High Vacuum insulated tubing is composed of host string, thermocase, coupling, sealing ring and liner pipe. The insulated tubing adopts double-walled enclosed welded structure; the inner tube is treated with prestressingduring welding. There are multi-layer insulation structure in the annulus space and getter in the thermocase that can reduce heat transfer, energy loss by convection and radiation, and avert hydrogen explosion and radiation, and prolong the service life with special handicraft treatment.
The high vacuum insulated tubing applies to such operating condition as the temperature of heat carrier is not over 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 high vacuum insulated tubing correctly can not only reduce the heat loss of steam injection and guarantee steam quality but also decrease casing deformation and protect cementing casing.
The thread of high vacuum insulated tubing is API buttress thread Or Premium Thread(similar CSHYD). With PTFE sealing ring in the coupling and insulated liner in the annulus space between inner and outer tube, they can not only assure positive confinement among pipe strings and connection reliable but also insure the laminar follow state of steam injection and reduce the resistance of steam transport and heat loss in the coupling.
High Vacuum insulated tubing is manufactured in accordance with the standard of SY/T5314-94 HighVacuum 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 well.
The high vacuum insulated tubing with high performance, which the thermal conductivity is less than 0.015 W/m•℃ (equal to high vacuum insulated tubing of grade D and E in SY/T5324-94), is the fourth generation vacuum insulated tubing for heavy oil thermal recovery leading in the domestic market.
High Vacuum insulated tubing of grade D and E applies to the heavy oil well and super heavy oil well, and can improve the quality of injected steam and development effect after steaming; it also applies to production well with high water, and protects oil string, too. At the seam time, the insulated tubing can’t only save fuel and shorten steaming circle obviously but have distinguished economic and social benefit.
Supercritical insulation tubes (SIT) is a new product territory in which hasn’t been set foot in the world, and also the fifth generation product of high vacuum insulated tubing in our company. The product can meet such well condition that temperature of steam injection is not more than 390℃; Injection pressure is not more than 36MPa. It can meet the requirements of the steamed thermal recovery for both heavy oil well and super heavy oil well.