New method for casing integrity checks

Corporate Responsibility

New method for casing integrity checks

At Canadian Natural, we focus on the integrity of our processes, equipment, and infrastructure as an essential part of ensuring safety and asset integrity Company-wide. One area of focus is casing integrity management. The casing is a steel pipe placed in the wellbore to stabilize it and then cemented in place to prevent pressurized fluids from travelling on the outside of the casing and reaching the surface.

Over the last two years, we have been researching an alternative process to perform casing integrity checks through the tubing at our Primrose cyclic steam stimulation (CSS) operation. Standard integrity checks involve applying pressure on the casing to confirm that there are no breaks, however, pressure testing reduces well life, and also requires the removal of the tubing to perform the test. Our goal was to determine if the principle of electromagnetic metal thickness detection, which is typically used for detecting corrosion wall loss, could also be used to detect casing connection breaks.

Shop testing and field trials conducted in 2015 indicated that electromagnetic logs are effective in detecting casing breaks reliably and consistently. In 2016, after gathering sufficient data on their performance in the field, the electromagnetic log became the standard casing integrity check for Primrose CSS wells. This tool is now a part of our well integrity management protocol, which outlines requirements for periodic assessment of wellbores based on our data monitoring systems.

Through proactive and innovative thinking, we have an enhanced method for checking casing integrity prior to steaming operations. This process does not involve pressuring up the casing and does not require the removal of the tubing, ultimately reducing well servicing costs.

Left: Rig over a well at Primrose thermal in situ operations. Right: Electromagnetic thickness detector log.