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Field Operations and Inlet Receiving
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Pigging is the process of forcing a solid object (a pig) through a pipeline. Two papers by Webb (1978a,b) provide an extensive discussion of pigging for both liquid and gas pipelines. The process involves inserting the pig, via a pig launcher, into the pipeline, moving it through the line using pressure drop, and removing it by using a pig receiver. Pigging is used to perform any of the following functions: Provide a barrier between different liquid products that use the same pipeline.Check wall thickness and find damaged sections of lines (“Smart Pigs”).Remove debris such as dirt and wax from lines.Provide a known volume for calibrating flow meters.Coat inner pipe walls with inhibitors.Control the buildup of condensed hydrocarbon liquids and water in multiphase pipelines.
Basic Materials Engineering
Published in David A. Hansen, Robert B. Puyear, Materials Selection for Hydrocarbon and Chemical Plants, 2017
David A. Hansen, Robert B. Puyear
Corrosion control by chemical inhibitors can be effective, particularly in clean systems in which turbulent flow does not interfere with the adsorption of the inhibitor. Chemical inhibition is usually not an effective mitigation measure in components subject to turbulent flow (such as pumps and control valves). It is also usually ineffective in systems having deposits that prevent the inhibitor from contacting the metal surface to be protected. In “dirty” systems, particularly in plants, chemical cleaning is sometimes a regularly scheduled measure. In most pipeline systems using inhibitors, regular cleaning by means of “pigging” is used. Pigging is done by using pipeline pressure to push a mechanical cleaning device through the pipeline.
Natural Gas Transmission Business: Project Management Aspects
Published in Pramod Paliwal, Sudhir Yadav, Natural Gas Transmission and Distribution Business, 2019
Pigging operations refer to the activity of cleaning the pipeline periodically or inspecting changes in the pipeline features due to corrosion and other conditions using the pigs. Pig refers to the pipeline inspection gauge usually used in piggable lines. The frequency of pigging is determined based on the quantity of debris found during pigging. Pigging cleans the pipeline so that the capacity and life of pipeline is maximized.
Experience and lessons in crude oil pipeline pigging: Case studies from field practices
Published in Petroleum Science and Technology, 2022
Weidong Li, Wenda Wang, Jirong Ran, Huiyuan Li, Jianxun Liu
Compared with wax deposition, pipeline pigging relatively lags behind. By far, multiple wax deposition mechanisms have been developed, such as molecular diffusion, shear dispersion, gravity settling and Brownian diffusion (Azevedo and Teixeira 2003; Aiyejina et al. 2011). Prediction models were accordingly established (Matzain 1999; Burger, Perkins, and Striegler 1981; Hsu and Brubaker 1995; Singh, Youyen, and Fogler 2001; Huang et al. 2011). However when it comes to pipeline pigging, the elusiveness in wax removal mechanism makes it quite a risky job. Pig stalling and wax blockage are the most disastrous accidents in field pigging operations. Pig stalling occurs when the wax layer resistive force exceeds the oil driving force across the pig. Wax blockage is the result of wax accumulation in front of the pig where the oil fails to scour the scraped wax particles downstream. Pig stalling and wax blockage could clog the bulk flow so as to trigger a complete pipeline shutdown, which requires labor-intensive and costly remediation and/or repair treatment.