--> Quantifying Effective Porosity of Oil and Gas Reservoirs

2018 AAPG International Conference and Exhibition

Datapages, Inc.Print this page

Quantifying Effective Porosity of Oil and Gas Reservoirs

Abstract

Microscopic pore structure characteristics of oil and gas reservoirs (e.g., sandstones, carbonates, and mudrocks) – pore shape, pore-size distribution, and pore connectivity – control fluid flow and hydrocarbon movement. Focusing on effective porosity, the portion of connected pore space as conductive pathways to participate in flow and movement (fe / f,, as an indicator of macroscopic connectivity), this presentation discusses various approaches to quantifying effective porosity for a range of oil and gas reservoirs. The approaches include pycnometry (liquid and gas), pore and bulk volume measurement after vacuum saturation, porosimetry (mercury injection capillary pressure, low-pressure gas physisorption isotherm, water vapor adsorption/desorption isotherm, nuclear magnetic resonance cyroporometry), imaging (X-ray computed tomography, Wood’s metal impregnation, field emission-scanning electron microscopy), scattering (ultra- and small-angle neutron, small-angle X-ray), and the utility of both hydrophilic and hydrophobic fluids as well as fluid invasion tests (imbibition, diffusion, vacuum saturation) followed by laser ablation-inductively coupled plasma-mass spectrometry imaging of different nm-sized tracers. Our results indicate a disparate characteristics and range of effective porosity, with a single-zone behavior and a value of connectivity at approximately 70% for sandstones, as compared to dual-connectivity zones at 70% and 0.01% for mudrocks.