03 Selecting The Right Pig - Pipeline Integrity, Hot...

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Unformatted text preview: Pipeline Integrity, Hot Tapping & Plugging Seminar Sol Elite Marbella, Anyer 10 May 2007 Selecting The Right Pig Iman Y Rahman Pipeline Integrity Engineer The Purpose of Pigging What Is Pigging & Why Pig Pigging Pigging During Pipeline Construction Pigging During Operation Cleaning Batching Displacement How Often Should You Pig What is Pigging ? A widely utilized process which is the act of propelling a properly sized Spherical or cylindrical device through the interior of a pipeline by manipulating the pressure & flow of the existing media, or by artificially introduced media or by mechanically pulling the device through the pipeline for the specific purpose of cleaning, inspecting or distributing inhibitor throughout the pipeline. Why Pig a Pipeline ? • Cleaning - Removal of undesirable materials from a pipeline (H20, Oils, solids, acids, ferrite dust, salts, CO2, O2 etc.) • Clean to improve pipeline operating efficiency • To Inspect a pipeline to locate & remove Anomalies/Defects (metal loss, dents, cracks, etc.) • Mapping a pipeline to assist in bending strain calculations • • • • Application of corrosion inhibitors as preventative maintenance Introduction & removal of Hydrostatic Test water Line Dehydration/Drying To gauge a Pipeline before as Go or No Go for Intelligent Pigging Selecting A Pig For Cleaning Applications • The best choice is a pig with discs, conical cups, spring mounted brushes and bypass ports. • Discs are effective at pushing out solids while also providing good support for the pig. • Conical cups provide excellent sealing characteristics, good support and long wear. • Spring mounted brushes provide continuous forceful scraping for removal of rust, scale and other build-ups on the pipe wall. • Bypass ports allow some of the flow to bypass through the pig and helps minimize solids build-up in front of the pig. Pigging During Construction During pipeline construction it is not uncommon that a certain amount of debris will find its way into the pipeline. This debris must be removed prior to commissioning the pipeline and it is normally removed by pigs that the contractor will run after construction with compressed air. Providing the pipeline is free of any major abnormalities the contractor will then use some aggressive wire brush pigs to remove any rust, scale, weld slag, etc., to clean the line prior to hydrostatic testing. Might Use : Vantage V or OptionAll DC/DC-BR Ideal for removing hard deposits : ( Rust ) ( Scale ) ( Hard Wax ) Vantage V OptionAll Pipeline Pigging During Operation Essentially there are four main reasons why a pipeline needs to be pigged during operation : Cleaning Batching Displacement Inspection Cleaning Cleaning a pipeline during operation is considered to be a maintenance procedure that needs to be done on a regular predetermined frequency using pigs adequately designed for the proper cleaning application. The pigging operation will almost always increase the flow efficiency and reduce operating costs. Might Use : The best choice is a pig with discs, conical cups, spring mounted brushes/blades and or bypass ports WCK-3 Vantage V PitBoss OptionAll Batching Batching is the process of moving different products through the same pipeline. It is much more economical to move several products in one pipeline than to lay dedicated pipelines for each product. Batching pigs are used to separate the products and are normally made up of either two or four cups. Cups are flexible and provide a better seal than discs for product separation. Might Use : The best choice would be a four or two cup pig with RealSeal conical cups or a bi-directional disc pig. BiDirectionAll Pigs OptionAll Pigs Displacement The most common displacement activity occurs in the hydro test phase of the pipeline. A pig is inserted and moved through the pipeline with the testing medium while displacing air in the pipeline. Once the pipeline has been tested, the pig direction is reversed and the water is displaced with air. Might Use : The best choice would be a bi-direction pig with multiple discs. BiDirectionAll Pigs Conclusion In pipelines that have low flow conditions it is more prevalent to see an increase in the collection of free water in the bottom of the pipeline, even in crude oil lines. In low flow conditions you need a mechanical means (pigs) to remove both the solids and liquids that collect in the bottom of the pipeline to help prevent the process of internal corrosion. Most pipelines designed today are designed for standard pigging applications, including the in-line inspection (ILI) tools. Pipeline maintenance programs are designed to maximize flow conditions and prolong the life of the pipeline by utilizing standard pigging applications and chemical batch treatments. How Often Should You Pig ? How much Liquid (gals/bls) are you removing from a pipeline segment ? How much particulate are you removing from filters on the pipeline segment ? How corrosive is the specific pipeline segment environment ? What is the range of dew point in the gas stream of the pipeline segment in question ? How much corrosion already exists in the pipeline segment ? Routine Pigging Pig Type & Frequency Pigging Reports & Data Gathering Determine Pigging Performance Pig Maintenance & Storage Pig Type & Frequency Pig • Based on type & quantity of debris expected • Normally hard bodied cup/disc pig • Should be reviewed regularly based on results Pigging Reports & Data Gathering Pigging • Pig Run report completed for each run - Launch & Receive time, run duration - Pig type, chemical treatments - Debris received, pig condition • Collect debris sample & analyse • Compile database of pigging records Determine Pigging Performance • • • • • • • Measurable increase in line efficiency Measurable increase in through-put Pressure drop Dew point differential before and after pigging Amount of foreign matter removed Amount of liquids removed Reduced corrosion Pig Maintenance & Storage Pig • Check pig condition before each run Bolts are tightened (nyloc, loctite) Cups/discs in good condition, size • Check the pig after run Clean Disc/cups/body from debris, paraffin Check damages or wear cups/disc Pig storage important for long life humidity, temperature, sunlight “thumbnail test” Other Pigging Batching & Displacement Corrosion Mitigation ILI Preparation Pig Tracking & Locating Batching & Displacement Batching • • • • Ultra lightweight batching pig BiDirectionAll batching pig Vantage + & Vantage V pigs RealSeal discs & cups Corrosion Mitigation Corrosion • PitBoss Cleaning Pig - Cleans debris from corrosion pits - Ideal for SRB deposits • V-Jet Pig - Top of the Line corrosion control - Developed in conjunction with Total - Sprays Corrosion Inhibitor to Top of Line ILI Preparation ILI • Preparation essential for good inspection • Minimum of Three Runs - Cup / disc pig with Gauge Plate - Cup / disc pig with Brushes - Magnetic Cleaning Pig Pig Tracking & Locating Pig • PigSigs on Launchers & Receivers - Standard PigSig - NI PigSig • Pig Tracking vs Pig Locating - Active (Trackmaster) - Passive (Flow, Pressure Monitoring) Pig Tracking (TrackMaster) Pig Metal Loss & Crack Detection Magnetic Flux Leakage (MFL) Magpie MFL Tool Defects & Features Options for ILI Tools Ultrasonics (UT) Magnetic Flux Leakage (MFL) Magnetic • • • • • • Induce Magnetic Flux in pipe wall In-direct measurement of remaining WT Permanent vs Electro Magnets Hall Sensors vs Coil Sensors Resolution (sensor spacing x sampling rate) Benchmarking with AGM’s Magpie MFL Tool Magpie • Tool Specification Sheet ( 30” ) • Basics of MFL Tool Defects & Features Defects Types of defects & features identified by MFL tool • Metal Loss or Corrosion • Dents • Fittings & attachments • Flanges & Valves Options for ILI Tools Options • Speed Control • Mapping (INS) Ultrasonics (UT) Ultrasonics • • • • Direct measurement of WT Based option for Crack Detection Normally requires liquid couplant Low maximum speed ( 1 m/s ) Thank You Your Source for… Global Pipeline Solutions Table 9-1 Anomaly Types and Tools to Detect Them METAL LOSS TOOLS ANOMALY TYPES MFL SR detection1, sizing3 no ID/OD discrimination no detection HR detection2, sizing3 no detection4 Ultrasonic (compression wave) detection2, sizing3 no detection4 CRACK DETECTION TOOLS Ultrasonic (shear wave) detection2, sizing3 detection2, sizing3 Circumferential MFL detection2 sizing3 detection2, sizing3 GEOMETRY TOOLS (CALIPER TOOLS) MAPPING TOOLS METAL LOSS (CORROSION) External Corrosion Internal corrosion Narrow Axial External Corrosion CRACKS AND CRACK-LIKE DEFECTS (axial) Stress Corrosion Cracking Fatigue cracks Longitudinal seam weld imperfections Incomplete Fusion (Lack of fusion) Toe-cracks Circumferential cracking DENTS Dents Plain Dents Dents with a Stress Concentrator Gouge Wrinkle Bends / Buckles LAMINATION OR INCLUSION no detection no detection no detection no detection no detection no detection no detection detection2, sizing3 detection2,5, sizing3 no detection no detection no detection detection7 detection and sizing with reduced POD detection7 sizing not reliable no detection detection7 sizing not reliable detection2 and sizing3 if modified6 detection7 sizing not reliable no detection detection7 sizing not reliable no detection no detection detection, sizing not reliable no detection detection8 sizing in case of detection, circumferential position is given as w ell no detection no detection detection and sizing3 detection only of steel sleeves and patches welded to pipe detection no detection detection and sizing3 detection only of steel sleeves and patches welded to pipe detection no detection no detection detection only of steel sleeves and patches no detection detection and sizing3 no detection PREVIOUS REPAIRS detection only of steel sleeves and patches no detection no detection no detection no detection MILL-RELATED ANOMALIES OVALITIES 1. 2. 3. 4. 5. 6. 7. 8. 9. no detection no detection detection sizing3,9 Limited by the minimum detectable metal loss Limited by the minimum detectable depth, length and width of the defects Defined by the specified sizing accuracy of the tool If the width is smaller than the minimum detectable defect width for the tool Reduced POD for tight cracks Transducers to be rotated by 90? Reduced reliability depending on the size and shape of the dent Depending on the configuration of the tool, also circumferential position If the tool is equipped for ovality measurement 9- 3 PEER REVIEW DRAFT –– September 7, 2000 ...
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