Identification of lost circulation zones

Abstract

Method and apparatus for identifying lost circulation in subterranean wells, in particular, methods for treating the identified lost circulation zones with fluid compositions that are pumped into a wellbore enter voids in the subterranean-well formation through which wellbore fluids escape, and form a seal that limits further egress of wellbore fluid into the lost-circulation zone.

1 . A method for identifying the depth, the severity, or both, of lost-circulation zones in a subterranean well, comprising:
 (i) placing a tubular body in a wellbore, the tubular body being equipped with:
 (a) a drill bit, the drill bit having at least one nozzle; 
 (b) at least one sensor attached to the outer surface of the tubular body, the sensor being capable of measuring a parameter that directly correlates to fluid-flow rate in the annulus between the outer surface of the tubular body and the wellbore wall; and 
 (c) means to transmit the parameter to the surface; and 
   (ii) recording the parameter and transmitting the parameter to the surface.   
     
     
         2 . The method of  claim 1 , wherein:
 (i) the wellbore is drilled by the tubular body; and   (ii) drilling fluid is pumped through the interior of the tubular body, through one or more drill-bit nozzles, and upstream in the annulus between the outer surface of tubular body and the wellbore wall.   
     
     
         3 . The method of  claim 1 , wherein:
 (i) the wellbore is filled with fluid; and   (ii) fluid is not being pumped through the tubular body as the tubular body is inserted into the wellbore.   
     
     
         4 . The method of  claim 1 , further comprising removing the tubular body from the wellbore while continuing to measure and transmit the parameter. 
     
     
         5 . The method of  claim 1 , wherein the sensor is chosen from the group comprising flowmeters, spinners, electromagnetic flowmeters, optical fluid sensors, ultrasonic flow-velocity sensors and differential-pressure-flow sensors. 
     
     
         6 . The method of  claim 1 , wherein the parameter is transmitted via hard wire, optical fiber, wireless, radio, mud-pulse telemetry, electromagnetic telemetry or microwave transmission. 
     
     
         7 . The method of  claim 1 , wherein the parameter is transmitted to the surface in real time. 
     
     
         8 . A method for subterranean well treatment, comprising:
 (i) placing a tubular body in a wellbore, the tubular body being equipped with:
 (a) a drill bit, the drill bit having at least one nozzle; 
 (b) at least one sensor attached to the outer surface of the tubular body, the sensor being capable of measuring a parameter that directly correlates to fluid-flow rate in the annulus between the outer surface of the tubular body and the wellbore wall; and 
 (c) means to transmit the parameter to the surface; 
   (ii) recording the parameter and transmitting the parameter to the surface;   (iii) identifying the depth, the severity, or both, of the zone to be treated; and   (iv) pumping a treatment fluid at the identified depth.   
     
     
         9 . The method of  claim 8 , wherein the treatment comprises lost-circulation or inflow of formation fluid. 
     
     
         10 . The method of  claim 8 , wherein:
 (i) the wellbore is drilled by the tubular body; and   (ii) drilling fluid is pumped through the interior of the tubular body, through one or more drill-bit nozzles, and upstream in the annulus between the outer surface of tubular body and the wellbore wall.   
     
     
         11 . The method of  claim 8 , wherein:
 (i) the wellbore is filled with fluid; and   (ii) fluid is not being pumped through the tubular body as the tubular body is inserted into the wellbore.   
     
     
         12 . The method of  claim 8 , further comprising removing the tubular body from the wellbore while continuing to measure and transmit the parameter. 
     
     
         13 . The method of  claim 8 , wherein the sensor is chosen from the group comprising flowmeters, spinners, electromagnetic flowmeters, optical fluid sensors, ultrasonic flow-velocity sensors and differential-pressure-flow sensors. 
     
     
         14 . The method of  claim 8 , wherein the parameter is transmitted via hard wire, optical fiber, wireless, radio, mud-pulse telemetry, electromagnetic telemetry or microwave transmission. 
     
     
         15 . The method of  claim 8 , wherein the parameter is transmitted to the surface in real time. 
     
     
         16 . The method according to  claim 8 , wherein the treatment fluid contains chemicals that react downhole to form a plug. 
     
     
         17 . A well-treatment apparatus, comprising a tubular body having at its bottom end a drill bit, the drill bit being equipped with at least one nozzle through which fluids may flow, wherein the outer surface of the tubular body is equipped with a least one sensor able to measure a parameter useful for identifying the depth and severity of a lost-circulation zone, the apparatus being further equipped with means for transmitting the parameter value to surface. 
     
     
         18 . The apparatus of  claim 16 , wherein the sensor is chosen from the group comprising flowmeters, spinners, electromagnetic flowmeters, optical fluid sensors, ultrasonic flow-velocity sensors and differential-pressure-flow sensors. 
     
     
         19 . The apparatus of  claim 16 , wherein the parameter is transmitted via hard wire, optical fiber, wireless, radio, mud pulse telemetry, wired drill pipe, electromagnetic telemetry or microwave transmission. 
     
     
         20 . The apparatus of  claim 16 , wherein the parameter is transmitted to the surface in real time.