Clay Rock Research Articles

Adsorption of methane and carbon dioxide by water-saturated clay minerals and clay rocks

Understanding the effects of water on gas adsorption in geological media is of high importance in order to efficiently control numerous subsurface engineering process operating at gas/rock interfaces. Due to preferential interaction with clay surfaces, water fills their porous body, greatly reducing CH4 and CO2 adsorption capacity. In order to quantitatively describe CH4 and CO2 adsorption by hydrated clay minerals, this work proposes to rely on the mechanism of gas uptake by dissolution in pre-adsorbed pore water. This approach was employed to characterise water-saturated porous media of increasing complexity: mesoporous silica SBA-15 and silica gel with different pore sizes and geometry, isolated illite and montmorillonite and natural clay-rich rock (the Callovo-Oxfordian formation – COx, France) in powdered and crushed states. It was found that the solubility in water can reliably explain the CO2 uptakes by hydrated pore systems regardless of their nature as well as the CH4 uptakes, but only for solids with large mesopores and montmorillonite mineral. A so called “adsorption enhanced gas uptake in pore water” for CH4, exceeding its solubility in bulk water by a factor of 5–8, was observed for the systems with narrow pore sizes, highlighting the impact of surface energy on gas uptake and the occurrence of the interaction of weakly-soluble methane with the surface, promoting its uptake in comparison to pure dissolution.

МОДЕЛИРОВАНИЕ АДСОРБЦИОННОЙ СПОСОБНОСТИ ГЛИН НА СТА ДИЯХ ЛИТОГЕНЕЗА

Clays are one of the most important minerals, they are widely used in industry. The development of mineral deposits by open or underground methods is carried out mainly at depths of up to 10 - 1000 m. Clay rocks (layers, layers and interlayers) of different genesis, located in the array of preparatory and mining workings (roof, soil and sides) or in the sides of quarries, have a significant impact on the stability of mine workings. Especially great influence on the safety of mining operations is exerted by clays subjected to technogenic impact, primarily by aqueous solutions and water vapor during open and underground mining of mineral deposits. During the development of mineral deposits, the clays that make up the exposed massifs have a very great influence on the stability of mine workings. The strength characteristics of clay rocks are largely determined by the degree of their water saturation. To develop technologies for increasing the strength properties of clay interlayers, it is necessary to study the effect of the composition and structure of clays formed at different stages of lithogenesis, as well as their adsorption (water absorption) capacity.

Clay–rock fracturing risk assessment under high gas pressures in repository systems

At the interface between the steel canister and the bentonite in a nuclear waste repository, we expect generation of hydrogen gas because of corrosion processes. The pressurized gas might fracture the engineered or natural clay barrier system, enhancing radionuclide transport into the geosphere. To assess the long-term integrity of the clay host rock under various conditions and scenarios, we need a large number of numerical simulations. However, a simulation tool for complex fracture propagation is often prohibitively expensive to run many realizations. Here, we developed a risk analysis tool based on the Design of Experiments to overcome the computational challenges by generating a computationally inexpensive proxy fracture model using a set of critical factors known as heavy hitters. We provided parameters and their probability distributions that are subject to uncertainty, as well as an objective function that assesses the risk of fracturing due to high gas pressures. Through various scenarios, we found that the fracture toughness dominates the impact on the risk.

Impact of salinity and alkalinity on the microstructure of partially saturated Opalinus Clay from the lower sandy facies (LSF) of Mont Terri site

In the context of deep waste disposals, the geological barrier (i.e., the host rock) will be exposed to saline plumes from bituminous waste and alkaline plumes from concrete degradation. These chemical disturbances will affect the hydraulic and mechanical properties of the clay rock by modifying its microstructure. As a result, the self-sealing of the fractures created during excavation could be affected,further affecting the long-term safety of the repositories. To this end, the effect of salinity and alkalinity on the microstructure of a partially saturated Opalinus Clay from the lower sandy facies of Mont Terri was investigated. It was found that at 𝑤 = 4.1%, salinity decreases the density and the peak of the mesopores compared to the synthetic water. This is due to the water transfer from the meso to the macro pores and to the decrease of the thickness of the diffuse double layer. For the same water content, alkalinity generates meso and macro pores. The dissolutions of clay and non-clay minerals are the main mechanisms involved.

Investigation of deformation characteristics impact of water-saturated rocks on the ecology of the coal-mining region

The purpose of the research is to evaluate the deformation properties of water-saturated clay shale to determine the displacements of the earth's surface. The analysis of the impact of mining on the environmental situation of town Shakhty in Rostov region was done. It is noted that the closure of coal mines and pumping termination of underground water led to flooding of the developed spaces of mining enterprises. This led to a change in the mechanical characteristics of clay rocks, their softening and compaction under the influence of rock pressure. Taking into account the significant capacity of clay shale in the structure of the rock mass and the technology of mining coal seams, there are currently surface deformations and the formation of cracks in the structures of buildings. According to the results of experimental studies, the deformation characteristics of clay shale under prolonged moistening have been established, affecting the precipitation of the foundations of buildings and, accordingly, lead to the formation of defects in buildings and structures. The obtained characteristics of fragmented clay shale can be used for modeling the stress-strain state of a rock mass and the development of deformations on the earth's surface by the finite element method.

Development of an inhibiting drilling fluid composition for drilling wells in unstable clay rocks

Development of an inhibiting drilling fluid composition for drilling wells in unstable clay rocks

Evaluation of the suitability of clay rock sites for geological disposal of high-level radioactive waste in the Tamusu area, Inner Mongolia, China

Evaluation of the suitability of clay rock sites for geological disposal of high-level radioactive waste in the Tamusu area, Inner Mongolia, China

A Comparative Study on Heterogeneity of Clay Rocks Using Pore‐Scale Diffusion Simulations and Experiments

AbstractAccurate modeling and simulation of radionuclide migration in clay rocks such as the Opalinus Clay (OPA) play a key role in the safety assessment of deep geological repositories for nuclear wastes. At the continuum scale, the representative elementary volume (REV) is a fundamental constraint to quantify the effective diffusivity, which is a key parameter in reactive transport (RT) models. Therefore, an accurate estimation of the REV is essential for a meaningful continuum‐scale RT simulation in heterogeneous clay rocks. This study presents a comprehensive analysis of the heterogeneities of porosity and effective diffusivity in clay rocks by using the classical sampling theory and pore‐scale simulations. First, in this study, the two‐dimensional representative elementary area is correlated with the REV for porosity via a characteristic length. Next, it is shown that the REV for diffusivity is larger than the REV for porosity. Moreover, these two REVs can be correlated using Archie's law. In such a way, the REV for diffusivity can be determined by the developed correlations through analyzing two‐dimensional microstructures, thus significantly reducing the computational cost. Finally, the applicability of our approach for clay rocks is validated by experimental data on the diffusion of tritiated water in the heterogeneous sandy facies of OPA. From both the experimental data and the modeling prediction, the REV for diffusivity in the sandy facies of OPA is in the order of cubic centimeters. This study provides critical insights into the diffusion in heterogeneous clay rocks toward an enhanced predictability of radionuclide migration.

Evaluation of Slope Stability at Interface using Thin Soil Material Model in Finite Element Software

Cases of landslides on clay shale slopes have been an intriguing study in Indonesia. Most of the slopes failed due to the weathering of the clay shale rock. As studies focused on the properties of clay shale, several FEM analyses indicated a unique translational type of failure between the interface of clay shale and its overburden. However, the modeling of the interface in a case study was still limited. This study aims to evaluate a landslide using a thin-soil interface model using FEM software. The model used two conditions, extreme groundwater level conditions. There were several iterations of the shear strength parameters of the interface layer conducted. Results indicated that the thin-soil interface could portray the interface condition at the landslide. Compared to laboratory interface results, the interface would fail at a high degree of saturation due to water infiltration at the surface. Also, granular overburden with high permeability had a higher chance of failure than cohesive overburden. From the results, this study opened the path to incorporating the interface layer in clay shale slope analysis. However, further studies are needed using the thin-soil interface model in other clay shale landslide cases to synthesize its repeatability.

Lithofacies Characteristics and Controlling Factors of Fine-Grained Sedimentary Rocks in the Lower First Member of the Shahejie Formation in the Northern Lixian Slope of Raoyang Sag, China

In order to further explore the potential of unconventional oil and gas in the northern Lixian Slope of Raoyang Sag, the lithofacies types and their controlling factors of the lower first member of the Shahejie Formation (Es1L) in the Xiliu area were analyzed through the comprehensive application of core log studies, micro-sections and their magnified analyses, mineral suits recognitions with XRD, and major and organic geochemistry. The results show that the lacustrine sedimentary rocks of Es1L in the Xiliu area comprise five lithofacies types: medium organic silty mixed fine-grained rock, medium organic massive clay rock, high organic shale calcareous mixed fine-grained rock, high organic matter shale calcareous clay rock, and high organic matter shale limestone. The vertical variation of the characteristic element reflects that the deposition in Es1L has different stages; that is, the bottom of Es1L is formed with low source influence, high water salinity, and strong reduction conditions, while the upper fine-grained rocks are formed in a sedimentary environment with high source influence, low water salinity, and weak reduction conditions. The change of the sedimentary environment controls the development of lithofacies and the occurrence of organic matter. These results advocate for the basic research of fine-grained sedimentary rocks in the faulted lacustrine basin aid for further unconventional oil and gas exploration.

Typical geotechnical profiles of the main soil deposits found in the Maceio city, Alagoas, from SPT boreholes

This work had as objective to carry out the construction of typical soil profiles of the main existing deposits in the city of Maceio from a database of SPT boreholes, built in GIS environment. In total, 1,686 records of drilling were specialized in sediments of the Barreiras Formation, Coastal Deposits, and lagoons-river, presenting the most frequent characteristics, exemplified through representative profiles. The Barreiras Formation, which covers about 75% of the urban area of the city, presented profiles with a predominance of clayey, without water level records. The deposits lagoons-river, located in the vicinity of Mundaú lagoon, were characterized by the significant presence of soft and organic clays, sometimes peat, it can reach large thicknesses and with the water table rising in certain regions. In the coastal plain, where the highest vertical construction indices in the city are concentrated, it presented an area with a predominance of fine to medium sand, with or without silt, and a water table varying between 1,00 m and 5,00 m. The analysis also allowed for the identification and mapping of the occurrence of limestone rock, sandstone rock, soft and organic clay rocks in the coastal plain, presenting a typical profile of their occurrence, helping to understand the geotechnical behavior of these materials in the studied region.

Increasing the strength of building ceramics made on the basis of low-melting clays

The object of the study is the physical and chemical processes of formation of the structure and properties, intensification of sintering of ceramic masses based on local raw materials (Krynichanska low-melting clay raw materials of the Kyiv region, Ukraine) by regulating the chemical and mineralogical composition and technological regimes. When choosing clay raw materials for specific ceramic technologies, it is necessary to be guided by a comprehensive assessment of the physicochemical properties of clay rock. These can be the granulometric and material composition, including the chemical and mineralogical composition of the clay and impurity components, the presence of amorphous material. The state of order in the structure of clay-forming minerals is also important, the knowledge of which makes it possible to determine the ways of regulating the basic technological properties of clay rock in order to bring them to the required level. Among physical and mechanical parameters, mechanical strength is one of the main criteria for determining the suitability of raw materials for the production of building ceramics. The conducted studies have shown that with an increase in the amount of rotten stone additive introduced from 10 to 20 % of low-melting clay, the mechanical strength of ceramic samples in compression and bending increases. The introduction of rotten stone additive provides an increase in the coefficient of sensitivity to drying low-melting clay raw materials, which has a positive effect on the crack resistance of raw bricks when drying clay rock in order to bring them to the required level. The use of silica materials in the composition of ceramic masses based on low-melting clays as an additive to improve the physical and mechanical characteristics of the finished product has shown its effectiveness. This can be explained by the fact that the nature of the interaction of silica additives, which was used as rotten stone, differs from the interaction of clay minerals present in ceramic raw materials with water. Since silica exists in rotten stone in the form of amorphous silica gel, it helps to improve the structure of clay, makes it monolithic, increasing mechanical strength. The impurities of low-melting oxides, which are part of the rotten stone, contribute to the formation of low-melting eutectic, reducing the refractoriness of amorphous silica and have a positive effect on the sintering process, forming a glass phase.

Experimental Study on Interfacial Friction Characteristics of Reinforced Clay.

Clay is one of the important base materials in slope restoration. The adhesion of clay-rock interface plays a decisive role in the repairing effect on rock slopes. Fibers and polymers are widely used as a clay improvement method in rock slope repair. In this paper, the friction effect of sisal fiber and polyvinyl acetate (PVAc)-reinforced clay was studied through the design of an indoor rock-like interface sliding model test. Using modelled test results and scanning electron microscope (SEM) images, the reinforced clay was analyzed. The test results showed that the critical sliding angle and maximum static friction force of clay decreased with the increase of moisture content. An excess of fiber content and moisture content weakens the coupling effect of fiber-anchoring clay. Fiber content of 0.8% and PVAc content of 2% had the best effect on enhancing the sliding resistance of clay and provided good adhesion for dangerous interfaces of rock slope at 35° and 45°, respectively. PVAc formed a three-dimensional networked elastic membrane structure to improve the skid resistance and dynamic friction coefficient of the clay. The results provide an effective way for soil improvement and ecological restoration.

PH and microbial community determine the denitrifying activity in the presence of nitrate-containing radioactive waste.

An important fraction of the currently stored volume of long-lived intermediate-level radioactive waste in Belgium contains large amounts of NaNO3 homogeneously dispersed in a hard bituminous matrix. Geological disposal of this waste form in a water-saturated sedimentary formation such as Boom Clay will result in the leaching of high concentrations of NaNO3, which could cause a geochemical perturbation of the surrounding clay, possibly affecting some of the favorable characteristics of the host formation. In addition, hyper-alkaline conditions are expected for thousands of years, imposed by the cementitious materials used as backfill material. Microbial nitrate reduction is a well-known process and can result in the accumulation of nitrite or nitrogenous gases. This could lead to the oxidation of redox-active Boom Clay components, which could (locally) decrease the reducing capacity of the clay formation. Here, we compared nitrate reduction processes between two microbial communities at different pH related to a geological repository environment and in the presence of a nitrate-containing waste simulate during 1 year in batch experiments. We showed that the microbial community from in Boom Clay borehole water was able to carry out nitrate reduction in the presence of acetate at pH 10.5, although the maximum rate of 1.3 ± 0.2 mM NO3 -/day was much lower compared to that observed at pH 9 (2.9 mM NO3 -/day). However, microbial activity at pH 10.5 was likely limited by a phosphate shortage. This study further confirmed that the Harpur Hill sediment harbors a microbial community adapted to high pH conditions. It reduced twice as much nitrate at pH 10.5 compared to pH 9 and the maximum nitrate reduction rate was higher at pH 10.5 compared to that at pH 9, i.e., 3.4 ± 0.8 mM NO3 -/day versus 2.2 ± 0.4 mM NO3 -/day. Both communities were able to form biofilms on non-radioactive Eurobitum. However, for both microbial communities, pH 12.5 seems to be a limiting condition for microbial activity as no nitrate reduction nor biofilm was observed. Nevertheless, pH alone is not sufficient to eliminate microbial presence, but it can induce a significant shift in the microbial community composition and reduce its nitrate reducing activity. Furthermore, at the interface between the cementitious disposal gallery and the clay host rock, the pH will not be sufficiently high to inhibit microbial nitrate reduction.

The mechanism of formation and prospects of non-structural traps in the South Caspian megadepression


 
 
 The article examines the geodynamic conditions for the formation and distribu- tion of non-structural traps in the oil and gas regions of Azerbaijan, such as the interfluves of the Kura and Gabirri, Yevlakh-Aghjabadi, Ganja, Lower Kura, the Baku archipelago, Shamakhi-Gobustan and Absheron. For this purpose, the surfaces of the Baikal basement, Mesozoic and Maikop deposits of the region were modeled and analyzed. The modeling revealed a submeridional uplift (positive tectonic element) that began to develop in the Maikop between the Kura and South Caspian basins. This has strongly influenced the folding and especially the formation of non-structural (tectonically sealed, lithologically limited, stratigraphic unconformity-associat- ed) traps in the region. As a result of the analyzes, we clarified the geotectonic characteristics of the formation of non-structural traps (tectonically sealed, lithologically limited, stratigraphic unconformity-associated) and compiled their distribution maps based on them. The analysis of these maps makes it possible to substantiate the features and reasons for the formation and distribution of non-struc- tural traps in the region. Thus, tectonically sealed traps were formed mainly in the oil and gas-bearing areas of the Kura and Gabirri interfluve, the Lower Kura, Shamakhy-Gobustan, Absheron and Baku archipelago, which are not only located in an active geotectonic zone, but likewise, the geological section of these oil and gas-bearing regions (OGBR) significantly differs from the Yevlakh-Aghjabadi and Ganja clay composition (clay rocks), and therefore, high parameters of the development of mud volcanism and clay diapirism are seen in the area. By contrast, in the Yevlakh-Aghjabadi and Ganja oil and gas regions, mainly effusive rocks have developed, which have incompetent properties and resist geotectonic – tangential-horizontal-compressive forces. Formed in this part of the region, thetraps associated with lithological wedging out have been mainly formed by covering the effusive or relief ledges. It should be noted that quantitatively, the traps with stratigraphic unconformity are developed relatively poorly and coincide with the distribution of lithologically wedge-out traps. The aim of the study was answ
 
 

THM Response in the Near Field of an HLW Disposal Tunnel in the Callovo-Oxfordian Clay Host Rock Caused by the Imposed Heat Flux at Different Water Drainage Conditions

Heat load from high-level radioactive waste (HLW) packages will result in elevated temperatures around the disposal tunnel. Differences in thermal expansion between rock and water will induce the redistribution of stresses. The assessment of the thermo-hydromechanical (THM) regime is necessary to evaluate the potential for fracture development. For this purpose, it is important to evaluate the nature and extent of induced strains, and their impact on rock permeability, which, subsequently, is important for radionuclide transport. This paper presents the modeling activities of the Lithuanian Energy Institute performed in the framework of the European joint program EURAD and the analysis of the influence of temperature on clay-based material behavior. Within this study, different stress conditions and material properties (isotropic, anisotropic) were analyzed with a thermo-poroelastic material model for the Callovo-Oxfordian clay host rock in the 100 m × 100 m domain. The heat load on the clay rock comes from a tunnel with a radius of 1.25 m. The overall THM response of the clay host rock system to the heat load is performed with the COMSOL Multiphysics (Burlington, MA, USA) software. The THM response near the HLW disposal tunnel was analyzed in terms of temperature, pore pressure, displacements, and stresses, and the results are presented in this work. Besides the impact of anisotropy, the effect of hydraulic conditions at the tunnel boundary was also analyzed. The modeling results revealed that anisotropy in stress and properties had an impact on the hydro-mechanical response of the material even during excavation and waiting phases. The analysis also showed that the water drainage condition on the tunnel boundary had no effect on the thermal state around the tunnel, but it had a significant impact on the hydro-mechanical response.

Numerical investigation of the couplings between strain localisation processes and gas migrations in clay materials

Deep geological repository is the preferred solution in many countries to manage radioactive wastes, such as in France where the Callovo-Oxfordian (COx) claystone is the candidate host rock. In such clay rock formation, the drilling of storage gallery creates an Excavation Damaged Zone (EDZ) with altered flow properties in the short term, while corrosion processes release large amounts of gas in the long term. Assessing the evolution of gas pressures in the near-field and predicting the effect of the EDZ on gas transport remains a major issue. This paper presents a second gradient two-phase flow hydro-mechanical (H2M) model tackling the multi-physics couplings related to gas transfers and fractures development. The EDZ is reproduced by shear strain localisation bands using a microstructure enriched model with a second gradient approach. The gas migration is captured by a biphasic fluid transfer model. The impact of fracturing on the flow properties is addressed by relating the permeability and the water retention curve to mechanical strains. Using this tool, numerical modelling of a drift in the COx claystone is performed with the aim of emphasising the influence of the HM couplings on gas migrations at nuclear waste disposal scale.

Improving the efficiency of methane extraction from coal seams

This article presents possible reasons for the low productivity of wells for coal methane extraction and ways to resolve them using hydrochloric acid treatment of wells. A common reason for the low productivity of wells is a decrease in the permeability of the bottom-hole formation zone. Starch, calcium carbonate, and drilling rocks, which are part of the drilling mud, change the filtration properties of the layer during the formation of a filtration crust and lead to a decrease in the initial permeability. Hydrochloric acid treatment, during which clay rocks are dissolved, is an effective method of increasing the productivity of wells. It is used to increase pick-up and prevent contamination of the bottom-hole zone of the carbonate formation. The parameters affecting the effectiveness of hydrochloric acid treatments were considered. The results of the experience of the interaction of hydrochloric acid with a clay crust are presented and analyzed using approaches to the mechanics of multiphase media. Dependences of the rate of dissolution of clay rock on the concentration of acid solution are obtained. It is established that the treatment of the productive intermediate layer of the well with hydrochloric acid in a certain concentration, its use increases the technological and economic efficiency of wells. As a result of experimental work, it was found that hydrochloric acid with an HCL concentration above 18% has a negative effect on the internal equipment of the well when processing clay shells.

Investigating diffusion mechanism for HTO and Se(IV)/Se(VI) in compacted Tamusu clay rock with different column lengths

Abstract Due to continuous self-sealing and good mechanical properties, the Tamusu clay rock of Inner Mongolia has been identified as the pre-selected site for high-level radioactive waste geological disposal site in China. The study of chemical behaviors related to Tamusu clay rock, such as nuclide migration, will be an important content of the performance assessment and safety assessment of the disposal repository in the future. The diffusion behavior of HTO and Se(IV)/Se(VI) with different compacted column lengths in Tamusu clay rock is discussed by the through-diffusion method. The diffusion coefficient, rock capacity factor, effective porosity, and other diffusion parameters closely related to nuclide migration are calculated, and the mechanism of nuclide diffusion is preliminarily discussed. The results show that D a (6.23 × 10−11∼17.96 × 10−11 m2 s−1), D e (1.62 × 10−11∼4.67 × 10−11 m2 s−1) for HTO increase with the increase of the compacted column length, and it is proposed that the diffusion process of HTO is affected by the change of geometrical factor and path tortuosity. D a (7.29 × 10−13∼1.74 × 10−13 m2 s−1), D e (5.15 × 10−12∼2.15 × 10−12 m2 s−1) for Se(IV), D a (3.11 × 10−12∼1.09 × 10−12 m2 s−1), D e (2.53 × 10−12∼1.09 × 10−12 m2 s−1) for Se(VI), which decrease with the increase of the compacted column length, it is mainly due to the existence of anion repulsion effect.

Strain partitioning between ductile and brittle stratigraphy

The Sand Wash fault zone is a segmented and discontinuous fault system that strikes northwest to south east in the central part of the Uinta Basin. It is approximately 34 kilometers long with an uncommonly wide damage zone, typically 100 to 200 meters wide. Due to recent, rapid, and large-scale incision by the Green River and its tributaries, the Sand-Wash fault zone is well exposed in several closely spaced canyons. These canyon exposures allow mapping of the lateral relationships through panoramic photographs and surface kinematic descriptions. Most movement on the Sand Wash fault zone occurred in the late Eocene, but minor, more recent movement likely occurred. Evidence for fault timing includes strata-bound, syndepositional movement which occurred during Lake Uinta time (55 to 43 Ma BP) resulting in debris flows, slump blocks, and small (>150 meters diameter) sag basins filled with poorly organized sediments. After lithification, elongate grabens formed with up to 33.5 meters of horizontal extension. Two styles of deformation are present. Brittle rocks, such as sandstone and limestone beds, are intensely fractured and faulted, whereas clay and organic-rich rocks are largely unfractured and unfaulted, with variably folded beds that have experienced some layer-parallel slip. Laterally, deformation is distributed up to 100 meters from the fault core, which is uncommonly large for faults with short lengths and little displacement. Vertically, displacement is concentrated in brittle sandstone and carbonate beds and rare in clay and hydrocarbon-rich units, such as the Mahogany oil-shale zone of the Eocene Green River Formation. The Mahogany oil-shale zone mostly displays ductile flow (granular flow) commonly forming small décollements between overlying and underlying units. Vertical displacement on separate fault segments is generally less than 5 meters and decreases down section, dying out completely around the top of the Mahogany oil-shale zone. In this paper we show evidence for syndepositional deformation along the Sand Wash fault zone, strain partitioning along décollement surfaces, fault surfaces that experience multiple deformational phases, pop-up blocks, and graben development. We also show that deformation on the fault zone is related to extension above a neutral surface of a larger fold. This larger fold is associated with a basement-rooted fault zone that moved during Laramide tectonism as the Uncompahgre uplift developed. The Sand Wash fault zone appears to have many similarities to the larger, and more deeply buried, Duchesne fault zone 25 kilometers to the north, and the more deeply eroded Cedar Ridge fault zone located 30 kilometers to the south. The high-resolution fault model, developed herein, is thus a good proxy for other complex fault zones in the Uinta Basin. Our model will be useful to oil and gas operators as they develop horizontal wells across this and other complex fault zones in the basin.