An Experimental Study of Seepage Properties in Crushed Sandstone and Mudstone

Abstract

To study the effects of compression rate and weight ratio of sandstone to mudstone on permeability, water flow tests were performed on crushed rocks using an in-house designed and built water flow apparatus. Seepage properties of sandstone and mudstone were tested on specimens under six axial displacement levels. e weight ratios of the six specimens of sandstone to mudstone were set to 1 : 0, 4 : 1, 3 : 2, 2 : 3, 1 : 4, and 0 : 1. A non-Darcy law was adopted to calculate the permeability in the experiments based on verification of the Reynolds number. Non-Darcy flow is found to be most significant when the axial displacement or mudstone content increases. e permeability in the experiments is found to be in the range of 9.1 × 10 −15 -9.492 × 10 −13 m 2 , which is calculated from a quadratic polynomial fit between the flow velocity and pressure gradient. A compression rate of 28.6% and weight ratio of sandstone to mudstone of 60% are found to be key values affecting permeability. When the axial displacement of specimen A (1 : 0) increases from 10 mm to 30 mm, the compression rate (ratio of axial displacement to original specimen height) increases from 9.5% to 28.6%, and the permeability decreases by 83.8% to 1.534 × 10 −13 m 2 . When the axial displacement is 10 mm and the content of mudstone is increased from 0% to 60%, the permeability decreases by 77.1% to 2.172 × 10 −13 m 2 .

Experimental Study on Acoustic Emission of Confined Compression of Crushed Gangue under Different Loading Rates: Disposal of Gangue Solid Waste

“…At present, relevant reports of crushed gangue's bearing compression characteristics mainly focus on the particle size distribution, stress level, and macroscopic deformation. In addition, the final crushing ratio of crushed gangue samples is mainly obtained by screening the samples after the experiment [30][31][32][33][34][35][36][37][38][39][40][41][42]. However, there is no research on particle crushing characteristics during the loading process, especially under the compression condition of different loading rates.…”

Study on the Mechanical Properties and Failure Law of Rocks with Interbedded Sand and Mud

“…With the change of borehole azimuth and inclination angles, the included angle between the radial direction of borehole wall and the direction of the bedding fracture changes constantly, so the radial seepage capacity of the borehole wall also changes. As there is a difference on the radial seepage capacity of the borehole wall rock, it is inevitable that there are differences in the seepage capacities between the borehole and formation under a bottomhole pressure environment and its influence on the pore pressure distribution and effective stress field near the borehole wall. − It is assumed that there are horizontal fractures at the lithologic interface of the sand–mud interbedding, and the azimuth angle of the well track is 90°; the variation law of radial seepage capacity of the borehole wall is evaluated and analyzed, as shown in Figure . Figure shows the geometric relationship between the angles.…”