Reliable Solid Organic Matter Thermal Maturity Assessment Using Surface Enhanced Raman Spectroscopy and Case Studies

Abstract

In the past years, continuous efforts have been made to assess the solid organic matter maturity, including the vitrinite reflectance and its equivalent (Roe) and T_max from Rock Eval analysis. Despite the enormous data collected, major difficulties still exist for these methods when applied to specific fields.

In this study, we will present a Surface Enhanced Raman Spectroscopy (SERS) technique on solid organic matter. For the SERS to function, aqueous solution of Ag nanoparticles will be prepared and applied to powders of coal and kerogen, which are then analyzed under the Raman Spectroscopy with optimal laser light intensity and duration. A high throughput method will be deployed to better assress the heterogeneity issue. Comparison of SERS results and known maturity values of different samples (coal vs. kerogen) leads to the establishment of the calibration curves . Kinetics parameters of the SERS parameter variation are thus achieved for two organofacies.

Application to source rock in the Anadarko Basin will be presented. The Woodford shale samples with different facies will be examined and compared with existing maturity data and SERS data we collected from previously obtained samples. We will also use the the fluid data from studied wells and the depth to achieve better interpretation of the maturity data. Fluid data such as American Petroleum Institute (API) gravity and/or gas to oil ratio (GOR) will be extracted from the studied wells. Our method will present key improvement in solid maturity assessment and will provide major constraints on the interpretation of generation, cracking and migration of hydrocarbons.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018