초록 ▼

A downhole telemetry system having discrete multi-tone modulation and dynamic bandwidth allocation is disclosed herein. In one embodiment, the downhole telemetry system comprises a surface transceiver, a cable, and a downhole transceiver coupled to the surface transceiver via the cable. The downhole

A downhole telemetry system having discrete multi-tone modulation and dynamic bandwidth allocation is disclosed herein. In one embodiment, the downhole telemetry system comprises a surface transceiver, a cable, and a downhole transceiver coupled to the surface transceiver via the cable. The downhole transceiver communicates to the surface transceiver using discrete multi-tone (DMT) modulation to transmit telemetry information over a set of frequency subchannels allocated for uplink communications. The surface transceiver may likewise communicate to the downhole transceiver using DMT modulation to transmit information over a set of frequency subchannels allocated for downlink communications. The number of uplink and downlink communications subchannels is preferably variable and preferably can be changed depending on the operating mode of the system. This allows additional subchannels to be allocated for downlink communications during programming and configuration of the downhole equipment, and additional subchannels to be allocated for uplink communications during normal logging operations. The set of uplink communications subchannels may be disjoint from the set of downlink communications subchannels, and the sets may be spaced apart in frequency or interleaved in frequency. The cable may be a single conductor or multi-conductor logging cable. In the case of the multi-conductor logging cable, one of several possible orthogonal transmission modes may be used to convey the information signals.

대표청구항 ▼

A downhole telemetry system having discrete multi-tone modulation and dynamic bandwidth allocation is disclosed herein. In one embodiment, the downhole telemetry system comprises a surface transceiver, a cable, and a downhole transceiver coupled to the surface transceiver via the cable. The downhole

A downhole telemetry system having discrete multi-tone modulation and dynamic bandwidth allocation is disclosed herein. In one embodiment, the downhole telemetry system comprises a surface transceiver, a cable, and a downhole transceiver coupled to the surface transceiver via the cable. The downhole transceiver communicates to the surface transceiver using discrete multi-tone (DMT) modulation to transmit telemetry information over a set of frequency subchannels allocated for uplink communications. The surface transceiver may likewise communicate to the downhole transceiver using DMT modulation to transmit information over a set of frequency subchannels allocated for downlink communications. The number of uplink and downlink communications subchannels is preferably variable and preferably can be changed depending on the operating mode of the system. This allows additional subchannels to be allocated for downlink communications during programming and configuration of the downhole equipment, and additional subchannels to be allocated for uplink communications during normal logging operations. The set of uplink communications subchannels may be disjoint from the set of downlink communications subchannels, and the sets may be spaced apart in frequency or interleaved in frequency. The cable may be a single conductor or multi-conductor logging cable. In the case of the multi-conductor logging cable, one of several possible orthogonal transmission modes may be used to convey the information signals. ve of a value for the sensed parameter at the given location which is utilized for monitoring and/or controlling an aspect of the water treatment system through a parameter control unit having a parameter control unit controller operated in response to the probe output signal, comprising the steps of: temporarily storing the probe output signal and operating the parameter control unit controller in response to the temporarily stored probe output signal; simulating for a first preselected period of time a probe output signal that is not the stored probe output signal; after the first preselected period of time, sensing whether the probe output signal returns to the value of the stored probe output signal within a second preselected period of time; and generating a malfunction signal in the event that the probe output signal does not return to the desired value in the preceding step. 6. The method of claim 5 further comprising the step of: generating a failsafe control signal to the parameter control unit controller to place the parameter control unit in a failsafe condition is response to at least one malfunction signal. 7. The method of claim 6 wherein the at least one malfunction signal is a plurality malfunction signals. 8. A system for probe failure detection in a water treatment system including at least one probe for monitoring a parameter of the water treatment system at a given signal indicative of a value for the sensed parameter at the given location which is utilized for monitoring and/or controlling an aspect of the water treatment system through a parameter control unit having a parameter control unit controller operated in response to the probe output signal, said system comprising: means for temporarily storing the probe output signal and operating the parameter control unit controller in response to the temporarily stored probe output signal; means for simulating for a first preselected period of time a probe output signal that is not the stored probe output signal, after the first preselected period of time, sensing whether the probe output signal returns to the value of the stored probe output signal within a second preselected period of time; and means for generating a malfunction signal in the event that the probe output signal does not return to the desired value in the preceding step. 9. The system of claim 8 further comprising: Means for generating a failsafe control signal to the parameter control unit controller to place the parameter control unit in a failsafe condition is response to at least one malfunction signal. 10. The system of claim 9 wherein the at least one malfunction signal is a plurality malfunction signals. 11. The system of claim 8 further comprising: A failsafe means for controlling a given characteristic of the fluid to the probe signal utilization system to cause the probe signal utilization system to modify the characteristics of the fluid in a failsafe manner in response to at least one sensor failure alarm signal for the probe. 12. The system of claim 11, wherein the at least one sensor failure signal is a plurality of sensor failure signals.