Disclosed is a method for detecting the flame front during the in situ combustion of a subterranean carbonaceous stratum which involves providing one or more radio transmitters below the surface of the ground, each of said transmitters being capable of sensing and transmitting information concerning the physical and chemical properties of its surroundings, and monitoring said transmissions as an indication of the extent and movement of said flame front. Also disclosed is a method for detecting non-uniform packing characteristics of rubblized material which involves providing one or more radio transmitters within the boundaries of a retort capable of sensing and transmitting information concerning the physical parameters of its surroundings, and monitoring said transmissions as an indication of the size and density distributions of the rubble in said retort.
Method and system for characterizing a vertical modified in situ oil shale retort prior to ignition of the retort. The retort is formed by mining a void at the bottom of a proposed retort in an oil shale deposit. The deposit is then sequentially blasted into the void to form a plurality of layers of rubble. A plurality of units each including a tracer gas cannister are installed at the upper level of each rubble layer prior to blasting to form the next layer. Each of the units includes a receiver that is responsive to a coded electromagnetic (EM) signal to release gas from the associated cannister into the rubble. Coded EM signals are transmitted to the receivers to selectively release gas from the cannisters. The released gas flows through the retort to an outlet line connected to the floor of the retort. The time of arrival of the gas at a detector unit in the outlet line relative to the time of release of gas from the cannisters is monitored. This information enables the retort to be characterized prior to ignition.
A data communication system has a transmitting antenna (18,19), a source (34) of data to be transmitted, a carrier source (45), and a modulator (41,42,43) located at a first point. The transmitting antenna includes an inductive winding (17) having an electrical length significantly smaller than the wavelength of the carrier. The carrier modulated with the data is applied to the transmitting antenna to generate a magnetic induction field about the first point. A receiving antenna (53,54) is located at a second point remote from the first point. The receiving antenna includes an inductive winding (53) having an electrical length significantly smaller than the wavelength of the carrier. The windings of the transmitting and receiving antennas enclose mutually exclusive regions and are uncoupled magnetically except for the medium between the first and second points. A portion of the field generated by the transmitting antenna is intercepted by the receiving antenna to produce a signal that is demodulated (51) and stored (52).
The present invention provides a self-contained sensor module for use in a subterranean well that has a well transmitter or a well receiver associated therewith. In one embodiment, the sensor module comprises a housing, a signal receiver, a parameter sensor, an electronic control assembly, and a parameter transmitter; the receiver, sensor, control assembly and transmitter are all contained within the housing. The housing has a size that allows the module to be positioned within a formation about the well or in an annulus between a casing positioned within the well and an outer diameter of the well. The signal receiver is configured to receive a signal from the well transmitter, while the parameter sensor is configured to sense a physical parameter of an environment surrounding the sensor module within the well. The electronic control assembly is coupled to both the signal receiver and the parameter sensor, and is configured to convert the physical parameter to a data signal. The parameter transmitter is coupled to the electronic control assembly and is configured to transmit the data signal to the well receiver.
