Brittleness Index: From Conventional to Hydraulic Fracturing Energy Model

Feng, Runhua; Zhang, Yihuai; Rezagholilou, Alireza; Roshan, Hamid; Sarmadivaleh, Mohammad

doi:10.1007/s00603-019-01942-1

Cited by 61 publications

(38 citation statements)

References 57 publications

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“…To eliminate the variabilities from the natural sample (e.g., heterogeneities, discontinuities, etc.) and verify the repeatability of experimental results, 45,46 synthetic samples were prepared and used in this study. The clay powders were initially mixed with synthetic formation brine (20 wt% NaCl/1 wt% KCl in deionised water), and the mixture was subsequently poured into an in-house built steel cylinder cell (i.e., length of 10 cm and 3.8 cm diameter) enclosed with a semi-permeable porous plate (porous alumina, 25% porosity, mean pore size <2 μm).…”

Section: Methodology Sample Preparationmentioning

confidence: 99%

Dependence of clay wettability on gas density

et al. 2021

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Understanding wettability of clay minerals is crucial in assessing primary migration of hydrocarbon and evaluating CO 2 storage capacities and containment security. In spite of recent efforts, there is considerable uncertainty of experimental data and theoretical predictions are lacking. We, therefore, developed new correlations to predict the advancing and receding contact angles of three different clay minerals (i.e., montmorillonite, Illite and kaolinite) as a function of gas density. To do so, we first measured clay minerals advancing and receding contact angles for helium, nitrogen, argon and carbon dioxide/brine systems at various pressures (5, 10, 15 and 20 MPa) and a constant temperature of 333 K. The statistical analysis shows that the developed correlations are capable of predicting the contact angles of the three clay minerals with very high accuracy (i.e., R > 0.95, for all the newly developed correlations). We thus conclude that the wettability of these clay minerals can be computed from knowledge of the gas densities, using these new empirical correlations. This work has important implications for improving wettability predictions, and thus reducing risks related to subsurface operations, such as CO 2 storage or hydrocarbon recovery.

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Section: Methodology Sample Preparationmentioning

confidence: 99%

Dependence of clay wettability on gas density

et al. 2021

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“…Previous cell in 2010 included ultrasonic transducers on all six sides of rock specimen, whereas transducers being pressed by springs within recessed indentations anticipated on loading faces [9]. New 50mm TTSC have 4 transducers per face, amounting to a total of 24 transducers each being sampled at every 0.1μsec [10,11]. All transducers will have the ability to record data in listen mode continuously recorded into a standard memory using software based on Labview.…”

Section: Ultrasonic Systemmentioning

confidence: 99%

Design and Application of a High-performance True Triaxial Stress Cell

Rezagholilou¹

2019

IMST

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Conventional triaxial tests are for axisymmetric stress condition, which is not necessarily correct for deep rock layers. Thus, orthotropic stress conditions and pore pressure are better simulated by new generation of high-performance True Triaxial Stress Cell (TTSC). New TTSC in Curtin university allows stresses up to 70 MPa on a 50×50×50mm cube of the rock sample. Additionally, pore pressure can be up to 20 MPa and temperature up to 70oC. Six sets of LVDT strain gauges and 24 acoustic transducers can monitor all deformations and crack events during fracturing of a sample. Through a hole in the center of the rock, a fluid can be injected to simulate hydraulic fracturing, or investigate fault reactivation during fluid injection. All of events are monitored in real-time manner using ultrasonic seismic transducers around the sample. Further details of this equipment are explained in this paper.

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“…The brittleness index can measure the ability of coal to resist fragmentation under pressure, it significantly affects the cutability and coal production rate during coal mining [2,4] and affects the drilling efficiency during the well drilling process [5]. The brittleness index is also the key index to evaluate the fracturability of coal reservoirs [1,6].…”

Section: Introductionmentioning

confidence: 99%

Brittleness Index of High-Rank Coal Reservoir and Its Influencing Factors in Mabidong Block, Qinshui Basin, China

et al. 2021

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Brittleness index is an important mechanical index to evaluate the fracturability of conventional oil and gas reservoirs. However, the brittleness index of an organic coal reservoir is more complex. In this study, based on array sonic logging and density logging data, coal brittleness index is calculated using an elastic parameter method in the Mabidong coalbed methane (CBM) block in southern Qinshui Basin. In combination with coal-body structure observation, the maceral analysis, and proximate data of coal cores, a comprehensive study of geological influencing factors of coal brittleness index has been carried out. According to coal fragmentation degree, the coal-body structure of coal seams can be divided into primary, cataclastic, and granulate structure. The average interval of brittleness index of primary, cataclastic, and granulate structural coals is 63.3-71.48, 73.01-74.85, and 77.41-82.77, respectively. The results indicate that generally the order of brittleness index is primary structural coal < cataclastic structural coal < granulate structural coal. Young’s modulus and the brittleness index have a good positive correlation. Poisson’s ratio and the brittleness index are negatively correlated in No. 3 coal seam but are positive correlated in No. 15 coal seam. The vitrinite content is positively correlated with brittleness index, and the inertinite content is negatively correlated. For the primary and cataclastic structure coal, the ash and volatile is positively correlated with the brittleness index. The correlation of brittleness index, macerals, and coal quality parameters in the primary structure coal is better than that of the cataclastic and granulate structure coal. The research results are helpful to guide the coal brittleness index and coal-body structure prediction in fracturing of CBM wells.

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Brittleness Index: From Conventional to Hydraulic Fracturing Energy Model

Cited by 61 publications

References 57 publications

Dependence of clay wettability on gas density

Dependence of clay wettability on gas density

Design and Application of a High-performance True Triaxial Stress Cell

Brittleness Index of High-Rank Coal Reservoir and Its Influencing Factors in Mabidong Block, Qinshui Basin, China

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