Comparative Study of Flowback Analysis Using Polymer Concentrations andFracturing Fluid Tracer Methods: A Field Study

摘要

This paper compares flowback efficiencies using polymerrnconcentration and frac fluid tracer methods. Results arernpresented for the flowback efficiency of each frac fluidrnsegment using non-radioactive chemical frac tracers injectedrnin a well as well as the results for the total flowbackrnefficiencies using polymer concentration and frac fluid tracernanalysis methods. Two wells were fraced and traced withrnvarious chemical frac tracers. Upon commencing flowback,rnsamples of produced aqueous solution were collectedrnaccording to a pre-designed sampling schedule that lasted forrn72 hours. Samples were analyzed for tracer, polymer,rncalcium, potassium, sodium, and chlorine concentrations.rnWith the use of the mass balance technique, the total flowbackrnvolume and flowback efficiency for each fluid segment wererncalculated using the tracer method. In addition, total flowbackrnand flowback efficiency were calculated using both polymerrnconcentration and tracer methods. To better evaluate andrncompare the results of polymer concentration and frac fluidrntracer analyses, dynamic fluid leakoff tests were conducted inrna laboratory environment using both low and highrnpermeability core samples. Detailed laboratory and fieldrnresults are presented along with comparison of flowbackrnresults from both polymer concentration and frac fluid tracerrnmethods.