Single well injection and production system

Claim 1

A method for multiple string fluid injection and production of viscous hydrocarbons from a single wellbore having a casing traversing a subterranean formation, comprising the steps of: a. providing lower perforations to establish lower communication point between a lower portion of the formation and the inside of the casing; b. providing upper perforations to establish upper communication point between an upper portion of the formation and the inside of the casing; c. setting a single string packer within the casing above the lower point of communication to establish a production zone below the single string packer and a thermal zone above the single string packer; d. setting a dual-string packer above the upper point of communication, said dual-string packer defining the upper boundary of the thermal zone; e. introducing a first tubing string into the wellboro; f. terminating the first tubing string at the production zone; g. introducing a second tubing string paralleling the first tubing string into the wellboro; h. terminating the second tubing string in the lower portion of the thermal zone; and i. flowing a drive fluid into the second tubing string and through the upper perforations wherein prior to entering the formation the drive fluid transfers heat to the wellbore casing to create a thermal communication path within the formation adjacent to the wellbore casing between the upper and lower perforations, said thermal communication path acting to direct at least a portion of the viscous hydrocarbons in the formation near the wellbore to the lower perforations for recovery; j. simultaneous with step i., flowing a produced fluid from the production zone through the first tubing string for said recovery.

Claim 2

A method for multiple string fluid injection and production of viscous hydrocarbons from a single wellbore having a casing traversing a subterranean formation, comprising the steps of: a. providing lower perforations to establish lower communication point between a lower portion of the formation and the inside of the casing; b. providing upper perforations to establish upper communication point between an upper portion of the formation and the inside of the casing; c. setting a single string packer within the casing above the lower point of communication to establish a production zone below the single string packer and a thermal zone above the single string packer; d. setting a dual-string packer above the upper point of communication, said dual-string packer defining the upper boundary of the thermal zone; e. introducing a first tubing string into the wellboro; f. terminating the first tubing string at the production zone; g. introducing a second tubing string paralleling the first tubing string into the wellboro; h. terminating the second tubing string in the lower portion of the thermal zone; and i. flowing a drive fluid into the second tubing string and through the upper perforations wherein prior to entering the formation the drive fluid transfers heat to the wellbore casing to create a thermal communication path within the formation adjacent to the wellbore casing between the upper and lower perforations, said thermal communication path acting to direct at least a portion of the viscous hydrocarbons in the formation near the wellbore to the lower perforations for recovery; j. simultaneous with step i., flowing a produced fluid from the production zone through the first tubing string for said recovery.