Integrated Cleat Analysis And Coal Quality On CBM Exploration In Sangatta II Field, Kutai Basin, East Kalimantan

Apriyani, Nita; Suharmono,; Momen, Muhammad; Djaelani, Setiabudi; Sodli, Arifin; Satria, Andrean; Murtani, Anom Seto

doi:10.29118/ipa.0.13.g.089

Cited by 5 publications

(6 citation statements)

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“…The basic parameters used in the permeability model are as follows: ,,,, E x ,b = 3.5 GPa, E y ,b = 3 GPa, E z ,b = 2.8 GPa, ν yx ,b = 0.28, ν zy ,b = 0.33, ν xz ,b = 0.31, and R C = 150. Other parameters, which are reasonable compared with the literature values, ,− are listed in Figure . In general, the model’s results match well with the experimental data (see Figure ).…”

Section: Model Validationsupporting

confidence: 86%

“…The basic parameters of the permeability model are as follows: ,,,, E x ,b = 3.6 GPa, E y ,b = 3.2 GPa, E z ,b = 2.9 GPa, ν yx ,b = 0.31, ν zy ,b = 0.35, ν xz ,b = 0.33, R C = 300, ε s = 0.04, and p mL = 3 MPa. Other parameters used in the model are shown in Figure and are reasonable compared with those in the literature (the flow channel aperture, − the tortuosity correction coefficient, and the internal swelling factor). The initial flow channel aperture and spacing are determined by matching with the initially measured permeability data .…”

Section: Model Validationsupporting

confidence: 65%

“…The basic parameters of the permeability model are selected according to the literature: ,,,, E x ,b = 3.4 GPa, E y ,b = 5 GPa, E z ,b = 3.7 GPa, ν yx ,b = 0.34, ν zy ,b = 0.32, ν xz ,b = 0.31, and R C = 300. Other parameters used in the model are listed in Figure and are reasonable compared with the literature. − Figure shows the comparison between experimental data and the model’s results. Under constant confining pressure conditions, permeability declines with the reduction of pore (fracture) pressure due to the effective stress increment.…”

Section: Model Validationmentioning

confidence: 66%

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Anisotropic Permeability Model for Coal Considering Stress Sensitivity, Matrix Anisotropic Internal Swelling/Shrinkage, and Gas Rarefaction Effects

et al. 2023

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Permeability is the most crucial property of coal in relation to coalbed methane production and CO2 sequestration. Due to coal’s anisotropic structure and mechanical properties, its permeability exhibits strong anisotropy. The main factors controlling coal permeability evolution are effective stress, anisotropic swelling/shrinkage near fracture surfaces (internal swelling/shrinkage), and gas rarefaction effects. Combined impacts of the above mechanisms make coal permeability evolution complex and difficult to predict. In this study, we establish a fully anisotropic coal permeability model incorporating stress sensitivity, anisotropic internal swelling/shrinkage, and gas rarefaction effects. Specifically, a mechanical-property-based internal swelling model is established to link up anisotropic internal swelling/shrinkage with mechanical anisotropy using the energy balance theory. A Knudsen-number-based model is utilized to describe gas rarefactions effects. The comparison with coal anisotropic swelling data and anisotropic permeability evolution data demonstrates the permeability model’s reliability. Results show that anisotropic internal swelling/shrinkage mainly determines the overall shape of permeability curves, the evolution trend, the range of permeability change in all directions, and the anisotropy level during evolution. It partially or totally offsets the permeability change caused by effective stress variation under certain stress conditions. Effective stress variation starts to dominate permeability evolution when the variation exceeds a certain value. Permeability increment/reduction caused by the gas rarefaction phenomenon enhancement/weakening is dependent on fracture (pore) pressure and aperture, but its influence on permeability is not as strong as that of anisotropic internal swelling/shrinkage. Anisotropic internal swelling/shrinkage and the gas rarefaction phenomenon show a synergistic influence on anisotropic permeability evolution with fracture (pore) pressure changing. The permeability model is applicable for different permeability measurement conditions.

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Section: Model Validationsupporting

confidence: 86%

Section: Model Validationsupporting

confidence: 65%

Section: Model Validationmentioning

confidence: 66%

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Anisotropic Permeability Model for Coal Considering Stress Sensitivity, Matrix Anisotropic Internal Swelling/Shrinkage, and Gas Rarefaction Effects

et al. 2023

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“…The 2D box-counting method also comes with certain limitations like it is very time consuming (Gillespie et al 1993) and can be subjective due to the complicated nature of the fracture networks in some cases. Nevertheless, measurement of cleat attributes along 1-D scanlines is popular amongst researchers (Apriyani et al 2014;Hooker et al 2009;Marrett et al 1999;Ortega et al 2006;Sapiie et al 2014;Solano-Acosta et al 2007;Weniger et al 2016) due to several reasons: (1) it is a relatively quick and straightforward technique as trigonometric corrections are not required for single/two sets of parallel fractures; (2) multiple related attributes, such as spacing, aperture, etc. can be measured together; (3) the technique is independent of the scale of measurement and of rock-types that facilitates comparison between similar dataset from different lithologies of varied scales.…”

Section: Measurement Of Aperture and Lengthmentioning

confidence: 99%

Dependence of fluid flow on cleat aperture distribution and aperture–length scaling: a case study from Gondwana coal seams of Raniganj Formation, Eastern India

Bandyopadhyay

Mallik

Ghosh

2019

Int J Coal Sci Technol

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Dimensions and mutual relationships amongst fracture (cleat) parameters such as maximum aperture width, average aperture width, length, spacing etc. control the connectivity within a fracture network and the fluid flow in a coal seam as the matrix permeability, here, is negligible. In this paper, we document cleat size distributions and investigate lengthaperture relationships from coals of Raniganj coalfield in Eastern India. This coalfield has a proven extractable reserve of six billion tons of coal and holds immense potential to be one of the largest coal bed methane fields serving India's growing energy needs. Here, cleat length (L) correlates with corresponding maximum aperture width (D max) in a power-law function with an exponent of 0.84 (D max a L 0.84) instead of the commonly observed exponents of 1 or 0.5 applicable for other natural 'opening-mode' fractures. The conventional wisdom pertains that laminar fluid flow (Q) through an isolated, smooth-walled, parallel-plate fracture, embedded in an impermeable matrix, is directly proportional to the cube of its aperture width (b, equivalent to D avg ; cubic law: Q a b 3). This assumes a linear relationship between length and fracture aperture. However, the modified relationship between cleat length and average aperture width changes the cubic law applicable for Raniganj coal seam and now fluid flow correlates with aperture width in a power-law function with an exponent of 4.25 (Q a b 4.25) instead of 3 (cube). Such simplifications will come handy for the modeling and estimation of fluid flow as it will reduce the effort of cleat length measurement which is anyway difficult and can be misleading due to the risk of undersampling.

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“…There is a considerable contrast to the cleats spacing value on LP 67 towards the LP 2A and LP 2B ones, the cleats spacing value of LP 67 tend to be more dense and intense. The determination of cleats genesis is done by dividing the genesis based on the rotation angle of the cleat to the bedding plane wherein if the resulting angle between 70 -90 o is classified as endogenic cleat and if the resulting corner <70 o is classified as an exogenic cleat (Apriyani, N ,, et al, 2013).…”

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confidence: 99%

Characteristics of Coal and Cleat Attributes in Ulak Lebar and Surroundings Area, Lahat Regency, South Sumatra

Rahmawati

Sari

Triyoga

et al. 2018

J. Geoscience Eng. Environ. Technol.

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The research conducted in Ulak Lebar Area, Lahat Regency, South Sumatra. The focus of this study is on the Muara Enim Formation as it is known as the main coal-bearing formation in South Sumatra Basin. The research is aimed to determine the characteristics of coal based on its physical properties, also knowing the cleat development at the coal seam in the research area. The methods used such as literature study, field observation and laboratory test. Field observations included the observations of coal megascopic appearance and cleat attributes analysis such as the measurements of cleat orientation, aperture, spacing and length. The analysis result of cleat at LP 2A and LP 2B shows a relatively similar such as spacing value ranged between 6 - 9 cm and 5.5 – 8.6 cm while the aperture value ranged from 0.05 - 0.2 cm, and 0.05 - 0.25 cm, whereas at LP 67 the spacing value ranged from 1.5 to 3.3 cm and the aperture valued between 0.1 - 0.3 cm. A rather significant difference between the cleat spacing values of LP 67 towards both previous observation stations is indicated by the geological processes occurred during the coalification process thus affected the development of cleats in coal, the geology structure control is characterized by a relatively large aperture and smaller spacing values. The laboratory test conducted is maceral analysis, shows the coal in the research area is dominantly composed of vitrinite (74,8%) and the vitrinite reflectance value is 0,40 indicating the coal classified as sub-bituminous rank.

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Integrated Cleat Analysis And Coal Quality On CBM Exploration In Sangatta II Field, Kutai Basin, East Kalimantan

Cited by 5 publications

References 0 publications

Anisotropic Permeability Model for Coal Considering Stress Sensitivity, Matrix Anisotropic Internal Swelling/Shrinkage, and Gas Rarefaction Effects

Anisotropic Permeability Model for Coal Considering Stress Sensitivity, Matrix Anisotropic Internal Swelling/Shrinkage, and Gas Rarefaction Effects

Dependence of fluid flow on cleat aperture distribution and aperture–length scaling: a case study from Gondwana coal seams of Raniganj Formation, Eastern India

Characteristics of Coal and Cleat Attributes in Ulak Lebar and Surroundings Area, Lahat Regency, South Sumatra

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