Reuse of Flowback Water from Hydraulic Fracturing for Drilling Mud Preparation and Secondary Hydrocarbon Recovery

Ewa Knapik,Katarzyna Chruszcz-Lipska,Sławomir Wysocki,Łukasz Łukańko

doi:10.3390/en14185921

Abstract

Flowback water after completion of hydraulic fracturing is one of major waste streams generated during the lifespan of a well so its beneficial reuse is crucial. The application of treated flowback is not limited to stimulation processes but also may include drilling operations and secondary oil recovery. The flowback water used in this work is characterized by high salinity reaching up to ~295 g/L caused mainly by NaCl. The presence of suspended solids, mainly corrosion products, prompts the use of coagulation and filtration as treatment methods. Among tested coagulants the most effective one was the SAX18 (NaAlO2) commercial coagulant applied at concentration of 12 mL/L which reduces the water turbidity from over 400 FTU to 23 FTU. The applied treatment greatly reduces the concentration of scaling ions and so the concentration of SiO2 is reduced by 64%, Ba2+–66%, Fe2–36%, Mn2+–65%, SO42−–66%. The treated flowback fluid can be reused in surfactant flooding for enhanced oil recovery where achieves 7% higher displacing efficiency than fresh water. The drilling muds which were prepared using the untreated flowback water exhibit good rheological properties. The obtained results show that recycling of flowback water in future drilling and exploitation operations is technically feasible.

Highlights

IntroductionHydraulic fracturing (HF) is a necessary stimulation method to achieve a profitable level of gas production
Large quantities of fresh water used for Hydraulic fracturing (HF) cause severe environmental concerns, such as large surface and/or groundwater withdrawal, induced earthquakes, generation of large volumes of produced and flowback water transported to disposal wells [2,3]
The reuse of produced and flowback water in hydraulic fracturing operations is commonly practiced by industry to reduce fresh water consumption

Summary

Introduction

Hydraulic fracturing (HF) is a necessary stimulation method to achieve a profitable level of gas production. Large quantities of fresh water used for HF cause severe environmental concerns, such as large surface and/or groundwater withdrawal, induced earthquakes, generation of large volumes of produced and flowback water transported to disposal wells [2,3]. The reuse of produced and flowback water in hydraulic fracturing operations is commonly practiced by industry to reduce fresh water consumption. This internal recycling minimizes the costs of flowback transport and disposal. According to Candia and Seth [4] the operators can save anywhere from

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