Coiled tubing is widely used in the operations as well as during repair works conducted on gas, oil and gas condensate wells.
The technology was invented in the 1950-ies; it has become widely used until the late 1980-ies. It is cheaper and more environmentally friendly in comparison with classical columns. One of the main limitations of classical coiled tubing is inability to use rotation.Because of this, during main well drilling traditional installations are used more frequently, although there are drilling projects with the use of coiled tubing, including rotating one. The equipment for coiled tubing includes not only the flexible metal tubes, but also the various downhole and surface equipment: coiled tubing unit (including the coil with pipes, injector head et al.), and the mud pump, a booster unit or special compressors for pumping inert gas, equipment for heating the process fluid, inert gas generator and various wellhead equipment.
Such equipment may include multiple nozzles, cutting tools, downhole motors, rock cutting tools, diverters, packers and many other devices. Coiled tubing units are divided into three classes: light, medium and heavy.
Intensification serviceswith the use of coiled tubing.
Applying coiled tubing using downhole measurement systems during the real-time operation.
Milling usingcoiled tubing.
Mini coiled tubing operations/ capillarycoiled tubingoperations (1/4”, 1/2”).
Radial drilling services.
Nitrogen unit services.
Cementing with the use of coiled tubing.
Technology of the hydraulic fracturing in oil production includes pumping into the well via powerful pumping stations fracturing fluid (gel, in some cases, water or acid in case of acid hydraulic fracturing) at pressures above the fracture pressure of an oil bearing layer fracturing. To maintain the cracks in open condition,generally proppant is used in sandstone reservoirs –proppant in carbonates– an acid, which corrodes the walls of the created fracture. Howeverproppant can be used in carbonate collectors. In the production of unconventional gas hydraulic fracturing allows to connect the pores of dense rocks and enables to release the natural gas.During the f hydraulic fracturing a special blend is pumped into the well. Usually, it is 99% water and sand (or proppant), and only 1% — of chemicals. The composition of the chemicals is open.
In order to prevent leakage of fluid for the hydraulic fracturing into the soil or ground water, large service companies use different methods of layer insulation, such as multicolumn well construction using ultra lasting materials during the cementation.