A primary concern of the Petroleum Engineer is protection of wellbore casing and cement. In a steam injection wells heat flux occurs across the entire length of injection tubing into the wellbore annulus, casing, cement and formation. Steam injection wells completed with bare(non-insulated) tubing strings offer minimum resistance to this heat flux and both casing and cement will have elevated temperatures being nearly the same as the temperature of injected steam. This temperature effect causes thermal elongation and thermal stress on the casing directly proportional to the increase in casing temperature. The use of Insulated Steam Injection Tubing (commonly called VIT – Vacuum Insulated Tubing) in one possible solution to mitigate these potential problems. Additional benefits of Vacuum Insulated Tubing (VIT) are:
- Improved bottom hole steam quality (place more Btu’s into the formation).
- Reduced volumes of steam delivered to the wellhead.
- In SAGD initial heat-up and stimulation the increased steam enthalpy (Btu’s) tends to reduce returns translating into smaller surface treating facilities.
- In deepwater offshore application VIT is used to mitigate the potential harmful effects of annular pressure buildup (APB).
- In deepwater offshore heavy oil field VIT is successfully used for well stem testing.
Formed in 1995, Oil Tech Services, Inc. (OTSI) is a leading manufacturer of Vacuum Insulated Tubing. Our team has been involved in the engineering and manufacture of VIT starting in 1983 with the initial development of the product by Babcock & Wilcox Company (Diamond Power Division). OTSI manufacturing and engineering is located in Houston, Texas. Sales and marketing are managed from the OTSI office in California.
Vacuum Insulated Tubing (VIT) is a Multilayered high vacuum Getter maintained insulation system for the control of downhole heat flux with many downhole applications including:
- Maximize bottom hole steam quality and minimize heat losses.
- Lower casing and cement temperature and thermal stress.
- Aquifers protection.
- Mitigate creation of hydrates in Deep-Water production wells.
- Mitigates paraffin and viscosity issues.
- Perfect completion tubular for Slimhole steam injection wells.
- Geothermal applications.