Measurement and Control of Liquid Level in Wells

Abstract

Methods and apparatuses are disclosed for measuring and controlling liquid levels in a well. The apparatus may include a plurality of sensors, the plurality of sensors comprising: a first sensor coupled to the well, the first sensor configured to measure a casing pressure, a second sensor coupled to the well, the second sensor configured to measure a tubing pressure, and a third sensor coupled to a motor that is further coupled to the well, the third sensor configured to measure at least one characteristic of the motor, and a processor coupled to the plurality of sensors, wherein the processor calculates a level of liquid in the well based upon measurements of at least two of the plurality of sensors.

1 . An apparatus for measuring data from a well, the apparatus comprises:
 a plurality of sensors, the plurality of sensors comprising:
 a first sensor coupled to the well, the first sensor configured to measure a casing pressure; 
 a second sensor coupled to the well, the second sensor configured to measure a tubing pressure; and 
 a third sensor coupled to a motor that is further coupled to the well, the third sensor configured to measure at least one characteristic of the motor; 
   a processor coupled to the plurality of sensors, wherein the processor calculates a level of liquid in the well based upon measurements of at least two of the plurality of sensors.   
   
   
       2 . The apparatus of  claim 1 , wherein the at least one characteristic of the motor is selected from the group consisting of the motor's revolutions per minute, the motor's current consumption, or the motor's power consumption. 
   
   
       3 . The apparatus of  claim 1 , wherein a first pressure at the bottom of the well is calculated based upon one or more of the following: the tubing pressure, the at least one motor characteristic, and/or a weight associated with liquid in a tubing. 
   
   
       4 . The apparatus of  claim 3 , wherein the weight associated with liquid in the tubing is expressed as a pressure measurement. 
   
   
       5 . The apparatus of  claim 3 , wherein a second pressure at the bottom of the well is calculated based upon one or more of the following: the casing pressure, a weight associated with liquid in a casing, and/or a weight associated with gas in the casing. 
   
   
       6 . The apparatus of  claim 5 , wherein the first and second pressures at the bottom of the well are equated to determine the level of liquid in the well. 
   
   
       7 . The apparatus of  claim 1 , further comprising a fourth sensor coupled to a liquid pumped to the surface by the pumping unit, wherein the processor is configured to calculate liquid flow rate using a measurement from the fourth sensor. 
   
   
       8 . The apparatus of  claim 7 , further comprising a fifth sensor coupled to a gas flowing in an annulus, the processor configured to calculate gas flow rate using a measurement from the fifth sensor. 
   
   
       9 . The apparatus of  claim 8 , wherein the gas flow calculation is based upon one or more standards set forth by the American Gas Association. 
   
   
       10 . A method of calculating liquid levels in a well, the method comprising the acts of:
 reading a plurality of data measurements;   calculating an annulus liquid level based upon at least two of the plurality of data measurements;   determining if the liquid level is decreasing; and   in the event that the liquid level approaches a predetermined location within the well, shutting off a motor coupled to the well.   
   
   
       11 . The method of  claim 10 , wherein the predetermined location within the well includes a location above a pump situated in the well, and in the event that the liquid level is approaching the pump's location in the well, the method further comprises the act of shutting off the motor. 
   
   
       12 . The method of  claim 10 , further comprising the act of shutting off the motor in the event that a predetermined period of time elapses. 
   
   
       13 . The method of  claim 12 , further comprising the act of turning the motor back on in the event that one of the plurality of data measurements indicates that a casing pressure falls below a predetermined value. 
   
   
       14 . The method of  claim 13 , further comprising the act of turning the motor back on in the event that the well's production increases above a predetermined value. 
   
   
       15 . The method of  claim 14 , further comprising the act of turning the motor back on in the event that a second predetermined period of time elapses. 
   
   
       16 . The method of  claim 10 , wherein the plurality of data measurements are read in analog form. 
   
   
       17 . The method of  claim 10 , wherein the plurality of data measurements include measurements related to the motor and measurements related to the well. 
   
   
       18 . The method of  claim 10 , wherein the plurality of data measurements include a data input pertaining to a physical parameter of the well. 
   
   
       19 . The method of  claim 18 , wherein the physical parameter is the length of a tubing in the well. 
   
   
       20 . The method of  claim 10 , wherein the plurality of data measurements include at least one characteristic of the motor selected from the group consisting of the motor's revolutions per minute, the motor's current consumption, or the motor's power consumption. 
   
   
       21 . A system for measuring data in a plurality of wells, the system comprising:
 a processing unit; and   a plurality of sensors coupled to the processing unit and coupled to at least one well within the plurality of wells, the plurality of sensors comprising:
 a first sensor coupled to the at least one well within the plurality of wells, the first sensor configured to measure a casing pressure; 
 a second sensor coupled to the at least one well within the plurality of wells, the second sensor configured to measure a tubing pressure; and 
 a third sensor coupled to a motor that is further coupled to the at least one well within the plurality of wells, the third sensor configured to measure at least one characteristic of the motor, wherein the processing unit calculates a level of liquid in the well based upon measurements of at least two of the plurality of sensors. 
   
   
   
       22 . The system of  claim 21 , further comprising one or more host computers coupled to the processing unit, wherein the processing unit is located in a different geographic location from the one or more host computers. 
   
   
       23 . The system of  claim 21 , wherein each well within the plurality of wells comprises a pump situated in the well, wherein a flow rate of the pump is calculated by the processing unit when determining the liquid level. 
   
   
       24 . The system of  claim 22 , wherein the at least one characteristic of the motor is selected from the group consisting of the motor's revolutions per minute, the motor's current consumption, or the motor's power consumption. 
   
   
       25 . The system of  claim 21 , wherein a first pressure at the bottom of the well is calculated based upon one or more of the following: the tubing pressure, the at least one motor characteristic, and/or a weight associated with liquid in a tubing. 
   
   
       26 . The system of  claim 25 , wherein the weight associated with liquid in the tubing is expressed as a pressure measurement. 
   
   
       27 . The system of  claim 25 , wherein a second pressure at the bottom of the well is calculated based upon one or more of the following: the casing pressure, a weight associated with liquid in a casing, and/or a weight associated with gas in the casing. 
   
   
       28 . The apparatus of  claim 27 , wherein the first and second pressures at the bottom of the well are equated to determine the level of liquid in the well. 
   
   
       29 . The system of  claim 21 , further comprising a fourth sensor coupled to a liquid pumped to the surface by the pumping unit, wherein the processor is configured to calculate liquid flow rate using a measurement from the fourth sensor. 
   
   
       30 . The system of  claim 21 , further comprising a fifth sensor coupled to a gas flowing in an annulus, the processor configured to calculate gas flow rate using a measurement from the fifth sensor. 
   
   
       31 . An apparatus for measuring data from a well, the apparatus comprises:
 means for receiving at least one signal pertaining to the well;   means for calculating a liquid level based upon the at least one signal;   means for determining if the liquid level is decreasing; and   in the event that the liquid level approaches a predetermined location within the well, means for shutting off a motor coupled to the well.   
   
   
       32 . The apparatus of  claim 31 , further comprising means for transmitting the at least one signal, wherein the means for transmitting is located in the well. 
   
   
       33 . The apparatus of  claim 31 , wherein the means for receiving is located within an annulus of the well. 
   
   
       34 . The apparatus of  claim 33 , wherein the means for transmitting the at least one signal includes at least one floating object. 
   
   
       35 . The apparatus of  claim 34 , wherein the at least one floating object includes an RFID transmitter. 
   
   
       36 . The apparatus of  claim 33 , wherein the means for receiving includes a wire along at least a portion of the annulus of the well. 
   
   
       37 . The apparatus of  claim 31 , wherein the means for calculating includes a processor located at the surface of the well. 
   
   
       38 . The apparatus of  claim 31 , wherein the means for receiving at least one signal is located at the surface of the well. 
   
   
       39 . The apparatus of  claim 38 , wherein the means for receiving receives a signal selected from the group consisting of the motor's revolutions per minute, the motor's current consumption, or the motor's power consumption 
   
   
       40 . The apparatus of  claim 31 , wherein the at least one signal pertains to a physical parameter of the well. 
   
   
       41 . The method of  claim 40 , wherein the physical parameter includes the length of a tubing in the well.