| 摘要 |
A method is described for recompleting and operating non-thermally cased wells in high temperature cyclic thermal heavy oil or bitumen recovery processes. Non-thermally completed wells such as those employed in primary "cold heavy oil production with sand", commonly referred to as CHOPS wells, are recompleted with insulated tubing for conveying mixtures of high temperature combustion gases, steam and other heating fluids into a hydrocarbon bearing formation. Concurrently, in order to protect the well's non-thermal casing and cement from excessive temperatures, a continuous stream of cooling fluid is introduced into the annulus, absorbing heat energy emitted from the insulated tubing as it flows downward to the bottom of the well where it mixes with the tubing conveyed fluids and is introduced into the formation. The continuous positive downward flow of cooling fluids through the annulus also prevents hot tubing conveyed fluids at the bottom of the well from flowing up into the annulus. Introduction of a continuous flow of cooling fluids into the annulus during a thermal injection cycle eliminates the need for a packer at the bottom of the well which would otherwise be required to isolate non-thermal casing from high temperature injection fluids. Since a packer is not required, the prior art requirement of recompleting the well for the subsequent production cycle by removing the insulated tubing and packer assembly and then reinstalling production tubing is eliminated. |
