in compare measurements 20 the variation of the composition with position is often the most important attribute to be determined i e the relative fraction of the injected fluid in the sampled interval this may be addressable by performing any of a number of fluid comparison analyses on the physical and or chemical measurement s of the two fluids in question see for instance l venkataramanan et al u201c system and methods of deriving differential fluid properties of downhole fluids u201d u s patent application ser nos 11 132 545 and 11 207 043 the reposition tool 18 determine presence of injected fluid 16 and compare measurements 20 process is typically repeated until all of the areas within the second wellbore under evaluation have been tested if one or more areas within the second wellbore that have high concentrations of the injected nonhydrocarbon and nonaqueous fluid are identified shown in fig2 as identify location having high concentration 22 a well treatment may be performed to enhance production shown in fig2 as treat well 24 this well treatment may inhibit fluid from entering the wellbore at the identified location and flowing to the surface such as the installation of a bridge plug a packer a casing patch gel or cement at a location within the wellbore that inhibits such fluid flow alternately the well treatment could enhance the production of fluid entering the wellbore from areas other than the identified location such as by pressure fracturing propellant fracturing acidizing or reperforating these other areas it is also possible to utilize the information obtained regarding the presence of nonhydrocarbon and nonaqueous.