ANALYSIS COMPATIBILITY OF RHODAMINE B AS A FLUORESCENT TRACER IN DRILLING FLUIDS FORMULATED WITH AND WITHOUT BENTONITE

Abstract

Drilling fluid is a critical component in oil and gas operations; however, fluid invasion into the formation can lead to significant uncertainties during core analysis. To enhance reservoir characterization accuracy, the use of fluorescent tracers has been developed to more precisely track mud contamination. This study evaluates the compatibility of Rhodamine B, a stable and inexpensive fluorescent dye, in water-based mud (WBM) systems, both with and without bentonite. Unlike previous studies that used carrier matrices such as silica or SAPs, this research investigates Rhodamine B in its free form. Compatibility was assessed based on fluorescence intensity and interaction with common mud additives, as well as its effects on mud properties and thermal stability. The results show that Rhodamine B is compatible with most additives, maintaining high visual fluorescence intensity in the presence of xanthan gum, PAC, NaOH, and others, while bentonite exhibited low intensity. The maximum compatible concentration was determined to be 0.03 g per 350 mL of bentonite-free mud and 0.4 g for mud containing bentonite. Fluorescence intensity decreased over time and with increasing temperature but remained detectable at concentrations of ≥0.03 g in non-bentonite mud and ≥0.5 g in bentonite-containing mud. These findings support the potential application of Rhodamine B as an effective fluorescent tracer in WBM systems.