scholarly journals Theoretical and Experimental Investigation of Characteristics of Single Fracture Stress-Seepage Coupling considering Microroughness

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Shengtong Di ◽  
Chao Jia ◽  
Weiguo Qiao ◽  
Weijiang Yu ◽  
Kang Li
Keyword(s):  
Particle Size ◽  
Laboratory Test ◽  
Permeability Coefficient ◽  
Fracture Stress ◽  
Rock Fracture ◽  
Test System ◽  
Theoretical Formula ◽  
Single Fracture ◽  
Hydraulic Pressure ◽  
Hydraulic Aperture

Based on the results of the test among the joint roughness coefficient (JRC) of rock fracture, mechanical aperture, and hydraulic aperture proposed by Barton, this paper deduces and proposes a permeability coefficient formula of single fracture stress-seepage coupling considering microroughness by the introduction of effect variables considering the microparticle size and structural morphology of facture surface. Quasi-sandstone fracture of different particle size is made by the laboratory test, and the respective modification is made on the coupled shear-seepage test system of JAW-600 rock. Under this condition, the laboratory test of stress-seepage coupling of fracture of different particle size is carried out. The test results show that, for the different particle-sized fracture surface of the same JRC, the permeability coefficient is different, which means the smaller particle size, the smaller permeability coefficient, and the larger particle size, the larger permeability coefficient; with the increase of cranny hydraulic pressure, the permeability coefficient increases exponentially, and under the same cranny hydraulic pressure, there is relation of power function between the permeability coefficient and normal stress. Meanwhile, according to the theoretical formula, the microroughness coefficient of the fractures with different particle size is obtained by the calculation, and its accuracy and validity are verified by experiments. The theoretical verification values are in good agreement with the measured values.

scholarly journals Study on the Permeability of Weakly Cemented Sandstones

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
XianZhou Lyu ◽  
Zenghui Zhao ◽  
Xiaojie Wang ◽  
Weiming Wang
Keyword(s):  
Fracture Surface ◽  
Permeability Coefficient ◽  
Confining Pressure ◽  
Theoretical Formula ◽  
Single Fracture ◽  
Hydraulic Pressure ◽  
Test Results ◽  
Rock Masses ◽  
Heterogeneous Rock ◽  
Two Sides

Fractured rocks are a type of complex media that widely exist in various projects including energy, hydraulic, and underground space engineering, whose permeability properties are a hotspot in current rock mechanics domain. Aiming at investigating the seepage characteristics of the fracture surfaces in different rock strata, uniaxial compressive test and permeability test were performed on single-fracture homogenous and heterogeneous rocks. Specifically, rock’s physical and mechanical parameters were measured in uniaxial tests while the initial width of the single fracture was determined through CT scanning. In combination with test results and the calculation model of the displacement of single-fracture heterogeneous rock under triaxial stress condition, the calculation formula of the permeability coefficient of single-fracture heterogeneous rock was derived. Results show that hydraulic pressure in the fracture can affect the permeability coefficient of the fractured rock. Hydraulic fracturing effect occurred with the increase of hydraulic pressure in the fracture, which then generates slight normal deformations of the rock masses on both two sides of the fracture surface, decreases the contact area in the fracture, and leads to the increases of both fracture width and permeability coefficient. For single-fracture rock, the lithological properties of the rock masses on both two sides of the fracture surface impose significant effects on the permeability coefficient. Under same hydraulic pressure and confining pressure, the permeability coefficient of single-fracture coarse sandstone is greatest, followed by that of single-fracture heterogeneous rock, and finally by single-fracture fine sandstone. Theoretical calculation results agree well with the test results, suggesting that the derived theoretical formula can adequately describe the variation tendencies of permeability coefficient with confining pressure and hydraulic pressure in the fracture.

scholarly journals Analysis of Fracture Roughness Control on Permeability Using SfM and Fluid Flow Simulations: Implications for Carbonate Reservoir Characterization

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Miller Zambrano ◽  
Alan D. Pitts ◽  
Ali Salama ◽  
Tiziano Volatili ◽  
Maurizio Giorgioni ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Reservoir Characterization ◽  
Flow Simulation ◽  
Carbonate Reservoir ◽  
Single Fracture ◽  
Parallel Plates ◽  
Surface Mapping ◽  
Navier Stokes Equation ◽  
Hydraulic Aperture ◽  
Fracture Modeling

Fluid flow through a single fracture is traditionally described by the cubic law, which is derived from the Navier-Stokes equation for the flow of an incompressible fluid between two smooth-parallel plates. Thus, the permeability of a single fracture depends only on the so-called hydraulic aperture which differs from the mechanical aperture (separation between the two fracture wall surfaces). This difference is mainly related to the roughness of the fracture walls, which has been evaluated in previous works by including a friction factor in the permeability equation or directly deriving the hydraulic aperture. However, these methodologies may lack adequate precision to provide valid results. This work presents a complete protocol for fracture surface mapping, roughness evaluation, fracture modeling, fluid flow simulation, and permeability estimation of individual fracture (open or sheared joint/pressure solution seam). The methodology includes laboratory-based high-resolution structure from motion (SfM) photogrammetry of fracture surfaces, power spectral density (PSD) surface evaluation, synthetic fracture modeling, and fluid flow simulation using the Lattice-Boltzmann method. This work evaluates the respective controls on permeability exerted by the fracture displacement (perpendicular and parallel to the fracture walls), surface roughness, and surface pair mismatch. The results may contribute to defining a more accurate equation of hydraulic aperture and permeability of single fractures, which represents a pillar for the modeling and upscaling of the hydraulic properties of a geofluid reservoir.

scholarly journals Impact of Tetrapeptide-FSEY on Oxidative and Physical Stability of Hazelnut Oil-In-Water Emulsion

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1400
Author(s):  
Chenshan Shi ◽  
Miaomiao Liu ◽  
Qinghua Ma ◽  
Tiantian Zhao ◽  
Lisong Liang ◽  
...  
Keyword(s):  
Particle Size ◽  
Physical Stability ◽  
Test System ◽  
Oxidation Products ◽  
Hazelnut Oil ◽  
Secondary Oxidation ◽  
Antioxidant Additive ◽  
Water Emulsion ◽  
Oil In Water ◽  
Oil In Water Emulsion

This study investigates the antioxidant behaviors of a hazelnut tetrapeptide, FSEY (Phe-Ser-Glu-Tyr), in an oil-in-water emulsion. The emulsion was prepared with stripped hazelnut oil at a ratio of 10%. O/W emulsions, both with and without antioxidants (FSEY and TBHQ), were incubated at 37 °C. The chemical stabilities, including those of free radicals and primary and secondary oxidation productions, along with the physical stabilities, which include particle size, zeta-potential, color, pH, and ΔBS, were analyzed. Consequently, FSEY displayed excellent antioxidant behaviors in the test system by scavenging free lipid radicals. Both primary and secondary oxidation products were significantly lower in the FSEY groups. Furthermore, FSEY assisted in stabilizing the physical structure of the emulsion. This antioxidant could inhibit the increase in particle size, prevent the formation of creaming, and stabilize the original color and pH of the emulsion. Consequently, FSEY may be an effective antioxidant additive to use in emulsion systems.

An eddy-current laboratory test system using commercial equipment

1989 ◽  
Vol 22 (3) ◽  
pp. 183
Author(s):  
C.V. Dood ◽  
L.M. Whitaker ◽  
W.E. Deeds
Keyword(s):  
Laboratory Test ◽  
Eddy Current ◽  
Test System ◽  
Commercial Equipment

Laboratory Test and Field Measurement of Settlement of Ballast Considering Particle Size and Loading Force

2019 ◽  
Vol 22 (5) ◽  
pp. 391-404
Author(s):  
Sung Jin Lee ◽  
Yeong Tae Choi ◽  
Il Yoon Choi ◽  
Se Gon Gwon
Keyword(s):  
Particle Size ◽  
Laboratory Test ◽  
Field Measurement

The Aggregate’s Influences on Properties of Porous Pervious Concrete Made of Recycled Aggregates

2014 ◽  
Vol 584-586 ◽  
pp. 1271-1275
Author(s):  
Ping Gong ◽  
Wen Liang Zhang
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Single Particle ◽  
Permeability Coefficient ◽  
Pervious Concrete ◽  
Recycled Aggregates ◽  
Particle Mixing ◽  
Compressive Strength Of Concrete

In this study,different particle size’s aggregates ,different aggregate correction coefficients and different sand ratio were selected to study the aggregate’s influences on properties of porous pervious concrete made of recycled aggregates.The results shows that the 28-day compressive strength of concrete with single particle size is lower than those with two kinds of particle mixing ,as for the permeability coefficient, the former is much higher than the latter .With the aggregate correction coefficient’s increase,the 28-day compressive strengths of concrete increases first and then decreases, the permeability coefficient increases . The 28-day compressive strengths of concrete increases with the increase of the sand ratio. the permeability coefficient increases first ,decreases then.

Development of Test System for Subsea Tree Equipment

2013 ◽  
Vol 440 ◽  
pp. 222-227
Author(s):  
Bao Ping Cai ◽  
Yong Hong Liu ◽  
Yan Ting Zhang ◽  
Jiang Tao Ma ◽  
Yun Wei Zhang ◽  
...  
Keyword(s):  
High Pressure ◽  
Test System ◽  
Acceptance Testing ◽  
Hydraulic Pressure ◽  
Hydraulic Pump ◽  
Test Procedures ◽  
Hydraulic Power ◽  
Hydraulic Unit ◽  
Pressure Cycling ◽  
Function Testing

A test system for subsea tree equipment is developed for tree function testing after repair. The test system mainly consists of hydraulic unit and electric unit. The hydraulic unit is developed by revamping an old hydraulic power unit, which consist of six components, including reservoir, flush/fill pump circuit, high pressure hydraulic pump circuits, accumulator group, hydraulic supply circuits and fluid return circuit. The electric unit for subsea tree is developed by using NI Compact DAQ system, In order to control the hydraulic unit and acquire the pressure signals easily. The test procedures for flowloops, valve, and hydrostatic hydraulic pressure cycling are proposed based on the factory acceptance testing of subsea tree. A test for a repaired subsea tree is performed by using the developed test system. The results show that the repaired subsea tree is good enough after repair, and verify that the developed test system works well.

A Microprocessor-Controlled Test System Utilizing Relevant Component Duty Cycles

1979 ◽  
Vol 101 (4) ◽  
pp. 656-662
Author(s):  
R. K. King ◽  
R. L. Decker
Keyword(s):  
Laboratory Test ◽  
Duty Cycle ◽  
Test System ◽  
Fatigue Tests ◽  
Material Failure ◽  
Test Results ◽  
Duty Cycles ◽  
Laboratory Test Results ◽  
Complex Shapes ◽  
Relevant Component

The need for meaningful fatigue tests of hydraulic and mechanical components is ever-increasing. Such tests are often performed in the laboratory. Previous investigations have shown that laboratory test lives will be different than field duty lives if laboratory test cycles used have either a different load or “time at load” than the field duty cycle. Field duty cycles often consist of complex shapes. The closer that the laboratory test cycles approximate the field duty cycle, the better the correlation that can be drawn between laboratory and field lives. This paper presents a technique for predicting field endurance life from laboratory test results which capitalizes on the OSU material failure number theory. It describes a microprocessor-controlled test system which provides an inexpensive, reliable means of producing test cycles which approximate the shape of the field duty cycle. An example application is presented.

Sign in / Sign up

Export Citation Format

Share Document