Wei Ke - Corrosion Nov 2014

Corrosion in General

KeweiNov 19, 2014

© 2014 HALLIBURTON. ALL RIGHTS RESERVED. 2

What’s included in this presentation

▌ I. A quick overview of corrosion problem▌ II. Types of corrosion - Chemistry & Mechanism▌ III. Ways of mitigation


Part I. A qucik overview of corrosion problem

▌ Q1. What is Corrosion?▌ Q2. Where Corrosion Occurs?▌ Q3. Why is it A Problem?▌ Q4. Who Should Care?


Q1. What is Corrosion?


Definitions...

▌ 1. Corrosion is the destructive attack of a material by reaction with its environment and a natural potential hazard associated with oil and gas production and transportation facilities. OR:

▌ 2. Corrosion is the oxidation of a metal due to an ELECTROCHEMICAL reaction. The oxidizing agent is most often O2 (atmospheric corrosion) or H+

(chemical corrosion) or both. OR:▌ 3. Corrosion is the deterioration of a substance (usually a metal) because of a

reaction with its environment. OR:▌ 4. Your definition?


▌ Literally, almost any aqueous environment▌ Numerous complex conditions in oil and gas production, processing, and

pipeline systems. ▌ Highly corrosive media in oil & gas industry: CO2, H2S, impure water, etc...

Q2. Where Corrosion Occurs?


Q3. Why is it A Problem?

1. Economy2. Health3. Safety4. Environment

What happens: material degradation loss of mechanical properties (strength, ductility, etc) loss of mass, reduced thickness malfunction / leakage / failure accident / expense / catastrophy...

Other effects: loss of economy; oil spillage and environmental threat;ecological damage, etc.


Total cost?

▌ 3-5% GNP (all industrilized countries)▌ In oil and gas industry?

Directly, 1,372 billion USD annual cost (2012/2013):

= 589 mil for surface pipeline and facilities

+ 463 mil for downhole tubings

+ 320 mil for other corrosion related capital expenditures

Indirectly: tens of billions USD for lost income and treatment costs.


▌ Field Operators▌ Pipeline engineers▌ Designers▌ Other industry participants dealing with metal▌ ...▌ And when it comes to everyday life, all of us

Q4. Who Should Care?


Part II. Types of Corrosion (Chemistry & Mechanism)

▌ Q5. How Does It Happen?


▌ Three elements: an anode (the corroding metal), a cathode, and a corrosive media: an electrolyte. Electrons flow from anode to cathode through elctrolyte.

▌ The metal gradually loses mass and becomes porous, and fragile, and loses original strength and shape, day by day.

Q5. How Does It Happen?


Corrosion types and associated agents in oil and gas industry

▌ Most common type: when steel meets aqueous environment and rusts▌ When metal is exposed to a corrosive solution (electrolyte), the metal atoms at

the anode site lose electrons, and the cathode, in contact with the electrolyte, conducts this exchange in an attempt to balance their positive and negative charges.

▌ Anodic reaction: Fe Fe2+ + 2e- (take iron rusting for example)▌ Then, based on the electrolyte and solution pH, there are four common cathode

reactions. One of the following four would occur.


Cathode reactions

▌ O2 +4 H+ + 4 e- 2 H2O (Oxygen reduction in acidic solution), OR:

▌ ½ O2 + H2O + 2 e- 2 OH- (oxygen reduction in neutral or basic solution), together with above when oxygen is present, is Oxygen corrosion. OR:

▌ 2 H+ + 2 e- H2 (hydrogen evolution from acidic solution, acid corrosion), OR:

▌ 2 H2O + 2 e- H2 + 2 OH- (hydrogen evolution from neutral solution, water corrosion)

Oxygen corrosion

Acid corrosion

Water corrosion


In oil and gas industry, we often have CO2 or H2S, or even both:

General reactions:

With CO2 : Fe + H2O + CO2 FeCO3 + H2 (Sweet corrosion)

With H2S: Fe + H2S + H2O FeS + 2 H + H2O (Sour corrosion)

(Water is also the catalyst in this case)

And if both CO2 or H2S are present, then both reactions take place.

Pipeline under sour corrosion

End of story? Not yet...

Steel under sweet corrosion


Galvanic corrosion

Corrosion of an iron nail wrapped in bright copper wire, showing cathodic protection of copper; a ferroxyl indicator solution shows colored chemical indications of two types of ions diffusing through a moist agar medium

http://en.wikipedia.org/wiki/Cathodic_protection

http://en.wikipedia.org/wiki/Cathodic_protection

http://en.wikipedia.org/wiki/Ferroxyl_indicator_solution

http://en.wikipedia.org/wiki/Ferroxyl_indicator_solution


ANODIC INDEX


Crevice corrosion

▌ Localized corrosion taking place in the narrow clearances or crevices in the metal and the fluid getting stagnant in the gap. Oxygne dissolved in drilling mud for instance promotes crevice and pitting attack.


Errosion corrosion

▌ Increases corrosion reaction rate by continuously removing the passive layer of corrosion products rom the wall of the pipe. Turbulence and high shear stress in the line could re omve this passive layer which could stabilize the corrosion reaction and slow it down.

▌ High velocities and presence of abrasive suspended material and the corrodents in drilling and produced fluids contribute to this destructive process.

▌ This form of corrosion is often overlooked or recognized as being caused by wear.


Microbiologically induced corrosion (MIC)

▌ Caused by bacteria activites.

▌ Bacteria produces waste products like CO2, H2S, and organic acids that corrode the pipes by increasing the toxicity of the flowing fluid in the pipeline. the formation of micorbe colony is promoted by neutral water especially when stagnant.

▌ Common bacteria species involved in this type of corrosion include: Bacillus, pseudomonas, Micrococcus, Mycobacterium, Clostridium and Escherichia.

▌ Recognized by the appearance of a black slimy waste material or nodules on the pipe surface as well as pitting of the pipe wall underneath these deposits.


Stress corrosion cracking (SCC)

▌ A form of locallized corrosion which produces cracks in metals by simultaneous action of a corrodent and tensile stress.

▌ Propagates from 10-3 to 10 mm per hour, depending on the combination of alloy and type of environment involved.


Part III. Ways of Mitigation

▌ Q6. How to Mitigate Corrosion?


▌ Material selection▌ use of inhibitors▌ Use of protective coatings▌ Cathodic protection▌ Adequate corrosion monitoring and inspection

Q6. How to Mitigate Corrosion?


Material selection

▌ Recommened materials

For Oil & Gas Industry

Quiz 1. Which metals you know that alone or with alloy can resist strong acid?


Use of inhibitors

▌ To protect metal surface either by merging with them or by reacting with the impurities in the environment that may cause pollution.

▌ Varied Mechanisms: 1. restrict rate of anodic or cathodicprocess by blocking active sites on surface; 2. increase the chemical potential of the metal surface so a natueal oxide film forms and slows down the overall reaction rate; 3. the inhibitor compounds form a thin layer on the surface to restrict the corrosion process.

▌ Factors to concern when using corrosion inhibitors:

1. Toxicity. 2. Environmnetal friendliness 3. Availability 4. cost


Choice of corrosion inhibitors

▌ Recommended inhibitors for

Oil and gas applications

World consumption of corrosion inhibitors


Corrosion Inhibitor Systems Portfolio in Halliburton

Check the following Technology Bulletins: ▌ SMA-01-001: HAI-OS Corrosion Inhibitor for Regular or Weighted Acids

▌ SMA-03-005: FDP-S692-03 Corrosion Inhibitor for Organic Acids▌ SMA-04-029: HAI-202 Environmental Corrosion Inhibitor for the North Sea

▌ SMA-05-025: HAI-303 Environmental Hydrochloric Acid Corrosion Inhibitor▌ SMA-06-002: HAI-150E Environmental Low-Temperature Corrosion Inhibitor

▌ SMA-06-011: FDP-S808A-05 and FDP-S808B-05 Corrosion Inhibitor System

▌ SMA-08-012: HAI-404MTMHigh-Temperature Acid Corrosion Inhibitor for HCl-based Acids

▌ SMA-08-035: HII-124T Corrosion-Inhibitor Intensifier

▌ SMA-09-037: FDP-S920-09 Acid-Corrosion Inhibitor for Sour Conditions

▌ SMA-09-079: HAI-GE Corrosion Inhibitor

▌ SMA-10-008: HAI-980 28% HCl Acid-Corrosion Inhibitor for HCl-based acids

▌ SMA-10-011: HAI-82TM Acid Corrosion Inhibitor


Use of Protective coatings▌ A protective or barrier layer on the material to avoid direct contact with the process media

and so to enhance the material and equipment life.

▌ Can be painting,coating or lining, metallic lining or metallic sheets. Also non-metallic linings like fiber glass, glass flake, epoxy, and rubber which are normaly carried out on the equipment like separators, knock-out drums, and storage tanks.

▌ Nickel, zinc or cadmium coatings are also preferred at times on certain components like flanges and boltings.

▌ Example: CoP Ekofisk wells completed with N-80 tubing. With/wo plastic coating with inhibitor batch treatment every 30 days: tubing life of 19 months VS. 7 years.

▌ Fusion-bonded epoxy (FBE) and a three-layer polyolefin (3LPO) are currently the most widely used external anti-corrosion coating systems.

3LPO treatment


Cathodic protection technique

▌ Can be designed to prevent both oxygen-controlled and microbiologically controlled corrosion.

▌ Two methods of applying cathodic protection:

▌ Sacrificial (or galvanic) anode cathodic protection (SACP)

▌ Impressd current cathodic protection (ICCP)

▌ The main difference is that ICCP uses an external power source with inert anodes and SACP uses the naturally occurring electrochemical potential difference between different metallic elements to provice protection.

SACP ICCP


Adequate corrosion monitoring and inspection

▌ Use of probes (electrical, mechanical, electrochemical)▌ Inserted into the process stream continuously exposed to the stream

conditions. ▌ Provides direct and online measurement of metal loss and corrosion rate in oil

and process systems.


A Few Things to Sum Up

▌ Corrosion is a complicated, worldwide problem and should always be considered prior to and during field practice.

▌ The most prominent and yet very applicable material type is often Ni – Cr – Fe alloys, especially for wellhead and flow lines with high sour and temperature applications.

▌ Corrosion inhibitors are one of the major tools for tackling corrosion in the oil and gas industry.

▌ About coating, think about the CoP case, 19 months VS. 7 years!

▌ Best way to check corrosion? Visual inspection, and checking up material degradation periodically. And remember, not just our industry has this problem, it is a global problem in all industries and value chains.


Are some environments more corrosive than others? YES!!!

▌ Moist Air > Dry Air▌ Hot Air > Cold Air▌ Polluted Air > Clean Air▌ Hot Water > Cold Water▌ Salt Water > Fresh Water▌ Acids > Bases▌ Ordinary Steel > Stainless Steel > Special alloys

Quiz 2: Will corrosion occur in a vacuum?

And at very high temperatures?


Quiz 3:

Does an airplane corrode faster when on the ground or when flying? Why?


References

▌ Popoola et al. “Corrosion problems during oil and gas production and its mitigation”. International Journal of Industrial Chemistry, 2013, 4:35

▌ USNA: “Corrosion Lecture”

▌ Net Lecture: “ Introduction to Corrosion”

▌ Halliburton Stimulation I Textbook

▌ Halliburton Technology Bulletins

▌ Wikipedia

▌ http://petrowiki.org/Corrosion_problems_in_production

▌ http://www.lehigh.edu/~amb4/wbi/kwardlow/corrosion.htm

http://petrowiki.org/Corrosion_problems_in_production



http://www.lehigh.edu/~amb4/wbi/kwardlow/corrosion.htm



Wei Ke - Corrosion Nov 2014

Documents

Transcript of Wei Ke - Corrosion Nov 2014