Abstract: A distributed temperature sensing (DTS) system is operated to detect fluid leaks from a pipeline. The DTS system obtains temperature profiles from a sensing element that is deployed along the pipeline, where the profiles are temperature measurements as a function of distance. The temperature profiles are examined to identify the presence of a characteristic temperature signature expected to occur in the presence of a leak. A leak condition signal for a particular distance point is generated based on a determination that the energy of the temperature signal exceeds a threshold energy for that point.

Abstract: A distributed temperature sensing (DTS) system is connected to a buried fiber optic cable that is used to monitor a structure. The DTS system is operated to obtain temperature measurements along the length of the fiber cable. The temperature measurements are then used to calculate a measure of diurnal temperature variability at each point along the cable. This calculation is used to identify points at which the diurnal temperature variability changes rapidly over a short length of the cable. These points can be identified with features along the cable, such as splice chambers, where the cable burial conditions change. The known geographic location of these features can then be identified with specific distances along the fiber.

Abstract: A distributed temperature sensing (DTS) system is operated to detect fluid leaks from a pipeline. The DTS system obtains temperature profiles from a sensing element that is deployed along the pipeline, where the profiles are temperature measurements as a function of distance. The temperature profiles are examined to identify the presence of a characteristic temperature signature expected to occur in the presence of a leak. A leak condition signal for a particular distance point is generated based on a determination that the energy of the temperature signal exceeds a threshold energy for that point.

Abstract: A distributed temperature sensing (DTS) system is connected to a buried fiber optic cable that is used to monitor a structure. The DTS system is operated to obtain temperature measurements along the length of the fiber cable. The temperature measurements are then used to calculate a measure of diurnal temperature variability at each point along the cable. This calculation is used to identify points at which the diurnal temperature variability changes rapidly over a short length of the cable. These points can be identified with features along the cable, such as splice chambers, where the cable burial conditions change. The known geographic location of these features can then be identified with specific distances along the fiber.

Abstract: A technique that is usable with a well includes changing the temperature of a local environment of a distributed temperature sensor, which is deployed in a region of the well and using the sensor to acquire measurements of a temperature versus depth profile. The region contains at least two different well fluid layers, and the technique includes determining the depth of a boundary of at least one of the well fluid layers based at least in part on a response of the temperature versus depth profile to the changing of the temperature.

Abstract: A technique that is usable with a well includes changing the temperature of a local environment of a distributed temperature sensor, which is deployed in a region of the well and using the sensor to acquire measurements of a temperature versus depth profile. The region contains at least two different well fluid layers, and the technique includes determining the depth of a boundary of at least one of the well fluid layers based at least in part on a response of the temperature versus depth profile to the changing of the temperature.

Abstract: A technique that is usable with a well includes changing the temperature of a local environment of a distributed temperature sensor, which is deployed in a region of the well and using the sensor to acquire measurements of a temperature versus depth profile. The region contains at least two different well fluid layers, and the technique includes determining the depth of a boundary of at least one of the well fluid layers based at least in part on a response of the temperature versus depth profile to the changing of the temperature.

Abstract: A technique that is usable with a well includes changing the temperature of a local environment of a distributed temperature sensor, which is deployed in a region of the well and using the sensor to acquire measurements of a temperature versus depth profile. The region contains at least two different well fluid layers, and the technique includes determining the depth of a boundary of at least one of the well fluid layers based at least in part on a response of the temperature versus depth profile to the changing of the temperature.

Abstract: A technique that is usable with a well includes changing the temperature of a local environment of a distributed temperature sensor, which is deployed in a region of the well and using the sensor to acquire measurements of a temperature versus depth profile. The region contains at least two different well fluid layers, and the technique includes determining the depth of a boundary of at least one of the well fluid layers based at least in part on a response of the temperature versus depth profile to the changing of the temperature.

Abstract: An optical tracker system comprises an optical sensor 1 and associated signal processing circuitry 12, 24 for conditioning signals output from the sensor and rejecting signal indicative of false sensor information. A signal rejection circuit 24 comprises a guard time monostable 28 arranged to generate a guard time pulse defining a guard time when a pulse is input from the sensor 1, an output monostable 35 arranged to generate an output pulse in response to the guard time pulse, and an output suppress monostable 30 arranged to suppress the output monostable 35 when a false signal condition occurs during the guard time.

Abstract: An amplifier circuit (1) is arranged to amplify a signal of variable magnitude from a photodiode (3) having capacitive characteristics. The circuit (1) comprises a first feedback path containing a voltage controlled variable resistor (8) for varying the gain of the amplifier in relation to the magnitude of the signal so as to provide an output signal of substantially uniform magnitude. The first feedback path also contains a capacitor (7) which compensates for adverse effects of reactance in the circuit caused by the capacitance of the photodiode (3) and of the variable resistor (8) in order to optimize the frequency response characteristics of the amplifier. A second feedback path comprising a fixed value resistor (9) becomes operable when the resistance of the first feedback path is large to provide fixed gain amplification of signals received from the photodiode (3).