Well productivity in the Ponta Grossa dike Swarm, Brazil: An integrated study with magnetic data inversion and clustering analysis of model solutions

Cavalcante, Felipe Lisbona; Mendonça, Carlos Alberto; Ofterdinger, Ulrich; Filho, Oderson Antônio de Souza

doi:10.1016/j.jhydrol.2020.125079

Cited by 8 publications

(15 citation statements)

References 28 publications

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“…Previous work has also similarly assessed the contribution of intrusions to well productivity (Chevallier et al 2004;Matter et al 2006;Mohamed et al 2015). Although median values around 700 m in the present study are almost double the values found in Cavalcante et al (2020),…”

Section: Oriented Magnetic Gradients (Omgs)contrasting

confidence: 42%

“…The mapped GMOs were able to elucidate regional geological structures that extend into the subsurface and semi-quantitative methods were able to estimate their depths. Cavalcante et al (2020) mapped NW-SE dykes in the northwestern portion of the CBAS with depths averaging around 300 m, whose wells mostly located close to this depth do not reach this depth, but their productivity was justified by the authors as being influenced by primary damage zones caused by the instrumentality of these dikes, allowing the wells to be fed not directly by the dikes, but by the structures associated with them. Previous work has also similarly assessed the contribution of intrusions to well productivity (Chevallier et al 2004;Matter et al 2006;Mohamed et al 2015).…”

Section: Oriented Magnetic Gradients (Omgs)mentioning

confidence: 99%

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Litho-structural conditioning in the exploration of fractured aquifers: a case study in the Crystalline Basement Aquifer System of Brazil

et al. 2021

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This research aimed to identify qualitatively and quantitatively productive regions through spatial correlations of wells and geological conditions, such as lineaments, hydrography, aeromagnetometry and different lithologies present in the Crystalline Basement Aquifer System (CBAS), state of Paraná, Brazil. Different methods applied in Precambrian metamorphic and igneous aquifers in the world and some Brazilian states were integrated and applied in CBAS seeking to understand the best scale and approach to productivity. The median productivity of the 224 wells analyzed is 0.29 m 3 /h/m. Under a multi-scale regional assessment, the results showed that the best condition is associated with: the distance of 350 m from the lineaments (1:100,000), especially those with directions N40W, N10E and N70E. Considering hydrolithological units, gneisses are the most productive, especially where lineaments coincide with regional structures, such as shear zones, foliations and Cenozoic tectonic reactivations. Quartzites, granitoids, schists, phyllites, and rhyolites were also favorable when close to important rivers and not necessarily coinciding with regional lineaments, high density, either vertical fractures.The areas of intersection of the lineaments and the weathering mantle did not serve as a discriminatory parameter in this research. As the median depths of the water wells reach 90 m from the surface, the extraction of oriented magnetic gradients referred to magnetic sources down to 800 m depth, thus corroborating surface mapped lineaments and new non-outcropable structures. Considering the complexity of the environment and the global groundwater use of fractured aquifers, this work contributed by discriminating geospatial parameters to decrease the exploratory risk in CBAS.

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Section: Oriented Magnetic Gradients (Omgs)contrasting

confidence: 42%

Section: Oriented Magnetic Gradients (Omgs)mentioning

confidence: 99%

Litho-structural conditioning in the exploration of fractured aquifers: a case study in the Crystalline Basement Aquifer System of Brazil

et al. 2021

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“…In addition, the relative crustal extension can be estimated by calculating the sum of the dikes' widths from a prole taken perpendicularly to the dike swarm divided by the total prole length (Castro et al, 2008). On the other hand, width and depth to the top can aect the circulation and ow of groundwater and hydrocarbon in several ways, such as compartmentalization, obstruction, and providing preferential pathways (Cavalcante et al, 2020). As McGrath and Hood (1970) pointed out, the depth to the top z 0 can be estimated independently on geological or magnetization directions assuming the dike model.…”

Section: Theory and Methodsmentioning

confidence: 99%

“…24) than in the source location (x 0 , z 0 ). Our study area is located in the Ponta Grossa Arch (PGA), southern Brazil, which has been the subject of several recent studies (e.g., Strugale et al, 2007;Gomes et al, 2011;Louro et al, 2019;Cavalcante et al, 2020).…”

Section: R a F Tmentioning

confidence: 99%

Interpretation of magnetic anomaly profiles using a decomposition in Hilbert transform pairs

Oliveira

Souza

Castro³

et al. 2022

Braz J Geophys

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ABSTRACT. We propose a simple transformation to aid the interpretation of magnetic anomalies generated by linear structures. The profile of such anomalies perpendicular to the strike can be decomposed into two signals, one symmetric and the other antisymmetric concerning the center of the source. The symmetric component serves as input data to various depth estimation techniques that often assume the anomaly is reduced to the pole. We use the fact that these components form a Hilbert transform pair to transform a skewed anomaly profile into a symmetric one. Unlike in previous works that rely on the decomposition into even and odd functions, the profile does not need to be shifted to the source's center of symmetry or limited to one isolated anomaly. Multiple effective magnetization directions presented by different dikes are modeled by a function representing the different local effective dip angles. We validate the method with synthetic data and ground magnetic survey data from a dike swarm at Ponta Grossa Arch, southern Brazil. We also illustrate the usefulness of reconstructed anomalies for depth estimation methods. The results also show that the method can handle interfering sources with distinct effective magnetization directions.

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“…For two-dimensional (2D) sources, ASA (Li, 2006) and AMA (Liu et al, 2015) are invariant with magnetization direction, further simplifying the interpretation of elongated anomalies and magnetic lineaments from dike swarms. Depending on their properties and geometry, such tabular features may have a significant impact on subsurface conditions including the flow regime and exploration for groundwater resources (Cavalcante et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Thin Sheet Automatic Interpretation of Dike Swarm Magnetic Transects Using Regularized Second Derivatives

Mendonça¹,

Cavalcante²,

Melo³

2023

Preprint

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Dike swarms are major continental structures recording large igneous provinces and crustal extension processes generating rifts and sedimentary basins. A key point in dike swarm studies is determining a minimum number of dikes that are necessary to explain the observed magnetic anomalies and inferences about position and depth for specific unities. We develop an automatic interpretation procedure to interpret the complex anomalies resulting from densely juxtaposed dikes forming a swarm, each dike with different depth and magnetization attributes. The automatic parameter estimation is based on the ratio of the amplitude of the magnetic anomaly (AMA) by its second-order derivative, the dike position and depth determined from simple algebraic expressions based on the thin-sheet model representation. The second derivative of the AMA serves to individualize intervals with specific dike units, thereby determining a minimum number of dikes based on their sharp or subtle concave-down expressions in the AMA profile. Tikhonov regularization is applied to prevent noise enhancement in evaluating numerical derivatives using a finite-difference scheme. A set of MATLAB programs are presented to evaluate the automatic interpretation of magnetic transects, a profile across the Ponta Grossa Dike Swarm in Southern Brazil serving as a testing data set since its results can be compared with a published dike model obtained from data inversion. Dike location and depth obtained with the automatic procedure accurately recover the model parameters obtained from nonlinear data inversion suggesting the utility of the proposed procedure to obtain a reliable model from complex anomalies.

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Well productivity in the Ponta Grossa dike Swarm, Brazil: An integrated study with magnetic data inversion and clustering analysis of model solutions

Abstract: Well productivity in the Ponta Grossa Dike Swarm, Brazil: An integrated study with magnetic data inversion and clustering analysis of model solutions.

Cited by 8 publications

References 28 publications

Litho-structural conditioning in the exploration of fractured aquifers: a case study in the Crystalline Basement Aquifer System of Brazil

Litho-structural conditioning in the exploration of fractured aquifers: a case study in the Crystalline Basement Aquifer System of Brazil

Interpretation of magnetic anomaly profiles using a decomposition in Hilbert transform pairs

Thin Sheet Automatic Interpretation of Dike Swarm Magnetic Transects Using Regularized Second Derivatives

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