Anisotropy measurements by formation tester tracer measurements

Abstract

Aspects of the subject technology relate to systems, methods, and computer readable media for determining a parameter of a formation based on withdrawal of an injected tracer solution. A changing concentration profile of a volume of tracer solution that is withdrawn from a formation is measured. A varying simulated concentration profile associated with the tracer solution in a simulated formation is generated by modifying simulated formation parameters of the simulated formation. The varying simulated concentration profile is compared to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation. A parameter of the formation is identified based on a comparison of the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution withdrawn from the formation.

What is claimed is: 
     
         1 . A method comprising:
 measuring a changing concentration profile of a volume of tracer solution that is withdrawn from a formation over a time interval, wherein the tracer solution is injected into the formation through one or more probes of a plurality of probes that are set into the formation at a location within a wellbore;   generating a varying simulated concentration profile associated with the tracer solution in a simulated formation by modifying simulated formation parameters of the simulated formation;   comparing the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation; and   identifying a parameter of the formation based on a comparison of the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation.   
     
     
         2 . The method of  claim 1 , wherein the parameter of the formation is a flow parameter of the formation. 
     
     
         3 . The method of  claim 2 , wherein the flow parameter is anisotropy. 
     
     
         4 . The method of  claim 1 , wherein the parameter of the formation is related to an affinity parameter of the tracer solution within the formation. 
     
     
         5 . The method of  claim 4 , wherein the affinity parameter is indicative of minerology information of the formation. 
     
     
         6 . The method of  claim 1 , wherein the tracer solution includes a dye that is optically detectable in a volume of solution that is withdrawn from the formation after the tracer solution is injected into the formation. 
     
     
         7 . The method of  claim 1 , wherein the tracer solution includes a tracer that is detectable through mass spectrometry in a volume of solution that is withdrawn from the formation after the tracer solution is injected into the formation. 
     
     
         8 . The method of  claim 1 , wherein the volume of tracer solution is captured for analysis at surface. 
     
     
         9 . The method of  claim 1 , wherein the tracer solution is contained within a formation tester disposed at the location within the wellbore and the formation tester is configured to inject the tracer solution through the one or more probes into the formation. 
     
     
         10 . The method of  claim 1 , wherein a rate at which the tracer solution is injected into the formation is varied. 
     
     
         11 . The method of  claim 1 , wherein the tracer solution includes a plurality of different tracers. 
     
     
         12 . The method of  claim 11 , wherein the plurality of different tracers are injected into the formation through two or more probes of the plurality of probes that are set into the formation. 
     
     
         13 . The method of  claim 11 , further comprising:
 normalizing changing concentration profiles of each of the plurality of different tracers based on a concentration profile of a reference tracer; and   comparing normalized concentration profiles of the plurality of different tracers to the simulation concentration profile as part of comparing the simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation.   
     
     
         14 . The method of  claim 1 , wherein the plurality of probes are asymmetrically spaced apart from each other. 
     
     
         15 . The method of  claim 1 , wherein a rate at which the tracer solution is injected into the formation is varied separately from a rate at which tracer of the tracer solution is injected into the formation. 
     
     
         16 . The method of  claim 1 , wherein the plurality of probes include an injection probe for injecting the tracer solution in the formation and a production probe for withdrawing the volume of tracer solution from the formation and operations of the injection probe and the production probe are varied with respect to each other. 
     
     
         17 . The method of  claim 1 , further comprising:
 numerically inverting the changing concentration profile of the volume of tracer solution that is withdrawn from the formation; and   comparing the numerically inverted changing concentration profile of the volume of tracer solution to the simulated concentration profile as part of comparing the simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation.   
     
     
         18 . The method of  claim 1 , wherein the tracer solution is mixed with formation fluid that is withdrawn from the formation over the time interval. 
     
     
         19 . A system comprising:
 one or more processors; and   at least one computer-readable storage medium having stored therein instructions which, when executed by the one or more processors, cause the one or more processors to:
 measure a changing concentration profile of a volume of tracer solution that is withdrawn from a formation over a time interval, wherein the tracer solution is injected into the formation through one or more probes of a plurality of probes that are set into the formation at a location within a wellbore; 
 generate a varying simulated concentration profile associated with the tracer solution in a simulated formation by modifying simulated formation parameters of the simulated formation; 
 compare the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation; and 
 identify a parameter of the formation based on a comparison of the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation. 
   
     
     
         20 . A non-transitory computer-readable storage medium storing instructions for causing one or more processors to:
 measure a changing concentration profile of a volume of tracer solution that is withdrawn from a formation over a time interval, wherein the tracer solution is injected into the formation through one or more probes of a plurality of probes that are set into the formation at a location within a wellbore;   generate a varying simulated concentration profile associated with the tracer solution in a simulated formation by modifying simulated formation parameters of the simulated formation;   compare the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation; and   identify a parameter of the formation based on a comparison of the varying simulated concentration profile to the changing concentration profile of the volume of tracer solution that is withdrawn from the formation.