Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores

Loucks, Robert G.; Reed, Robert M.; Ruppel, Stephen C.; Hammes, Ursula

doi:10.1306/08171111061

Cited by 1,952 publications

(1,577 citation statements)

References 59 publications

Supporting

Mentioning

1,421

Contrasting

Unclassified

Order By: Relevance

“…[2][3][4][5][6][7] The pore volume of shales can be determined by various techniques such as mercury injection capillary pressure (MICP) porosimetry and grain density/ helium pycnometry, scanning electron microscopy (SEM) images and gas sorption techniques, with each method characterizing a specific pore size range. Ultra small angle neutron scattering and small angle neutron scattering techniques are also useful for the determination of pore connectivity in shales.…”

Section: Introductionmentioning

confidence: 99%

“…Kerogen samples were isolated using chemical methods. 6 Furthermore, high-pressure methane sorption isotherms were determined on both shales and isolated organic kerogen matter to investigate the interrelations between high-pressure sorption capacity, maturity, pore structure and the sorbed gas distribution between organic and inorganic phases.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

et al. 2014

View full text Add to dashboard Cite

. (2014) 'High-pressure methane adsorption and characterization of pores in Posidonia shales and isolated kerogens.', Energy fuels., 28 (5). pp. 2886-2901. Further information on publisher's website:http://dx.doi.org/10.1021/ef402466mPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Energy Fuels, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/ef402466m. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractSorption capacities and pore characteristics of bulk shales and isolated kerogens have been determined for immature, oil-window and gas-window mature samples from the Lower Toarcian Posidonia Shale formation. Dubinin-Radushkevich (DR) micropore volumes, sorption pore volumes and surface areas of shales and kerogens were determined from CO 2 adsorption isotherms at -78°C and 0°C, and N 2 adsorption isotherms at -196°C. Mercury injection capillary pressure porosimetry, grain density measurements and helium pycnometry were used to determine shale and kerogen densities and total pore volumes.Total porosities decrease through the oil-window and then increase into the gas-window.High-pressure methane isotherms up to 14 MPa were determined at 45, 65 and 85°C on dry shale and at 45 and 65°C on kerogen. Methane excess uptakes at 65°C and 11.5 MPa were in the range 0.056-0.110 mmol g -1 (40-78 scf t -1 ) for dry Posidonia shales and 0.36-0.70 mmol g -1 (253-499 scf t -1 ) for the corresponding dry kerogens. Absolute methane isotherms were calculated by correcting for the gas at bulk gas phase density in the sorption pore volume. The enthalpies of CH 4 adsorption for shales and kerogens at zero surface coverage showed no significant variation with maturity, indicating that the sorption pore volume is the primary control on sorption uptake. The sum of pore volumes measured by a) CO 2 sorption at -78°C and b) mercury injection, are similar to the total porosity for shales. Since mercury in our experiments occupies pores with constrictions larger than ca. 6 nm, we infer that porosity measured by CO 2 adsorption at -78°C in the samples used in this study is largely within pores with effective diameters smaller than 6 nm. The linear correlation between maximum CH 4 surface excess sorption and CO 2 sorption pore volume at -78°C is very strong for both shales and kerogens, and goes through the origin, suggestin...

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

et al. 2014

View full text Add to dashboard Cite

show abstract

“…(1); have complex pore shapes, e.g., Loucks et al (2012); and currently their pore level description is incomplete. Even "pore size" determinations are ill-defined, inconsistent, and often incomplete.…”

Section: Discussionmentioning

confidence: 99%

“…In this case, adsorption and MICP analysis should yield similar results. To add to the confusion, Loucks et al (2012), for example, measured pore lengths using FIB/SEM, and reported them as pore sizes.…”

Section: Introductionmentioning

confidence: 99%

Knudsen-Like Scaling May Be Inappropriate for Gas Shales

Patzek

2017

SPE Annual Technical Conference and Exhibition

View full text Add to dashboard Cite

SummaryWe assert that a classification of gas flow regimes in shales that is widely accepted in the petroleum industry, may be inconsistent with the physics of high-pressure gas flow in capillaries. This classification follows from the 1946 work by Brown et al. (1946) that deals with the flow of gases in large industrial metal pipes, elbows and orifices under vacuum, with gas pressures of the order of 1 mm Hg or less. In another pioneering paper that year, Tsien (1946) analyzed the hypersonic flight of rockets in the thermosphere (above 50 miles of altitude), and established the widely accepted Knudsen flow regimes for the high-Reynolds, high-Mach flow of rarified gases. We show why both these papers are not quite applicable to flow of compressed gas in the hot, high-pressure shale pores with rough surfaces. In addition, it may be inappropriate to use the capillary tube metaphor to describe shale micropores or microcracks, simply because each is fed with gas by dozens or hundreds of intricately connected nanopores, which themselves may be slits rather than circular cylinders, and are charged with the dense, liquid-like gas.In the small-scale, low-velocity flows of gases, failure of the standard Navier-Stokes description (the standard Darcy law in petroleum engineering) can be quantified by the Knudsen number, ratio of the mean free path, λ, of gas molecules at the reservoir pressure and temperature to the characteristic pore radius, R. We carefully enumerate the multiple restrictive conditions that must hold for the slip-flow boundary condition to emerge. We also describe the dependence of the slip correction factor on the gas pressure and temperature, as well as the median pore size and rock roughness. In the derivation, we revisit the original approaches of Helmholtz and von Piotrowski (1860) and Maxwell, Niven (1890), which were somehow lost in the multiple translations from physics to petroleum engineering.For example, in Barnett mudrocks, naturally occurring pores are predominantly associated with organic matter and pyrite framboids. In organic matter, the median pore length is 100 nm, Loucks et al. (2009), and the pore radii are likely to be between 1 and 10 nm, Clarkson et al. (2013). Other thermally mature mudrocks may be similar, Bustin (2009), or not, Clarkson et al. (2013). With R = 50 nm, the ratio of λ/R is less than 0.1 for pressures exceeding 60 bars. When we compare the actual slip-flow correction with the accepted classification of gas flow regimes, there is an order of magnitude discrepancy. It appears that our new classification is conservative for pores larger than 5 nm in radius. Therefore, unless the fraction of gas molecules that are bounced off diffusively from the rough pore walls is very low, slip flow is unlikely to dominate in shales. SPE 187068-MSThe generally accepted "Knudsen-diffusion" in shales is based on a mistranslation of the flow physics and may give theoretically unsound predictions of the increased permeability of shales to gas flow. This increase of permeability is real...

show abstract

“…According to the pore occurrence and pore association with mineral particles under SEM, three types of pore are identified in TYS: interparticle pores, intraparticle pores and organic-matter pores (Fig. 7) (Loucks et al, 2012;Wu et al, 2014;Zhang et al 2016). The SEM evaluation shows that pores in TYS are mainly interparticle pores and organic-matter pores (varying from several nanometers to a few microns), which suggests that mineralogical composition and TOC are the important controlling factors for porosity of the TYS.…”

Section: Porosity and Permeabilitymentioning

confidence: 99%

Characterization of marine-terrigenous transitional Taiyuan formation shale reservoirs in Hedong coal field, China

Li¹,

Chen²,

Li³

et al. 2018

Adv. Geo-Energy Res.

View full text Add to dashboard Cite

Abstract:To better understand the basic characteristics of Marine-terrigenous Transitional Taiyuan formation shale (TYS) reservoirs in Hedong coal field, a series of reservoir evaluation experiments were conducted on 33 core samples, which were collected from an exploration shale gas well (SL-1). The results show that organic matters in TYS are Type III gas prone kerogen and are in the high-maturity stage with an average Ro value of 1.87% (ranging from 1.71 to 2.10%). The total organic carbon (TOC) is ranging from 0.29% to 11.87% with an average value of 2.91% and gas content is from 0.41 to 2.96 ml/g, which indicates that TYS still has certain hydrocarbon generation potential despite a mass generation of hydrocarbons occurred during the geological history. XRD analysis shows that TYS is composed mainly of quartz minerals and clay minerals with an average brittleness index of 46.5%, which is relatively favorable for hydraulic fracture. Pore size of TYS ranges from a few nanometers to hundreds of nanometers. The permeability is irrelevant with porosity and its values are all lower than 0.1 md. The average value of BET surface area and BJH volumes are 8.57 m 2 /g and 1.84 cm 3 /100g, respectively. Similar to previous studies, TOC content is a decisive control on gas adsorption capacity in this study.

show abstract

Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores

Cited by 1,952 publications

References 59 publications

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

High-Pressure Methane Adsorption and Characterization of Pores in Posidonia Shales and Isolated Kerogens

Knudsen-Like Scaling May Be Inappropriate for Gas Shales

Characterization of marine-terrigenous transitional Taiyuan formation shale reservoirs in Hedong coal field, China

Contact Info

Product

Resources

About