Determining Corrosion Mechanisms in Failurescorrosionshortcourse.com/2017 slides/2017 UCSC Purdue/06... · 2017-03-17 · February 21-23, 2017 . Jane Nicole Brown & Jerry Brown

Determining Corrosion

Mechanisms in Failures

Internal Corrosion Course

2017

February 21-23, 2017 Jane Nicole Brown & Jerry Brown

BROWN CORROSION SERVICES, INC. 1

Period 2


BROWN CORROSION SERVICES, INC. Page 2

2017 Underground Corrosion Short Course Internal - Period 2

As much as we try to prevent failures –

they do occur!



2017 Underground Corrosion Short Course

The Energy Sector – Down, Mid & Up Stream – Failures Tend to be Headline Grabbing!

Internal - Period 2



2017 Underground Corrosion Short Course Internal– Period 2

Platform Failure




Pipeline Failure San Bruno, CA



2017 Underground Corrosion Short Course Internal – Period 2

Pipeline Failure

Oklahoma




Pipeline Failure

Wyoming



2017 Underground Corrosion Short Course Internal – Period 2

Pipeline Failure Oklahoma



2017 Underground Corrosion Short Course Internal– Period #2

Wyoming

Third party failure




The Root Cause Analysis of a Failures

A Root Cause Analysis is a specialized type of incident

investigation process that is designed to find the lowest level

contributing causes to the failure.

The root is often a system of causes. There is rarely only one

root cause. The very basic understanding of cause and affect

is that every effect has causes (plural).

As an example an investigation determined that failed coating

contributed to a leak. The leak and coating are repaired and all

is well. Another leak occurs a few years later. It then turn out

that the main root cause was soil movement that damaged the

coating. In this case the investigators did not get to the root

cause of the coating failure thus leading to another failure.




The Root Cause of Failures can be attributed

to two categories: (often working together)

1. Mechanical

a. Earthquakes

b. Floods

c. Explosions

d. Crashes

e. Fires

f. Loads, pressures, stresses

g. Changes (Temperature, etc.)

h. Third party damage

2. Electrochemical

a. Corrosion

We will look at corrosion failures in the oil and gas industry in

this presentation and how to determine the actual mechanism

that caused the corrosion to occur.




Failures of metal pipes and vessels can occur from the inside

or the outside surfaces, and sometimes from both surfaces.

When this occurs the corrosion control measures (if any) did

not work as designed or were compromised in some way.

The Categories of Corrosion Control Measures are:

1. Material Selection

2. Design of the Structure

3. Coatings

4. Cathodic Protection

5. Alteration of the Environment

6. Inhibition

7. Repair and/or Replace




In the real world corrosion occurs when either the corrosion

control measures fail or the environment changes thus making

the corrosion control no longer able to control the corrosion.

The causes of corrosion are many and can be generally

divided into the following areas:

1. The chemical composition of the internal / external

environment.

2. The physical factors of the environment.

3. The physical factors of the structure.




The main things influencing internal corrosion in the oil and gas sector are:

a. H2O

b. H2S

c. CO2

d. Cl

e. O2

f. Bacteria

The main things influencing external corrosion in the oil and gas sector are:

a. H2O

b. Soil resistivity and pH

c. Cl

d. O2

e. Bacteria

It is important to know not only the present chemistry of the environment both

inside and outside of the pipe/vessel, but what was the environment from the

manufacture of the pipe through storage, delivery, installation, hydro testing,

start-up and condition over the life of the structure.

In many cases this data is not available. Even when it is available - is it accurate

and reliable - probably not!

1. The Chemical Composition of the Internal / External

Environment




2. The Physical Factors of the Environment.

A. Flow – no flow, velocity

B. pH

C. Solids in the flow

D. Depositions on the structure

E. Mixing of various products

F. Vibrations

G. Surfaces

H. Flow regimes

I. Pulsating flow

J. Mixing – or not – of gas, oil, water

K. Contamination

L. Subsidence, spanning, and earth movement

M. Wind, waves, storms, flooding, etc.

N. Third party damage




3. The Physical Factors of the Structure.

A. Pipe sizes

B. Change of direction – elbows

C. Dead legs

D. Material changes

E. Surfaces

F. Weld bumps

G. Heat affected areas

H. Pipe Flaws

I. Incorrect materials

J. Different stress levels

K. Erosion

L. Cracking

M. Stresses - unplanned




In all cases the following data is necessary:

A. Location

B. Weather

A. Temperature

B. Humidity

C. Other conditions

C. Date and time

D. Who was on duty

E. Any recent changes

F. Cell phone records

G. Coms records

H. Archived data

A. Operational

B. Logs

C. MOC’s

I. Original documents




When failures occur the failed section of pipe must be evaluated by a qualified metallurgical laboratory and overseen by a qualified Corrosion Engineer. As much data as possible must be obtained and the sections of pipe must be prepared for shipment with as little disturbance as possible and carefully protected from further damage or contamination. The flow direction and top of pipe should be marked on the cut-out section of pipe.




Sample Marking, Observation, & Recording

1. Top or ?

2. Flow Direction

3. Date & Time

4. Weather

5. GPS Coordinates

6. Who did it?

7. Etc.




Samples of the environment should be obtained – if at all possible.




Sampling of the Environment




Sampling of the Environment




Sampling of the Environment – Bugs




Solids Observation & Analysis




Water Analysis




Visual Observation & Photography




Photographic Observation & Recording




When You Get to the Laboratory

1. Record receipt and custody transfer information.2. Photograph and note as received.3. Unwrap carefully.4. Photograph and note opened samples.5. Take samples of any available products, label and contain.6. Plan sectioning and cutting if necessary.7. Section as required.8. Prepare samples for testing.9. Perform testing as per protocol.10. Record all data.11. Prepare report.12. Send report and store samples for sending back, storage or disposal.13. Issue report (draft or final per agreement).




Various Tests Can be Performed

Environment 1. Gas Analysis

2. Liquid Analysis

3. Solids Analysis

4. MIC Testing

5. pH and Resistivity

Structure 1. Material

2. Measurement

3. Depth

4. Deposition

5. Hardness

Four Main Areas of Analysis: 1. Chemical Analysis

2. Metallurgical Analysis

3. Microbial Analysis

4. Corrosion Testing.

Chemical Analytical Methods Include: XRD (X-Ray Diffraction), Ion

Chromatography, AAS (Atomic Absorption), DCP/ICP (Direct Current Plasma & Inductively

Coupled Plasma), Wet Chemistry, Gas / Mass Spectrometry, Scaling Index,

Conductivity, pH, SEM (Scanning Electron Microscopy), EDS (Energy Dispersive

Spectroscopy), TEM (Transmission Electron Microscopy), AES (Auger Electron Spectroscopy), SIMS

(Secondary Ion Mass Spectroscopy), FTIR (Fourier Transform Infrared Spectroscopy), ETC.




Lay out the failed portions so you get an understanding

of what went wrong and where. Then sampling of the

actual failed parts can be determined and cut into lab

size samples




Various Tests Can be Performed

Pit Depth

Thickness

Cracks

Weight

Hardness




Metallurgical Analytical Methods Include: Grain Size,

Inclusion Content & Distribution, Uniformity, Type, Phase Percentage,

Grade, Striations, Pitting, Distribution of Elements,

Metallurgical Analysis for Corrosion in used 3 Primary Ways: 1. Characterization of the Microstructure

2. Relationship of Microstructure to Corrosion

3. Size & Shape of Any Pits & Cracks




SEM & EDS Data







Bacteria Detected




Once all the testing is completed comparisons must be

made to include the material, properties of the material,

the environment (chemical and physical), the

operations, and any and all data available. With this,

and comparisons to other known failures, positive

conclusions can be drawn.

Typical conclusions might be:

1. Microbiological influenced corrosion.

2. CO2 induced corrosion.

3. Corrosion / Erosion.

4. Cracking corrosion due to H2S.

5. O2 corrosion.

6. Combinations of these and other factors.

7. Failure of the corrosion control used.

8. Third party damage.

9. Operating beyond design life.




Once the root cause analysis reveals the corrosion

mechanism that caused the corrosion in the first place

is determined, steps can be taken to create corrosion

control measures to prevent further corrosion failures.

Chemicals

Changes

Coatings Replacement Material Changes



2017 Underground Corrosion Short Course IInternal - Period 2

When all the testing, analysis, document gathering, research

is done the final REPORT must be written, checked,

approved and issued. The report should be complete

concise, clear and have all conclusions backed-up and

referenced.

1. Dates and names must be clear and concise.2. There must be an Executive Summary.3. There should be a clear Background regarding the failure.4. All details as to the failure must be included.5. All photos should be included.6. Conclusions must be made with back-up for each.7. References must be included.8. Recommendations must be included.9. All anachronisms must be spelled out.10. Proper and formal English must be used (spell-checked).11. The document must be signed.




Before you have a failure: Document everything.

Ensure compliance.

Keep up with technology.

Be an active NACE member.

Get involved in decision making in your company.

Be a good Steward of our world.

If you do have a failure: Put out the fire!

Document everything!

Determine the Root Cause of the failure!

Work to implement changes that will not allow future failures!




The general population, the politicians, the

progressives, and the media have little if any

understanding of the complexity of the assets we are

responsible for and the failures that do occur.

In addition, management often do not take corrosion

seriously, especially if a period of time has gone by

with no failures. Therefore, your corrosion control

budgets are cut - if not eliminated.

E & C & operation budgets are often cut not allowing

proper corrosion control to take place.

Offshore structures were designed for a 20 year life –

50 years ago & still in operating - aging infrastructure!




This is never the answer!




To understand why a Failure occurs we must determine the

root cause. If this is done thoroughly and accurately we can

then move forward to fix existing structures to remove these

causes and be sure future structures are designed without

the possibility of these known causes being present.

Unfortunately, we do not

always get to the root case,

and even if we do, time

moves on and we repeat the

mistakes leading to further

failures.



2017 Underground Corrosion Short Course

"Those that fail to learn from history, are doomed to repeat it."

Winston Churchill

Internal - Period 2

February 21-23, 2017

Jane Nicole Brown & Jerry Brown

BROWN CORROSION SERVICES, INC.

Page 44


Questions ???

Thank your for this opportunity to present our views.

Documents

Determining Corrosion Mechanisms in Failurescorrosionshortcourse.com/2017 slides/2017 UCSC Purdue/06... · 2017-03-17 · February 21-23, 2017 . Jane Nicole Brown & Jerry Brown