Bed Thickness Research Articles

Concrete ablation depth analysis method during top water flooding ex-vessel cooling by considering phenomena in dry and flooded conditions

This study proposes a method to analyze the concrete ablation depth during top water flooding ex-vessel cooling by considering the phenomena occurring in dry and flooded reactor cavity conditions. In the dry condition, it is assumed that there is radiation heat transfer between a melt and an upper concrete. In the flooded condition, it is assumed that dryout heat flux decreases and converges to a certain value as the thickness of porous bed in a crust increases. The thermal concrete ablation depth is obtained assuming that there is convection heat transfer to the underlying concrete and that it is an ideal insulator so no thermal conduction exists below the concrete melting surface. The present method also considers the phenomena such as decay heat, chemical reaction, formation and growth of the crust, and so on.Concrete ablation depth analyses during ex-vessel cooling are performed according to cavity flooding delay time using the present method and the CORQUENCH 3.03 code for a postulated severe accident. The code applying the method proposed in this study conservatively predicts the concrete ablation depth by 6.9~12% more than the results from the CORQUENCH 3.03 code. If the cavity flooding delay time is 1 h, the concrete ablation depth at the end of ex-vessel cooling from the present code is about 41 cm, however, the result from the CORQUENCH 3.03 code is 37 cm.

Analyze Infrared Heating Characteristics of Potato Starch and Measure its Functional Film Properties

Objectives: To analyze the effect of potato starch infrared heating (IR) and the functional characteristics of the starch film. Methods: Potato starch was heated by IR heater at different time intervals (45 min, 65 min and 85 min) and starch was used to develop polymer films by the addition of glycerol as a plasticizing agent. The surface temperature of starch at different bed thickness was measured using a thermal imaging camera. The temperature of the starch varied from 72.77oC to 80.83oC. The functional properties of developed films were analyzed by their thickness, solubility, contact angle, puncture strength and coefficient of friction with different surfaces. Findings: The results indicate that the puncture strength of IR treated starch film varied from 2.5 to 3.79N and the value was found less in control recorded as 1.87N. The modified starch film thickness and opacity were increased from 0.11 to 0.128mm and 1.15 to 1.22 percent respectively. The solubility percent was found less in IR heated starch than in control. SEM and FTIR analysis results show that IR heat treatment has significant effect on morphology and functional characteristics of the starch film. Novelty: Infrared heating modified the structural characteristics of potato starch and improved the functional properties of the starch film. Keywords: Starch film; Infrared heating; Functional; Physical; Mechanical

"Groove and Peel" Deep Anterior Lamellar Keratoplasty: How Deep Can You Go?

The aim of the current research was to measure the thickness of the residual central corneal bed after performing the manual "Groove and Peel" deep anterior lamellar keratoplasty (GP-DALK) technique on human cadaveric eyes. The manual GP-DALK technique was performed on 6 human cadaver eyes by an experienced corneal surgeon. After surgery, the eye globes were fixed in 10% buffered formalin and embedded in paraffin. For each eye, 4-μm-thick hematoxylin and eosin sections involving the pupillary axis were obtained and examined. Using an image-processing software, 2 observers measured the corneal thickness of the residual central corneal bed and the peripheral corneal rims. The overall mean central corneal bed thickness was 35.5 ± 12.9 μm, whereas the mean right and left peripheral rim thicknesses were 993.0 ± 141.1 and 989.3 ± 147.1 μm, respectively ( P = 0.0006 ). In most corneas, the level of dissection reached almost to the pre-Descemetic collagen (Dua) layer. The GP-DALK technique is effective in removing most of the corneal stroma and may be non-inferior to "big-bubble" deep anterior lamellar keratoplasty in some cases.

Facies analysis and distribution of Late Palaeogene deep‐water massive sandstones in submarine‐fan lobes, NW Borneo

Deep‐water massive sandstones (DWMS) are characterized by large volumes of sand accumulations which are considered as potential reservoir intervals in deep‐marine environments. Lithological variations and bed thickness statistics are used to interpret the distribution of massive sandstones in a deep‐marine fan‐lobe system. These massive sandstones are interpreted based on lithological heterogeneities and detailed facies analysis in seventeen exposed sections of the Late Palaeogene deposits in Sabah, NW Borneo. Sedimentary logs containing details of lithology textures and structures were used to recognize nine sedimentary facies of DWMS. These lithofacies were then grouped into three sedimentary facies associations: (1) massive facies association with basal part of turbiditic Bouma sequence, (2) massive facies association having soft‐sediment deformation structures, and (3) massive facies association with erosional features. The facies analysis portrays inner to middle submarine fan deposition and was later applied to reconstruct the distribution of a channel‐lobe complex. Individual sandstone bed thicknesses vary from 1 m to more than 8 m and the number of massive sandstones in submarine lobes range from less than 10% to more than 50%. The thicknesses of massive sandstones in channels are more than 8 m, whereas distal lobes have thicknesses from 1–2 m only. These sandstones are concentrated in channels, proximal and medial lobe settings that can also be verified from calculating the average of all maximum thickness of massive sand intervals that is, 8.91 m. The lithological heterogeneities and the processes associated with the deposition of these massive sandstones are vital for potential hydrocarbon reservoirs in the deep‐marine environments around the globe.

Historic subsurface dimension stone quarry and the stability of its galleries as a function of pillar width and thickness of cover bed

There are historic subsurface dimension stones in the capital of Hungary (Budapest) that were excavated in porous limestone. The stability of these subsurface openings is important, since most of them are located in urban areas, where existing buildings or new structures are planned to be built. The paper presents a detailed study considering the geometry of the system and the mechanical parameters of the limestone. The geometry of the cellar system was obtained using terrestrial laser scanning (TLS). The cover beds are few meters in thickness, and the width of the pillar is between 2.50 and 3.98 m, according to the measurements. The rock mass parameters which were used in the calculations were obtained from laboratory tests. A finite element (FEM) software Rocscience (RS2) were applied to model the stability of the galleries. Calculations were made for various geometries taking into account the thickness of cover beds and the width of pillars. Altogether 70 models were made. A surface load of 150 kN/m2 was also applied to model the buildings. New relationships between cover bed thickness, pillar width and displacements are outlined to compare these results to previous works. The strength reduction factor was also calculated for all geometries, indicating the changes in the stability of these underground quarries and pointing out the importance of cellar geometries.

Importance of Petrochemical Clustering in the Central Anatolia-Central Black Sea Region

Chemical industry products, make great scale contributions to the other industrial productions and chemical industrial cluster can only be completed by seaport based petroleum refinery. Increasing demand and imports of Turkey for the petrochemical products will mostly be met when the planned blue stream oil pipeline is connected to the proposed Samsun seaport oil refinery and its coordination with the regional industry and mineral deposites. Great salt mineral reserves like tenardite-glauberite in Ankara Polatlı, trona in Ankara Beypazarı and Kazan and rock salt in Kırıkkale, Çankırı, Çorum which have been discovered within the last few years, have increased twice the reserves and varieties of Central Anatolian salt deposits and will assure the second important raw material of petrochemical industry after nafta. The real loss in petrochemical foreign trade of Turkey, is big imports of primary and secondary chemicals produced from salt raw materials. The salt solutions from the natural gas storing caverns opened within the thick rock salt beds by solution mining process can be transported to future chloralkaline facilities in the region and to the Kırıkkale and proposed Samsun petroleum refineries by pipeline siphoning with minimum cost and the surplus can be swinged into the sea so that the environmental pollution is prevented. It is possible to see the existences of Kırıkkale petroleum refinery, defence industry, iron-steel-coke industry, Samsun sulphuric acid and fertiliser factory, gas-oil pipelines, various salt mineral resources, sea-ports, and transportation lines and other infrastructures suitable for the chemical industrial clustering within Central Anatolia and Central Blacksea Regions.

Flaky cuttings bed distribution model in a shale gas horizontal well based on experiment and numerical simulation

During the drilling of shale gas wells, the shape of shale cuttings cut by polycrystalline diamond compact bits has an obvious flaky structure. The accumulation of such flaky cuttings is one of the main reasons for high drilling torque and drag and serious back pressure, which affect the drilling speed of the horizontal section of shale gas wells. Therefore, predicting the thickness of the flaky cuttings bed and restraining it are essential for ensuring safe and efficient drilling of the horizontal section of shale gas wells. However, most of the previous research on migration laws for cuttings were based on spherical particles, which affected the accuracy of cuttings bed thickness prediction. In this study, through visualization experiments combined with computational fluid dynamics numerical simulation, the hole cleaning laws of shale gas wells in the long horizontal section were studied, and a set of cuttings bed thickness prediction models and cuttings bed removal process parameter optimization methods were established. Field application was conducted in the Changning 209H24-1 well in the southern Sichuan Basin, China. The results revealed the following: (1) There are significant differences in the migration laws of flaky cuttings and spherical cuttings in the horizontal section. (2) The fitting accuracy of the established long horizontal fragmentation layer distribution model considering multiple factors and the experimental data is as high as 0.973. (3) Based on this model, the drilling parameters of the Changning 209H24-1 well were optimized, which played a good role in wellbore cleaning and ensured the safe and smooth implementation of the later casing operation.

Depositional rate, grain size and magnetic mineral sulfidization in turbidite sequences, Hikurangi Margin, New Zealand

ABSTRACT Sedimentological and rock magnetic analysis was performed on 67 turbidite samples recovered from Lithostratigraphic units I–III at IODP Site U1520 with the aim to characterise the sedimentary processes and post-depositional diagenesis within a Quaternary sequence in the Hikurangi Trough, New Zealand. Lithostratigraphic Unit I was rapidly emplaced with frequent turbidite deposition with high sedimentation rate (∼1.9 m/kyr). In contrast, in units II–III, the turbidites were finer grained and more thinly bedded, and were deposited at less than half the deposition rate of Unit I. The turbidites were classified into three clusters based on the magnetic properties. Clusters 1 and 2 are characterised by a high coercivity and SIRM/χ, but low to moderate Bcr/Bc. The recognition of gyroremanent magnetisation acquisition in their clusters indicates the diagenetic sulfidization. Cluster 3 was represented by low coercivity and SIRM/χ, but high Bcr/Bc, indicating lack of sulfidization. Restricted occurrence of Cluster 3 in Unit I may be ascribed to the high sedimentation rate, which prevents sulfidization at the sulfate–methane transition zone. Degree of sulfidization might be related with sedimentary features of turbidites in the trough, such as grain size, bed thickness and depositional rate.

Modeling and Optimization of Energy and Exergy Parameters of a Hybrid-Solar Dryer for Basil Leaf Drying Using RSM

This study deals with the optimization of energetic and exergetic parameters of a hybrid-solar dryer to dry basil leaves under determined experimental conditions at three air temperatures (40 °C, 55 °C, and 70 °C) and three bed thickness levels (2, 4, and 6 cm). The optimization of the thermodynamic parameters was performed using the response surface method (RSM) based on the central composite design (CCD) and the desirability function (DF) to maximize the drying rate, exergy efficiency, improvement potential rate and the sustainability index, and to minimize the energy utilization, energy utilization ratio and exergy loss rate. These parameters were calculated on the basis of the first and second laws of thermodynamics as the response variables. Based on the results obtained, it was determined that the optimal conditions for basil drying were at a drying air temperature of 63.8 °C and a bed thickness of 2 cm. At this point, the parameters of the drying rate, energy utilization, energy utilization ratio, exergy efficiency, exergy loss rate, improvement potential rate and sustainability index were obtained with the maximum utility function (D = 0.548) as 0.27, 0.019 (kJ/s), 0.23, 65.75%, 0.016 (kJ/s), 1.10 (kJ/s) and 0.015, respectively.

The effects of red beds on fluid flow and implications for the formation of volcanic-type uranium deposits in the Xiangshan basin, China

The South China uranium metallogenic province is an important hydrothermal uranium metallogenic region in China, which is spatially and temporally associated with the Cretaceous-Neogene red beds. Previous studies suggest that the red beds might have played critical role in the ore-forming processes by providing oxidizing fluids. However, the effects of the red beds on fluid flow are poorly understood. In this study, numerical modeling was conducted to investigate the roles of red beds on ore-forming fluid flow in the Xiangshan basin in Jiangxi Province, hosting the largest volcanic hydrothermal uranium deposit in China. The modeling results show that the variation of the slope gradient of the red beds greatly affects the fluid flow patterns, whereas the change of thickness and permeability of the red beds has little influence on fluid flow pattern. The fluid can circulate into the volcanic and basement rocks driven by topographic relief of the red beds. Furthermore, for models with fault, although the fluid velocities in the fault were more than one order of magnitude larger than those in the surrounding strata, the overall fluid flow patterns in the strata did not show great variation. The modelling results suggest that the topographic relief of the red beds may have driven the oxidizing fluids into the underlying rocks which are necessary for uranium mineralization in the Xiangshan basin.

Novel locally resonant and widely scalable seismic metamaterials for broadband mitigation of disturbances in the very low frequency range of 0–33 Hz

Most current shielding mechanisms against seismic disturbances fail in protecting structures from low-frequency vibrations typically in the range of 1–10 Hz. This paper proposes a novel locally resonant Zero-Frequency Stop Band (ZFSB) metamaterial in the form of cylindrical resonators clamped to a 0.5 m thick concrete bed. This concept is convenient for practical implementation, and yields effective broadband wave inhibition in the ultra-low frequency range of 0–33 Hz. Through numerical simulations validated first against published experimental data, the concept is shown to achieve an attenuation zone due to the local resonance occurring between surface waves and the metamaterial features. Dynamic response- and transient time-analyses are used to gain insight into phononic dispersion in the proposed metamaterial, allowing the authors to demonstrate the working of the proposed concept. The effect of the material properties of the clamping bed on the performance of the proposed seismic metamaterial is also studied. The numerical results are then further validated through 1:40 scaled-down laboratory experiments. The proposed metamaterial when combined with soil with layered material properties, is later shown to nucleate wider ZFSB. The concept proposed is widely scalable for practical implementations and thus of much interest for isolation and protection of civil structures from low-frequency seismic disturbances.

High-resolution taphonomy and sequence stratigraphy of internally complex, bakevelliid-dominated coquinas from the Aptian Romualdo Formation, Araripe Basin, NE Brazil

The Aptian Romualdo Formation (Araripe Basin, NE Brazil) was deposited in a restricted epeiric sea, during the opening of the South Atlantic Ocean, with a coeval record to that in the Brazilian Pre-Salt succession. The upper part of the Romualdo Formation encompasses the Highstand Systems Tract of a third-order stratigraphic sequence, and contains shell beds interbedded with shale, siltstone, and fine-grained sandstone. Based on distinct taphonomic features (shell sorting, fragmentation, abrasion, rounding, and orientation), sedimentological criteria (shell abundance, type of matrix, sedimentary structures, and presence/absence of quartz grains), and stratigraphic attributes (bed thickness, geometry, contacts), the paleoenvironmental conditions and the bed-by-bed accumulation history of the coquinas is disentangled. Eight carbonate microfacies were recognized, including ostracod carbonate mudstone, bivalve-gastropod wackestone, gastropod-bivalve packstone, bivalve-gastropod grainstone, bivalve-gastropod floatstone, bivalve-gastropod rudstone, bakevelliid floatstone, and bakevelliid rudstone, which are organized in six, cm-thick shell concentrations. Mudstone and wackestone facies mark the settling of carbonate muds without significant bottom currents and wave action, probably below storm wave base, whereas packstone, floatstone, and rudstone, with fragmented, rounded, and oriented shells, were deposited in agitated waters, between the fair-weather and the storm wave bases. Ripple cross-laminated grainstone is interpreted as high-energy facies deposited above fair-weather wave base. The shell beds are internally complex and consist of cm-scale alternations of microfacies differing in packing, sorting, and composition. They tend to fine upwards within dm-thick shell beds, generating shallowing-upward facies sequences. The concentrations, the uppermost one with in situ bakevelliid shells in the top, record high-frequency base level oscillations influenced by eustasy and climate changes. These bioclastic accumulations originated by the superposition of sedimentologic and primary biologic processes (e.g., post-deposition meiofaunal bioturbation). The cm-thick, low-diversity shell beds are excellent examples of multiple-event carbonate deposits generated in a siliciclastic-dominated, restricted epeiric sea, revealing high-frequency cycles in proximal to distal restricted marine settings.

Fluid resonance in the narrow gap for a box close to a bottom-mounted wall with permeable bed

The behavior of fluid resonance in a narrow gap formed between a ship and a wharf on a permeable bed is investigated by using a two-dimensional viscous numerical model based on OpenFOAM package. The influence of the permeable bed is significant in the region of low-frequency and resonant frequency ranges, where the decreased free surface amplitude in the narrow gap can be observed, especially for large box draft and large porosity. The increased effect of permeable bed can be generated by large bed thickness and small bed width. With the increase of incident wave amplitude, the influence of permeable bed gives rise to weak. All of these phenomena can be explained by the variation of the fluid entering the seepage surface, where the large vertical velocity and more fluid volume entering the permeable bed can be computed for the cases of larger permeable bed effect. Finally, the variation tendency of wave forces on the box and the wall is consistent with that of wave amplitude in the narrow gap.

Laser-particle interaction-based heat source model of laser powder bed fusion additive manufacturing

The use of powder is one of the special features in laser powder bed fusion additive manufacturing (L-PBF AM). How the powder affects the L-PBF process is the basic mechanism determining the accurate prediction of the melt pool and the temperatures in finite element heat transfer simulations. The laser is treated as electromagnetic wave essentially and the powder particles can be heated by the formation of the inducted current on the particle surfaces. The laser energy density absorbed by the powder particles was calculated based on the laser-particle interaction. Based on the statistical analysis of particles in spatial distribution, the new volumetric heat source model was obtained and then applied to finite element heat transfer simulations. Results indicate that the temperature rise of the individual particle is not uniform and relates to the distribution of electromagnetic energy density on the surface of particles. The distribution of electromagnetic energy density on the surface of the individual particle at different positions is different. The energy absorbed by the upper particles is mainly determined by the direct irradiation of the laser. The energy absorbed by the bottom particles is mainly caused by the laser reflections. Due to the change of the mechanism for energy absorption, the maximum energy absorption occurs at the location which is near the average diameter away from the top surface of the powder bed. When the powder bed thickness is small, the laser energy density along build direction is in Gaussian distribution. With the increase of the powder bed thickness, the laser energy density distribution along build direction can be fit for 4-order polynomial function.

Fabrication of micron-sized protrusions on metal surface for metal/polymer easy-disassembly joining by selective laser melting technology

Artificial protrusions fabricated on metal surfaces are adequate for the mechanical interlocking to strengthen the metal/polymer joint. The morphology and its adhesion with the metal substrate of the fabricated protrusions greatly influence the joint strength and joint detachability. However, the large-sized protrusion can cause carbon fiber damage when embedded into the polymer plate, which results in the decline of the joint strength. This paper applied a diode-pumped solid-state laser system to melt stainless powders to fabricate micron-sized protrusions on metal surfaces. The effect of four impacting factors, original powder size, powder bedding thickness, laser power density, and laser irradiation time, on the formation of micro-protrusions was investigated. SEM was used to characterize the morphology and diameter of the formed micro-protrusions. The results showed that the fabricated micro-protrusions present a spherical shape under the stable manufacturing process, and the diameter ranged from 100 µm to 500 µm. The micro-protrusions size positively correlated with the original powder size and powder bedding thickness. Laser power density directly affected the forming of micro-protrusions, and the suitable process window was between 160 W/mm2 to 290 W/mm2. When the laser irradiation time was 10 s, it helped stabilize the fabrication process.

Experimental Study of the Effects of Silica-gel Bed Thickness on The Regeneration Process in a Desiccant Column

A desiccant column contains a silica gel as a solid moisture absorbent material has been used in this study, in which the regeneration or desorption process was discussed. The dimensions of the silica-gel column are 30 cm long*30 cm wide with three thickness of desiccant bed (5,10, &15) cm, respectively. The mass flow rate and the inlet temperature of the regeneration air used are 3.72 kg/min and 53 °C respectively. This air was obtained using solar air heater in addition to an electric heating unit for temperature control purpose. The results obtained showed that the regeneration period is affected by the bed thickness. Increasing the bed thickness of silica increase the regeneration period and vice versa For example, the complete drying process of silica gel from moisture took 21 min with thickness of bed (5 cm), while it took 42 min with thickness of bed (15 cm)

Design of an Innovative Tractor-Operated Seeder for Mat Type Paddy Nursery

This study contains the design approach, development details, and field evaluation of an innovative tractor-operated seeder for sowing mat type paddy nursery. In order to design and select the various components of mat type nursery seeder, the fundamentals of farm machinery design were taken into due consideration. The machine comprises of soil cutting unit, inclined conveyor unit, screw type conveyor auger, sieving unit, compaction roller, polythene sheet laying unit, soil metering and seed metering unit. The basic criteria for design were to prepare a soil bed with a width of 1000 mm and width of cut of channel 240 mm on both sides of the bed to irrigate the prepared soil bed. The soil cutting unit and conveyor unit were designed based upon amount of soil required on soil bed to have 20–30 mm soil mat bed thickness and seed metering unit was designed to deliver 2–3 seeds∙cm−2 on the bed. The machine was fabricated based on design calculations and then evaluated in laboratory as well as actual field conditions. During field evaluation of this machine, it was found that the coefficient of uniformity for seed spread was 7.33%, coefficient of uniformity for soil spread 5.67%, fuel consumption 39.6 l.ha−1 and actual field capacity 0.11 ha∙h−1 with 1.7 km∙h−1 forward speed of machine. Labour saving using the designed tractor-operated seeder was observed to be 86.4% as compared to the manual method of sowing mat type nursery using steel frames.

Gas-solid hydrodynamics in a stator-rotor vortex chamber reactor

The gas–solid vortex reactor (GSVR) has enormous process intensification potential. However the huge gas consumption can be a serious disadvantage for the GSVR in some applications such as fast pyrolysis. In this work, we demonstrate a recent novel design, where a stator-rotor vortex chamber (STARVOC) is driven by the fluid’s kinetic energy, to decouple the solids bed rotation and gas. Gas-solid fluidization by using air and monosized aluminum balls was performed to investigate the hydrodynamics. A constructed fluidization flow regime map for a fixed solids loading of 100 g shows that the bed can only be fluidized for a rotation speed between 200 and 400 RPM. Below 200 RPM, particles settle down on the bottom plate and cannot form a stable bed due to inertia and friction. Above 400 RPM, the bed cannot be fluidized with superficial velocities up to 1.8 m/s (air flow rate of 90 Nm3/h). The bed thickness shows some non-uniformities, being smaller at the top of the bed than at the bottom counterpart. However by increasing the air flow rate or rotation speed the axial nonuniformity can be resolved. The bed pressure drop first increases with increasing gas flow rate and then levels off, showing similar characteristics as conventional fluidized beds. Theoretical pressure drops calculated from mathematical models such as Kao et al. model agree well with experimental measurements. Particle velocity discrepancies between the top and bottom particles reveal that the impact of gravity cannot be completely neglected. Design guidelines and possible applications for further development of STARVOC concept are proposed based on fundamental data provided in this work.

Evaluation of drying characteristics, energy consumption and quality of parboiled paddy: Two stage drying

This study aims to investigate the drying kinetics, energy analysis and milling performance of two common rice varieties namely BRRI-28 and BR-16 by two stage drying. Parboiled paddy samples were dried employing two schemes of two stage drying. First scheme is first stage by fluidized bed drying at temperature profile of (150–170 °C) with fixed bed thickness of 10 cm, tempering (30 min) and followed by fluidized bed drying again using lower temperature 80±2 °C and second scheme is first stage fluidized bed drying (150–170 °C) and tempering and followed by sun drying method. In addition, sun drying method as complete single stage drying was considered as control drying. Drying results indicated that total drying time required in first scheme, second scheme and control drying are 1.4, 4.75 and 11–12 h, respectively. Energy analysis showed that for both paddy varieties, first scheme yielded the highest specific electrical (12.6 MJ/kg H 2 O evaporated) and thermal energy consumption (10.5–11.6 MJ/kg H 2 O evaporated) compare to second scheme (0.58–1.6 MJ/kg H 2 O evaporated) of drying. Milling quality as head rice yield (HRY) was significantly varied among the drying schemes. For BR-16 variety, first scheme yielded the highest HRY (66 ± 0.706%) compare to BRRI-28 variety that yielded the lowest HRY (43.9 ± 0.571%). Better milling recovery (75 ± 0.64%) was obtained in first scheme compare with control dried sample (71 ± 0.56%). Therefore, parboiled paddy is suggested to be dried by any scheme of two stage drying for achieving quality dried grain with minimum energy consumption. • Two schemes of two stage drying was investigated for parboiled paddy. • Energy consumption for drying of parboiled paddy was evaluated. • Total energy consumption varied from 2.06 to 24.6 MJ/kg moisture evaporation. • Head rice yield for two stage dried parboiled paddy varied from 37.5 to 75.66%.

Mineralogy controls fracture containment in mechanically layered carbonates

AbstractUnderstanding the distribution and geometry of faults and fractures is critical for predicting both subsurface permeability architecture and the integrity of geological fluid barriers, particularly in rocks with low primary porosity and permeability. While fracture patterns in relatively competent, weathering-resistant (therefore often well-exposed) rocks are generally well studied in outcrop, the role of mechanically weak layers in defining fracture patterns is frequently overlooked or under-represented. Here we show that rock composition, specifically clay and silicate minerals versus carbonate content, exerts a strong control on fault and fracture propagation and bed-containment within a mechanically layered, Cretaceous carbonate sequence at Canyon Lake Gorge, Texas. We find that relatively incompetent, clay-rich layers limit fault and fracture propagation, and cause bed-containment of fractures in more competent beds. In our results, no clear relationships exist between mechanical layer thickness and fracture abundance. These results are important for understanding the relative importance of composition versus bed thickness on fracture abundance in the subsurface, and for predicting fracture-controlled fluid flow pathways, seals and fracture connectivity across beds with variable compositions, thicknesses and competences.