Developing new method for casing integrity checks

Corporate Responsibility

Developing 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. Our goal was to determine if the principle of electromagnetic metal thickness detection typically used for detecting corrosion wall loss could also be used to detect casing connection breaks. Standard integrity checks involve applying pressure on the casing to confirm there are no breaks, however, pressure testing reduces well life, and also requires the removal of the tubing to perform the test.

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

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