Thousands kilometers of pipelines go through all 5 continents. They are designed, constructed and tested in accordance with severe standards and building rules and regulations. Particular important is to provide required performance and operation data for safe and reliable supply of product to be transported. Regular inspection is required to know actual pipeline condition and to predict its performance degradation. Thus, one of the major issues today is to choose a proper cost-effective pipeline inspection technique.

Subsidiary Company "Orgenergogaz" is a high-ranked company affiliated with "Gazprom". It developed inspection technology enabling to detect, to identify and to size main pipeline defects. Precise defect location and severity of anomalies in terms of pipeline integrity allow organization involved in pipeline maintenance to make cost-efficient and safe repair policy.

"Orggazdefectoscopy" Engineering and Technical Center incorporated in "Orgenergogaz" gained 10-year experience in performing main pipeline inspection via in-pipe inspection.

Integrated inspection of tens of thousands kilometers of gas, oil and product pipelines, 1000, 1200 and 1400 mm in diameter, has been conducted by qualified specialists of the Center. During inspection the latest generation smart pigs have been used and hundreds of defects have been detected hazardous to safe pipeline operation.

Specialists of the Center are tooled with high quality equipment made by themselves and by well-known world companies.

Smart pig operation is based on magnetic flux leakage (MFL), reliable, stable and suitable technique for in-service pipeline. Each inspection vehicle is equipped with a large amount of sensors logging signals with several mm spacing around and along the pipe. The optimized inspection vehicle design provides high resolution and allows to detect minor defects in terms of pipeline integrity and safety. Thus, organizations involved in pipeline operation have the opportunity to obtain information about hazardous pipeline segments at the early stage of defect origination and its further evolution and to take corrective actions.

Inspection vehicles are capable to detect a wide range of severe defects including:

• External and internal corrosion
• Metal loss in girth weld and spiral weld joints
• Metal loss
• Dents (including dent identification)
• Defects hidden under housing
• Defects under repair sleeves

Other detectable defects and pipeline components:

• Manufacturing (mill induced) defects
• Faults induced during pipeline construction (scratches, scores)
• Foreign matters along pipeline that can damage pipe coating and cause cathodic protection failure
• Casing including eccentric ones, eccentricity of which can effect pipe coating integrity and cathodic protection efficiency.

Currently the following types of inspection vehicles ("smart pigs") are available at "ORGGAZDEFECTOSCOPY" Engineering and Technical Center: DU-1020 mm, DU-1220 t, DU-1420 t.

Velocity range of product to be transmitted when in-pipe inspection is performed is 0,5 - 6 m/sec. Inspection vehicle can negotiate pipe bend radius as large as 3 pipe D. Maximum pipeline segment length that can be inspected during one inspection vehicle run is 300 km.

Test rig is used to determine inspection vehicle performance. It allows to push caliper in environment close to live pipelines.

In-pipe inspection is performed according to well-developed technology:

• Assessment of pig launcher and pig receiver to decide what in-pipe inspection tools can be used.
• Meeting with organization in charge of pipeline operation to schedule gas flow direction and inspection vehicle run and to determine right-of-way and inspection vehicle to be matched etc.
• Shipping of inspection vehicle and attached hardware in the field.
• Cleaning pig run to remove welding electrodes and foreign matters from pipe and provide condition for reliable inspection.
• Profile and caliber pig run to determine pipeline geometry and provide condition for safe inspection vehicle run.
• Field reply and post-run diagnostics are used to verify data validation. Upon validation of successful inspection vehicle run collected data is analyzed and within 24 hours customer is given data about hazardous defects.

Signal analysis and defect identification

Signal analysis and defect identification is one of the major issues of pipeline inspection. During inspection vehicle run hundreds of millions of measurements are logged that are handled and converted into list of pipeline defects and components with indication of defect size and location. A significant item of pipeline inspection data handling is advanced mathematical analysis technology developed to support in-pipe inspection.

The bulk of data handling is carried out at Information Center of ORGGAZDEFECTO-SCOPY" in Saratov.

Subsidiary Company "Orgenergogaz" can render assistance in pipeline defect assessment. High-qualified specialists will perform complete pipeline inspection to evaluate its fitness for service.

Long-term experience in pipeline inspection and comprehensive approach to its implementation provide prerequisites for establishment of partnership spirit relations with customers to render them expedite assistance in resolving the issue of safe pipeline inspection.