Coil Tubing Facts
In oil and gas operations, coil tubing (or coiled tubing) refers to metal tubing, typically 1" to 3" in diameter, used to drill and/or service oil and gas wells. Coil tubing can also be used as production or velocity tubing in depleted wells to improve production. Coil tubing is an integral and critical technology in the new horizontal wells that are required for cost effective production of oil sand, oil shales, and gas shales. Some of the largest oil and gas plays in the world depend heavily on coil tubing for cost effective drilling, logging, completion and service operations.
Coil tubing can also replace wireline in many operations where the coil tube provides distinct advantages. The main benefits over wireline are the ability to push the tubing into the hole rather than relying on gravity (deviated or horizontal wells), and the ability to pump through the coil.
The tool string at the bottom of the coil is often called the bottom hole assembly (BHA). It can range from something as simple as a jetting nozzle for jobs involving pumping chemicals or cement through the coil, to a larger string of logging tools, all depending on the customer requirements.
Coil tubing has also been used as a more cost-effective technology for work-over operations. It is used to perform open hole drilling and milling operations. It can also be used to fracture the reservoir, a process where fluid is pressurized to thousands of psi on a specific point in a well to literally break the rock apart and allow the flow of product. Coil tubing can perform almost any operation for oil well operations if used correctly.