Fracturing Effectiveness Evaluation Based on Flowback Data Using Pressure Transient Testing
Luo Hong Tian, Q. Zhang, Xingcai Li, C. Li
Abstract
This study addresses fracturing performance evaluation during shale oil well flowback by developing a seepage flowback mathematical model and a water-phase evaluation framework. A method calculating effective fracture pore volume via flowback water production data is proposed. Using Well H flowback records, variable-production log-log well test plots and RNP-tm diagnostic charts were constructed for time-dependent fracturing effectiveness quantification. Key findings include: (1) Initial maximum cumulative water production derived from Arps harmonic decline model shows a semilogarithmic relationship between daily/cumulative water output; (2) Unit slope in fracturing fluid flowback indicates pseudosteady single-phase fracture depletion, while early positive slope deviation represents radial flow regime; (3) Complex fracture networks from stimulation reduce fluid seepage distances, transforming imbibition displacement into dominant mechanism and establishing fracture-dominated early flow imbibition-controlled sustained production progression. Field applications demonstrate the significance of flowback water production data in flow regime characterization and fracturing performance evaluation.