Automated real-time solids content and salinity analysis of well construction fluids using in-line XRF measurements

Abstract

Measurements and monitoring of solids content and salinity in fluids to maintain these at ideal levels is essential for optimum well construction operations during drilling, completion, workover and abandonment phases. Currently, API measurements are used for solids and salinity determination, which have certain drawbacks and are difficult to automate.As an alternative, a novel in-line X-ray fluorescence (XRF) measurement approach was investigated to make determination of solids content and salinity of well construction fluids much simpler and more efficient through automation. Laboratory experiments were conducted to generate a comprehensive dataset of X-ray photon counts from an in-line XRF setup coupled to a flow loop to evaluate common solids and solutes in well construction fluids. Using this dataset, calibration curves were generated to determine the high-gravity solids (HGS) and low-gravity solids (LGS) content as well as the salinity of water/brine, oil, and synthetic-based fluids at a high level of accuracy in real-time with full automation.It was observed that with the XRF measurements, certain solids can be measured and monitored by analyzing the concentration of certain elements in the compounds (i.e., barium (Ba) for barite concentration, potassium (K) for potassium chloride concentration, iron (Fe) for clay concentration). The mean average errors in estimating the HGS, LGS and salinity values were found to be less than 2%. Using this method together with automated rheology, density and water-cut measurements decreases these errors to significantly lower levels.The system presented here offers the possibility for real-time solids content management and optimization, opening the door to fully automated fluid measurements, maintenance, and solids control in well construction operations. This will benefit well construction efficiency (e.g. lowering drilling costs), quality, productivity (e.g. reducing reservoir impairment from unwanted solids) and safety (e.g. lowering incidence of well control and lost circulation events due to better equivalent circulating density (ECD) management in narrow margin drilling environments).