Vacuum insulated tubings (VIT) are tubings with high heat insulation performance. With 20 years of production experience, Freet is one of the leading companies in producing VIT.
VIT is composed of host string, thermo case, coupling, sealing ring and liner pipe. The insulated tubing adopts doublewalled enclosed welded structure. The inner tube is treated with prestressing process during welding. There are multilayer insulation structures in the annulus space as well as getter in the thermo case that can reduce heat transfer, energy loss by convection and radiation, and avert hydrogen explosion and prolong the service life. The vacuum insulated tubing operates under the condition that the temperature of heat carrier is less than 350℃ The insulated tubing mainly applies to steam thermal recovery well with "huff and puff" and "steam drive" as well as heavy oil well with "integration of production and injection". Using VIT correctly can not only reduce the heat loss of steam injection and guarantee steam quality, but also decrease the speed of casing deformation and protect the cementing casing.The thread of vacuum insulated tubing is API buttress thread. With PTFE sealing ring in the coupling and insulated liner in the annulus space between the inner and outer tubes, it can ensure positive confinement among pipe strings, connection reliability, ensure the laminar flow state of steam injection and reduce the resistance of steam transport and heat loss in the coupling process.VIT is manufactured in accordance with the standard SY/T5324-94 of Vacuum Insulated Tubing. Insulated tubing with different performance grades can meet the needs of thermal recovery for heavy oil, super heavy oil with different depth and horizontal wells.VIT with high performance, which the thermal conductivity is less than 0.015w/m℃(equal to vacuum insulated tubing of grade D and E in SY/T5324-94), is the fourth generation VIT for heavy oil thermal recovery in the domestic market.VIT of grade D and E can be applied in heavy oil well, super heavy oil well and production well with high water. Using of VIT can save fuel and shorten the steaming circle substantially.Supercritical insulation tubes (SIT) is the fifth generation product of vacuum insulated tubing produced by Freet. The product can be applied under the environment that the temperature of steam injection is less than 390oC and the injection pressure is less than 26MPa. It can meet with the requirements of the thermal recovery for both heavy oil well and super heavy oil well.
