Well kick detection

Abstract

A kick detection system includes an apparatus configured to be retrievably attached to a production tubing in a well. The apparatus includes a housing, a first pressure sensor, a second pressure sensor, and a flow detection device. The first and second pressure sensors are configured to sense respective local pressure of downhole fluid flowing through the housing. The flow detection device is configured to detect a direction of downhole fluid flowing through the housing. The kick detection system includes a computer configured to determine one or more downhole well properties of the downhole fluid based on respective signals received from the first pressure sensor, the second pressure sensor, and the flow detection device. The computer is configured to determine whether a kick is occurring in the well based on the determined one or more downhole well properties of the downhole fluid.

What is claimed is: 
     
         1 . A kick detection system, comprising:
 an apparatus configured to be retrievably attached to a production tubing positioned in a well, the apparatus comprising:
 a housing configured to, while the apparatus is attached to the production tubing positioned in the well, allow downhole fluid to flow through the housing; 
 a first pressure sensor positioned within the housing; 
 a second pressure sensor positioned within the housing, the second pressure sensor spaced apart from the first pressure sensor, the first pressure sensor and the second pressure sensor configured to sense respective local pressure of the downhole fluid flowing through the housing and to transmit a respective signal representing the sensed respective local pressure; and 
 a flow detection device within the housing, the flow detection device configured to detect a direction of the downhole fluid flowing through the housing and to transmit a respective signal representing the detected direction of fluid flow; and 
   a computer configured to:
 determine one or more downhole well properties of the downhole fluid based on respective signals received from the first pressure sensor, the second pressure sensor, and the flow detection device; and 
 determine whether a kick is occurring in the well based on the determined one or more downhole well properties of the downhole fluid. 
   
     
     
         2 . The kick detection system of  claim 1 , wherein the computer comprises:
 a memory; and   a processor interoperably coupled to the memory and configured to:
 determine a density of the downhole fluid flowing through the housing based on a distance between the first pressure sensor and the second pressure sensor and the respective signals received from the first pressure sensor and the second pressure sensor; and 
 transmit an alarm signal in response to determining that the kick is occurring in the well. 
   
     
     
         3 . The kick detection system of  claim 2 , wherein:
 the apparatus comprises a centralizer surrounding an outer diameter of the housing;   the centralizer is configured to contact the production tubing of the well;   the processor is configured to be coupled to the production tubing of the well; and   the apparatus and processor are cooperatively configured to establish communication between each other via the production tubing of the well.   
     
     
         4 . The kick detection system of  claim 3 , wherein the housing comprises a fishing neck configured to attach to a slickline, such that the apparatus can be installed within the production tubing and retrieved from the production tubing. 
     
     
         5 . The kick detection system of  claim 4 , wherein:
 the flow detection device comprises a rotatable vane flowmeter; and   the processor is configured to determine a direction of the downhole fluid flowing through the housing based on a rotation direction of the rotatable vane flowmeter in response to the downhole fluid flowing through the rotatable vane flowmeter.   
     
     
         6 . The kick detection system of  claim 4 , wherein:
 the apparatus comprises a temperature sensor positioned within the housing;   the temperature sensor is configured to sense a local temperature of the downhole fluid flowing through the housing and to transmit a respective signal representing the sensed local temperature; and   determining whether the kick is occurring in the well comprises determining whether a change in the sensed local temperature is equal to or greater than a threshold temperature change value within a predetermined time span.   
     
     
         7 . The kick detection system of  claim 4 , wherein the apparatus comprises a seal on an outer circumferential surface of the housing, the seal configured to form a seal with the production tubing. 
     
     
         8 . A method, comprising:
 with a kick detection system,
 measuring a first local pressure of a downhole fluid at a first location in a well; 
 transmitting a first signal representing the first local pressure; 
 measuring a second local pressure of the downhole fluid at a second location in the well, the second location spaced apart from the first location; 
 transmitting a second signal representing the second local pressure; 
 detecting a direction of flow of the downhole fluid; 
 transmitting a third signal representing the detected direction of flow; 
 determining one or more downhole well properties of the downhole fluid based on receiving at least one of the first signal, the second signal, or the third signal; and 
 determining whether a kick is occurring in the well based on the determined one or more downhole well properties of the downhole fluid. 
   
     
     
         9 . The method of  claim 8 , wherein determining the one or more downhole well properties of the downhole fluid comprises determining a density of the downhole fluid based on the first signal, the second signal, and a distance between the first location and the second location. 
     
     
         10 . The method of  claim 8 , wherein detecting the direction of flow of the downhole fluid comprises determining a rotation direction of a rotatable vane flowmeter of the kick detection system in response to the downhole fluid flowing through the rotatable vane flowmeter. 
     
     
         11 . The method of  claim 8 , comprising causing a pump to flow fluid into the well in response to determining that the kick is occurring in the well. 
     
     
         12 . The method of  claim 8 , comprising causing a blowout preventer of the well to close in response to determining that the kick is occurring in the well. 
     
     
         13 . The method of  claim 8 , comprising transmitting an alarm signal in response to determining that the kick is occurring in the well. 
     
     
         14 . The method of  claim 8 , comprising:
 measuring a local temperature of the downhole fluid; and   transmitting a fourth signal representing the measured local temperature.   
     
     
         15 . The method of  claim 14 , comprising:
 determining whether a change in the measured local temperature is equal to or greater than a threshold temperature change value within a predetermined time span; and   transmitting an alarm signal in response to determining that the change in the measured local temperature is equal to or greater than the threshold temperature change value within the predetermined time span.   
     
     
         16 . The method of  claim 8 , comprising attaching at least a portion of the kick detection system to a downhole portion of a production tubing positioned in the well. 
     
     
         17 . The method of  claim 16 , comprising:
 detaching the portion of the kick detection system from the production tubing; and   retrieving the portion of kick detection system from the well.   
     
     
         18 . A kick detection system, comprising:
 an apparatus configured to be retrievably attached to a production tubing positioned in a well, the apparatus comprising:   a housing comprising a first end and a second end, the housing having a longitudinal axis defined through the first end and the second end, the housing configured to, while attached to the production tubing positioned in the well, allow downhole fluid to flow through the first end and the second end;   a first pressure sensor positioned within the housing at a first distance from the first end, the first pressure sensor configured to measure a first local pressure of the downhole fluid flowing through the housing and to transmit a first signal representing the first local pressure;   a second pressure sensor positioned within the housing at a second distance from the first end, the second distance different from the first distance, the second pressure sensor configured to measure a second local pressure of the downhole fluid flowing through the housing and to transmit a second signal representing the second local pressure; and   a flow detection device within the housing, the flow detection device configured to detect a direction of the downhole fluid flowing through the housing and to transmit a third signal representing the detected direction of downhole fluid flow;   a memory; and   a processor interoperably coupled to the memory and configured to be communicatively coupled to the first pressure sensor, the second pressure sensor, and the flow detection device, the processor configured to:
 determine a density of the downhole fluid flowing through the housing based on the first signal, the second signal, and the difference between the first distance and the second distance; 
 determine whether a kick is occurring in the well based on at least one of:
 determining that a difference between the determined density of the downhole fluid flowing through the housing and a predetermined fluid density is equal to or greater than a threshold density difference value; or 
 determining a change in direction of the downhole fluid flowing through the housing based on the third signal; and 
 
 transmit an alarm signal in response to determining the kick is occurring in the well.