Measurement of total porosity for gas shales by gas injection porosimetry (GIP) method

Sun, Jianmeng; Dong, Xu; Wang, Jinjie; Schmitt, Douglas R.; Xu, Chunlu; Mohammed, Tariq; Chen, Dewen

doi:10.1016/j.fuel.2016.09.010

Cited by 67 publications

(27 citation statements)

References 28 publications

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“…The porosity of the core is a basic physical quantity that is usually able to be easily and accurately measured by gas expansion method and liquid saturation method and so on, [17][18][19] under the existing experimental conditions. As the porosity gives the share of the pore space in the rock, it will improve the quality of image segmentation by combining the porosity as the constraint condition to the CT image segmentation.…”

Section: The Porosity Methodsmentioning

confidence: 99%

A New Improved Threshold Segmentation Method for Scanning Images of Reservoir Rocks Considering Pore Fractal Characteristics

Lin

Yang

et al. 2018

Fractals

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Based on the basic principle of the porosity method in image segmentation, considering the relationship between the porosity of the rocks and the fractal characteristics of the pore structures, a new improved image segmentation method was proposed, which uses the calculated porosity of the core images as a constraint to obtain the best threshold. The results of comparative analysis show that the porosity method can best segment images theoretically, but the actual segmentation effect is deviated from the real situation. Due to the existence of heterogeneity and isolated pores of cores, the porosity method that takes the experimental porosity of the whole core as the criterion cannot achieve the desired segmentation effect. On the contrary, the new improved method overcomes the shortcomings of the porosity method, and makes a more reasonable binary segmentation for the core grayscale images, which segments images based on the actual porosity of each image by calculated. Moreover, the image segmentation method based on the calculated porosity rather than the measured porosity also greatly saves manpower and material resources, especially for tight rocks.

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Section: The Porosity Methodsmentioning

confidence: 99%

A New Improved Threshold Segmentation Method for Scanning Images of Reservoir Rocks Considering Pore Fractal Characteristics

Lin

Yang

et al. 2018

Fractals

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“…The gas expansion or gas injection porosimeter technique, a widely used one, is another method that can measure effective porosity. Some challenges, such as gas injection pressure and the dimension of core plugs, are associated with this technique (Sun et al 2016). Using this method, gas is simply injected into Cell-1 (known as reference cell) at a specific pressure, and then Cell-1 is opened and connected to Cell-2 (sample cell) to drive gas molecules into the sample's pores.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have investigated the effects of many parameters, such as gas transport and adsorption effect, pyrolysisinduced thermal maturation, water content, the relationship between static and dynamic properties, temperature, anisotropy, and bedding orientation effects using shale samples (Aljamaan et al 2017;Aljamaan et al 2013;Allan et al 2016;Alnoaimi* et al 2014;Guo et al 2013;He et al 2019;Holt et al 2015;Holt et al 2012;Kim et al 2020;Kuila et al 2011;Lai et al 2016;Masri et al 2014;Sone and Zoback 2013a;Sone and Zoback 2013b;Zhai et al 2021). However, few studies have conducted to examine the rock physical and/or dynamic elastic properties of shale formations (Badrouchi et al 2019;Cho et al 2016;He and Ling 2016;Heller et al 2014;Khalil et al 2019;Ramezanian and Emadi 2020;Sun et al 2016). Heller et al (2014) investigated the effects of confining and pore pressures on matrix permeability of gas-shale plugs from Barnett, Eagle Ford, Marcellus, and Montney reservoirs.…”

Section: Introductionmentioning

confidence: 99%

An experimental study to investigate the physical and dynamic elastic properties of Eagle Ford shale rock samples

Altawati

Emadi

Khalil

2021

J Petrol Explor Prod Technol

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Unconventional resources, such as Eagle Ford formation, are commonly classified for their ultra-low permeability, where pore sizes are in nano-scale and pore-conductivity is low, causing several challenges in evaluating unconventional-rock properties. Several experimental parameters (e.g., diffusion time of gas, gas injection pressure, method of permeability measurement, and confining pressure cycling) must be considered when evaluating the ultra-low permeability rock's physical and dynamic elastic properties measurements, where erroneous evaluations could be avoided. Characterizing ultra-low permeability samples' physical and elastic properties helps researchers obtain more reliable information leading to successful evaluations. In this study, 24 Eagle Ford core samples' physical and dynamic elastic properties were evaluated. Utilizing longer diffusion time and higher helium injection pressure, applying complex transient method, and cycling confining pressure were considered for porosity, permeability, and velocities measurements. Computerized tomography (CT) scan, porosity, permeability, and ultrasonic wave velocities were conducted on the core samples. Additionally, X-ray Diffraction (XRD) analysis was conducted to determine the mineralogical compositions. Porosity was measured at 2.07 MPa injection pressure for 24 h, and the permeability was measured using a complex transient method. P- and S-wave velocities were measured at two cycles of five confining pressures (up to 68.95 MPa). The XRD analysis results showed that the tested core samples had an average of 81.44% and 11.68% calcite and quartz, respectively, with a minor amount of clay minerals. The high content of calcite and quartz in shale yields higher velocities, higher Young's modulus, and lower Poisson's ratio, which enhances the brittleness that is an important parameter for well stimulation design (e.g., hydraulic fracturing). The results of porosity and permeability showed that porosity and permeability vary between 5.3–9.79% and 0.006–12 µD, respectively. The Permeability–porosity relation of samples shows a very weak correlation. P- and S-wave velocities results display a range of velocity up to 6206 m/s and 3285 m/s at 68.95 MPa confining pressure, respectively. Additionally, S-wave velocity is approximately 55% of P-wave velocity. A correlation between both velocities is established at each confining pressure, indicating a strong correlation. Results illustrated that applying two cycles of confining pressure impacts both velocities and dynamic elastic moduli. Ramping up the confining pressure increases both velocities owing to compaction of the samples and, in turn, increases dynamic Young's modulus and Poisson's ratio while decreasing bulk compressibility. Moreover, the results demonstrated that the above-mentioned parameters' values (after decreasing the confining pressure to 13.79 MPa) differ from the initial values due to the hysteresis loop, where the loop is slightly opened, indicating that the alteration is non-elastic. The findings of this study provide detailed information about the rock physical and dynamic elastic properties of one of the largest unconventional resources in the U.S.A, the Eagle Ford formation, where direct measurements may not be cost-effective or feasible.

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“…Good agreement between MIP and HP porosities using 20-35 mesh (500-841 μm) samples suggested that this sample size is optimal for shale porosity measurements [37]. Working with the Longmaxi shale in China, Sun et al [38] suggested that sample sizes smaller than 60 mesh (250 μm) may alter the integrity of the original particle size composition. Thus, in this work samples with 20-35 mesh (500-841 μm) were prepared to measure the porosity using HP method, whereas cube-shaped samples (~1 cm 3 ) were prepared for WIP, NMR, MIP, and HP measurements.…”

Section: Introductionmentioning

confidence: 99%

Multiple Approaches to Quantifying the Effective Porosity of Lacustrine Shale Oil Reservoirs in Bohai Bay Basin, East China

Yang

et al. 2020

Geofluids

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An effective porosity is defined as the ratio of volume of interconnected pore space to total volume of a porous sample. It controls the magnitude of fluid flow and is a key parameter in the assessment of recoverable resources. However, its accurate measurement in tight formations is challenging, due to their complex pore structure and lithofacies heterogeneity. In this study, porosities of sixteen lacustrine shale samples from the second Member of the Kongdian Formation (Ek2) in the Cangdong Sag, Bohai Bay Basin were measured and compared using multiple methods and sample sizes to compare and contrast the effective porosity results. The methods included helium pycnometry (HP; cubes of 1 cm3 and grains at 500-841 μm), water immersion porosimetry (WIP; cubes), mercury intrusion porosimetry (MIP; cubes), and nuclear magnetic resonance (NMR; cubes). Finally, samples were completely sealed using paraffin for bulk density measurements to evaluate the extent of potential clay swelling in shale samples involving probing fluids. Results from the HP, WIP, and MIP methods for skeletal density, bulk density, and effective porosity with cubic samples were compared. While very similar skeletal densities were found for all three methods, a lower bulk density, and therefore lower porosity, from the MIP approach can be attributed to the experimental conditions (e.g., vacuum efficiency, applied pressure, wettability of water/helium vs. mercury) and the probable presence of pores with diameters larger than 50 μm not measurable by MIP. Furthermore, the HP porosity of granular samples with 500-841 μm grain sizes can be regarded as approaching the total porosity. The complicated relationship between WIP and NMR porosities may result from the heat-induced volatilization of moisture in pores during NMR tests, and countercurrent imbibition of water replacing the residual hydrocarbons during the saturation process for sample preparation in both tests. The swelling behavior of the lacustrine Ek2 shale with water is not significant because of the low content of expansive clay minerals. In summary, the WIP and HP methods are recommended for effective porosity measurement, whereas the NMR and MIP methods are invaluable for the measurement of pore-size distribution, with additional information on the effective porosity.

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Measurement of total porosity for gas shales by gas injection porosimetry (GIP) method

Cited by 67 publications

References 28 publications

A New Improved Threshold Segmentation Method for Scanning Images of Reservoir Rocks Considering Pore Fractal Characteristics

A New Improved Threshold Segmentation Method for Scanning Images of Reservoir Rocks Considering Pore Fractal Characteristics

An experimental study to investigate the physical and dynamic elastic properties of Eagle Ford shale rock samples

Multiple Approaches to Quantifying the Effective Porosity of Lacustrine Shale Oil Reservoirs in Bohai Bay Basin, East China

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