Imaging pores in sedimentary rocks: Foundation of porosity prediction

Abstract

This review examines the history and current practice of technologies for imaging of pores in sedimentary rocks. Pores are that portion of the rock volume occupied by components of relative mobility such as water of various salinities, microbial life, petroleum liquids, gases, and supercritical fluids. Through a rock's history the contained pores evolve as the primary detrital assemblage responds chemically and mechanically to changing conditions in the subsurface. Description and classification of pores based upon their paragenesis depends upon inspection by imaging that allows the pores to be seen and interpreted in the context of historical processes responsible for formation of the pore walls. Since the late 1960s, sample preparation and imaging methodologies that clarified our understanding of pores in their correct historical context have been at the root of important advances in prediction of porosity and related bulk properties in the subsurface. These older approaches are now joined by new technologies that serve current efforts to extend predictive capabilities to nm-scale pores in the fine-grained, low-permeability rocks that dominate in the deeper parts of sedimentary basins, and indeed, in the sedimentary record as a whole. Placing the smallest pores into their proper paragenetic context presents a challenge in the quest to develop predictive models for porosity evolution in fine-grained rocks.

Multi-scale Characterization of Pore Structure of Shale: a Case Study of the First Member of Qingshankou Formation in the Songliao Basin

“…The PC is the inlet pressure, σ is the interfacial tension (Dane / cm, θ is the contact angle, and R is the pore throat radius [13] .…”

A dual-porosity model for evaluating petroleum resource potential in unconventional tight-shale plays with application to Utica Shale, Quebec (Canada)

“…The size of matrix pores is predominantly in the order of the micrometre although nano-pores exist as crystal defects and intercrystal spaces in clay minerals (Milliken and Curtis, 2016); as a general rule primary pore diameter and volume decrease with increasing burial depth ( Figure 1). The matrix pore is saturated with water when sediments are deposited and likely remains water wet (e.g., .…”

The effects of solvent extraction on nanoporosity of marine-continental coal and mudstone

“…Pore networks of sediments in petroleum systems control the storage of adsorbed and free gas and fluid flows, which determine whether the sediments can be a reservoir or a cap rock. There have been studies on how pore structures are affected by lithology, mineralogy, total organic carbon (TOC), thermal maturity, fabric and diagenetic history [3][4][5][6][7][8][9], and how pore structures control the gas storage and migration [10][11][12][13][14].…”