Assessment of Corrosion under Insulation and Engineered Temporary

Wraps using Pulsed Eddy-Current Techniques

Bill J. Brown and Mike Dixon

TRAC Oil & Gas Ltd, Aberdeen,

UK

Maxim Morozov*, Gordon Dobie and Anthony Gachagan

University of Strathclyde Abstract

Inspection of Corrosion under Insulation (CUI) and material degradation under

Engineered Temporary Wraps (ETW) has proven to be a challenge to reliably detect

and monitor using a number of NDT methods. Pulsed eddy-current has recently been

identified as a potential NDT method for this application. Importantly, the lift-off

between the sensor and the structure being inspected can accommodate the insulation or

ETW layer. This work evaluates the effectiveness of current instrumentation to detect

and assess the degradation under in-service conditions. Moreover, the components

tested and the degradation effects are representative of those found in-service. A

comprehensive inspection and recording process has been undertaken and the resultant

data analysed to identify operating constraints of the method relative to typical

components, representative degradation, dimensions of the degradation and standoff

ranges.

1. Introduction

Carbon steel is a widespread construction material used for the offshore structures in the

oil and gas industry [1]. Carbon steel is an alloy of carbon and iron containing up to 2 %

mass fraction carbon, up to 1.65 % mass fraction manganese, up to 0.60% of silicon and

residual quantities of other elements [2].

Offshore installations are subject to corrosive environment and heavy operational

conditions including elevated temperatures and loads which impose high requirements

on the structural integrity of these structures [3]. External corrosion of carbon steels is determined by the marine atmospheric

environment containing water and chloride salts [1]. Corrosion under insulation (CUI) is

a significant problem associated with offshore carbon steel structures. Internal corrosion

of carbon steel in oil and gas industry is mainly caused by water and dissolved oxygen

in the petrochemical products and can have following mechanisms [1, 4]:

• CO2 and H2S corrosion

• Microbiologically induced corrosion

• Sulfide stress cracking (SSC)/stress corrosion cracking (SCC) caused by H2S

• Hydrogen-induced cracking/step-wise cracking (HIC/SWC)

• Alkaline stress corrosion cracking (ASCC).

2

Traditional methods of NDT used for corrosion monitoring in offshore oil and gas

installations encompass visual examination, ultrasonic testing (UT), acoustic emission

(AE), radiography, eddy current testing (ECT) and magnetic flux [4].

UT requires preliminary surface preparation and acoustic couplant (often water). UT is

not suitable for CUI without removing insulation which is a costly operation. Corrosion

reactions generate elastic waves which can be detected by AE sensors. The main

disadvantage of AE technique is that offshore environment is generally noisy and the

AE signals are weak resulting in poor signal-to-noise ratio. Radiography is only suitable

for limited pipe diameters and involves ionising radiation hazardous for the inspectors.

MFL is efficient when deployed from inside a pipe. Sensitivity of MFL quickly

decreases at large standoffs determined by the insulation when testing from outside a

pipe/vessel.

ECT is a non-contact electromagnetic NDT technique based on induction of eddy

currents in an electrically conducting test piece by means of an excitation coil and

detection of the EC response either by any suitable sensor(s), as shown in Figure 1 [5].

Pulsed Eddy Current (PEC) is an electromagnetic technique using rectangular magnetic

field excitation (see Figure 2a) which induces eddy currents in the steel wall [6, 7].

NDT of ferromagnetic metallic components by means of PEC is regulated by BS ISO 20669:2017 [5]. Insulation and weather jacket constitute coating [5].

Figure 1. Eddy currents testing of a component under coating [5]: 1 sender coil, 2 receiver devices, 3

primary magnetic field, 4 secondary magnetic field, 5 eddy currents, 6 cover/sheeting, 7 insulation, 8

tested component

The eddy currents pulse diffuses into the test specimen until it reaches the far surface.

Secondary magnetic field of eddy currents is acquired by the receiver device of the PEC probe [8]. The moment in time when the EC first reach the far surface is indicated

by a sharp decrease in the received PEC signal shown in Figure 2b [6]. Beginning of the

sharp decrease (bending point) is the measure of wall thickness. PEC is highly efficient

for evaluation of corrosion under coatings [9] and is being to monitor wall thickness of

offshore steel structures [10].

3

This paper presents results of evaluation of wall thickness of carbon steel pipes with

internal corrosion and external corrosion under insulation by means of state-of-art PEC

instrumentation. A comprehensive inspection and recording process has been

undertaken and the resultant data analysed to identify operating constraints of the

method relative to typical components, representative degradation, dimensions of the

degradation and standoff ranges.

Figure 2. (a) PEC excitation signal; (b) PEC response signal

2. Methodology 2.1 Samples

The following carbon steel samples were examined in this study: 1) TRAC Sample 1, a Blistered Pipe, shown in Figure 3 which illustrates extension of

CUI in this sample without insulation and aluminium weather jacket which were

applied during testing:

• Outer diameter: 331.0 mm

• Nominal wall thickness: 10.5 mm

• Insulation: 50.0 mm

• Weather Jacket: Aluminum 1.0 mm

• Corrosion type: external CUI 2) TRAC Sample 2, Epoxy Coated, Figure 4: • Outer diameter: 200.0 mm

• Nominal wall thickness: 10.5 mm

• Coating: epoxy 5.0 mm

3)

• Corrosion type: Pipe with drilled holes:

internal

• Outer diameter: 160.0 mm

• Nominal wall thickness: 8.0 mm

• Artificial defects: through holes with diameters of 25mm and 50mm

4

Probe Nominal lift-off range, mm Nominal footprint, mm

P1 (small) 0 – 20 60

P2 (medium) 20 – 50 120

Figure 3. TRAC Sample 1

Figure 4. TRAC Sample 2

2.2 Experimental setup

The following commercial PEC instrumentation was used in this study: eddyfi Lyft and

Maxwell NDT. Figure 5 shows the used PEC instrumentation: (a) eddyfi Lyft with

various probes, (b) Lyft probe PEC-089-G2-HT05S, (c) Maxwell NDT PECT, (d)

Maxwell NDT small probe P1 and medium probe P2. Properties of the LYFT probe

were as follows:

• Model: PEC-089-G2-HT05S

• Probe Footprint: 95.2 mm

• Circumferential Footprint: 124.5 mm

Properties of Maxwell NDT probes are given in Table 1.

Table 1. Maxwell NDT probes

5

(a) (b)

(c) (d)

Figure 5. PEC instrumentation used: (a) eddyfi Lyft with probes, (b) Lyft probe PEC-089-G2-HT05S, (c)

Maxwell NDT PECT, (d) Maxwell NDT small probe P1 and medium probe P2

2.3 Thickness Measurement Approach

Coordinate grids were applied to sections of the tested samples. C-scans (2D surface

images) of each section were acquired in grid-mapping mode using both eddyfi Lyft

PEC-089-G2-HT05S probe and Maxwell PECT with an appropriate probe depending on

the nominal wall thickness and standoff. Standoff was varied either by placing coating

(combination of insulation and weather jacket) upon the sample or using plastic spacers.

3. Results and discussion

3.1 Eddyfi Lyft

Figure 6 shows C-scan acquired using Eddyfi Lyft on the TRAC Sample 1 with

insulation and weather jacket.

6

mfe

ren

tial [m

m]

Axial [mm]

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 1200 1250

0 10.6 10.8 10.8 10.6 10.4 9.9 9.7 9.9 10.0 10.3 10.5 9.9 9.5 9.8 10.2 10.1 10.1 10.0 10.1 9.7 9.1 9.0 8.8 8.2 8.1 9.1

50 10.9 10.9 10.8 10.8 10.5 10.2 9.9 9.8 9.9 10.3 10.6 10.2 9.8 10.0 10.3 10.2 10.2 10.1 10.2 10.0 9.4 9.2 8.9 8.4 8.4 9.3

100 10.9 10.9 10.9 10.9 10.6 10.3 10.0 9.8 9.9 10.6 10.7 10.3 10.2 10.4 10.3 10.2 10.2 10.3 10.5 10.2 9.6 9.3 9.0 8.5 8.8 9.6

150 11.0 11.0 10.9 10.9 10.6 10.4 10.2 10.0 10.2 10.7 10.7 10.5 10.4 10.5 10.3 10.2 10.3 10.5 10.6 10.3 9.7 9.5 9.3 8.7 9.3 9.9

200 11.1 11.0 11.0 10.8 10.6 10.5 10.4 10.3 10.4 10.7 10.6 10.5 10.5 10.4 10.3 10.3 10.4 10.6 10.7 10.2 9.7 9.8 9.4 8.9 9.6 10.0

Cir

cu

250 11.1 10.9 11.0 10.9 10.8 10.6 10.6 10.6 10.6 10.6 10.4 10.4 10.4 10.4 10.3 10.4 10.5 10.7 10.6 10.1 9.6 9.9 9.6 9.2 9.7 10.1

300 11.1 11.0 11.0 10.9 10.9 10.8 10.7 10.8 10.7 10.5 10.4 10.5 10.5 10.4 10.3 10.4 10.5 10.7 10.5 9.9 9.6 10.0 9.8 9.3 9.7 10.2

350 10.7 10.9 11.0 11.0 10.9 10.9 10.8 10.7 10.7 10.5 10.4 10.4 10.4 10.3 10.3 10.3 10.6 10.7 10.5 9.9 9.7 10.0 9.9 9.5 9.7 10.2

400 10.7 10.7 10.9 11.1 11.0 10.8 10.9 10.8 10.6 10.3 10.4 10.4 10.3 10.2 10.2 10.3 10.5 10.5 10.4 9.9 9.8 10.2 10.0 9.5 9.4 8.7

Figure 6. Eddyfi Lyft: TRAC Sample 1 with insulation and weather jacket

3.2 Maxwell PECT

Figure 7 shows C-scan acquired using Maxwell PECT & medium probe P2 on the

TRAC Sample 1 with insulation and weather jacket. It shows a good qualitative

agreement with Eddyfi Lyft results. Average deviation between Maxwell and Eddyfi

Lyft results is 0.23mm, maxim deviation being 0.75mm. Figure 8 shows C-scan

acquired using Maxwell PECT & medium probe P2 on the TRAC Sample 1 with

insulation without weather jacket. Average deviation between results for the TRAC

Sample 1 with insulation and with and without weather jacket acquired with Maxwell

PECT is 0.10mm.

Figure 7. TRAC Sample 1 with insulation and weather jacket

Figure 8. TRAC Sample 1 with insulation without weather jacket

7

Axial [mm]

0 20 40 60 80 100 120 140 160 180 200

0 10.5 10.7 10.5 10.4 10.8 10.6 10.1 10.3 10.1 10.0 10.0

23 10.3 10.2 10.3 9.8 9.5 9.8 9.6 10.0 10.2 10.3 10.3

[mm

]

46 9.9 9.9 9.5 8.7 8.7 8.8 9.0 9.6 10.0 10.3 10.4

en

tia

l

69 10.1 9.8 9.4 8.7 8.7 8.9 9.2 9.6 9.6 10.2 10.3

u m

fer

92 10.1 9.9 9.5 9.3 9.4 9.3 9.7 10.0 10.2 10.1 10.0

Cir

c

115 10.1 9.9 9.6 9.9 10.5 10.2 10.5 10.2 10.2 10.1 10.0

138 10.2 9.9 9.9 10.0 10.1 10.2 10.4 10.3 10.3 10.1 10.3

161 10.7 10.6 10.3 10.4 10.1 10.6 10.7 10.8 10.7 10.7 10.6

Figure 9. Individual blister without corrosion product (scab) in contact (no coating)

Axial [mm]

0 20 40 60 80 100 120 140 160 180 200

0 10.5 10.3 10.2 10.1 10.1 10.1 10.2 10.1 10.0 9.8 9.4

23 10.4 10.4 10.2 10.1 10.0 9.8 9.9 9.9 10.0 9.9 9.6

[mm

]

46 10.4 10.2 10.0 9.8 9.7 9.7 9.7 9.8 9.9 9.9 9.8

en

tia

l

69 10.3 10.3 10.0 9.8 9.6 9.6 9.7 9.8 9.9 9.9 10.0

u m

fer

92 10.2 10.2 10.0 9.8 9.7 9.7 9.8 9.9 10.1 10.1 10.1

Cir

c

115 10.2 10.1 10.1 10.0 9.9 9.9 10.0 10.0 10.2 10.3 10.3

138 10.1 10.1 10.1 10.2 10.2 10.2 10.2 10.4 10.4 10.6 10.6

161 10.1 10.2 10.3 10.4 10.5 10.5 10.6 10.6 10.7 10.8 10.9

Figure 10. Individual blister without corrosion product (scab) through insulation and weather jacket

An individual blister located on the TRAC Sample 1 was scanned both in contact and

through coating (insulation and weather jacket) with corrosion products (scab) of

thickness above 5mm present and after corrosion products were mechanically removed.

Figure 9 shows C-scan of the individual blister without corrosion product (scab) in

contact (no coating) acquired using small probe P1. Figure 10 shows C-scan of the

individual blister without corrosion product (scab) through insulation and weather jacket

acquired using medium probe P2. Average deviation with respect to the contact

measurements is 0.31mm, maximum deviation being. This result demonstrates that

presence of coating within the operating range of PEC equipment does not significantly

influence results. Figure 11 shows C-scan of the individual blister with corrosion

product (scab) through insulation and weather jacket acquired using medium probe P2.

Average deviation with respect to the case of no corrosion product is 0.36mm,

maximum deviation being 0.57mm. This result demonstrates that moderate amount of

corrosion product does not significantly influence results.

Figure 12 shows C-scan acquired in contact using P1 probe on the Enquest sample with

internal corrosion and erosion channel.

Figure 13 shows C-scan acquired in contact using small P1 probe on the sample with a

hole of 25mm diameter. The PEC signature of a hole is clearly detectable although the

thickness readings in the centre of the hole are higher than 0mm due to EC response

averaging effect over the probe footprint. Figure 14 shows C-scan acquired at standoff

of 20mm using small P1 probe on the sample with a hole of 25mm diameter. Thickness

readings in the centre of the hole are higher compared to the contact measurement (see

Figure 13) since the effective footprint of the probe increases with standoff as 1.5 x

8

rc u

m

(Standoff + Wall Thickness). Figure 15 shows C-scan acquired at standoff of 20mm

using small P1 probe on the sample with a hole of 50mm diameter. As expected,

thickness readings in the centre of the larger hole are lower than that in case of the

25mm hole (Figure 14) since the average “weight” of the no-metal signal is higher for

the bigger hole.

Axial [mm]

0 20 40 60 80 100 120 140 160 180 200

0 10.5 10.1 10.0 9.9 9.7 9.7 9.8 9.8 9.7 9.4 9.2

23 10.0 10.0 9.9 9.7 9.6 9.6 9.5 9.7 9.6 9.4 9.2

[mm

]

46 10.0 9.9 9.7 9.5 9.4 9.5 9.5 9.5 9.5 9.5 9.5

en

tia

l

69 10.0 9.9 9.6 9.4 9.3 9.4 9.5 9.5 9.6 9.6 9.6

u m

fer

92 9.8 9.8 9.6 9.5 9.4 9.4 9.5 9.6 9.7 9.8 9.7

Cir

c

115 9.8 9.7 9.7 9.6 9.6 9.5 9.6 9.7 9.8 9.9 9.9

138 9.8 9.7 9.8 9.8 9.8 9.8 9.9 10.0 10.0 10.1 10.0

161 9.8 9.8 10.0 10.0 10.0 10.1 10.1 10.2 10.3 10.3 10.3

Figure 11. Individual blister with corrosion product (scab) through insulation and weather jacket

Axial [mm]

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840

0 19.0 18.9 18.7 18.9 18.8 18.9 19.1 18.9 19.0 18.9 18.8 18.7 18.5 18.4 18.3 18.1 18.4 18.4 18.0 17.9 18.0 17.4 17.6 18.0 18.6 18.5 18.3 18.3 18.2 18.3 18.9 18.9 18.9 18.5 18.6 18.4 18.0 18.2 18.3 18.3 18.1 18.0 18.4

23 18.7 18.4 18.0 18.1 18.1 18.0 18.2 18.6 18.7 18.7 18.6 18.4 17.9 17.7 17.5 17.8 17.4 17.7 17.4 17.4 17.5 16.9 17.2 18.0 18.2 18.3 18.0 17.9 17.6 17.7 18.1 18.3 18.4 18.4 18.6 18.4 18.4 18.7 18.9 18.6 18.4 18.1 18.7

46 18.1 17.2 16.1 15.7 15.8 16.0 16.5 16.8 17.1 17.6 17.5 16.5 15.8 15.8 15.6 15.7 16.0 16.1 16.0 15.7 16.1 16.1 16.8 17.1 17.0 17.1 16.8 16.6 16.3 16.4 16.5 16.7 17.1 17.2 17.4 17.7 17.9 18.2 18.5 18.6 18.2 18.2 18.4

m]

69 15.9 15.0 13.8 13.6 13.8 14.1 14.4 14.7 15.1 15.6 15.5 14.6 13.8 13.7 13.8 13.4 13.7 13.7 13.5 13.7 14.1 14.3 15.1 14.6 14.9 14.5 14.6 14.3 13.7 13.5 13.7 13.9 14.4 14.5 14.9 15.4 15.9 16.7 17.1 17.4 17.4 17.7 17.5

ial

[m

92 13.7 13.0 12.6 12.5 12.4 12.6 12.8 12.9 13.2 13.4 13.5 12.8 12.4 12.2 12.2 12.0 11.9 11.7 11.7 11.8 11.9 12.6 12.9 12.8 12.6 12.4 12.5 12.0 11.5 11.4 11.4 11.6 11.5 11.6 11.7 12.3 13.3 14.2 15.0 15.8 16.3 16.4 15.8

fere

n t

115 12.1 11.9 11.9 11.8 11.9 11.9 11.9 12.0 12.0 11.9 11.9 11.9 11.6 11.4 11.5 11.2 11.1 10.7 10.7 10.5 10.8 11.8 13.1 13.2 13.1 13.4 12.9 12.4 12.1 12.2 11.8 10.9 10.8 10.2 9.9 9.9 10.6 11.6 12.6 14.0 14.7 15.6 14.1

138 11.9 11.8 11.7 11.8 11.9 12.0 11.9 11.9 11.8 11.8 11.8 11.8 11.7 11.6 11.6 11.4 11.2 11.0 10.8 10.7 11.1 12.6 14.4 15.1 15.7 15.6 15.3 15.0 14.7 14.8 14.1 13.2 12.4 11.1 10.1 9.3 9.8 10.7 11.8 13.0 14.6 15.0 13.3

Ci

161 13.1 12.8 12.7 12.6 12.7 12.9 12.7 12.7 12.7 12.8 12.9 12.9 13.1 13.1 13.2 13.0 13.1 13.0 12.8 12.7 13.0 14.3 15.5 16.2 16.3 16.5 16.7 16.3 16.0 15.9 15.5 15.2 14.5 13.2 12.3 12.1 12.3 13.0 13.7 14.5 15.7 15.8 14.5

184 14.5 13.9 13.8 13.7 13.9 14.0 13.7 13.8 14.1 14.3 14.6 14.9 14.9 15.2 15.2 15.2 15.4 15.5 15.4 15.3 15.5 16.2 16.7 17.0 16.4 16.9 17.1 16.9 16.3 16.1 16.2 16.4 16.2 15.7 15.1 15.2 15.3 15.7 16.1 16.7 17.1 16.7 15.9

207 16.5 15.5 15.3 15.3 15.7 15.9 15.8 15.8 16.1 16.4 16.9 17.3 17.5 17.3 17.0 17.0 17.2 17.5 17.7 17.5 17.7 17.9 18.0 17.4 17.1 17.6 17.8 17.8 16.7 16.8 16.9 17.2 17.2 17.4 17.1 17.3 17.6 17.6 17.6 18.2 18.1 18.0 17.6

230 17.4 16.7 16.6 17.0 17.3 17.7 17.8 17.6 17.9 17.9 18.1 18.6 18.8 18.7 18.2 17.8 17.7 18.2 18.3 18.2 18.4 18.4 17.9 17.7 18.2 18.2 18.3 17.9 18.0 17.9 17.8 17.7 18.2 18.3 18.4 18.5 18.5 18.5 18.3 18.4 18.7 18.5 18.3

253 17.7 17.1 17.2 17.6 18.0 18.4 18.3 18.1 18.5 18.3 18.1 18.3 18.6 18.5 18.1 17.6 17.6 17.8 18.2 18.1 18.2 18.0 17.8 17.7 18.2 18.2 18.0 18.1 17.9 18.5 18.4 18.1 18.4 18.3 18.6 18.7 18.0 18.2 18.1 18.1 18.4 18.4 18.4

Figure 12. Enquest sample with internal corrosion and erosion channel

Ax ial [mm]

0 23 46 69 92 115 138 161 184 207 230 253 276

mm

]

0 8.0 8.0 7.9 7.8 7.7 7.6 7.7 7.9 8.0 8.0 7.8 7.9 7.9

en

tia

l [

20 7.9 7.9 7.8 7.8 7.7 7.6 5.9 7.4 8.0 8.0 8.1 8.1 8.0

u m

fer

40 7.8 7.8 7.8 7.8 7.7 7.8 4.8 6.8 8.1 8.1 8.2 8.0 7.9

Cir

c

60 7.7 7.8 7.8 7.7 7.7 7.7 6.3 7.8 8.1 8.1 8.1 8.0 7.8

80 7.8 7.8 7.8 7.7 7.8 7.9 8.0 8.1 8.1 8.2 8.2 8.0 7.9

Figure 13 Hole ⌀25mm in contact

Ax ial [mm]

0 23 46 69 92 115 138 161 184 207 230 253 276

mm

]

0 8.0 8.2 8.1 8.1 8.0 7.9 7.7 7.9 8.2 8.3 8.3 8.3 8.2

en

tia

l [

20 8.0 8.1 8.1 8.0 8.0 8.0 6.3 7.3 8.3 8.3 8.3 8.3 8.2

u m

fer

40 7.9 8.0 8.1 8.1 8.0 8.2 5.8 7.3 8.4 8.4 8.4 8.4 8.2

Cir

c

60 8.0 8.0 8.0 8.0 7.9 8.0 7.1 7.6 8.3 8.4 8.5 8.3 8.2

80 8.0 8.0 8.0 8.0 8.0 8.1 8.0 8.2 8.4 8.5 8.5 8.4 8.1

Figure 14 Hole ⌀25mm at 20mm standoff

9

Ax ial [mm]

0 23 46 69 92 115 138 161 184 207 230 253 276

0 8.0 8.0 8.0 8.1 8.1 7.8 7.5 7.5 7.8 8.0 8.0 7.9 7.9

mm

]

20 8.0 8.2 8.1 8.1 8.1 7.7 5.9 6.5 7.7 8.0 8.0 7.9 7.9

en

tia

l [

40 8.1 8.2 8.3 8.1 8.3 7.7 4.1 4.5 7.9 7.9 8.0 8.0 8.0

u m

fer

60 8.1 8.2 8.1 8.2 8.3 7.8 4.0 4.4 8.1 8.0 8.0 8.1 8.1

Cir

c

80 8.0 8.0 8.0 8.2 8.1 7.3 4.5 5.1 7.8 8.0 8.0 8.0 8.0

100 8.0 8.1 8.0 8.0 8.0 7.4 6.3 7.0 7.7 7.9 7.9 8.0 8.0

120 8.0 8.0 8.0 8.0 7.9 7.8 7.4 7.5 7.7 7.8 7.9 7.9 7.9

Figure 15 Hole ⌀50mm at 20mm standoff

3. Conclusions

This work presented results of PEC NDT to detect and evaluate corrosion in offshore

carbon steel structures. The components tested and the degradation effects are

representative of those found in-service. A comprehensive inspection and recording

process has been undertaken and the resultant data analysed to identify operating

constraints of the method relative to typical components, representative degradation,

dimensions of the degradation and standoff ranges. • Wall thickness was measured through insulation of 50mm and aluminium weather

jacket in walls of thickness up to 20mm with accuracy of 0.25mm; • Thin aluminium weather jacket has virtually no impact on results;

• Standoff increases the area over which thickness is averaged;

• Larger probe footprint increases the area over which wall thickness is averaged;

• Corrosion products (ferromagnetic scab) of thickness of up to 10mm has similar

influence on the PEC response as standoff;

• Holes in walls of thickness of 8mm produce an indication in C-scan when scanned

with medium (P2) probe at stand-off distance of up to 20mm.

Acknowledgements

This work is funded by the Centre Sensor and Imaging Systems (CENSIS) and TRAC

Oil & Gas Ltd in partnership with the Oil & Gas Technology Centre (OGTC).

References

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