Abstract: In connection with thermal recovery projects, a system determines temperature gradients for a heat affected zone associated with a subterranean hydrocarbon reservoir. An exemplary system includes a plurality of temperature sensors distributed in the wellbore at least partially along the heat affected zone. A downhole processor positioned proximate and substantially outside of the heat affected zone receives and digitizes the temperature measurements. A data link such as a data cable coupled to the downhole processor conveys the temperature measurements to a surface interface.

Abstract: A device for determining a location of an interface between a first fluid and second fluid includes a non-mechanical sensor that measures a selected parameter of interest relating to the fluid surrounding the sensor (“the surrounding fluid”) and a processor for processing the sensor measurements. The non-mechanical sensor measures a parameter relating to the surround fluid without physically co-acting with the surrounding fluid. Exemplary parameters such as thermal properties, electrical properties, fluid properties, and magnetic properties can be measured. The processor is programmed to process the sensor measurements to identify one or more characteristics in the measurements that can indicate the nature of the fluid being measured and thereby determine the location of the interface. The determined location can be used to operate a downhole device such as a pump, to provide real-time monitoring of well conditions, to record data for long-term reservoir characterization, or to actuate an alarm.

Abstract: In connection with thermal recovery projects, a system determines temperature gradients for a heat affected zone associated with a subterranean hydrocarbon reservoir. An exemplary system includes a plurality of temperature sensors distributed in the wellbore at least partially along the heat affected zone. A downhole processor positioned proximate and substantially outside of the heat affected zone receives and digitizes the temperature measurements. A data link such as a data cable coupled to the downhole processor conveys the temperature measurements to a surface interface.

Abstract: A shock absorber for damping shock energy generated by downhole perforating guns or stimulation devices is described. The shock absorber includes a spring assembly including at least a first spring and a second spring, the first spring having a tension greater than the second spring; a damper assembly; and a housing retaining the spring assembly and the damper assembly and including ends adapted for connection into a casing perforation assembly. The provision of springs of increasing stiffness permits the force generated by the perforating gun to be absorbed gradually and smoothly.