ICORR Corrosion Awareness - Monitoring 22 08 12 · 2020. 6. 3. · NACE High Corrosion Limit (

Corrosion Awareness Day -

Corrosion Monitoring

1


INTRUSIVE MONITORING

(A Specialized Area of

Corrosion Monitoring)

Steve Tate – (Stork)



2


The RBI / CRA Process…..

• Requires Constant Feedback /

Updating from all Available

Sources.

• Inspection Frequencies Require

Regular Review.




3


KEY RISKS

(Water and Dissolved Gases)




4



Generally the higher the concentration of dissolved gases in

solution the higher the corrosion tendency.

Oxygen most Aggressive.

Gases



5



Effect of Water Cut on Oil Line Corrosion Rate

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 10 20 30 40 50 60 70 80 90

Water Cut (%)

Corrosion Rate, mm/yr

Water



6



FLOWLINE CO2 CORROSION and EROSION

Subsequent Erosion / Scale Undercutting in Direction of Flow

FLOW

DIRECTION

Corrosion and Erosion Damage



7


Corrosion Monitoring…..

• Applications and Benefits (as Part

of an Overall CRA / RBI Process)




8



Corrosion MonitoringCorrosion Monitoring

Sand MonitoringSand Monitoring

MultiMulti--probeprobe

(Sand/Corrosion)/ (Sand/Corrosion)/

Pressure TemperaturePressure Temperature

FSMFSM

Flexible Pipe MonitoringFlexible Pipe Monitoring

and Riser/ Caisson inspectionand Riser/ Caisson inspection

Inspection, IntegrityInspection, Integrity

Management.Management.

CP DesignCP Design

FSMFSM

Plant RBI,Plant RBI,Plant RBI,Plant RBI,Plant RBI,Plant RBI,Plant RBI,Plant RBI,FSM (Refinery)FSM (Refinery)FSM (Refinery)FSM (Refinery)FSM (Refinery)FSM (Refinery)FSM (Refinery)FSM (Refinery)Ports & Harbours: Ports & Harbours: Ports & Harbours: Ports & Harbours: Ports & Harbours: Ports & Harbours: Ports & Harbours: Ports & Harbours: Asset Management, Asset Management, Asset Management, Asset Management, Asset Management, Asset Management, Asset Management, Asset Management, Corrosion ManagementCorrosion ManagementCorrosion ManagementCorrosion ManagementCorrosion ManagementCorrosion ManagementCorrosion ManagementCorrosion ManagementWell Well TestingTesting

CP SurveyCP Survey

Topsides StructuresTopsides StructuresTopsides StructuresTopsides Structures RBI, Plant RBI, RBI, Plant RBI, RBI, Plant RBI, RBI, Plant RBI, PSV RBI, Integrity Management, FSM, PSV RBI, Integrity Management, FSM, PSV RBI, Integrity Management, FSM, PSV RBI, Integrity Management, FSM, Well Testing / Solids Monitoring Risk Well Testing / Solids Monitoring Risk Well Testing / Solids Monitoring Risk Well Testing / Solids Monitoring Risk Based Maintenance, Vessel InspectionBased Maintenance, Vessel InspectionBased Maintenance, Vessel InspectionBased Maintenance, Vessel Inspection

Pipeline RBI,Pipeline RBI,Pipeline RBI,Pipeline RBI, Integrity Integrity Integrity Integrity Management, CP Survey, Management, CP Survey, Management, CP Survey, Management, CP Survey, FSM, CP Engineering FSM, CP Engineering FSM, CP Engineering FSM, CP Engineering ER and Sand probesER and Sand probesER and Sand probesER and Sand probesJacket Risk Based InspectionJacket Risk Based InspectionJacket Risk Based InspectionJacket Risk Based Inspection, Integrity , Integrity , Integrity , Integrity Management, Caisson / Riser Integrity, Management, Caisson / Riser Integrity, Management, Caisson / Riser Integrity, Management, Caisson / Riser Integrity, Caisson / Riser Inspection, CP SurveyCaisson / Riser Inspection, CP SurveyCaisson / Riser Inspection, CP SurveyCaisson / Riser Inspection, CP Survey

FPSO Integrity ManagementFPSO Integrity ManagementFPSO Integrity ManagementFPSO Integrity Management, , , , Corrosion Management, Corrosion Management, Corrosion Management, Corrosion Management, ProcessesProcessesProcessesProcessesIntegrity Management



9


Reasons For Monitoring…..

• To help identify the location, rate,

and underlying causes of

corrosion and erosion.




10


Types of Monitoring…..

1.Intrusive

2.Non-Intrusive




11


Intrusive…..

• Test Coupons (of Same Material as

Pipe.

• Corrosion Probes – Electrical

Resistance, Galvanic, Weld etc.

• Erosion (Sand Monitoring) Probes.




12


Non-Intrusive…..(NDT)

• Electro-magnetic

• Radiographic

• Ultrasonic




13


What Monitoring Gives Us

• Corrosion Coupons – Pitting + Microbial + Corrosion Product Analysis.

• Corrosion Probes – Alarms For Process Trends / Corrosion Trends / Upsets / Loss of Inhibition.

• UT Parent Metal Scan at Probe / Coupon Sites – More Accurate Determination of WT Losses / Regular WT Trending, (Monthly Preferred at Main Complexes).

• TOFD – Additional Weld Monitoring (where Appropriate), e.g. Manifold Tees.




14

1. A Coupon is not a direct measurement of wall

loss but remains a useful guide to process

trends and process ‘corrosivity.

2. An insulating washer separates the test

coupon from the coupon holder and the pipe

wall itself.

3. Coupons should be pulled at least annually for

Examination / Weight Loss Measurement /

Micro Swabbing.


The Corrosion Coupon




15Steve Tate – ConocoPhillips (Stork)

1. Electrical Resistance probes (when used for Corrosion

Monitoring), monitor material loss directly* and do not

require a continuous conductive path. Therefore the

ER technique can be used to monitor corrosion in

areas where water wetting is not continuous or under

deposits where conductive may be limited.

1. The replacement interval for electrical resistance

probes is dependant on probe sensitivity and the

corrosion rate. Readings from ER probes will be

obtained manually or automatically via an offline or

online logging system (PI).


The Corrosion ER Probe



16

1. ER probes of stainless steel, with similar

mechanical properties as for the pipe that is the

subject for monitoring. Hence the erosion sensors

will not corrode and all material loss and can then

be attributed to erosion.

1. Often there is little general evidence of solids

posing a serious problem, other than very

locally at Choke Valves / Sudden Geometry

Changes.


The Erosion ER Probe




17


POSITIONING




18


TOL

12 O’Clock

Watch Future Maintenance / Accessibility !


Positioning



19


Watch Orientation

TOL

12 O’Clock

BOL

5 O’Clock

Better Than 6 O’clock

For Liquids

(Less Debris)

O.K For

Wet Gas

(Orientation

Less

Critical)


Positioning



20


MAIN PROBE TYPES




21



ER Electrical Resistance Probe – is used to track rates of metal loss.

The probe directly measures the increase in resistance of a metal

as its cross-sectional area is reduced by corrosion. At suitable times, after

probe bedded-in readings can be converted into corrosion rates

ER Probe

Electrical resistance probes can be

used in conductive systems, as well

as non-conductive environments

such as oil, gas, and atmosphere.



22



Verifying Metal Loss

Culmulative

Metal Loss v.

Reference

Electrodes



23



Combined Sand/Erosion and

Corrosion Probe

Erosion Elements

Corrosion Element at Rear of Probe

Combination Probe



24



Galvanic Probe - operates by measuring the galvanic current in the circuit between

a steel and a brass electrode and is particularly sensitive to

the amount of oxygen in the water. Although the galvanic current, within certain

restrictions, is proportional to the oxygen concentration in a system.

It is not intended to replace an oxygen sensor (Orbisphere).

Galvanic Probe



25



Weld Probe Counter (Electrochemical Noise Measurement)

Reference Electrode

Weld Metal

Parent Metal

WELD PROBE LAYOUT

Weld Probe

Weld probes - are

fabricated to

simulate Weld Composition

but are not widely used.



26



LPR Probe – LAB Use

LPR probes - are used in

conductive environments

such as water or any

electrolyte. The operating

principle is based on

measuring the flow of

current between

multiple electrodes.



27


MORE EQUIPMENT DETAILS




28



Types of Access Fitting



29



2” Mechanical System Components

Thread

Cap

Flareweld

Fitting

Plug

Assembly

Mechanical to

Hydraulic Fitting

Adapter

Pressure

Retaining Cover

Mechanical System



30



Mechanical to Hydraulic Conversion

2” Mechanical access

fitting 2” Mechanical fitting

converted to hydraulic

system with adaptor

Modern Conversion



31



Service ValvesDouble Isolating

Single Isolating

Safety Valves



32



Safety

Valve

Retrieval

Tool

Pressure

Equalisation

(Fitting

Retrieval

Process)

Valve

Closed

Retriever

Removed

(With

Fitting)

Retrieval Process



33

Heavy Duty Cap with Gauge –

Secondary Pressure Containment





34


DATA TRANSMISSION

(REAL-TIME LOGGING)




35



Logger Logger (or Wireless

Transmitter)

Field BusSand/Erosion

Probe

Corrosion

Probe

Data

PC/Software

Logger Logger (or Wireless

Transmitter)

Field BusSand/Erosion

Probe

Corrosion

Probe

Data

PC/Software



36



Gas Import – BOL Transmitter (White) / ER Probe and HD Cap (Blue)



37


PROBE INFORMATION




38Steve Tate – (Stork)


Probe Retrieval



39



ER probe metal loss results with the introduction of

corrosion inhibitor at maximum production

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

11/11 21/11 01/12 11/12 21/12 31/12 10/01 20/01 30/01 09/02 19/02

Date

Metal loss/ um

E

FGE - Inhibitor injected for 1 day only

F - Inhibitor injection for 5 days

G - Inhibitor injection stopped

H - Inhibitor injection resumed

H

Corrosion rate increasing

from 0.2 to 0.8mm/yr

Corrosion rate

reduced to

approx

0.04mm/yr

Tracking Inhibitors



40



-10

0

10

20

30

40

Jun Jul Aug Sep Oct Nov Dec Jan Feb

µm

16/05/2007 to 01/02/2008

MultiTrend for Windows © 2002 CorrOcean ASA

CE3720 Metal Loss (µm)

Gas KO Drum

Inhibited Operations

Un-inhibited Operations

From Start-Up (Approx 5

Months)

Platform

Shutdown

Corrosion Inhibitor

Commenced

Probe Failure

Metal Loss

Prevented

Previous Trend

Tracking Inhibitors



41



250

260

270

280

290

300

310

Jun Jul Aug

µm

21.05.2001 to 23.08.2001

17.2

17.4

17.6

17.8

18.0

18.2

18.4

18.6

18.8

19.0

19.2

19.4

19.6

µm

MultiTrend for Windows © 2001 CorrOcean ASA

GA-09S ER Metal Loss (µm) GA-09S Metal Loss (µm)

Data from Combined Sand/ER Probe

Sand elementCorrosion element (0.25 mm)

Twin Trace



42


MONITORING EXAMPLES




43



• ER Corrosion Probe Data – early warning for

loss of inhibition measured at tree.

• Sand / Erosion Probe Data - early warning of

sand production and extent of erosion damage.



44

Effect of Corrosion Inhibitor Outage



Excursions



45

Effect of Corrosion Inhibitor Outage





46

Effect of Well Openings



Excursions



47

Effect of Well Openings



Excursions



48


The larger spikes in the middle of the

plot are when production was halted

then restarted and the choke stepped open.

Further Choke Change

Acoustic Monitoring




49


COUPON INFORMATION




50



Gas System Coupons –

Low Corrosion Rates



51



Heavy Weight Loss

and Microbial Attack

Water Injection Coupons – High

Corrosion Rates

Before Cleaning



52



PIPER / TWEEDSMUIR GAS / OIL SYSTEMS

Results of iiCorr Corrosion Coupon Retrieval Analysis - January 2008

Note. Unable to Retrieve Coupons From Amine Sweetening Plant Area This Trip.

0.042 0.045

0.003

0.069

0.168

0.024

0.000

0.050

0.100

0.150

0.200

0.250

0.300

CP 2230 - D/S C2230 -

Piper Cond. KO Drum

CP 2302 - D/S C-2300 -

Tweedsmuir

Separator

CP 2652 - D/S AP-2652

- Pre MOL Export

CP 3230 - D/S E-3230 -

2nd Stage Aftercooler

CP 3720 - U/S C-3720 -

Dehyd In Gas KO

Drum

CP 3722 - D/S C-3720 -

Dehyd In Gas KO

Drum

Estimated Annual Corrosion Rate mm/yr (based on Coupon Findings)

Estimated Annual Corrosion Rate (mm/yr) -Typically 3 x Measured Rate

NACE Low Corrosion Limit (< 0.025 mm/yr)

NACE Moderate Corrosion Limit (<0.126mm/yr)

NACE High Corrosion Limit (<0.254 mm/yr)

EXAMPLE GAS SYSTEM CORROSION RATES

Highest Rates on Dehydration Unit

NACE High

NACE Moderate

NACE Low



53

Coupon Trending





54

International Codes


Typical Standard is 0.100 mm/yr,

(for 30 yr life).

i.e. NACE Medium Rate




55


MAINTENANCE




56Steve Tate – ConocoPhillips (Stork)


Logging

Control

System

Export

Riser Acoustic

All Acoustic

All Intrusive

PI / Experion Control



57

Management Codes


Probe malfunction - Known Reason

Probe malfunction - Reason Unknown

Alarm malfunction - Known Reason Action Implemented or Underway

Action Implemented or Underway

Action Required

Probe Status Indication Codes

OK No Action Required

Coupon changed out

Coupon change out visit due

Coupon not changed out

B/D Below Detection No Action Required

Action Implemented or Underway

Action Required

Coupon Status Indication Codes

No Action Required




58


QUESTIONS ?


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ICORR Corrosion Awareness - Monitoring 22 08 12 · 2020. 6. 3. · NACE High Corrosion Limit (

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