Nowadays, the annual heavy oil production is more than 15 million tons in China and more than 60% of which are developed by cyclic steam stimulation (CSS) technology. Vacuum insulated tubing (VIT) with thermal packer is the mostly adopted thermal insulation manner during steam injection progress. This usually leads to two major problems. One is casing integrity issues like casing crack, casing collapse, and cement sheath damage induced by thermal packers's failure or cyclic casing as Well as cement heating. Another problem is frequent injection and production strings transformation, and this leads to operation cost increasing and high temperature production time wasting especially when CSS is of short cycle in super-heavy oil or thin thickness reservoirs.
In order to solve the two problems, the vacuum insulated casing (VIC) and relevant integral completion technique are researched taking well completion, heat insulation and hereafter production into consideration simultaneously rather than separately. This completion technique injects steam by VIC while not by VIT and produces in normal tubing, thus eliminates the thermal packer's failure problems, meanwhile, simplifies the injection and production pipe conversion process and saves production time. VIC's heat loss and steam quality along wellbore are compared with that of VIT. The related techniques like cementing, perforation while adopting VIC are also studied.
Field trials in Henan oilfield in China verify this completion's suitability for CSS in heating insulation, production performance and economics compared with normal method of CSS. The completion provides a long-term Well integrity solution for thermal Well recovery not only by CSS, also by other thermal manners like SAGD. Also, it can play an important role in heat proof exploitation of other resources like gas hydrate and geothermal energy.