Stabilization of Crude Oil Emulsions by Flowback Fluid Solids Post Well Drilling and Workover Activities

SUMMARY In order to increase efficiency and to align with the United Nations’ Sustainable Development Goals (SDGs) to cut down on greenhouse gas (GHG) emissions and achieve net zero, flowback fluids from drilling operations are sent to the production line and not to rig burners for treatment with zero flaring. However, due to different nature of substances present in the flowback fluid, crude oil emulsions can be stabilized by the flowback fluid leading to a difficult and complex oil and water separation process. In this paper, a study to find the root cause of poor oil-water separation and process upset due to crude oil emulsion stabilization by flowback fluids was presented. Advanced analytical techniques including rheo-microscopy, high performance liquid chromatography (HPLC), Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), Fourier-transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) were deployed to better understand the nature, behavior and molecular-level characteristics of the crude oil emulsion during flowback activities. Crude oil emulsion sample collected at the beginning of the process upset showed elevated viscosity and pour point, along with a high asphaltene content, indicative of increased heavy and interfacial molecular compounds as shown by petroleomics analysis. XRD analysis identified higher concentrations of magnetite (Fe3O2) and iron (Fe) particles in the early-stage sample when compared with the samples obtained at latter stage of the process upset. The study confirmed that asphaltenes, magnetite and iron particles from flowback fluid, synergistically stabilized the emulsion by forming a rigid interfacial film that hinders water droplet coalescence. The research suggests that rapid compatibility and emulsion separation testing of flowback fluids after workover activities can prevent similar process upsets. The findings also highlighted the need for ensuring corrosion products and other solid particles are completely removed from the drilling and workover fluids using appropriate technologies for successful flowback operations. The research will enhance the understanding of emulsion dynamics and offer actionable insights for optimizing separation processes in the oil industry and for enhanced total flowback to production lines with zero flaring for reducing carbon emissions from drilling and workover operations.