Well monitoring system

Abstract

A monitoring system for monitoring resources such as water in a bore having an air column extending from a wellhead to a surface level and a resource column extending from the surface level to an extraction inlet includes a sensor unit and a base unit. The sensor unit includes a sensor mounted within the bore and including a transmitting unit for transmitting at least a single sound pulse formed of a pulsed sinusoidal waveform into the bore and a receiving unit for receiving a return signal representing the single sound pulse reflected from the water surface level. The base unit uses the measured round trip time to determine an air column length from the sensor to the water surface level and a water column length from the water surface level to the extraction inlet and, from a cross sectional area of the bore, a water resource value representing a volume of water contained between the water surface level and the extraction inlet. The base unit may also determine resources values such as a current water level, a static water level, a highest recorded water level, a lowest recorded water level, a water level trend, a usage rate, and a recovery rate, and may generate alarms for various values.

What is claimed is:  
     
         1 . A well monitoring system for monitoring water resources in a bore having an air column extending from a wellhead to a water surface level and a water column extending from the water surface level to an extraction inlet, comprising: 
 a sensor unit including, 
 a sensor mounted within the bore and including a transmitting unit for transmitting at least a single sound pulse into the bore and a receiving unit for receiving a return signal representing the single sound pulse reflected from the water surface level, and  
 a sensor control for controlling the transmission of the single sound pulse and determining a round trip time between transmitting the single sound pulse and receiving the corresponding return signal, 
 each single sound pulse having a duration in the range of 20 milliseconds to 50 milliseconds,  
 
   a base unit for determining, from the round trip time, 
 an air column length from the sensor to the water surface level and a water column length from the water surface level to the extraction inlet, and  
 from a cross sectional area of the bore, 
 a water resource value representing a volume of water contained between the water surface level and the extraction inlet.  
 
   
     
     
         2 . The well monitoring system of  claim 1 , the base unit further including: 
 a data memory for storing measurement data values including the round trip times of a plurality of single sound pulses,    a processor for generating historic resource data values for the well from the plurality of round trip times, including at least one of 
 a current water level,  
 a static water level,  
 a highest recorded water level,  
 a lowest recorded water level,  
 a water level trend,  
 a usage rate, and  
 a recovery rate, and  
   a display for displaying at least one of the water resource value, the current water level, the static water level, the highest recorded water level, the lowest recorded water level, the water level trend, the usage rate, and the recovery rate.    
     
     
         3 . The well monitoring system of  claim 2 , the base unit further including: 
 a user input for entering at least one alarm limit,    the data memory for storing the at least one alarm limit, and    the processor for comparing the at least one alarm limit and a corresponding one of a measurement data value and a historic resource data value and 
 generating an alarm signal when the corresponding one of a measurement data value and a historic resource data value concurs with the at least one alarm limit.  
   
     
     
         4 . The well monitoring system of  claim 3 , wherein the at least one alarm limit represents one of: 
 the water resource value,    the current water level,    the usage rate, and    the recovery rate.    
     
     
         5 . The well monitoring system of  claim 1 , wherein each single sound pulse is a pulsed sinusoidal signal.  
     
     
         6 . A method for monitoring water resources in a well bore having an air column extending from a wellhead to a water surface level and a water column extending from the water surface level to an extraction inlet, comprising: 
 transmitting from the wellhead and into the bore at least a single sound pulse and receiving a return signal representing a reflection of the single sound pulse from the water surface level, and    determining a round trip time between transmitting the single sound pulse and receiving the corresponding return signal, 
 each single sound pulse having a duration in the range of 20 milliseconds to 50 milliseconds, and  
   from the round trip time, 
 determining an air column length from the wellhead to the water surface level and a water column length from the water surface level to the extraction inlet, and  
   from a cross sectional area of the bore, 
 determining a water resource value representing a volume of water contained between the water surface level and the extraction inlet.  
   
     
     
         7 . The well monitoring method of  claim 6 , further comprising the steps of: 
 storing measurement data values including the round trip times of a plurality of single sound pulses, and    generating historic resource data values for the well from the plurality of round trip times, including at least one of 
 a current water level,  
 a static water level,  
 a highest recorded water level,  
 a lowest recorded water level,  
 a water level trend,  
 a usage rate, and  
 a recovery rate, and  
   displaying the at least one of the water resource value, the current water level, the highest recorded water level, the lowest recorded water level, the water level trend, the usage rate, and the recovery rate.    
     
     
         8 . The well monitoring method of  claim 7 , further including the steps of: 
 determining at least one alarm limit, and    comparing the at least one alarm limit and a corresponding one of a measurement data value and a historic resource data value and    generating an alarm signal when the corresponding one of a measurement data value and a historic resource data value concurs with the at least one alarm limit.    
     
     
         9 . The well monitoring system of  claim 8 , wherein the at least one alarm limit represents one of: 
 the water resource value,    the current water level,    the usage rate, and    the recovery rate.    
     
     
         10 . The well monitoring system of  claim 6 , wherein each single sound pulse is a pulsed sinusoidal signal.  
     
     
         11 . A monitoring system for monitoring a resource in a bore having an air column extending to a resource surface level and a resource column extending from the surface level to an extraction inlet, comprising: 
 a sensor unit including, 
 a sensor mounted within the bore and including a transmitting unit for transmitting at least a single sound pulse into the bore and a receiving unit for receiving a return signal representing the single sound pulse reflected from the resource surface level, and  
 a sensor control for controlling the transmission of the single sound pulse and determining a round trip time between transmitting the single sound pulse and receiving the corresponding return signal, 
 each single sound pulse having a duration in the range of 20 milliseconds to 50 milliseconds,  
 
   a base unit for determining, from the round trip time, 
 an air column length from the sensor to the resource surface level and a resource column length from the resource surface level to the extraction inlet, and  
 from a cross sectional area of the bore, 
 a resource value representing a volume of the resource contained between the surface level and the extraction inlet.  
 
   
     
     
         12 . A method for monitoring resources in a bore having an air column extending to a resource surface level and a resource column extending from the resource surface level to an extraction inlet, comprising: 
 transmitting at least a single sound pulse into the bore and receiving a return signal representing a reflection of the single sound pulse from the resource surface level, and    determining a round trip time between transmitting the single sound pulse and receiving the corresponding return signal, 
 each single sound pulse having a duration in the range of 20 milliseconds to 50 milliseconds, and  
   from the round trip time, 
 determining an air column length to the resource surface level and a resource column length from the resource surface level to the extraction inlet, and  
   from a cross sectional area of the bore, 
 determining a resource value representing a volume of resource contained between the resource surface level and the extraction inlet.