Control of a steam zone

Claim 1

In a hot aqueous flood of an oil containing formation wherein a water zone is utilized as a conduit for passing hot fluid from an injection well to a producing well to conductively heat an adjacent, overlying oil zone, a method for controlling the movement of hot fluid through the formation which comprises: measuring the produced fluid temperature; and when the measured temperature of the produced fluid reaches a selected value which indicates that steam breakthrough into the producing well is imminent but before steam breakthrough occurs, plugging back the lower portion of the producing well to cause the hot fluid to rise into the oil zone.

Claim 5

A method of producing viscous oil from a subsurface earth formation having an upper predominantly oil saturated zone and a lower predominantly water saturated zone comprising the steps of: providing at least two wells which are opened into fluid communication with the oil zone and the water zone of the formation; injecting a hot aqueous fluid through a first of these wells and into the water zone; producing fluid from the formation through the second of the wells by pumping the fluid with a subsurface pump; measuring the temperature of the produced fluid; when the measured temperature of the produced fluid indicates that the temperature of fluid in the well at the subsurface pump has reached a selected value less than the boiling point of water entering the subsurface pump, plugging back the producing well to a point above the original contact between the upper predominantly oil saturated zone and the lower predominantly water saturated zone; thereafter continuing to inject hot aqueous fluid through the first well and continuing to produce fluid from the formation through the second well.

Claim 6

A method of producing viscous oil from a subsurface earth formation having an upper predominantly oil saturated zone and a lower predominantly water saturated zone comprising the steps of: providing at least two wells which are opened into fluid communication with the oil zone and the water zone of the formation; injecting a hot aqueous fluid through a first of these wells and into the water zone; producing fluid from the formation through the second of the wells by pumping the fluid with a subsurface pump; measuring the temperature of the produced fluid; when the measured temperature of the produced fluid indicates that the temperature of fluid in the well at the subsurface pump has reached a selected value less than the boiling point of water entering the subsurface pump, plugging back the producing well to a point above the original contact between the upper predominantly oil saturated zone and the lower predominantly water saturated zone; thereafter continuing to inject hot aqueous fluid through the first well and continuing to produce fluid from the formation through the second well.