Coil flow tubing is often used in oil well testing and is a cost- and time-effective way to provide well intervention solutions. Operations such as cleanout and perforating the wellbore (the hole that creates the well), in addition to retrieving and replacing damaged equipment, can be efficiently performed with coiled tubing.
Nitrogen coils comprise one type of coiled tubing, primarily used in exploration as a heat exchanger to keep heat away in a high-temperature application and/or to control pressure to open and close a valve. High pressure and high temperature are huge challenges to the oil exploration industry. Such coils are used to regulate differential pressures to help close “flapper springs” on subsurface safety valves in deep well applications.
When a valve is opened to allow either natural gas or crude oil to flow out, a safety valve is necessary. The flammable nature of what flows through the tubing requires precise and rugged manufacturing. For example, during Operation Desert Storm in the Gulf War, the Kuwaiti oil fields caught fire when Iraqi soldiers blew off the wellheads, the component at the surface of an oil well with the structural and pressure-containing interface for the drilling and production equipment. The wellheads had no subsurface safety valves; if they had, the oil would have automatically stopped flowing, and an enormous amount of environmental damage could have been avoided. Today, nitrogen coils are used to close the valve and prevent such disasters from occurring.
The tubing varies in length from deep to shallow wells, depending on whether the application is for natural gas or crude oil. The amount of well pressure put onto the valve is determined by the nitrogen coil. Deep drilling results in higher temperatures, and companies are drilling increasingly further into the earth. Currently, one of the largest nitrogen coils ever produced is being built: a safety valve for a very high-pressure application rated at greater than 40,000 psi. That’s the type of challenge customers often ask for help with: Companies need nitrogen coils that can handle more pressure and more heat than older ones.
Other challenges pertain to getting information from the drilled hole itself. Electronic extender springs are used by drilling companies as a communication link between two instrumentation housings in the drilling or sampling process to take measurements while drilling (MWD). Customers use MWD to evaluate the production value of the reservoir during and after drilling.
Wire is fed through the coiled body, which acts as a spring that connects the housings. This extender spring stabilizes the tool string and allows it to compress and extend in both directions. Again, this type of device must withstand high pressure and temperature. Some such devices are already safe up to 35,000 psi and being redesigned by manufacturers to withstand more than 40,000 psi.
Electronic extender springs get real-time data to operators on the surface in minutes. Prior to this component design, it would take weeks to get the same information.
New technology has allowed downhole drilling to reduce downtime and increase output. The more uptime drillers have, the greater their output. And more output means greater profits.
For more information, visit www.mw-ind.com/brands/engi neered-spring-products.
