Beyond Particle Sizing ArabLAB 2008 DUBAI

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Beyond Particle Sizing

ArabLAB 2008

Glen McLellan - Opus Plus Ltd

drs.ing Jacco Schipperen- Ankersmid Intl.

Robert Stevens – Ankersmid Intl.

Oil-in-Water Monitoring , February 2008

1 Introduction

This presentation discusses:

· The importance & benefits of gathering good quality data on the characteristics of produced water at off-shore oil-rigs.

· How informed decisions can be made about process optimisation & oil/water separation technology

· The EyeTech particle sizing instrument

· Verification trials and the applicability of the technology to the oil & gas industry

1 The characteristics of produced water

· Produced water at an oil-rig is a complex mixture containing:

- Dispersed & dissolved organic components- Inorganic components & dissolved formation

minerals- Traces of production chemicals- Produced solids & dissolved gas

· Factors such as shear history, salinity, anion/cation balance, oil type, pressure & temperature can all influence the characteristics of the produced water

All of the above influence decisions about processing options

1 The characteristics of produced water

Produced Water Characterisation

· PWC aims to understand the characteristics of the fluids and the interaction of the process upon them

· Only then can we tackle the core issues of process trouble shooting or production optimisation

· PWC provides valuable data in the selection of appropriate treatment technology

· Less waste (good for OPEC savings!!)

2 Produced Water Characterisation

· What can we measure?

- Oil droplet size distribution analysis

- Oil in water concentration

- Suspended solids size distribution

- Suspended solids concentration

- Other, including water in oil analysis

Typical process

2 Applying EyeTech technology in an oil/water separation process train

Export

Hydrocyclones

1st StageSeparator

2nd Stage Separator

Degasser

Oil droplet sizeOil contentSolids contentSolids sizeSolids typeIon content

Oil water cutEmulsion stabilityWIO characteristicsOIW characteristicsSolids content

Emulsion stabilityWIOOIW

Shearing across pump?

Shearing across chokes?

Oily solids discharged to sea?Oil content

Oil on solidsSolids content

Small inlet droplet size?

Separator efficiency

3 The Benefits - examples

· Oil droplet shear in a process visualised by dropletsize

UpstreamMedian droplet size 26.79 µm

3 The Benefits - examples

· Oil droplet shear visualised in a process by droplet size

Downstream Median droplet size 10.98 µm

3 The Benefits

· Mapping of oil droplet size can identify sources of shear

· Small oil droplet size distribution may be indicative of high shear conditions

· Chemical dosing can be optimised and dosing reduced in relation to the impact it has on water quality - can lead directly to OPEX savings

· Allows operators to make informed decisions about choice of treatment technologies

· Can be used as a tool to optimise existing process trains by giving real-time feedback on the impact of changes in operational conditions, such as:- Separator interface level- Processing rates- Chemical dose rates, which can lead directly to OPEX savings

4 The EyeTech – Measurement Principle

Single Instrument – Dual Measurement ChannelsScanning Laser Obscuration and Dynamic Video

4 The EyeTech – Measurement Principle

4 The EyeTech – Measurement Principle (Laser)

The rotating laser beam scans single particles within its focus.

The diameter of the particle is directly correlated to the duration of the obscuration.

The principle measurement is a time interval, not an intensity measurement.

The time domain is independent of particles’ optical or physical properties

A B C D E F

Ta Tb Tc Td Te Tf

Scanning Laser

Laser Obscuration Time (LOT)

Opaque Particles Translucent Particles Transparent Particles

Pulse Profile

Particle Size Measurement is independent of particle’s transparency

Using Pulse Shape to Discriminate in Oil /Sand Mixtures !!!!!

• Asymmetric pulses are normally rejected as corresponding to

highly irregular shapes, chords, or out-of-focus particles.

• This capability allows discrimination oil droplets and sand

particles.

• SELECTION OF ONLY OILDROPLETS !!!!

Advantages

• Data is collected on single particles or oil-droplets

• Detection of minor fractions

• Direct measurement of correct oil-droplet – or particle size, not influenced by physical or optical properties

• No calibration required

• Robust measurement, no alignment required by user

• Concentration measurement

4 The EyeTech – Measurement Principle (Video)

· Video Channel collects digital images used for:- Visualisation during laser measurement- Dynamic Shape Analysis- Grabbing Images and Recording Movie

Dynamic Shape Analysis

• For each individual particle, size and shape parameters are detemined.

• The EyeTech Image Analysis software automates set-up and measurement.

• EyeTech software includes many IA procedures such as:

Pre-processing procedures Image Filters Out-of-focus Rejection Morphology Operations Grouping according to size/shape (Re-)processing of stored images

and movies

Dynamic Shape Analysis

A solution for characterisation of non-spherical materials:

• Multiple size & shape parameters to adapt to any application.

• No assumptions about particle’s sphericity.

• Random orientation of particles. No preferred orientation as in microscopy.

• Grouping & sselection of particles based upon size or shape.

• Visualisation for measurement validation/verification.

Feret DiametersDetermination of distributions of:- Minimum Feret- Maximum Feret- Average Feret

Average Feret diameter:

F1 + F2 + F3 + F4 … F36

For a sphere size = diameter

[ min Feret diam.]

Aspect Ratio = --------------------------

[ max Feret diam.]

[Area * 4 ]Shape Factor = ------------------ (=

Circularity) [Perimeter]2

Comparing Shape Factor to Aspect Ratio

Shape Factor Aspect Ratio

<0,1 1

0,785 0,707

0,604 0,577

0,436 0,250

0,160 0,100

Additional Parameters:

• All ISO parameters• Legendre Ellipse• Ellipse Ratio• Elongation• Curl• Modification Ratio• Compactness• Roughness• Wadell’s Shericity• Solidity• Convexity• Average Concavity• Fractal Dimensions

Summary

• Two dimensional analysis of video images enables the determination of different shape parameters.

• Feret Diameters, Shape Factor and Aspect Ratio for shape characterisation.

• Isolation of classified particles using strategic Shape Filter options.

• Validation of particle size results: “SEEING IS BELIEVING”

• More accurate characterisation of non-spherical materials

• Re-processing of stored data

4 The EyeTech – The Analysis Package

Features

· Laser and video in one program

· Easy setup and measurement using software

wizards (one click operation)

· Automated Report Generator

· Results stored in SQL database

· Hardware Diagnostics

· Calibration and verification tools available

· Multiple data display of graphs, tables etc

· On-Line cycle compare

· On-Line help

4 The EyeTech – Advantages

Advantages

• Easy setup and measurement

• Advanced preprocessing algoritmes

• Size and Shape grouping/selection of oildroplets

• Automated report generator

• Storage of real raw data (un processed images)

• Re-processing of raw data (movie files)

• Concentration measurement including calibration

• Integrated laser and video software

• Simultaneous laser and video results

5 System Trials - Objectives

Objectives

• To verify this technology against a range of typical process conditions experienced offshore• Parameters varied included oil concentration &

droplet size, solids concentration and particle size and varying combinations of both.

• To compare the technology to existing industry standard particle size analysers

5 System Trials - Conclusions

· Very close size correlation with the reference analysers with equal or better reproducibility

· The raw data suggest successful discrimination of oil droplets and solids particles with the laser channel

· Applicability of the technology to produced water characterisation confirmed

· Trials highlighted the flexibility of both the dual channel capabilities and the data presentation software

· The ability to identify specific particles and their characteristic parameters will enable the technology to be simply applied to additional areas of characterisation such as the identification of Calcium Naphanate particles in fluid streams

6 Summary

· Produced water characterisation techniques provide a specialist tool in optimising existing oil-rigs and in selecting new technology for retrofit applications

· Based on the trials carried out , the performance of the EyeTech instrument matches or exceeds that of industry standard particle size analysers

· The measurement, data manipulation and highly user friendly software makes the instrument very attractive with regards to use in the offshore environment.

· We have determined that the EyeTech technology is applicable to use for fluids characterisation in the oil & gas industry

Beyond Particle Sizing ArabLAB 2008 DUBAI

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