Qatar Foundation Research, Development, and Innovation (QF RDI) along with several partners, has developed a smart version of corrosion coupon to understand more than just the corrosion rate of oil and gas pipelines.
“We have revamped the traditional corrosion coupon and created a smart version that tells us more than just the corrosion rate," said Dr Abitha Ramesh, corrosion researcher at Qatar Shell Research and Technology Centre (QSRTC), an anchor partner company of Qatar Science & Technology Park, part of QF RDI.
The newly developed coupon incorporates three of the most commonly found deposits in sour gas pipelines and can also include an embedded sensor to monitor conditions beneath those deposits, she explained.
A corrosion coupon is a small piece of metal, made of the same material type and grade as the pipeline. These coupons are retrieved from the pipeline at specific time intervals, cleaned and weighed. The difference in weight is used to calculate the average corrosion rate which in turn can be used to determine the integrity of the pipeline.
These new corrosion coupons are manufactured in Qatar. The cost of manufacturing the first unit was equivalent to that of conventionally used coupons from the US. However, the cost is expected to go down considerably if they are mass-produced in Qatar.
A conventional coupon cannot help in the complex scenario where UDC (under-deposit corrosion) occurs. In an effort to tackle one of the most prominent corrosion challenges in the oil and gas industry, a team of academic and industrial experts from QSRTC, Qatar University, Imperial College London teamed up to develop this innovative corrosion monitoring device through the financial support of QF’s Qatar National Research Fund.
The purpose of having these deposits on the newly developed coupon is to measure the local chemistry (chloride ions, potential drop and pH) under these deposits and to pick up early warning signs that UDC may be occurring. The role of the sensor is to identify potential problems even earlier by detecting local changes in chemistry that are a precursor to corrosion.
“These coupons are retracted every two months for detailed analysis, thereby allowing us to very closely follow changes associated with UDC and its most dangerous manifestation called pitting – a rapid and localised form of corrosion in which cavities or "holes" are produced in the material,” explained, Dr Ramesh.
The smart-coupons developed in this project are expected to make an immense contribution towards the early detection of UDC and pitting. In addition, the sensor in the coupon will be able to relay information in real-time as it detects changes in the local chemistry.
Having an online sensor that can communicate this crucial information in real-time will contribute significantly towards maintaining safe operations.
Dr Ramesh noted, “Such early detection of pitting is very beneficial because when pitting starts the rate of pit propagation can be very fast and can have significant impact on the pipeline. The smart-coupons are currently being tested in the field. We deployed the coupons at Pearl GTL - a joint development by Qatar Petroleum and Shell in January this year; if things go as per plan, there is a real potential for these modified corrosion coupons to replace conventional coupons in the near future.”
“Internal corrosion in pipelines, if not detected early, can affect the economics of production and processing, threaten lives and cause long-lasting environmental damage in case of failure. We can say with certainty that this novel UDC online sensor will play a significant role in ensuring the structural integrity of oil and gas pipelines not just in Qatar but also worldwide in locations with sour service pipelines,” Dr Ramesh added.