Method and system for using tracer shots for estimating influx volumes of fluids from different influx zones to a production flow in a well

Abstract

A method for estimating influx volumes of fluids to a production flow in a well with two or more influx locations along the well includes arranging tracer sources with unique tracer materials in fluid communication with two or more of the influx zones, each tracer material having a predefined short duration release dose to the fluids in the well, allowing the tracer sources to release the tracer material to the fluids at a given release instant, after the release instant, consecutively collecting samples of the production flow at the topside, analysing the samples for identifying types of tracer material and concentration of the identified tracer materials, based on the concentrations and their sampling sequence and the well geometry, sequence of the separate influx zones, calculating the influx volumes from transient flow models using the calculated influx volumes as parameters for controlling the production flow or for characterizing the reservoir.

1 . A method for estimating influx volumes of fluids to a production flow in a well with two or more influx locations along the well, said method comprising the steps of:
 arranging tracer sources with unique tracer materials in fluid communication with said influx zones;   each said tracer material having a predefined short duration release dose to the fluids in the well;   allowing said tracer sources to release said tracer material to said fluids at a given release instant;   after said release instant, consecutively collecting samples of said production flow at the topside;   analysing said samples for identifying types of tracer material and concentration of said identified tracer materials;   based on said concentrations and their sampling sequence and the well geometry, sequence of said separate influx zones, calculating said influx volumes from transient tracer flow models; and   using the calculated influx volumes as parameters for controlling the production flow or for characterizing the reservoir.   
     
     
         2 . The method of  claim 1 , said tracer sources arranged for releasing preferably simultaneously at a given release instant in time. 
     
     
         3 . The method of  claim 1 , wherein said release dose is released during less than one minute. 
     
     
         4 . The method according to  claim 1 , wherein said given release instant being an advance determined instant in time. 
     
     
         5 . The method according to  claim 4 , said given release instant being one of a series of release instants, all predetermined before assembly and installation of the production pipe assembly. 
     
     
         6 . The method according to  claim 1 , said given release instant being commanded from the surface. 
     
     
         7 . The method according to  claim 1 , said two or more influx locations being separate, influx locations mutually isolated in the annulus around the production pipe. 
     
     
         8 . The method according to  claim 1 , said tracer sources arranged in fluid communication with said influx zones. 
     
     
         9 . The method according to  claim 1 , said influx locations having known positions along the well. 
     
     
         10 . The method according to  claim 1 , after said release instant, sampling after a time reasonably comparable to the minimum transit time for a first of the tracers to reach the sampling site. 
     
     
         11 . The method according to  claim 1 , further comprising the step of collecting said consecutive samples of said production flow at the topside at sampling times, said sampling sequence being sampling times. 
     
     
         12 . The method according to  claim 1 , further comprising the step of collecting said consecutive samples of said production flow at the topside at consecutive cumulative production volumes, said sampling sequence being cumulative production volumes. 
     
     
         13 . The method according to  claim 1 , the well geometry comprising the sequence and positions of said separate influx zones, and the length and geometry of the production pipe from the influx zones to the topside. 
     
     
         14 . The method according to  claim 1 , said production flow being in a general steady state. 
     
     
         15 . The method according to  claim 1 , said production flow a ramp-up. 
     
     
         16 . A system for estimating influx volumes of fluids to a production flow in a well with two or more influx locations along the well, comprising:
 tracer sources with unique tracer materials arranged in fluid communication with said influx zones;   each said tracer material having a predefined short duration release dose to the fluids in the well;   said tracer sources provided with a timer to release said tracer material to said fluids at a given release instant;   a sampling device for consecutively collecting samples of said production flow at the topside after said release instant;   an analysing apparatus for said samples for identifying types of tracer material and concentration of said identified tracer materials;   an algorithm for calculating said influx volumes from transient tracer flow models based on said concentrations and their sampling sequence and the well geometry, sequence of said separate influx zones; and   said calculated influx volumes for being used as parameters for controlling the production flow or for characterizing the reservoir.   
     
     
         17 . The system of  claim 16 , said tracer sources arranged for releasing preferably simultaneously at a given release instant in time. 
     
     
         18 . The system of  claim 17 , wherein said release dose is arranged for being released during less than one minute. 
     
     
         19 . The system according to  claim 16 , wherein said given release instant is an advance determined instant in time. 
     
     
         20 . The system according to  claim 16 , said given release instant being one of a series of release instants. 
     
     
         21 . The system according to  claim 16 , said given release instant arranged for being commanded from the surface. 
     
     
         22 . The system according to  claim 16 , said two or more influx locations being separate, influx locations mutually isolated in the annulus around the production pipe. 
     
     
         23 . The system according to  claim 16 , said tracer sources arranged in fluid communication with said influx zones. 
     
     
         24 . The system according to  claim 16 , the well geometry comprising the sequence and positions of said separate influx zones, and the length and geometry of the production pipe from the influx zones to the topside. 
     
     
         25 . The system according to  claim 16 , the production tubing comprising a sub with one or more breakable tracer material-containing ampoules arranged to be broken individually by one or more mechanical devices triggered by a timer unit arranged in said sub, said sub provided with an electrical battery, each said breakable ampoule provided with a discharge channel to the fluid. 
     
     
         26 . The system according to  claim 25 , said discharge channel leading to the central production pipe. 
     
     
         27 . The system according to  claim 26 , said discharge channel leading to the annulus space outside the central production pipe, said annulus space provided with holes to said central production pipe, so as for said annulus space to form a delay chamber for released tracer material.