MULTIPLE APPROACHES TO QUANTIFYING EFFECTIVE POROSITY OF THE DEVONIAN-AGED WOODFORD SHALE IN OKLAHOMA

Woodford Shale is an important unconventional play in midcontinent area, but its effective porosity has not been well studied. As for the porosimetry assessment, nuclear magnetic resonance (NMR) and mercury intrusion porosimetry (MIP) have been widely used in reservoir rock pore characterization; while some traditional methods such as fluid immersion porosimetry (FIP) and paired helium particle density & envelop bulk density (PPBD) are also valuable for their low costs and capabilities of accommodating large sample sizes. Each of these methods have different measurement ranges and limitations. In the literature, those four methods have not been combined to compare the porosity results using different principals and probing fluids (e.g., water, mercury, helium). In this project, we propose to measure the porosities of ten outcrop samples with different lithologies (dolomitic mudstone, siliceous shale, argillaceous shale) from Woodford Formation, Southern Oklahoma. Working with 10 sample sizes ranging from ~10 cm down to <75 µm, the research objectives are to (1) compare the reliability and accuracy of porosity results collected from multiple NMR, MIP, FIP, and PPBD approaches; (2) evaluate the effective porosity as a function of sample size for the Woodford Shale with different lithologies.