Multifaceted Solution of Analytical Challenges in Complex Oilfield Materials With Synchrotron Techniques

The versatility of synchrotron techniques for the solution of oilfield questions is illustrated by the application of powder X-ray diffraction (PXRD) and X-ray absorption near-edge structure (XANES) spectroscopy to a toluene-insoluble oilfield-residue sample from an alkaline/surfactant/polymer (ASP) -flood site in Taber, Alberta, Canada. The primary questions regarding the sample were the sources of the barium and nitrogen (both at levels of approximately 0.8 wt%). Synchrotron PXRD provided better signal–noise and detection limits than previously obtained laboratory PXRD data, enabling the identification of four additional crystalline minerals including heulandite, (Ba, Ca, Sr, K, Na)₅ Al₉ Si₂₇ O₇₂ (H₂O)₂₂, a tecto-silicate zeolite known for accommodation of a wide variety of cations. Heulandite provides a plausible location for barium (and strontium) observed with chemical analysis. Synchrotron XANES spectra at the nitrogen K-edge suggested that the source of the nitrogen content was a corrosion inhibitor, rather than a polyacrylamide (PAM) -based compound, as originally assumed.