The design, testing, construction and installation of a prototype insulated concentric coiled tubing (ICCT), 1700m in length for continuous steam injection in a horizontal well, was recently completed. The concentric tubing consists of a 1-3/4" inner and 2-7/8" outer coiled tubing separated by loose-fill insulation and specially designed composite-construction centralizers. The ICCT R & D required the development of a new, low thermal conductivity centraliser, the design of thermal expansion joints utilizing advanced seal technology suitable for a high pressure and greater than normal steam temperature of 350C (662F) and the application of modem orbital welding processes for ICCT welded connections. The experimental steam injection process consists of continuous steam injection and oil production from the same well bore. Oil production commenced

January 9, 1995 and successful operation has been achieved to date.

This paper describes and presents the results of insulation heat loss and frictional resistance laboratory testing, shop trial assembly and structural integrity testing, construction of the prototype ICCT string in a suspended vertical well and installation of the ICCT prototype in ELAN's heavy oil lease at Cactus Lake, Saskatchewan. Also presented are the results of computer thermal simulations and ICCT field performance evaluation. In addition, a comparison of the advantages of the new ICCT technology with conventional jointed thermal tubing, is presented.

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