Intelligent Pigging - In Line Pipe Inspection

Standard

Recommended Practice Operation Process

In-Line Inspection of Pipelines

prepared for

ChevronTexaco

April, 2005

ILI INDEX

PHASE I

1.- TOOL SELECTION

1.1 Appropriateness of the Inspection Tool

1.2 Operational Issues

1.3 Tool Environment

1.4 Pipeline Features

1.5 Product, Product Flow, and Speed Requirements

1.6 Surveys

1.7 Pipeline Cleanliness

1.8 Information Gathering

PHASE II

2.- LOGISTICAL GUIDELINES

2.1 Primary Contracting Considerations

2.2 Definition of scope of work

2.3 Liability issues

2.4 Post-Run Operational Report

2.5 Data Specifications

2.6 Reporting Schedule

2.7 Verification Requirements

PHASE III

3.- INSPECTION SCHEDULING

3.1 Factors that should be considered when scheduling the inspection include the following:

3.2 Resourcing (Manpower and Equipment)

3.3 Benchmarking and Tracking

3.4 Contingency Planning

PHASE IV

4.- NEW CONSTRUCTION--PLANNING FOR ILI SURVEYS

4.1 Planning for ILI surveys should begin with system design.

4.2 Materials

4.3 Collection of Construction Information

4.4 Baseline Surveys

4.5 Repair Records

PHASE V

5.- DATA ANALYSIS REQUIREMENTS

5.1 Data Analysis Methodologies

5.2 Pipeline Features Listed and Reported

5.3 Geometry Tool--Specific Analysis and Prioritization Methods

5.4 Metal Loss (Corrosion)--Tool-Specific Analysis and Prioritization Methods

5.5. Crack-Detection Technology--Tool-Specific Analysis and Prioritization Methods

5.6 Inertial Tools/Mapping Technology--Tool-Specific Analysis and Prioritization Methods

5.7 Correlation of ILI Reported Results with Field Measurements

PHASE VI

6.- DATA MANAGEMENT

6.1 The inspection data should be incorporated into an overall integrity plan.

6.2 Operational and implementation information for successful and unsuccessful inspection can be of significant benefit for re-inspections.

6.3 Use of Growth Rates for Corrosion Inspections

GENERAL

This standard is applicable to carbon steel pipeline systems used to transport natural gas, hazardous liquids including anhydrous ammonia, carbon dioxide, water including brine, liquefied petroleum gases (LPGs), and other services that are not detrimental to the function and stability of ILI tools.

This standard is primarily applicable to "free-swimming" ILI tools but not tethered or remotely controlled inspection devices. This standard provides recommendations to the pipeline operator based on successful, industry-proven practices in ILI.

This standard is specific to the inspection of line pipe installed along a right-of-way, but the general process and approach may be applied to other pipeline facilities such as hydrocarbon distribution and gathering systems, water injection systems, station piping, and isolated crossings of railroads, highways, or waterways.

PHASE I

1.- TOOL SELECTION

1.1 Appropriateness of the Inspection Tool

Representatives from the pipeline operator and the ILI service vendor should analyze the goal and objectives of the inspection and match relevant facts known about the pipeline and expected anomalies with the capabilities and performance of an ILI tool. A discussion of these items follows:

* Accuracy and detection capabilities of the ILI method (i.e., probability of detection, classification, and sizing must match the expectations) should be evaluated.

* Detection sensitivity: The minimum detectable anomaly size specified for the ILI tool must be smaller than the size of defect anticipated to be detected.

* Classification capability: The ILI tool should be able to differentiate the targeted defect type from other types of anomalies.

* The sizing accuracy should be sufficient to enable prioritization.

* The location accuracy should enable locating anomalies.

* Requirements for defect assessment: Results of ILI must be adequate for the expected defect assessment algorithm.

1.2 Operational Issues

Pipeline operators should provide a completed questionnaire that lists all relevant parameters and characteristics of the pipeline section to be inspected to the ILI vendor. Operational issues that should be considered are discussed below:

* Mechanical characteristics of the pipe

* Characteristics

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