Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Abstract Understanding the frictional properties of discontinuities is crucial to ensure the stability of underground structures. In particular, the frictional behavior at depth depends on the complex interaction among mechanical, hydrological, thermal and chemical characteristics and their coupled effects. In this study, a series of triaxial compression tests were carried out to investigate the behavior of rough shear surface of synthetic rocks. The frictional behavior showed little variation at different confining and water pressures. The test results were analyzed using Coulomb's failure criterion. In addition, numerical analysis was carried out using PFC2D to simulate the test. Introduction Understanding coupled behavior of rock at depth is of great importance in design, construction and operation of underground structures such as a disposal facility of radioactive waste, hot dry rock geothermal system and oil reservoir. In particular, many uncertainties are involved in characterizing deep rock mass deformation in the designing process and interactions among fluid flow of groundwater, high temperature and stress disturbance should be considered. Many independent studies have been carried out to investigate the thermal, hydro, mechanical and chemical coupled effects in numerical and experimental methods. They include the researches by Lockner, Summers, Moore and Byerlee (1982), Jafari, Amini Hosseini, Pellet, Boulon and Buzzi (2003), Tembe, Lockner and Wong (2010), Lee, Lee and Jeon (2012), Indraratna, Premadasa, Brown, Gens and Heitor (2014). However few studies have been carried out on the shearing behavior of rough rock surfaces under various T-H-M conditions due to the difficulties of reproducing identical shear surfaces and complexity of experiments. In this study, as a preliminary stage of the research, to investigate shear characteristics of a joint surface under various hydro-mechanical (H-M) conditions, triaxial tests were conducted on synthetic rocks including rough shear surface. To reproduce identical joint surfaces, the samples were made of high strength cement using a mould duplicated from a natural single rock joint. The H-M testing conditions were selected considering analogical conditions at near field of various underground structures. The experimental results were analyzed based on Coulomb's failure criterion and in addition, to validate the experimental results, numerical analysis was conducted using two dimensional particle flow code.
- North America > Canada (0.34)
- North America > United States > California (0.28)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource (0.48)
Abstract The last three decades have seen significant mining development in northern regions of Canada, where the freeze and thaw cycle of permafrost and the corresponding surface subsidence and heave represent a significant challenge to the design and maintenance of infrastructures. Identifying areas at risk is of great assistance to reduce the impact of this issue. Over the past ten years, Synthetic Aperture Radar Interferometry (InSAR) has been widely used to monitor ground surface deformation. With this technique, changes in phase between two SAR acquisitions are used to detect centimeter to millimeter surface displacements over a large area and with high spatial resolution. InSAR can be used as a tool to assist the siting and design of new infrastructure as well as highlighting the risk to existing structures in areas of unstable terrain. This paper presents the results of a project carried out by Effigis, which made use of SAR interferometry in the context of monitoring terrain and infrastructure stability in a northern mining environment that is affected by permafrost seasonal and long term changes. TerraSAR-X images acquired during two periods, August to November 2012 and March to October 2013, were used to measure the deformations and/or movement of ground surface, infrastructure and stockpiles caused by seasonal changes in permafrost extent in and around a mining site located in Nunavik, Quebec. The results showed that spatial and temporal distributions of surface displacements are in accordance with scientific and terrain knowledge. Some displacements were observed in loose soil areas while, as expected, none were detected in bedrock and rock outcrop areas. The areas most affected by active layer changes showed surface subsidence in the thaw settlement period. This study confirms that SAR interferometry has a great potential for operational applications related to risks induced by surface deformation in mining environments. It shows that this technique can be used to produce reliable maps of surface movement and monitor the vertical displacement of important infrastructure.
- North America > Canada > Quebec (0.37)
- North America > Canada > Nunavut (0.28)
- Materials > Metals & Mining (1.00)
- Energy > Oil & Gas > Upstream (0.56)
In-Mine Measurements and Analysis of Ground Movements while Crossing a Geologic Fault using a Longwall Mining Method
Chugh, Yoginder P. (Southern Illinois University Carbondale) | Gurley, Harrold (Southern Illinois University Carbondale) | Abbasi, Behrooz (Southern Illinois University Carbondale) | Hirschi, Joseph (Illinois Clean Coal Institute)
Abstract The research goal was to assess if analytical tool/s can be developed to quantify displacements around a geological fault as longwall face moves toward it and past it. A company was faced with crossing a 2–3 m (6–10 ft.) normal up-thrown fault in the development entries and the face while mining a 375 m (1,200 ft.) wide longwall face. A field monitoring and numerical modeling study was performed to develop data. Field measurements consisted of roof-to-floor convergence and rectangular rosettes in the immediate roof. Numerical modeling consisted of constructing a 3-D structural model using the FLAC3D software with the fault plane incorporated as ubiquitous joint. Based on analyses and field observations data, the coal company was informed of impending movements along the fault plane and likely impacts on the development entries. Additional stiff supports were installed in head gate entries around the stage loader and equipment about 60 m (200 ft.) outby of the longwall face (solid). As the longwall face approached the fault, predicted displacements were documented and manifested by severe loading on the installed supports. Background and Study Overview This paper summarizes results of a cooperative study aimed at improving longwall mining operations in Illinois. More specifically, the study focused on:In-mine measurements in development entries while mining ahead of and behind a faulted zone, Making observations on stability of pillars and entries while mining through the fault, and Developing simplified analytical structural models using FLAC3D to assess if predictive techniques can be developed to plan mining operations through fault zone. Available data on geometry of the fault with estimates of the cohesion and frictional parameters were used for modeling. Experimental and Anlytical Procedures Mine and fault descriptions The study mine extracts Illinois No. 6 seam coal at an average depth of about 180 m (600 ft.). The immediate roof lithology consists of black shale (Anna), limestone (Brereton), dark gray shale, coal (Jamestown), and sandy shale. Gray shale intrusions or "wedges" are occasionally encountered in the immediate roof overlying the coal seam strata and sometimes they extend into the coal seam. Immediate roof lithology changes rapidly within 30 m (100 ft.). Limestone can thin or disappear and water-bearing sandstone can come within a bolting distance of 1.8 m (6 ft.) above the coal seam. In these areas, water typically drips or flows from the mine roof and/or roof bolts. The immediate floor stratum is a relatively weak claystone underlain by competent shale. The mine uses a longwall mining method with panels typically mined in the east-west direction. Entry widths in gate roads and mains are typically 5.7 m (19 ft.) and the crosscut spacing (center-to-center distance) ranges from 30 m to 45 m (100 ft. to 150 ft.).
- Geology > Rock Type > Sedimentary Rock > Organic-Rich Rock > Coal (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
Abstract This research determines shear strength and stiffness properties of bedding planes and joints in the roof strata rocks within 7.5 to 9 m (25–30 ft.) overlying the Illinois #6 coal seam (within the pressure arch zone). A shear test loading device was designed into a 1.334 kN (150 t) Forney Compression Loading Machine to perform direct shear tests in accordance with ASTM D5607–08 "Standard Test Method for Performing Laboratory Direct Shear Strength Tests of Rock Specimens under Constant Normal Force". The data were used to determine peak and residual friction angles and the dilation angle. A total of 49 bedding plane samples were tested, out of which 46 (36 intact and 10 relatively weak and loose) samples passed QA/QC procedures in accordance to ASTM D5607. Samples from eight (8) different bedding planes- shale/limestone (SL), shale/sandstone (SSs), shale/bone (SB), laminated sandstone (LS), shale/shale (SS), bone/bone (BB), bone/limestone (BL), and limestone/limestone (LL) were tested. The number of samples tested for each bedding plane were: SL- 11, SSs- 8, SB- 5, BB- 4, LS- 6, SS- 9, BL- 1, and LL- 2. Peak and residual shear strength values at 2.75 MPa normal stress range 1.06 – 6.26 MPa and 0.82 MPa to 0.82 – 4.14 MPa, respectively. The average normal and shear stiffness values are about 11.98 GPa/m and 3.11 GPa/m. Dilation angles are low (<10?) and negative in some cases. Angle of sliding friction values range from 9? to 42?. Joint Roughness Coefficient (JRC) values were less than 10. Introduction Rock mass may be defined as the total in situ rock medium containing bedding planes, faults, joints, folds and other structural features. Therefore, it is discontinuous and may have heterogeneous and anisotropic engineering properties. Upon creation of an excavation in a rock mass, bedding planes and joints are the most likely points of failure initiation. The failure typically occurs either in tensile or shear mode. Upon failure initiation stresses are transferred to the neighboring rock mass and the failure progresses until stability is achieved through equilibrium of stresses and strength. An example of this mechanism is development of the pressure arch. This study determined the shear strength and stiffness properties in shear and compression of bedding planes and joints in the immediate roof strata rocks within 7.5–9 m (25–30 ft.) overlying the Illinois No. 6 coal seam (within the pressure arch zone). Since such data are currently not available for Illinois Coal Basin mines, researchers and engineers have been using estimated values for design purposes. The immediate roof lithology in the proposed mining area consists of shale 0.62 m; Bone 0.09 m (0.3 ft.); Limestone, 0.10 m (0.33 ft.); Shale 2.37 m (7.9 ft.); and sandstone 0.55 m (1.83 ft.). The bedding plane samples were provided by a mine in south-eastern Illinois operating at a depth of about 180 m (600 ft.).
- Geology > Rock Type > Sedimentary Rock > Organic-Rich Rock > Coal (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline (1.00)
- North America > United States > Kentucky > Illinois Basin (0.99)
- North America > United States > Indiana > Illinois Basin (0.99)
- North America > United States > Illinois > Illinois Basin (0.99)
Abstract The Mitchell Creek Landslide is a large, structurally controlled, complex bedrock instability located in northwestern British Columbia. Characterization of the landslide using aerial photograph, exploration geology, and geotechnical investigation data has been completed allowing the development of a three dimensional conceptual model of the landslide domains and slope behaviour. Three domains have been identified in the landslide, from top to bottom: the Sliding domain, a relatively intact slab slowly sliding into the valley; the Transition domain, located in the mid slope of the landslide and showing evidence of significant extension and continuing to subside and displace into the valley; and a Toppling domain, at the toe of the landslide in an area of overturned foliation. Movement is greatest in the Toppling domain, with long term estimated rates of movement up to 4 times that of the Sliding domain; the Transition domain exhibits the greatest range of displacement rates, with average long term values approximately double the slower Sliding domain. This paper documents the results of numerical modelling of the Mitchell Creek Landslide with variation in geomechanical properties, basal rupture surface configuration, structural fabric, and pore water pressure conditions. The locations of internal shear surfaces within the landslide have been estimated from surface scarps, structural fabric orientation, and borehole monitoring data. The performance of each numerical model was evaluated against observed behaviour of the landslide. The configuration and properties of the basal rupture surface were identified as critical to model behaviour, as was spacing and location of internal structures. Introduction Large bedrock landslides can present a major risk to society and understanding their behaviour remains a challenge for the engineering community due to their often complex deformation patterns. Our knowledge of landslide behaviour has been informed by studying past catastrophic events in detail and attempting to identify contributory factors and triggers of failure. Studies may involve using engineering geomorphological and geological assessment of pre and post failure slopes, laboratory testing of rock and soil materials, and geophysical investigations of the subsurface. A conceptual model comprising geometry, material properties and discontinuity fabric of the landslide mass is then synthesized from the available data. Numerical modelling plays a large role in testing our understanding of rock landslides. Simplistic models can be created to test hypotheses of landslide geometry, structural interfaces (e.g. faults and foliation), material properties, and failure mechanisms. The Mitchell Creek Landslide (MCL) in northwestern British Columbia is a large, 75 Mm, complex bedrock instability, with ongoing annual movements of 0.1 to 0.8 m/yr that initiated between 1956 and 1972 in response to rapid glacial retreat, Figure 1. It provides a unique opportunity to study a relatively young landslide with a large database of subsurface data and a comprehensive record of movement from remote sensing imagery. This work details a discontinuum numerical modelling study completed utilizing UDEC v6.0 testing the proposed conceptual landslide model developed through engineering geomorphological and geological studies (BGC, 2012; Clayton, 2014).
Abstract A numerical method is proposed to propagate multiple discrete fractures leading to primary fragmentation in a mine that is being worked using block caving. Deformation is computed using the finite element method, fractures are represented explicitly, and the mine domain is discretized by an unstructured mesh. Bedding planes are represented by systematically varying the elastic modulus of the rock and by defining horizontal weakness planes. Fractures and matrix are represented using parametric surfaces, and tips are defined by their boundary curves. Tip advance is controlled by a failure criterion, and a criterion for propagation direction and magnitude, based on the evaluation of the modal stress intensity factors. A novel domain integral approach is applied to accurately compute stress intensity factors (K) ahead of fracture tips in three dimensions. The method does not require a structured volumetric mesh structure around the crack tip, as integration is performed over a series of virtual surface domains along the crack front. The method is efficient, as it makes direct use of automatically generated, arbitrary tetrahedral meshes, and approximates stress intensity factors (KI, KII, KIII) along each crack front using Interaction-integrals. As opposed to the J-Integral, the method does not decompose K a-posteriori, but instead uses an auxiliary field to directly compute modal K. When using this method, numerical approximations of K do not exhibit dependence on the mesh layout, and require meshes that can generally be ten times coarser than are required by displacement- and stress-based methods. Volumetric meshing requires only, on average, 17% of each computation step. Thus, cracks do not follow any pre-existing mesh structure, and the method is well suited for high-density fracture datasets. The method is demonstrated for primary fragmentation of a mine area covering 110 initial draw points, immediately beneath a 2m high undercut. Displacement is constrained at all boundaries except the surface of the undercut. The growth of the fractures is investigated at the onset of the undercut. Ninety initial disc-shaped fractures are taken into account, each having an initial radius of 10 m. Fractures grow around the undercut, intersect the bedding plane boundaries, and the domain is fragmented as a result.
- Oceania > Australia (0.29)
- Europe (0.28)
- North America > Canada (0.19)
Abstract Limit Analysis Theorems has revealed to be a powerful tool for the development of numerical models aiming the determination of the load bearing capacity of structures reached by plastic collapse. This work presents a numerical formulation for the computation of strict upper bounds of the collapse loads of rigid-perfectly plastic mechanical systems, derived within the kinematical theorem framework. A key advance of this present method is that the problem is described only in terms of nodes and discontinuities connecting those nodes rather than element or bodies. The alternative approximation procedure to the traditional finite element method might involve discretization of a given body using a suitably large number of nodes laid out on a grid, with the failure mechanism comprising the most critical subset of potential discontinuities interconnecting these nodes. Potential discontinuities which interlink nodes laid out across the problem domain are permitted to crossover one another, giving a much wider search space than when such discontinuities are located only at the edges of finite elements of fixed topology. Highly efficient interior point method solvers can be employed when certain popular failure criteria are specified (e.g. Mohr-Coulomb). By adopting this processing approach it is possible to solve very large problems which normally exceed the memory capacities of a single computer. The developed numerical tool reveals to be robust and versatile, able to solve a wide range of 2D problems. Velocity singularities are automatically identified and visual interpretation of the output is straightforward. Several numerical examples including rock slope are studied by the new method, and the results are very close to those calculated by using analytical method and FEM. Introduction Though the strength of the rock plays an important role in the slope stability, geological structure of the rock often govern the stability of slopes in jointed rock masses. Geological characteristics of rock mass include location and number of joint sets, joint spacing, joint orientations, joint material and seepage pressure. There are several tools available at present to carry out slope stability analyses of jointed rocks and are well documented by several researchers. Limit equilibrium method used in conjunction with numerical modeling still remains the most commonly adopted method in rock slope engineering, even though most failures involve complex internal deformation and fracturing which bears little resemblance to the rigid block assumptions required by most limit equilibrium back-analyses. Some of the numerical techniques proposed by the earlier researchers include: the shear strength reduction technique developed by Matsui and San (1992); Universal Discrete Element Code (UDEC) developed by Cundall (1979). A comprehensive study on the stability analysis of a Himalayan rock slope is carried out in this paper with an emphasis on slope stability of the natural slope in jointed rock mass using discontinuity topology optimization (DTO).
- Asia (0.28)
- North America > Canada (0.18)
Abstract We modeled mode I fracture in shale with an equivalent damage zone (CDM), a cohesive zone (CZM) and discontinuous enrichment functions (XFEM). In the Differential Stress Induced Damage model (DSID model) used in the continuum approach the total work input is equal to the sum of the energy released by crack debonding, the energy dissipated by crack opening, and the elastic strain energy stored in the bulk outside of the damage zone. In CZM and XFEM, the overall stiffness of the rock mass in the process zone drops as soon as the fracture starts propagating (unstable fracture propagation), whereas rock elastic properties in the CDM equivalent damage zone evolve smoothly with the displacement imposed at the boundary of the domain. In the CZM and XFEM, fracture propagation stabilizes after a turning point: this point coincides with damage initiation in the DSID model. As a result, the total energy of the rock mass calculated with CDM is about twice as large as in CZM and XFEM. The relative energy components of the rock mass are in the same order of magnitude and follow the same trends in the three models. This numerical study compares the evolution of dissipated energy potentials during mode I fracture propagation, and is expected to provide a basis to predict the amount of energy released by discrete fracture growth vs. damage propagation in the fracture process zone. Introduction In numerical codes, large-scale discontinuities such as hydraulic fractures and faults are usually modeled as separated surfaces or weakly bonded surfaces, or are represented with notch shapes at the macro-scale (Lund, 2007; Adachi et al., 2007). On the contrary, Excavation Damaged Zones are most often modeled with Continuum Damage Mechanics (CDM) models of elasto-plasticity models (Tsang et al., 2005). In Cohesive Zone Models (CZM), fractures propagate along predefined paths, and a governing law (traction-separation law) determines fracture and dissipated energy evolution. In Extended Finite Element Methods (XFEM), the propagation path is not predefined. Discontinuous enrichment functions are added to the shape functions used in standard Finite Element Methods (FEM), in order to account for the presence of fractures (Mohammadi, 2008). CZM and XFEM models are based on fracture mechanics principles: the total energy dissipated during the loading is the energy released to produce new material surfaces within the bulk of the material, and small-scale discontinuities that form the damage process zone around the fracture tip are neglected. Because the initiation and propagation of micro-cracks consume energy, neglecting their effects imply that solid stiffness degradation is neglected, which can lead to underestimating fracture propagation. At the scale of the Representative Elementary Volume, CDM allows modeling micro-crack propagation with a damage variable that is usually defined as a micro-crack density tensor. An attempt to bridge CDM and fracture mechanics was made by Mazars and Pijaudier-Cabot (1996), who assumed that the energy dissipated prior to large scale fracture instability is solely due to the degradation of elastic properties due to the propagation of micro-cracks in a localized zone, which is fully characterised by a material internal length. Mazars and Pijaudier-Cabot assumed that the internal length parameter and the energy release rate marking the transition between smeared damage propagation and discrete fracture propagation are known. This energy equivalence is impractical for the prediction of damage and fractures in shale, which is a sedimentary rock with a complex fabric that involves discontinuities at multiple scales. In this paper, we compare three numerical approaches to predict the forms of energy dissipated during mode I fracture propagation in shale. We explain how we calibrated the mechanical model parameters in the first section. The three following sections present the numerical results obtained with the CDM Differential Stress Induced Damage (DSID) model, the CZM and the XFEM, respectively. We compare the evolution of the relative energy components in the last section of the paper.
- North America > United States > Gulf of Mexico > Central GOM (0.24)
- North America > United States > North Dakota (0.15)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- North America > United States > South Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > North Dakota > Williston Basin > Bakken Shale Formation (0.99)
- North America > United States > Montana > Williston Basin > Bakken Shale Formation (0.99)
AN ADVANCE in MULTI-SCALE ANALYSIS of TABULAR DEPOSITS William G. Pariseau University of Utah 135 S. 1460 East Rm 315 Salt Lake City, Utah, 84112-0113, U.S.A. W.Pariseau@utah.edu ABSTRACT This contribution describes linkage of stress concentration at the face of tabular excavations, for example, longwall coal mine panels, at a meter scale to surface subsidence at a kilometer scale. Joints are considered according to orientation and spacing at an intermediate scale. A new dual-node, dual-mesh technique based on first principles uses a multi-scale technique that allows for computing whole mine surface subsidence while also allowing for computational details of stress, strain and displacement about main entries and pillars, panel entries, and bleeder entries. The technique is implemented in a conventional continuous Galerkin finite element program that has been in use for many years. The advantage of the dual-node, dual-mesh technique is the capability to do a whole mine analysis that takes into account interaction between all sections of a mine where stress transfer over long distances is often the rule rather than the exception while at the same time allowing for details of stress concentration at working faces where caving is initiated and subsidence begins. The technique, outlined recently during ARMA 2014 (Pariseau, 2014), is applied to an underground coal mine in central Utah where mines are developed from outcrops in steep canyon walls. Meshes contain over 10 million, three-dimensional nodes; runtimes are typically overnight, as a practical matter. Results compare favorably with mine subsidence measurements made over a period of several years and show the capability of this new technique to provide useful design guidance for tabular deposits such as underground coal mines. The role of variability or uncertainty in strata properties is illustrated in element safety factor distributions about development, bleeder and main entries and pillars. Such details are new in this contribution. Energy tracking for mine-induced seismicity is also new.
- Geology > Rock Type > Sedimentary Rock > Organic-Rich Rock > Coal (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- North America > United States > Utah > Book Cliffs Field (0.93)
- North America > United States > Colorado > Piceance Basin > Plateau Field > Williams Fork Formation (0.93)
- North America > United States > Colorado > Piceance Basin > Plateau Field > Iles Formation (0.93)
Study of the Potential Fault Reactivation Induced by CO2 Injection in a Three-Layer Storage Formation
Figueiredo, B. (Uppsala University) | Tsang, C. F. (Uppsala University) | Niemi, A. (Uppsala University) | Rutqvist, J. (Lawrence Berkeley National Laboratory) | Bensabat, J. (Environmental and Water Resources Engineering Ltd.)
Abstract A hydro-mechanical model was developed to study the interaction between mechanical deformation and fluid flow in the fault zones during CO2 injection and storage at the Heletz site which was chosen as a test site for CO2 injection experiments in the framework of the EU-MUSTANG project. The potential reservoir for CO2 storage at the Heletz site consists of three sand layers separated by lowpermeability shale layers. The potential consequences caused by fault reactivation, focusing on the shortterm integrity of CO2 storage, are evaluated. The difference in the results obtained by considering the three-layer as an equivalent layer storage formation is analyzed. Introduction Large-scale storage of CO2 in deep underground reservoirs may cause considerable pore-pressure perturbation as well as flux migration and concern has been raised over whether shear slip displacements may be induced in nearby faults, as a consequence of their reactivation. A state-of-the-art review can be found in Rutqvist (2012), which describes the various possible effects resulting from CO2 injection into a deep sedimentary basin, including those involved in reservoir stress–strain changes, micro-seismicity, caprock sealing performance, and potential fault reactivation. Moreover, several studies have recently shown how CO2 injection may produce seismic events both on major faults (i.e., large faults with large initial shear offset) (Cappa & Rutqvist, 2011a, b, 2012), and on minor faults that might have gone undetected during the site characterization, e.g., faults less than 1 km long and without detected initial offset (Mazzoldi et al., 2012). The present paper is concerned with the Heletz formation which was chosen as a test site for CO2 injection experiments in the framework of the EU-MUSTANG project. The Heletz site located at the southern Mediterranean coastal plain of Israel and the structure is an anticline fold with a crest of about 4 km by 2 km. The structure is gently dipping to the east, truncated by a pinch-out line to the west and subdivided into a number of blocks by transversal normal faults with small displacements. The water table is located at 300 m below the land surface. An areal sketch of the site with the elevation of the caprock and the location of the borehole that has been chosen for the CO2 injection experiment is presented in Figure 1. The potential reservoir for CO2 injection at the Heletz site consists of three high-permeability sandstones, named K, W and A, one, two and nine meters thick respectively, separated by lowpermeability shale layers of various thickness and overlaid by an additional limestone (LCC) with 5 m thickness, which is the main geological marker in the entire area, and constitutes the lower and upper confinement formations.
- Asia > Middle East > Israel (0.34)
- North America > United States (0.28)
- Europe > Norway > Norwegian Sea (0.25)
- Geology > Structural Geology (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.95)
- Asia > Middle East > Israel > Southern District > Southern Levant Basin > Heletz-Kokhav License > Heletz Kokhav Field > Heletz Field > Helez Formation (0.98)
- Asia > Middle East > Israel > Southern District > Southern Levant Basin > Heletz-Kokhav License > Heletz Kokhav Field > Heletz Field > Barnea Formation (0.98)