Within the oil and gas industry, coiled tubing is an important component. The term refers to the very long metal pipe—typically between 1 and 3.25 inches (25 to 83 mm) in diameter—supply-spooled on a large reel.
What is Coiled Tubing Used For?
Companies that the DCM group work with may use coiled tubing for interventions in oil and gas wells. Sometimes, coiled tubing can be used as production tubing in low-volume gas wells. Often, coiled tubing is employed for carrying out executions similar to wire lining applications (but better). Coiled tubing is also often used as a production string within shallow gas wells that can sometimes produce water.
Coiled Tubing for Circulation
Actually, the most typical use for coiled tubing in the oil and gas industry is for circulation; or, more accurately, deliquification. Sometimes a hydrostatic head—this is a column of fluid in the well bore—can inhibit flow of formation fluids because it is heavy (often referred to as a “killed well”). The safest—though, admittedly, not necessarily the most affordable—solution would be to try and circulate the fluid out (like you would with a gas, commonly nitrogen; and often called a “Nitrogen Kick”). Circulating is generally used just for cleaning out light debris that might have accumulated within the hole.
Coiled Tubing For Pumping
Coiled tubing can also be used for pumping as a means for dispersing fluids towards a specific location in the well in order to cement perforations or to perform certain chemical washes of downhole components. In the case of cementing perforations, coiled tubing is generally regarded as more advantageous over simply pumping cement into the hole from the surface because that would allow cement to flow through the whole complex and potentially damage components along the way.
Coiled Tubing and Drilling
In recent years, coiled tubing has been used as a drilling technique. Engineers have found this has many advantages over the conventional drill pipe. Generally, coiled tubing requires less effort to trip in and out of the well than a conventional drill pipe. In addition, coiled tubing enters the hole through an injector-mounted stripper. This provides a hydraulic seal around the coil which offers the well superior control capabilities, which in turn greatly surpass that which would be offered by traditional drill pipes.