Portable Energy-Dispersive X-Ray Fluorescence Integrates Mineralogy And Chemostratigraphy Into Real-Time Formation Evaluation

Marsala, A.F. (Saudi Aramco) | Loermans, T. (Saudi Aramco) | Shen, S. (Saudi Aramco) | Scheibe, C. (Halliburton) | Zereik, R. (Halliburton)

OnePetro 

ABSTRACT
Our objective is to unlock the wealth of information contained in drill cuttings in real-time for complementing petrophysical characterization while drilling. The approach is to integrate the direct measurement from drill cuttings with Logging While Drilling (LWD) data to sup-port drilling, geosteering and formation evaluation.
Our objective is to unlock the wealth of information contained in drill cuttings in real-time for complementing petrophysical characterization while drilling. The approach is to integrate the direct measurement from drill cuttings with Logging While Drilling (LWD) data to sup-port drilling, geosteering and formation evaluation.
A way to tackle the above challenge is to perform a geochemical elemental analysis, by means of Energy-Dispersive X-Ray Fluorescence (ED-XRF). A reliable, portable ED-XRF instrument, robust enough for rig site employment is routinely used for a wellsite chemostratigraphy service. The instrument produces accurate elemental data, which can, in addition to its chemostratigraphic applications, be used for mineral and lithology modeling.
A methodology has been developed to convert the elemental analysis into a mineralogical composition of the rock sample that is comparable to measurements from full scale X-Ray Diffraction (XRD) laboratory equipment.
An experimental setup was deployed to assess the ability of modeling mineralogy from geochemical analysis (wellsite ED-XRF) of a set of rock samples in a blind test (Marsala et al., 2011). The analytical results were compared to results obtained from the same samples through state-of-the-art laboratory ED-XRF and wave-length dispersive XRF (WD-XRF) instruments. The geochemical data from the wellsite and the two lab-based instruments show good agreement.
Finally, the modeled mineral compositions from whole-rock geochemical data were compared with the mineralogy determined from XRD analysis and showed good agreement.
Modeled mineralogy from whole-rock geochemical data has been utilized in a wide range of applications rang-ing from mineralogy and lithology, to "brittleness index" determination for frac design in shale gas reservoirs.