Integrated Formation Evaluation Workflow for Estimating Source Rock Hydrocarbon Potential

Abstract

A complex reservoir usually requires tools and workflow which are beyond conventional formation evaluation techniques. In the case of source rock plays, the complex petrophysics are solved with the addition of advanced logging tools such as NMR for porosity and permeability determination, dielectric for fluid saturation, elemental spectroscopy for identification and quantification of minerals, and core data, ideally pressure core for petrophysical calibration. Formation evaluation for source rocks must be integrated with geochemical analysis to evaluate TOC and/or kerogen, geomechanics analysis to evaluate rock fracability and quantification of faults and natural fractures if present. TOC analysis can be done with standard logging tools with the DeltalogR or Schmoker methods, and the geomechanical analysis can be done with dipole or multipole sonic tools through anisotropy evaluation and elastic properties computations to help quantify areas where fracture conductivity is easier to achieve. Geochemistry and geomechanics log results require high quality core data to calibrate TOC and organic material maturity using pyrolysis or LECO combustion technique and to calibrate elastic properties using triaxial pressure test., Leak Off Test (LOT/XLOT), or microfrac/DFIT. This paper presents a proven workflow and lessons learnt from recent source rock reservoir evaluations using advanced logging tools. The goal of this presentation is to improve understanding on how source rock reservoirs must be evaluated to be completed and commercially produced, such as in emerging Indonesian Source Rock plays.