Flow rate measurement tool based on fluid transit in wells with polymer injection, sealing and recharging system of said tool, flow rate measurement method using said tool and signal processing method

Abstract

A fluid transit-based flow rate measurement tool for polymer injection wells. A sealing and refilling system for said tool. A flow rate measurement method that utilizes said tool. A signal processing method for the fluid transit-based flow rate measurement for polymer injection wells

1 . A polymeric fluid transit-based flow rate measurement tool for polymer injection wells, comprising:
 an ejection assembly comprising:
 a motor that drives, through a reduction gearbox, a rod connected to a plunger, 
 a retraction chamber and an ejection chamber separated by the plunger, said retraction and ejection chambers defining an inner volume of the ejection assembly, and 
 an ejection body comprising the ejection chamber, 
 wherein said retraction chamber comprises a plurality of pressure equalization holes, 
 wherein said ejection body comprises a plurality of angularly spaced ejection holes, and 
 wherein said ejection chamber allows for storing a radioactive tracer fluid; 
   a first detection assembly comprising a first radiation sensor, the first detection assembly being located downstream of the ejection assembly;   a second detection assembly comprising a second radiation sensor, the second detection assembly being located downstream of the first detection assembly; and   control means that allow for motor operation and consequently the movement of the plunger, enabling the ejection of tracer fluid through the plurality of ejection holes in the form of shots.   
     
     
         2 . The tool according to  claim 1 , wherein the plurality of ejection holes comprises four ejection holes. 
     
     
         3 . The tool according to  claim 1 , wherein each ejection orifice has a diameter between 0.30 mm and 0.50 mm, preferably 0.50 mm. 
     
     
         4 . The tool according to  claim 1 , wherein the distance between the plurality of ejection holes and the first radiation sensor is between 3.5 m and 5.5 m, preferably between 4.5 m and 4.9 m. 
     
     
         5 . The tool according to  claim 1 , wherein the distance between the first radiation sensor and the second radiation sensor is between 1 m and 1.5 m, preferably between 1.1 m and 1.3 m, and more preferably 1.18 m. 
     
     
         6 . The tool according to  claim 1 , wherein each of the first radiation sensor and the second radiation sensor is a Geiger sensor. 
     
     
         7 . The tool according to  claim 1 , wherein the ejection chamber comprises a volume between 20 ml and 30 ml, preferably 20 ml. 
     
     
         8 . The tool according to  claim 1 , wherein the reduction gearbox allows a gear ratio of 14:1 or 23:1, preferably 14:1. 
     
     
         9 . The tool according to  claim 1 , further comprising at least one weight bar. 
     
     
         10 . A sealing and recharging system for the tool according to  claim 1 , comprising:
 a clamp comprising an upper body and a lower body joined together by a hinged connection located on one side thereof, the upper body having a through-hole and a plurality of centering projections, and the lower body having a plurality of through holes and a plurality of centering projections, wherein the centering projections are evenly distributed around the clamp and extend radially inwards to hold and keep the tool centered with respect to the clamp;   a funnel located in the through-hole of the upper body of the clamp, said funnel allowing for the storage of radioactive tracer fluid;   three fastening means, each located in the through-holes of the lower body of the clamp, each fastening means comprising a lever and a rod with a rubber stop; and   a quick-closing mechanism comprising a spring and linking the upper and lower bodies of the clamp, ensuring its closure.   
     
     
         11 . The system of  claim 10 , wherein the upper body has two centering projections. 
     
     
         12 . The system of  claim 10 , wherein the lower body has three through-holes and two centering projections 
     
     
         13 . The system of  claim 10 , wherein the centering projections are spaced 72° apart. 
     
     
         14 . A fluid transit-based flow rate measurement method in polymer injection wells, wherein the method comprises the following steps:
 lowering the tool according to  claim 1  through an injection well to a given depth.   performing at least one shot of radioactive tracer fluid from the tool, once polymer solution is being injected through said injection well;   obtaining signals from the first radiation sensor and the second radiation sensor; and   processing the signals obtained from the first radiation sensor and the second radiation sensor, wherein the processing of the signals comprises:
 applying a plurality of flow rate determination techniques and obtaining respective flow rate values from said flow rate determination techniques, and 
 weighting the flow rate values so as to obtain the polymer solution flow rate in the well at the determined depth. 
   
     
     
         15 . The method according to  claim 12 , wherein the plurality of flow rate determination techniques comprises up to thirteen flow rate determination techniques selected from the group consisting of area-under-the-curve and fractions thereof techniques, first-arrival techniques, techniques based on time intervals between maximums, cross-correlation techniques applied to the signal and its time derivatives, and initial slope techniques of the curves. 
     
     
         16 . The method according to  claim 13 , wherein the plurality of flow rate determination techniques consists of four area-under-the-curve and fractions thereof techniques, three first-arrival techniques, one technique based on time intervals between maximums, two cross-correlation techniques applied to the signal and its time derivatives, and three initial slope techniques of the curves. 
     
     
         17 . The method according to  claim 12 , wherein the tool is connected via cable to a control system that enables control of the tool and power supply to the tool, wherein said control of the tool comprises controlling the depth to which the tool is lowered and operations such as the shot time, the start of recharging of the ejection chamber, and the start of ejection. 
     
     
         18 . A signal processing method for flow rate measurement by tracer fluid transit in polymer solution injection wells, wherein said method comprises the following steps:
 obtaining signals from radiation sensors of a fluid transit tool located at a determined depth within a polymer injection well; and   processing the signals obtained from said radiation sensors, wherein the processing of the signals comprises:
 applying a plurality of flow rate determination techniques and obtaining respective flow rate values from said flow rate determination techniques, and 
 weighting the flow rate values so as to obtain the polymer solution flow rate in the well at the determined depth. 
   
     
     
         19 . The method according to  claim 16 , wherein the plurality of flow rate determination techniques comprises up to thirteen flow rate determination techniques selected from the group consisting of area-under-the-curve and fractions thereof techniques, first-arrival techniques, techniques based on time intervals between maximums, cross-correlation techniques applied to the signal and its time derivatives, and initial slope techniques of the curves. 
     
     
         20 . The method according to  claim 17 , wherein the plurality of flow rate determination techniques consists of four area-under-the-curve and fractions thereof techniques, three first-arrival techniques, one technique based on time intervals between maximums, two cross-correlation techniques applied to the signal and its time derivatives, and three initial slope techniques of the curves.