Geochemical Characterization of Critical Minerals in Oil/Gas Drilling Waste: A Comparative Study Across Midland Basin

Critical minerals (CMs) are essential for advancing renewable energy infrastructure, consumer electronics, and electric vehicle technology. As global demand for these materials continues to grow, securing a stable and sustainable supply has become a strategic priority. However, conventional mining practices are often environmentally destructive, economically costly, geologically limited, and geopolitically constrained, necessitating alternative sources of CMs. One potential solution lies in the extraction of CMs from unconventional oil and gas solid wastes, particularly drill cuttings generated during drilling operations. Despite the significant volume of these waste materials, their potential as a secondary CM resource remains underexplored. This study investigates the geochemical composition and mineralogical distribution of CMs in drill cuttings from four deep exploration wells across the Midland Basin to evaluate vertical and areal extent of CMs, including type, concentration, and extraction potential. A multimethod approach was employed beginning with an initial screening of drill cutting samples using X-ray fluorescence (XRF) and X-ray diffraction (XRD). After an initial screening and down selecting samples based on CM concentrations a variety of synchrotron-based techniques including μ-XRF imaging and X-ray absorption spectroscopy (XAS) were employed to identify the elemental associations between CMs and rock forming elements, redox states of key CMs, and their overall phases. Elements targeted for XAS analysis were selected based on their concentrations exceeding synchrotron detection limits and their classification as critical minerals. These characterization studies were correlated with different lithologies and specific units in the Midland Basin. Among the elements analyzed, titanium is consistently enriched throughout the entire stratigraphic column, associated with detrital inputs. Barium is primarily concentrated in evaporitic intervals, while vanadium is strongly associated with organic-rich black shale facies especially within the Wolfcamp Formation. Zinc and yttrium are enriched in shale environments, and zirconium and nickel generally increase with depth, corresponding to heavier detrital phases. Surprisingly, for a given element the phase detected is consistent regardless of the depth in the well and among the four well. CMs that were elevated in the drill cuttings and were assessed via XAS include Ti, V, Zn, Mn, Y, and Ba: Ti predominantly exists as TiO2 (rutile/anatase), V as V(III)-carbonate, Zn as ZnS (sphalerite), Mn as MnCO3 (rhodochrosite), Y as YPO4 (monazite), and Ba as BaSO4 (barite) indicating predictable geochemical behavior in subsurface environments. Despite the absence of economically viable rare earth elements (REE) concentrations, elevated critical mineral levels such as V highlight the potential viability of in situ extraction strategies. These findings underscore the potential of drilling waste as a secondary CM resource, providing an opportunity to enhance resource sustainability while reducing environmental impacts. Future research should focus on refining extraction methodologies for processing drill cuttings prior to landfilling, as well as evaluating the feasibility of in situ recovery strategies and their potential integration into unconventional energy operations.