Comparative Study of Flowback Analysis Using Polymer Concentrations and Fracturing-Fluid Tracer Methods: A Field Study

摘要

This paper compares flowback efficiencies using polymer concentration and frac fluid tracer methods. Results are presented for the flowback efficiency of each frac fluid segment using non-radioactive chemical frac tracers injected in a well, along with the results for the total flowback efficiencies using polymer concentration and frac fluid tracer analysis methods. Two wells were fraced and traced with various chemical frac tracers. Upon commencing flowback, samples of produced aqueous fluid solution were collected according to a pre-designed sampling schedule that lasted for 72 hours. Samples were analyzed for tracer, polymer, calcium, potassium, sodium, and chloride concentrations. With the use of the mass balance technique, the total flowback volume and flowback efficiency for each fluid segment were calculated by use of the tracer method. In addition, total flowback and flowback efficiency were calculated by use of both polymer concentration and tracer methods. To better evaluate and compare the results of polymer concentration and frac fluid tracer analyses, dynamic fluid leakoff tests were conducted in a laboratory environment by use of both low and high permeability core samples. Detailed laboratory and field results are presented along with a comparison of flowback results from both polymer concentration and frac fluid tracer methods.