A fault well found 

01 February 2015

Casey Henry, marketing program manager

Shortly after he had purchased a compact dual-channel time domain reflectometer, Antonio Torres, the owner of Mr T Spooling and Banding, a company that specialises in the installation and maintenance of electrical cables in oil wells, had a convincing demonstration of the instrument’s usefulness and accuracy.

To gain experience in using his new instrument and in interpreting the results, Antonio Torres took Megger engineer, Mike Palmer, to a working well site in Long Beach California, with the objective of carrying out tests on a cable that was being installed in the well. The cable is used to control an oil pump some 10,000 feet into the well.

“The operators stopped the well so that I could capture some TDR traces,” said Mike Palmer, “and, as soon as I saw the first trace, I noticed that there was an event at around 2,200 feet. I commented that this looked like a tear in the outer sheath of the cable, but the lead superintendent dismissed this, saying that it was a coupling in the cable and was, therefore, of no concern.”

This confident assertion proved to be wrong, however, when pressure tests were carried out on a 3/8” compressed air line that was pulled into the well at the same time as the cable. The air line could not be pressurised and, to determine the cause of the problem, it was pulled out of the well along with the cable. Visual inspection then showed that, as the TDR had indicated, the cable sheath was damaged 2,200 feet from the cable end.

So impressed was Antonio Torres with this result that he now believes that the TDR – a Megger CFL535G – will revolutionise his business and give him a valuable competitive advantage over his peers in the maintenance and repair sector of the oil and gas industry.

Key features of the CFL535G include comprehensive dual-channel capability with a dual-aspect display, an auto set-up mode to aid speedy operation, an ultra fast pulse option for near-end fault location, and integrated expert guidance. The instrument also has a 100-trace on-board memory with facilities for downloading results to a PC for further analysis and for inclusion in reports.

Tags: cable, domain, electrical, fault, finding, megger, oil, reflectometer, TDR, time