the flow rate through the capillary tube based on real-time pressure differential measurements, optimizing the balance between measurement speed and accuracy by maintaining flow conditions that prevent turbulence while minimizing measurement time, rather than using a fixed high flow rate

Inventive Principle:
Principle #15Dynamics

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 provides accurate and reliable measurements of drilling fluid properties, reducing errors and improving the precision of density and viscosity assessments, even for non-Newtonian fluids, by using pressure sensors and capillary rheometer technology.

Implementation Method 1

A system utilizing a capillary rheometer with pressure sensors and a control system to measure drilling fluid properties, including density through pressure differences and viscosity by converting pressure drop and flow rate measurements

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Implementation Method 2

measure drilling fluid properties, including density through pressure differences

Methodology Applied
Scientific EffectPressure differences: Pressure Drop

Data Source

PatentEP3182092B1Method for measuring drilling fluid properties
Publication Date: 2019.06.26 NAT OILWELL VARCO LP
  • EP3182092B1 patent drawingFigure 1
  • EP3182092B1 patent drawingFigure 2A
  • EP3182092B1 patent drawingFigure 2B

AI summary

A method of measuring drilling fluid properties that includes pumping drilling fluid into a feed chamber (135) of a capillary rheometer (134), said feed chamber (135) comprising a cavity (135a, 135b) and a double wall (136) defining an annulus (140) that opens to said cavity (135a, 135b) and controlling a delivery rate of said drilling fluid into said feed chamber (135) during said pumping such that a first strain rate is imparted to said drilling fluid flowing through said capillary rheometer (134). The method further includes draining said drilling fluid from said cavity (135a, 135b) through at least one drain port (144) of said feed chamber (135) and into an inlet of a capillary tube (146) coupled to said at least one drain port (144), determining a flow rate and a pressure drop of said drilling fluid flowing through said capillary tube (146) for said first strain rate, and determining a viscosity of said drilling fluid from said flow rate and said pressure drop.