The effect of applied stresses on the permeability of a middle rank coal to water

Pomeroy, C. D.; Robinson, Delia J.

doi:10.1016/0148-9062(67)90014-9

Cited by 24 publications

(8 citation statements)

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“…Based on this one sample, the permeability-stress relation for this basin is: (2) Using the results of Appendix B to convert hydrostatic stress results to depth of burial in the basin: (1) to recast hydrostatic stress results in terms of pore pressure. The resulting equation for permeability of Warrior Basin coals during depletion is…”

Section: Warrior Basinmentioning

confidence: 99%

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Application of Matchstick Geometry To Stress Dependent Permeability in Coals

Seidle¹,

Jeansonne²,

Erickson³

1992

All Days

263

132

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Several investigators have reported coal permeability decreases with increasing stress, but no conceptual model has been advanced to explain this effect. To better understand the permeability of stressed coal, a theoretical and experimental program was undertaken. A common naturally fractured reservoir geometry, a collection of matchsticks, was extended to stressed coalbeds and tested against laboratory measurements using samples from the San Juan and Warrior Basins. Good agreement was obtained between theoretical behavior and laboratory data. Equations are presented for converting laboratory measured stress-permeability data to (a) in-situ permeability as a function of depth of burial in a basin, and (b) to reservoir permeability during coalbed depletion.Coal cleat compressibility, analogous to pore volume compressibility of conventional reservoirs, has historically been difficult and expensive to measure and the results of such measurements are often ambiguous. A method is presented for calculating cleat volume compressibility from stress permeability experiments, resulting in considerable savings of both time and money. Stress-permeability and cleat volume compressibility results reported here are compared with those published in the literature.Evidence in the literature indicates that coal matrix shrinks when gas is desorbed, increasing cleat permeability. Assuming a matchstick geometry and using a coal matrix shrinkage coefficient reported in the literature, the increase in cleat permeability due to matrix shrinkage was calculated. The increase in permeability due to matrix shrinkage during depletion is compared with the decrease in permeability due to increased stress.References and illustrations at end of paper.

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Section: Warrior Basinmentioning

confidence: 99%

“…The present study was undertaken to: (1) develop a theoretical expression for coal permeability as a function of stress which reflects the naturally fractured nature of a coal deposit, and (2) to measure permeability as a function of stress for selected coals.…”

Section: Introductionmentioning

confidence: 99%

Application of Matchstick Geometry To Stress Dependent Permeability in Coals

Seidle¹,

Jeansonne²,

Erickson³

1992

All Days

263

132

View full text Add to dashboard Cite

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“…A second way is to use a triaxial or Hassler-type cell [13] in which the specimen holder walls in contact with the specimen are flexible membranes which can be forced by external fluid pressure to fit tightly against the specimen. A third way is to cast the specimen in either silicone rubber, some type of fine grained-high strength cement such as "araldite", or in epoxy, and mount this in a sample holder [14], [15], [16], [9].…”

Section: Conventional Methods For Measuring the Permeability Of Solidmentioning

confidence: 99%

Laboratory Measurement of the Permeability of Selma Chalk Using an Improved Experimental Technique

Sadler¹,

Rahnama²,

Whittle³

1992

Hazardous Waste and Hazardous Materials

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The permeabilities to water of 12 monolithic specimens of Selma chalk were determined in the laboratory using an apparatus featuring a micro-syringe pump which could be operated in either the controlled flow or controlled output pressure mode. Specimens 0.4 in. dia. x 2 in. long were diamond-core drilled from large blocks of Selma chalk obtained from a surface mine at Epes, AL. The mean pore radius of the chalk was found to be about 0.15 urn, and the specific surface was 13.9 m2/g. The specimens were mounted with epoxy in thick-walled cylindrical specimen holders under vacuum to assure that the epoxy penetrated a short distance into the specimens to prevent the possibility of liquid bypassing. Permeability values were found to range from 3.47 x 10"8 to 1.68x 10'7 cm/s -within the range of values reported by other investigators. There was some indication that the permeability in the direction parallel to the chalk bedding plane was greater than that in the direction perpendicular to it. This work represents the only study published in the open literature in which measured values of permeabilities of monolithic Selma chalk specimens to water are reported.

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“…The concept of using cubic samples and applying directional stresses to study the anisotropy of coal permeability in experiments has been recorded in the literature. For example, Pomeroy and Robinson (1967) used a 51.8 mm coal cube to measure absolute permeability using water across the face cleats and butt-cleats. Hydraulic jacks were used to apply the confining pressure in biaxial directions.…”

Section: Core Holders For Measuring the Permeability Of The Coal Samplementioning

confidence: 99%

“…Hydraulic jacks were used to apply the confining pressure in biaxial directions. Based on the similar concept used by Pomeroy and Robinson (1967) (Massarotto 2002), and the rather complex experimental setup. (Pomeroy and Robinson 1967).…”

Section: Core Holders For Measuring the Permeability Of The Coal Samplementioning

confidence: 99%

Dynamics of anisotropic permeability in coal seam gas reservoirs

Raza¹

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In this work, the effect of stresses and the reservoir boundary conditions on the permeability anisotropy, mechanical properties and swelling/shrinkage of the coals will be examined.Permeability is the fundamental parameter to understanding and modelling the fluid flow in the porous coal, and thus crucial to estimating the commercial gas and water production from coal seam gas (CSG) reservoir. Although permeability is a primary parameter to determine the reservoir production, the fundamental research behind the permeability change during pressure drawdown is not extensively examined in context with reservoir stresses and boundaries which can directly affect the reservoir production estimates. This project provides a mean to understand permeability change in CSG reservoir by conducting experiments and modelling studies to relate coal permeability, mechanical properties and sorption behaviour to different reservoir stresses and boundary conditions.The first objective of this project was to manage the design, construct, and demonstrate a state of the art triaxial stress permeameter (TSP) to measure anisotropic-permeability and stress-strain on coal sample simultaneously. The TSP was designed to measure anisotropic permeability by rotating a 40 mm cubic coal sample in orthogonal direction so that permeability can be measured in directions that align with face cleats, butt cleats, and bedding-plane of the coal. TSP is used in a series of experiments on coal sample UQ-B1 from the Surat Basin to determine in the modulus of elasticity (E) and cleat compressibility (Cf) of the coal sample UQ-B1 (Chapter 4), measure permeability using helium and methane gases (Chapter 5), and the effect of using either constant-stress (free swelling) or constant-volume boundary conditions on the observed relationship between net stresses and permeability changes (Chapter 5).Chapter 4 reports experiments in the TSP to determine the modulus of elasticity (E) and cleat compressibility (Cf) of coal sample UQ-B1 at effective stresses of 0.5 -4.0 MPa. These experiments confirm that these coal properties are anisotropic and stress-dependent. The experimental data also shows that cleats become 'softer' as stress is reduced on the sample which can result in the permeability rise by increasing the cleat width. The calculated modulus of elasticity of the bulk coal was E1 = 4.35 GPa, E2 = 4.90 GPa and E3 = 7.06 GPa perpendicular to face cleat, butt cleat, and bedding-plane directions, respectively. The cleat compressibilities (Cf) calculated from the relationship of pore size to pore compressibility were Cf1=0.1102-0.0333MPa -1 perpendicular to the face cleats and Cf2=0.0588-0.0251MPa -1 perpendicular to butt cleats at effective stresses of σeff = 0.5 -4.0 MPa.

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The effect of applied stresses on the permeability of a middle rank coal to water

Cited by 24 publications

References 0 publications

Application of Matchstick Geometry To Stress Dependent Permeability in Coals

Application of Matchstick Geometry To Stress Dependent Permeability in Coals

Laboratory Measurement of the Permeability of Selma Chalk Using an Improved Experimental Technique

Dynamics of anisotropic permeability in coal seam gas reservoirs

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