Corrosion Assessment


Assessment of corrosion and metal loss to evaluate well conditions, performance, MAASP and other operating parameters is a constant activity during the life cycle of a well. For operating companies, the ability to perform precise diagnostics rigless is a significant advantage as well as a cost-saving solution.

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The Customer was preparing to launch a well integrity logging campaign including corrosion and metal loss diagnostics. Prior to it, they decided to evaluate through-tubing electromagnetic technologies from different providers available in the market to assess their accuracy.


TGT, among four major companies, was requested to conduct a blind yard test. The Customer made, through a third-party company, a number of random defects to assess tool accuracy and sensitivity. The following three scenarios were used in a set of tests:

A: 4-1/2” tubing inside 9-5/8” casing (centralised, tilted and laid down)

B: 3-1/2” tubing inside 9-5/8” casing

C: 5-1/2” tubing inside 9-5/8” casing


The attached log shows the results of Scenario A.

– TGT’s EmPulse® was able to measure the individual thicknesses of three different strings and detect corrosion in them, and was ranked first among all competitors

– TGT’s first-string evaluation produced better results, even compared with multi-finger calipers

– All defects were detected in both tubing and casing, confirming the specifications and accuracy of the tool as well as a significant advantage over competitors

– When the tubing was tilted or decentralised, the sensitivity of the tool was less affected than that of the competitors’ tools

– Logging speed had a minor effect on the tool sensitivity compared with other assessed technologies

– With over 180 channels, TGT’s EmPulse® was superior in terms of both data acquisition and processing


The Customer chose TGT as the best technology provider in the market to independently assess multiple strings for thickness and corrosion, and assigned the above-mentioned scope of work to the company.
July, 2016