A Method for Fluid Loss Quantification and Hydrocarbon Characterization in Tight Rocks

Introduction

Unconventional (‘tight’ rock as defined by less than 1 mD of permeability) bulk property analyses often hinge on key assumptions including the lost fluid profile which is typically not quantified due to inadequate laboratory methods. Recent advances via GeoMark’s TruSat™ approach provide vital measured data constraints regarding the percent fluid (hydrocarbon + water) lost from the intact versus crushed rock mass in the as-received state.

The total fluid loss is quantified by utilizing nuclear magnetic resonance (NMR) T2 pore body comparisons of the whole rock (as received intact) and the powdered rock (as-received crushed). Laboratory rock crushing techniques and processes can be responsible for ~0-20% of total fluid loss (n>1000 samples) and if not accounted for, subsequent measured total water and oil saturations via dual retort analysis could be significantly underestimated (~10-20%).