Advancements towards DFKN modelling: Incorporating fracture enlargement resulting from karstic dissolution in discrete fracture networks

Lopes, Juliana A.G.; Medeiros, Walter E.; Bruna, Vincenzo La; Lima, Ana Paula de; Bezerra, Francisco H.R.; Schiozer, Denis José

doi:10.1016/j.petrol.2021.109944

Cited by 24 publications

(10 citation statements)

References 74 publications

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“…Dye tracer tests have confirmed these patterns in this area (Assunção et al, 2023). In contrast, in S2 and S3, the rapid circulations observed can be attributed to (i) the concentrated recharge through numerous karst surface landforms, (ii) presence of enlarged sub‐vertical fractures that increase the transmissivity of the karstified fracture network (Lopes et al, 2022), (iii) connected conduit system formed by bedding planes and regional structural lineaments promoting karstogenesis, and (iv) considerable hydraulic gradient between the recharge area and the spring.…”

Section: Resultsmentioning

confidence: 99%

Natural responses of Neoproterozoic dynamic karst springs to rainfall events, São Miguel Watershed, Minas Gerais, Brazil

Marques,

Galvão,

Assunção

et al. 2024

Hydrological Processes

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Karst aquifers consist of complex networks of conduits in which groundwater flows and recharge/discharge processes are generally more dynamic than in other types of aquifers. Due to their intrinsic heterogeneity and anisotropy, monitoring, quantifying, and analysing natural responses of karst springs is an efficient tool. Unlike Cenozoic and Mesozoic rocks, in Neoproterozoic karst systems, groundwater circulates and stores generally in dissolution features known as tertiary porosity, as the rock's primary porosity is recrystallized, considered negligible. This article studies the hydrodynamics of a karst portion of the São Miguel River basin, southwest of the state of Minas Gerais, Brazil. The region is predominantly composed of Neoproterozoic carbonate rocks, dating from about 570 to 540 million years ago. During a hydrological year (2019–2020), three karst springs (S1, S2, and S3) were daily monitored through their natural responses (variations of electrical conductivity, EC, temperature, T, and discharge, Q) to rainfall episodes. The data were interpreted based on the analysis of spring hydrographs, time series, recession curves (seasonal and intra‐annual), and statistics of EC, T, and Q variations. The results show the three springs generally exhibit quick flow, typically karstic, in the case of hydrosystems with a well‐structured and functional underground drainage network. The time series indicate the hydrosystem drained by S1 presents slower circulation and a lower degree of linearity, resulting from the higher sinuosity of the system, while the hydrosystems of S2 and S3 have similar behaviours, of quick water circulations immediately after a rainy episode. The degrees of karstification classify S1 and S2 as complex and extensive karst systems consisting of several subsystems, and S3 as a system in which the conduit network is more developed at the upper epiphreatic zone than near the outlet.

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Section: Resultsmentioning

confidence: 99%

Natural responses of Neoproterozoic dynamic karst springs to rainfall events, São Miguel Watershed, Minas Gerais, Brazil

Marques,

Galvão,

Assunção

et al. 2024

Hydrological Processes

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“…With the rapid development of fracture research and computer technology in recent years, fracture prediction has evolved from conventional interpolation methods to space subdivision methods, such as discrete fracture network modeling (Benedetto et al, 2014;Pellerin, 2014;Hyman et al, 2015;Azim, 2021;Ceccato et al, 2021;Wang et al, 2021;Berrone and Raeli, 2022;Lopes et al, 2022;Yan et al, 2022). Stress-intensity factors are relative to fracture pressure, fracture height, and layer stress .…”

Section: Fracture Modeling Under Multicondition Constraint and Static...mentioning

confidence: 99%

3D geological modeling of deep fractured low porosity sandstone gas reservoir in the Kuqa Depression, Tarim Basin

et al. 2023

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The fractured reservoir is one of the significant petroleum reservoir types in China, representing over one-third of total reserves. The Kuqa Depression in the Tarim Basin is dominated by fractured low-porosity sandstone gas reservoirs with characteristic tight matrix, developed fractures, and edge and bottom water. However, the continued development of these reservoirs has led to various problems, including strong reservoir heterogeneity, low well control, complex gas-water relationships, and early water invasion. Addressing these issues requires a detailed understanding of the reservoir’s geological characteristics. One method for achieving a fine reservoir description is through the use of 3D geological modeling. This high-level, comprehensive characterization technique is widely used throughout the entire life cycle of oil and gas field development. A 3D geological model can accurately predict the actual underground reservoir characteristics and provide a geological basis for later numerical simulation work. Based on a study of the geological characteristics of the Kuqa Depression in the Tarim Basin, a 3D geological modeling technique was developed, which includes structural modeling, facies modeling, petrophysical modeling, and fracture modeling. This technology has been successfully applied to many deep gas reservoirs in the Kuqa Depression of the Tarim Basin, leading to enhanced gas recovery.

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“…Two-dimensional pavement and fracture trace analysis allow for the interpretation and modelling of geometric and topological data (fracture orientation, length, intersections, aperture) from the fracture networks using advanced techniques of data acquisition, e.g. monopod and drone photogrammetry (Bisdom et al 2017;Prabhakaran et al 2019, Smith, 2020Lopes et al 2022).…”

Section: A Two-dimensional Fracture Modelling From Surface Analoguesmentioning

confidence: 99%

Using fractured outcrops to calculate permeability tensors: implications for geothermal fluid flow and the influence of seismic-scale faults

et al. 2022

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Faulted and fractured systems form a critical component of fluid flow, especially within low-permeable reservoirs. Therefore, developing suitable methodologies for acquiring structural data and simulating flow through fractured media is vital to improve efficiency and reduce uncertainties in modelling the subsurface. Outcrop analogues provide excellent areas for the analysis and characterization of fractures within the reservoir rocks where subsurface data are limited. Variation in fracture arrangement, distribution and connectivity can be obtained from 2D fractured cliff sections and pavements. These sections can then be used for efficient discretization and homogenization techniques to obtain reliable predictions on permeability distributions in the geothermal reservoirs. Fracture network anisotropy in the Malm reservoir unit is assessed using detailed structural analysis and numerical homogenization of outcrop analogues from an open pit quarry within the Franconian Basin, Germany. Several events are recorded in the fracture networks from the Late Jurassic the Alpine Orogeny and are observed to be influenced by the Kulmbach Fault nearby with a reverse throw of 800 m. The fractured outcrops are digitized for fluid flow simulations and homogenization to determine the permeability tensors of the networks. The tensors show differences in fluid transport direction where fracture permeability is controlled by orientation compared to a constant value. As a result, it is observed that the orientation of the tensor is influenced by the Kulmbach Fault, and therefore faults within the reservoirs at depth should be considered as important controls on the fracture flow of the geothermal system.

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Advancements towards DFKN modelling: Incorporating fracture enlargement resulting from karstic dissolution in discrete fracture networks

Cited by 24 publications

References 74 publications

Natural responses of Neoproterozoic dynamic karst springs to rainfall events, São Miguel Watershed, Minas Gerais, Brazil

Natural responses of Neoproterozoic dynamic karst springs to rainfall events, São Miguel Watershed, Minas Gerais, Brazil

3D geological modeling of deep fractured low porosity sandstone gas reservoir in the Kuqa Depression, Tarim Basin

Using fractured outcrops to calculate permeability tensors: implications for geothermal fluid flow and the influence of seismic-scale faults

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