6th european sand management forum · cfd example: choke body erosion . nel 14-03-31 spe-sme - 6th...

Erosion Management-

Using Erosion Testing

Combined with Erosion

Modelling

John Peters, NEL, UK

6th European Sand Management Forum, 26-27 March 2014, Aberdeen

Energy, Oil & Gas Low Carbon Technologies Environment

• Holds UK National Standards for fluid flow & density measurement

• A global centre of excellence in flow measurement, flow systems and fluid

dynamics

• World class research, development, modelling, calibration, consultancy,

measurement and testing

NEL Slide 2 SPE-SME - 6th EUROPEAN SAND MANAGEMENT FORUM 14-03-31

NEL

• (Particle) Erosion Basics

• Factors Which Affect Erosion

• NEL – Erosion Testing

• CFD Erosion Modelling

• Benefits of Testing & Modelling Combined

• Summary


Presentation Contents

• A major issue world-wide in oil & gas exploration & production piping

systems

• Causes major wear, damage to piping, equipment, components

• Potential damage, significant errors in flow metering systems

• Possible Loss of Containment


(Particle) Erosion

Erosion in a hydrocyclone

Flow

Eroded Hole-

originally 4 mm

wall

Erosion in a 50 mm bend

downstream of a

reduced-bore ball valve


Erosion – (Sand) Particle Erosion Damage

New vs worn


View of badly worn choke parts!

Wear at base of coupon / probe fitting

Particle Erosion Damage Around Probe Base

14-03-31 NEL Slide 7 SPE-SME - 6th EUROPEAN SAND MANAGEMENT FORUM

New


(Particle) Erosion Basics

t

• Sand particle hits a metal/hard surface

• Material removed

In THIS Presentation ... Particle Erosion


• Sand particles go between surfaces and cause abrasive wear:

Between seats, seals, into bearings

Sliding surfaces - Gate Valve Rotating surface - Ball Valve


... and Abrasion Wear ... ONLY

• Cavitation erosion - collapse of bubbles on surfaces

• Liquid jet erosion - high velocity liquid jets impinging on a surface

• Droplet erosion - liquid droplets in a high velocity gas stream


... NOT TO BE CONFUSED WITH

NOT COVERED IN THIS PRESENTATION

ALL THESE EROSION MECHANISMS REMOVE MATERIAL

• The potential for compound wear should also be considered

• One mechanism may be more dominant than the other, or two stage, such as:

Particle erosion AND corrosion

Sand induced corrosion: e.g. interference/ removal of corrosion inhibitor film

Erosion then Corrosion:

e.g. Failure of Inconel lining


Compound Wear Mechanisms

• Impingement of high fluid/particle velocities, produces rapid wear (material

removal), severe damage:

Safety Issues, Hazards

Loss of pressure containment- pipe rupture,

Bends,Tees, wall erodes through

Component breaks up, e.g. choke internals

Severe wear of flow paths


Erosion – Sand Particle Erosion Damage


Factors Which Affect Erosion

• Do not need much sand to give high wear:

... sand + high velocity

• Sand production varies significantly - often small fraction % by weight < 0.01% can cause major erosion problems

e.g. 0.2 kg sand for 1 MMSCF gas,

or 2 kg per 1000 barrels

• Sand particle size ~ varies widely

• From 25-40 microns (flour) to ...150…....300…..…450+

Typical UK North Sea ... ~ 250 microns


How Much Sand?


Erosion Basics – Particle Velocity

• Erosion highly dependent upon particle impact velocity ...

E = K.f V2.6

• Generally, small particles, < 100 microns (µm) are less erosive

• For a given fluid, operating conditions


Erosion Basics – Particle Size

a. Small, light particles b. Medium particles c. Large, heavy particles

- few impacts on wall - more impacts, abrasion - lot of impacts and deflections

• Most steels, Inconel & Stellite - similar resistance

• Ceramics & Tungsten Carbide ~ 10-100 times better BUT they are brittle


Erosion Basics – Materials, Erosion Resistance

Erosion Basics – Impact Angle

• Erosion Rate v Impact Angle

• Maximum Erosion Rate occurs in different locations


• Particle velocity; wear = f (velocity)2.6

• Average Particle size, e.g. 250 microns, typical

• Materials of construction

• Impact Angle

• Quantity (mass) of sand

• Sand shape, sharpness, hardness

• Fluid flow regime - liquid, gas, multiphase

• Piping configuration, flow path profile, shape, complexity

• Equipment, component design


Factors Affecting Erosion Levels

• May be evenly distributed ‘all-over’

• Often small steps up/ down, changes in internal bore, surface irregularities

trigger local vortices, sand becomes trapped within, rotating grinding

wheel ! ... an erosion crater rapidly develops

• Often very localised ‘erosion hot-spots’

• Once an erosion scar starts, it keeps ‘digging’

• Can be unstable and rapid, complex process

• Often not well managed or understood


Nature of Erosion

HOLE

90°bend- hole on

inside radius of bend

Erosion at weld beads


Rotating Vortex at weld-bead


Rotating vortex-

with sand

Erosion down-stream of a weld bead, - crater often develops

FLOW

Abrasion Wear


• Sand particles go between surfaces and cause abrasive wear:

Gate valves ~ sliding surfaces

Ball valves ~ rotating surfaces

Into bearings and seals

• Leaking seals, & damaged seats

• Higher friction, higher operating forces/ torques

• Excessive forces, seizure of parts.

• Short operating life, unreliable

• An erosive flow test is often the only way to verify

equipment’s abrasion performance


Abrasion (Wear) Sand Particles

NEL Erosion Testing


Particle Size Aperature/Mesh size

microns

% Retained by Weight to BS 410

710 500 355 250 180 125 <125

0.7 3.9 16.2 44.8 28.4 5.5 0.5

Average size 275 microns


Typical Sand Size Distribution Used by NEL for Testing

NEL Erosive Flow Facility (Sand / Water)


Computer 3-D image of NEL Erosive Flow Facility

(sand/water) with various flowmeters installed

• Controlled erosive flow conditions

• 20 years experience erosion testing, wear assessments

• Test Fluid - Water/sand,

- Water /sand + viscosifier ( API slurry)

- Gas/sand

• Different erosive wear characteristics and patterns in piping and components

• Accelerated testing techniques:

High sand concentrations

Comparison materials- hard, soft, reference materials

Higher velocities

• Sand particle size, hardness? Scaling Wear - component life-prediction /

• How long to test? How much wear?


NEL Erosive Flow Testing

• Detect, measure, assess wear (quantify/qualify)

• A balance, sufficient wear (measurable) v test duration

• Before, … during … and after tests …

– Visual Inspection, photos

– Dimensional Measurements Vernier calipers, micrometer

Co-ordinate measurements (CMM)

Laser 3-D scanning -Profilometry

– Ultrasonic wall thickness measurements

– Weight Loss of components - Precision weighing

– Coupon Material Erosion tests


Erosion Testing, Wear (Material Loss)

• A good performance on test is a good omen for a good performance in the field.

• Testing is essential to test seals, bearings and all moving parts

• Accelerated erosion tests are simulated under controlled conditions

• Testing quickly identifies any design weak points

• Testing identifies local erosion hot-spots

• Testing may show surprises, not evident from CFD


Benefits of Erosive Flow Testing

CFD Erosion Modelling


e.g. DNV RPO501- Bend erosion equation

n

pipet

lsand UKG

A

CFmerosion ...

.

).sin().(.

bend geometry

particle size effect

material properties

Particle velocity

mass of sand

n.~ 2.6


Example Erosion Equation

The flow paths are predicted using CFD

CFD Erosion Modelling – Basics


The path of sand particles is modelled



Erosion Damage caused by each particle wall collision is calculated



Potential Erosion Areas

Piping

configurations -

Bends, Tees,

Reducers

Flowmeter system

&

inlet piping config.

Wellhead Flow

paths, chokes,

Piping, bends

Down-hole

equipment


Flow Streamlines – Gas Flow

CFD Model – Piping Configuration

FLOW

Erosion Rate – Gas Flow

CFD Model – Piping Configuration

Choke Piping Configuration … With 5 Bends!

Pipe 1

Pipe 2

Choke Valve

Pipe 3FLOW


Erosion Areas


CFD Example: Choke Body Erosion


Erosion Scar Around a Port in a Choke Valve Cage


Choke Plug – Accelerated Wear Test!

Test

CFD


CFD View: Cone Flowmeter – Water/Sand Erosion

• Testing often reveals erosion hot-spots not identified by the CFD .

• Testing can be used to validate CFD erosion model predictions

• Erosive Flow Testing in conjunction with CFD erosion modelling is a powerful

design package to optimise component design for minimum wear

• Use validated CFD model to predict field wear-life of components, equipment,

pipelines

• Form part of the ‘tool-kit ‘ for risk management: optimising production, managing

wear levels, developing sand management and maintenance strategies.


Benefits of Testing & Modelling Combined

Summary


• Erosion is a complex wear regime, many factors affect wear; high velocities give

rapid wear

• Testing is essential to test seals, bearings, moving parts

• Test data validates CFD erosion model; gives increased confidence in modelling

field conditions

• Predict the wear life of components in field conditions

• Design optimisation for minimal wear

• Part of the tool-box for pipeline integrity, risk and maintenance management.


Summing Up: CFD Erosion Modelling & Testing Benefits-

Thank You for Listening

Any Questions?

John Peters, NEL

Contact: [email protected]


Forthcoming NEL Training Courses & Conferences

• Multiphase & Wet-Gas Flow Measurement Training Course; April 30th 2014,

• Principles and Practice of Flow Measurement Training Course; May 13th 2014

• Produced Water & Environmental Conference; June 10th 2014

• Please visit our web-site for latest details: www.tuvnel.com


http://www.tuvnel.com/

Switchboard : +44 (0)1355- 220222

Audit & Allocation Alick MacGillivray [email protected]

CFD John Dods [email protected]

Densitometers Norman Glen [email protected]

Erosion John Peters [email protected]

Flow Consortium Phil Mark [email protected]

Heavy Oil Chris Mills [email protected]

Measurement Consultancy

Calum Hardie

Craig Marshall

Chris Mills

[email protected]

[email protected]

[email protected]

Measurement Uncertainty Alick MacGillivray [email protected]

Meter Diagnostics Craig Marshall [email protected]

MeterVue Phil Mark [email protected]

Multiphase Terri Leonard [email protected]

PPDS Lynn Hunter [email protected]

Single Phase Metering Bob Belshaw [email protected]

Training Helen Tulloch [email protected]

Umbilicals Janice MacLeod [email protected]

Valve Testing John Dods [email protected]

Wet Gas Emmelyn Graham [email protected]

For general queries contact the Sales Team on [email protected]


NEL Contacts

Contact us

+ 44 (0)1355 220222

[email protected]

www.tuvnel.com


6th european sand management forum · cfd example: choke body erosion . nel 14-03-31 spe-sme - 6th...

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