Abstract: An automatic control system that protects downhole equipment and surface equipment from high temperatures resulting from the breakthrough of injection vapor. The system operates to derive an estimate of the temperature of production fluid at a location upstream from the downhole equipment. An alarm signal is generated in the event that this temperature exceeds a threshold temperature characteristic of injection vapor breakthrough. Electric power to the downhole equipment is automatically shut off in response to receiving the alarm signal. A bypass valve selectively directs production fluid to a bypass path. The system operates to derive an estimate of the temperature of the production fluid at a location upstream from the surface equipment. An alarm signal is generated when this temperature exceeds a threshold temperature characteristic of injection vapor breakthrough. The bypass valve is automatically controlled to direct production fluid to the bypass path in response to receiving the alarm signal.

Abstract: A method and system used for testing a subterranean well. A sensor (34), such as a distributed temperature sensor, comprising a sensing optical fiber (48) connected to an interrogation unit (50), is deployed together with a drill stem test string (20) so that the sensor extends below the packer of the drill stem test string and across at least one formation (22) of the wellbore.