ICDA of Gas Transmission, Gathering & Storage Systems

GOAL: Develop a protocol for Validation of dry gas ICDA method:– Identify data needs– Develop procedures for validation– Develop evaluation criteria

TASK:– Identify sources of field data for validation– Validate ICDA method for dry gas– Demonstrate the method using an example

Dry Gas ICDA Approach

Utilizing a fluid flow model, the critical angle for water accumulation is determined as a function of gas velocity.

The actual angle of inclination of pipe with respect to gas flow direction is determined through digital elevation maps and pipe burial depths

Example 1

Example 1. (Plot 1 of 4)ICDA Region 1; ICDA Region 16

24.29424.29424.29924.29924.29924.299 25.259

25.26027.77427.774

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24.0 24.5 25.0 25.5 26.0 26.5 27.0 27.5 28.0 28.5 29.0

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Elevation Inclination Anomalies Critical Angle S to NCritical Angle N to S Creeks/ Water Highways Dirt RoadsLaunch Valve, MP24.27 MP 24.29 (historical) Line B Tie-in (MP28.66)

Region 1Region 16

a d e1

c2f2

Moving North

Moving South

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f1 b1 c1g1

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ICDA Process

corrosion

No corrosion No corrosion

0-2 -1 1 2 3-3-4

Region

First highest angle

Gas flow

corrosion corrosion

corrosioncorrosion

Example 1 ICDA Score Card

Percentage of Internal Anomalies Predicted, by Percent Depth:% Depth Number of Anomalies Number of Anomalies Predicted % of Anomalies Predicted20-29 33 31 93.930-39 5 4 80.040-49 2 1 50.0TOTAL 40 36 90.0

Percentage of Internal Anomalies Predicted, by Defect Length:Length (in) Number of Anomalies Number of Anomalies Predicted % of Anomalies Predicted0 to 6 38 35 92.16 to 12 2 1 50.0TOTAL 40 36 90.0

• A historical IC leak was predicted by ICDA.

ICDA Methodologyfor Wet Gas ICDA Goal

GOAL: Develop a method for wet gas ICDA to:– Identify locations most likely to have maximum

internal corrosion– Transmission, gathering & storage pipelines– Focus on HCA rule

Status:– Consensus developed on overall methodology– Detailed flow modeling using FLUENT indicates

applicability of a critical angle– Work ongoing to develop probability distributions for

corrosion severity with distance – Need ILI (or other integrity) data

Improvements to ECDA Assessment Methodology by Incorporating

Soils Data

GOAL: Obtain field data for soils to develop a soils model for existing external corrosion direct assessment (ECDA) datasets and methodology

– Identify corrosion/soils model protocolTask:

– Establish dataset of existing field inspection sites with indirect soils inspection data

– Collect soils-related data from on-going ECDA effort – modify existing soils model, which was developed for stress-

corrosion cracking assessments, for ECDA. – Effort will be conducted concurrently with an ECDA

demonstration project funded by GTI/PRCI.

Improvements to ECDA Assessment Methodology by Incorporating

Soils Data

Status:– Completed collecting soils data from existing operator

dataset– On-going effort to collect soils-related data from parallel

R&D effort with GTI/PRCI – Soils model modification currently under development

Develop high-amplitude guidedwave for long range pipeline inspection

GOAL: Develop a method for rapid screening in long lengths of pipe for corrosion & other defects

– Need high-power, guided-wave inspection technology in buried applications with bituman coating

– Target goal is an increase by 20 fold of amplitude

Task:– Investigate multiple sensor/strip pairs & sensor

optimization– Evaluate alternate strip materials– Modify existing system and validate performance– Conduct field demonstrations