Which method is best to study the subsurface structures in a densely desert basin?
Dear Mohammed,
The following publication describe different methods for studying the subsurface structures in a densely desert basin:
1-Journal of Applied Sciences Research, 6(6): 616-636, 2010
© 2010, INSInet Publication (See attached file).
An Integrated Study of Gravity and Magnetic Data on South Sitra Area, Western
Desert, Egypt
1
Saad, M.H. 2
El-Khadragy, A.A. 3
Shabaan, M.M. and 4
Azab, A.
1,4Egyptian Petroleum Research Institute, Naser City, Cairo,
2,3Geology Department, Faculty of Science, Zagazig University, Egypt
Abstract: The potential field data ( Bouguer gravity and total intensity aeromagnetic maps) carried out in the South-Sitra area had been analyzed and integrated with other Geophysical and geological studies to extract information about the regional subsurface structural and tectonic framework of the burried basement rocks, as well as locating promising sites that probably favoring for the hydrocarbon accumulations. The execution of this study was initiated by transformation of the total intensity aeromagnetic data to the Reduced to Pole (RTP) magnetic map. This followed by applying several transformation techniques and various filtering processes through qualitative and quantitative analyses on
both gravity and magnetic data. These techniques include: qualitative interpretation of gravity, total magnetic intensity and RTP magnetic maps. Regional-residual separation was carried out using four methods are: nine-points, least-squares polynomial fitting, second vertical derivative and analytical signal
analysis technique. Surface and subsurface statistical trend analysis was applied on both the surface lineaments of Landsat images to identify the surface structural features, and on gravity and magnetic maps to define the major subsurface tectonic trends of the buried basement rocks. In addition, depths to the basement rocks were estimated by using three empirical methods. The results of qualitative and
quantitative techniques mentioned earlier were integrated together with other geological information to construct a tectonic basement map for the study area. This map is mainly composed of folded basement rocks of alternated synclinal and anticlinal structures cut across the study area in NNW- SSW and ENEWSW
directions. It shows that the Abu Gharadig Basin was divided into two sub-basins; North-Abu Gharadig Basin and South-Abu Gharadig Basin separated by Apollonia-Kattania high. Also, the older NNW-SSE trending structures (folding and faulting) seem to be intersected by a younger set of E-W to ENE trending faults, resulted in large vertical as well as horizontal displacements that complicate the
subsurface situations. The average depth to the basement rocks in the northern basin ranges between 4 and 5.5 km. meanwhile, the average calculated depth along South-Abu Gharadig Basin ranges from 3 km to 4 km. The southwestern area is occupied by the NNW-SSE trending Faghur Basin of Paleozoic age,
with average depth up to 4.9 km. whereas, the depth to the northern anticlinal structure (Gib Afia High) is about 3 km and is considered to be approximately the same depth for the anticlinal uplift in the southeastern part (Cairo-Bahariya uplift).
2-Int J Earth Sci (Geol Rundsch) (2010) 99:1427–1436
DOI 10.1007/s00531-009-0458-9
Integrated geoelectrical survey for groundwater and shallow
subsurface evaluation: case study at Siliyin spring,
El-Fayoum, Egypt
Mohamed Metwaly Æ Gad El-Qady Æ
Usama Massoud Æ Abeer El-Kenawy Æ
Jun Matsushima Æ Nasser Al-Arifi
Received: 7 May 2008 / Accepted: 18 May 2009 / Published online: 5 June 2009
Springer-Verlag 2009
Abstract Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient
electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available
geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of
Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.
3- International Journal of Geophysics
Volume 2014 (2014), Article ID 876180, 11 pages
http://dx.doi.org/10.1155/2014/876180
Research Article
Diacritical Seismic Signatures for Complex Geological Structures: Case Studies from Shushan Basin (Egypt) and Arkoma Basin (USA)
Mohamed I. Abdel-Fattah1 and Hamed A. Alrefaee2
1Geology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
2Geology Department, Faculty of Science, Kafr Elsheikh University, Kafr Elsheikh, Egypt
Received 24 July 2014; Revised 8 October 2014; Accepted 8 October 2014; Published 2 December 2014
Academic Editor: Joerg Schleicher
Copyright © 2014 Mohamed I. Abdel-Fattah and Hamed A. Alrefaee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Seismic reflection techniques show an imperative role in imaging complex geological structures and are becoming more acceptable as data interpreting tools in 2D/3D view. These subsurface geological structures provide complex seismic signature due to their geometrical behavior. Consequently, it is extremely difficult to interpret these seismic sections in terms of subsurface configuration. The main goal of this paper is to introduce seismic attributes as a powerful tool to interpret complex geological structures in different geological settings. In order to image these complex geological features, multiple seismic attributes such as coherence and curvature have been applied to the seismic data generated over the Shushan Basin (Egypt) and Arkoma Basin (USA). Each type of geological structure event usually generates a unique seismic “signature” that we can recognize and identify by using these seismic attributes. In Shushan Basin (Egypt), they provide a framework and constraint during the interpretation and can help prevent mistakes during a 3D structural modeling. In Arkoma Basin (USA), the seismic attributes results provide useful information for broader analyses of the complex structural relations in the region where the Ouachita orogenic belt intersects with the southern Oklahoma aulacogen. Finally, complex geological structures provide dramatically diacritical seismic signatures that can be easily interpreted by collaborating conventional seismic interpretation techniques with multiple seismic attributes.
4- Egyptian Journal of Petroleum
Volume 23, Issue 2, June 2014, Pages 229–245
Open Access
Full Length Article
Agnes high, Western Desert, Egypt: A structural study in view of potential data modelling
A.A. Azab
doi:10.1016/j.ejpe.2014.05.010
Abstract
The spatial relationship between the gravity and magnetic maxima of Agnes horst had been studied utilizing a joint modelling technique. The process depends mainly upon combining the Bouguer and Reduced To north Pole (RTP) aeromagnetic data for constructing 2D/2.5D models of the upper crustal layers. These integrated approaches were accomplished in regional and shallow senses along two profiles, for better obtaining source parameters and finding out the structural style.
Results of the qualitative analysis show that Agnes high gravity and magnetic association is mainly caused by a near surface igneous intrusion of NW orientation. Quantitatively, regional models indicate a normal continental type of crust, which is divided into upper and lower by the Conrad surface (21.5–22 km). The crust–mantle interface lies at 32–33 km meanwhile the magnetic crust reaches a depth of 16 km. Local models reveal that the basement rocks north and south of the Agnes high were offset by some 6–8 km and 3–4.5 km, respectively. Statistically, the area was controlled by two main old trends; the most prevailing WNW to NNW (East African) and the less abundant ENE (Syrian Arc) trends. These two principal trends almost have its doubtless impact on preservation of possible accumulations.
5-GRAVITY AND MAGNETIC METHODOLOGY
ABSTRACT
The Smoke Creek Desert is a large basin about 100 km (60 mi) north of Reno near the California-Nevada border (fig. 1), situated along the northernmost parts of the Walker Lane Belt, a physiographic region defined by diverse topographic expression consisting of northweststriking topographic features and strike-slip faulting. Because geologic and geophysical framework studies play an important role in understanding the hydrogeology of the Smoke Creek Desert, a geophysical effort was undertaken to help determine basin geometry, infer structural
features, and estimate depth to basement. In the northernmost parts of the Smoke Creek Desert basin, along Squaw Creek Valley, geophysical data indicate that the basin is shallow and that granitic rocks are buried at shallow depths throughout the valley. These granitic rocks are faulted and fractured and presumably
permeable, and thus may influence ground-water resources in this area.
The Smoke Creek Desert basin itself is composed of three large oval sub-basins, all of which reach depths to basement of up to about 2 km (1.2 mi). In the central and southern parts of the Smoke Creek Desert basin, magnetic anomalies form three separate and narrow EW-striking features. These features consist of high-amplitude short-wavelength magnetic anomalies and probably reflect Tertiary basalt buried at shallow depth. In the central part of the Smoke Creek Desert basin a prominent EW-striking gravity and magnetic prominence extends from the western margin of the basin to the central part of the basin. Along this ridge, probably composed
of Tertiary basalt, overlying unconsolidated basin-fill deposits are relatively thin (< 400 m). The central part of the Smoke Creek Desert basin is also characterized by the Mid-valley fault, a continuous geologic and geophysical feature striking NS and at least 18-km long, possibly connecting with faults mapped in the Terraced Hills and continuing southward to Pyramid Lake. The Mid-valley fault may represent a lateral (east-west) barrier to ground-water flow. In addition, the Mid-valley fault may also be a conduit for along-strike (north-south) ground-water flow, channeling flow to the southernmost parts of the basin and the discharge areas north of
Sand Pass.
Hoping this will be helpful,
Rafik
Dear Mohammed,
The following publication describe different methods for studying the subsurface structures in a densely desert basin:
1-Journal of Applied Sciences Research, 6(6): 616-636, 2010
© 2010, INSInet Publication (See attached file).
An Integrated Study of Gravity and Magnetic Data on South Sitra Area, Western
Desert, Egypt
1
Saad, M.H. 2
El-Khadragy, A.A. 3
Shabaan, M.M. and 4
Azab, A.
1,4Egyptian Petroleum Research Institute, Naser City, Cairo,
2,3Geology Department, Faculty of Science, Zagazig University, Egypt
Abstract: The potential field data ( Bouguer gravity and total intensity aeromagnetic maps) carried out in the South-Sitra area had been analyzed and integrated with other Geophysical and geological studies to extract information about the regional subsurface structural and tectonic framework of the burried basement rocks, as well as locating promising sites that probably favoring for the hydrocarbon accumulations. The execution of this study was initiated by transformation of the total intensity aeromagnetic data to the Reduced to Pole (RTP) magnetic map. This followed by applying several transformation techniques and various filtering processes through qualitative and quantitative analyses on
both gravity and magnetic data. These techniques include: qualitative interpretation of gravity, total magnetic intensity and RTP magnetic maps. Regional-residual separation was carried out using four methods are: nine-points, least-squares polynomial fitting, second vertical derivative and analytical signal
analysis technique. Surface and subsurface statistical trend analysis was applied on both the surface lineaments of Landsat images to identify the surface structural features, and on gravity and magnetic maps to define the major subsurface tectonic trends of the buried basement rocks. In addition, depths to the basement rocks were estimated by using three empirical methods. The results of qualitative and
quantitative techniques mentioned earlier were integrated together with other geological information to construct a tectonic basement map for the study area. This map is mainly composed of folded basement rocks of alternated synclinal and anticlinal structures cut across the study area in NNW- SSW and ENEWSW
directions. It shows that the Abu Gharadig Basin was divided into two sub-basins; North-Abu Gharadig Basin and South-Abu Gharadig Basin separated by Apollonia-Kattania high. Also, the older NNW-SSE trending structures (folding and faulting) seem to be intersected by a younger set of E-W to ENE trending faults, resulted in large vertical as well as horizontal displacements that complicate the
subsurface situations. The average depth to the basement rocks in the northern basin ranges between 4 and 5.5 km. meanwhile, the average calculated depth along South-Abu Gharadig Basin ranges from 3 km to 4 km. The southwestern area is occupied by the NNW-SSE trending Faghur Basin of Paleozoic age,
with average depth up to 4.9 km. whereas, the depth to the northern anticlinal structure (Gib Afia High) is about 3 km and is considered to be approximately the same depth for the anticlinal uplift in the southeastern part (Cairo-Bahariya uplift).
2-Int J Earth Sci (Geol Rundsch) (2010) 99:1427–1436
DOI 10.1007/s00531-009-0458-9
Integrated geoelectrical survey for groundwater and shallow
subsurface evaluation: case study at Siliyin spring,
El-Fayoum, Egypt
Mohamed Metwaly Æ Gad El-Qady Æ
Usama Massoud Æ Abeer El-Kenawy Æ
Jun Matsushima Æ Nasser Al-Arifi
Received: 7 May 2008 / Accepted: 18 May 2009 / Published online: 5 June 2009
Springer-Verlag 2009
Abstract Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient
electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available
geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of
Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.
3- International Journal of Geophysics
Volume 2014 (2014), Article ID 876180, 11 pages
http://dx.doi.org/10.1155/2014/876180
Research Article
Diacritical Seismic Signatures for Complex Geological Structures: Case Studies from Shushan Basin (Egypt) and Arkoma Basin (USA)
Mohamed I. Abdel-Fattah1 and Hamed A. Alrefaee2
1Geology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
2Geology Department, Faculty of Science, Kafr Elsheikh University, Kafr Elsheikh, Egypt
Received 24 July 2014; Revised 8 October 2014; Accepted 8 October 2014; Published 2 December 2014
Academic Editor: Joerg Schleicher
Copyright © 2014 Mohamed I. Abdel-Fattah and Hamed A. Alrefaee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Seismic reflection techniques show an imperative role in imaging complex geological structures and are becoming more acceptable as data interpreting tools in 2D/3D view. These subsurface geological structures provide complex seismic signature due to their geometrical behavior. Consequently, it is extremely difficult to interpret these seismic sections in terms of subsurface configuration. The main goal of this paper is to introduce seismic attributes as a powerful tool to interpret complex geological structures in different geological settings. In order to image these complex geological features, multiple seismic attributes such as coherence and curvature have been applied to the seismic data generated over the Shushan Basin (Egypt) and Arkoma Basin (USA). Each type of geological structure event usually generates a unique seismic “signature” that we can recognize and identify by using these seismic attributes. In Shushan Basin (Egypt), they provide a framework and constraint during the interpretation and can help prevent mistakes during a 3D structural modeling. In Arkoma Basin (USA), the seismic attributes results provide useful information for broader analyses of the complex structural relations in the region where the Ouachita orogenic belt intersects with the southern Oklahoma aulacogen. Finally, complex geological structures provide dramatically diacritical seismic signatures that can be easily interpreted by collaborating conventional seismic interpretation techniques with multiple seismic attributes.
4- Egyptian Journal of Petroleum
Volume 23, Issue 2, June 2014, Pages 229–245
Open Access
Full Length Article
Agnes high, Western Desert, Egypt: A structural study in view of potential data modelling
A.A. Azab
doi:10.1016/j.ejpe.2014.05.010
Abstract
The spatial relationship between the gravity and magnetic maxima of Agnes horst had been studied utilizing a joint modelling technique. The process depends mainly upon combining the Bouguer and Reduced To north Pole (RTP) aeromagnetic data for constructing 2D/2.5D models of the upper crustal layers. These integrated approaches were accomplished in regional and shallow senses along two profiles, for better obtaining source parameters and finding out the structural style.
Results of the qualitative analysis show that Agnes high gravity and magnetic association is mainly caused by a near surface igneous intrusion of NW orientation. Quantitatively, regional models indicate a normal continental type of crust, which is divided into upper and lower by the Conrad surface (21.5–22 km). The crust–mantle interface lies at 32–33 km meanwhile the magnetic crust reaches a depth of 16 km. Local models reveal that the basement rocks north and south of the Agnes high were offset by some 6–8 km and 3–4.5 km, respectively. Statistically, the area was controlled by two main old trends; the most prevailing WNW to NNW (East African) and the less abundant ENE (Syrian Arc) trends. These two principal trends almost have its doubtless impact on preservation of possible accumulations.
5-GRAVITY AND MAGNETIC METHODOLOGY
ABSTRACT
The Smoke Creek Desert is a large basin about 100 km (60 mi) north of Reno near the California-Nevada border (fig. 1), situated along the northernmost parts of the Walker Lane Belt, a physiographic region defined by diverse topographic expression consisting of northweststriking topographic features and strike-slip faulting. Because geologic and geophysical framework studies play an important role in understanding the hydrogeology of the Smoke Creek Desert, a geophysical effort was undertaken to help determine basin geometry, infer structural
features, and estimate depth to basement. In the northernmost parts of the Smoke Creek Desert basin, along Squaw Creek Valley, geophysical data indicate that the basin is shallow and that granitic rocks are buried at shallow depths throughout the valley. These granitic rocks are faulted and fractured and presumably
permeable, and thus may influence ground-water resources in this area.
The Smoke Creek Desert basin itself is composed of three large oval sub-basins, all of which reach depths to basement of up to about 2 km (1.2 mi). In the central and southern parts of the Smoke Creek Desert basin, magnetic anomalies form three separate and narrow EW-striking features. These features consist of high-amplitude short-wavelength magnetic anomalies and probably reflect Tertiary basalt buried at shallow depth. In the central part of the Smoke Creek Desert basin a prominent EW-striking gravity and magnetic prominence extends from the western margin of the basin to the central part of the basin. Along this ridge, probably composed
of Tertiary basalt, overlying unconsolidated basin-fill deposits are relatively thin (< 400 m). The central part of the Smoke Creek Desert basin is also characterized by the Mid-valley fault, a continuous geologic and geophysical feature striking NS and at least 18-km long, possibly connecting with faults mapped in the Terraced Hills and continuing southward to Pyramid Lake. The Mid-valley fault may represent a lateral (east-west) barrier to ground-water flow. In addition, the Mid-valley fault may also be a conduit for along-strike (north-south) ground-water flow, channeling flow to the southernmost parts of the basin and the discharge areas north of
Sand Pass.
Hoping this will be helpful,
Rafik
Dear Mohammed,
The following publication describe different methods for studying the subsurface structures in a densely desert basin:
1-Journal of Applied Sciences Research, 6(6): 616-636, 2010
© 2010, INSInet Publication (See attached file).
An Integrated Study of Gravity and Magnetic Data on South Sitra Area, Western
Desert, Egypt
1
Saad, M.H. 2
El-Khadragy, A.A. 3
Shabaan, M.M. and 4
Azab, A.
1,4Egyptian Petroleum Research Institute, Naser City, Cairo,
2,3Geology Department, Faculty of Science, Zagazig University, Egypt
Abstract: The potential field data ( Bouguer gravity and total intensity aeromagnetic maps) carried out in the South-Sitra area had been analyzed and integrated with other Geophysical and geological studies to extract information about the regional subsurface structural and tectonic framework of the burried basement rocks, as well as locating promising sites that probably favoring for the hydrocarbon accumulations. The execution of this study was initiated by transformation of the total intensity aeromagnetic data to the Reduced to Pole (RTP) magnetic map. This followed by applying several transformation techniques and various filtering processes through qualitative and quantitative analyses on
both gravity and magnetic data. These techniques include: qualitative interpretation of gravity, total magnetic intensity and RTP magnetic maps. Regional-residual separation was carried out using four methods are: nine-points, least-squares polynomial fitting, second vertical derivative and analytical signal
analysis technique. Surface and subsurface statistical trend analysis was applied on both the surface lineaments of Landsat images to identify the surface structural features, and on gravity and magnetic maps to define the major subsurface tectonic trends of the buried basement rocks. In addition, depths to the basement rocks were estimated by using three empirical methods. The results of qualitative and
quantitative techniques mentioned earlier were integrated together with other geological information to construct a tectonic basement map for the study area. This map is mainly composed of folded basement rocks of alternated synclinal and anticlinal structures cut across the study area in NNW- SSW and ENEWSW
directions. It shows that the Abu Gharadig Basin was divided into two sub-basins; North-Abu Gharadig Basin and South-Abu Gharadig Basin separated by Apollonia-Kattania high. Also, the older NNW-SSE trending structures (folding and faulting) seem to be intersected by a younger set of E-W to ENE trending faults, resulted in large vertical as well as horizontal displacements that complicate the
subsurface situations. The average depth to the basement rocks in the northern basin ranges between 4 and 5.5 km. meanwhile, the average calculated depth along South-Abu Gharadig Basin ranges from 3 km to 4 km. The southwestern area is occupied by the NNW-SSE trending Faghur Basin of Paleozoic age,
with average depth up to 4.9 km. whereas, the depth to the northern anticlinal structure (Gib Afia High) is about 3 km and is considered to be approximately the same depth for the anticlinal uplift in the southeastern part (Cairo-Bahariya uplift).
2-Int J Earth Sci (Geol Rundsch) (2010) 99:1427–1436
DOI 10.1007/s00531-009-0458-9
Integrated geoelectrical survey for groundwater and shallow
subsurface evaluation: case study at Siliyin spring,
El-Fayoum, Egypt
Mohamed Metwaly Æ Gad El-Qady Æ
Usama Massoud Æ Abeer El-Kenawy Æ
Jun Matsushima Æ Nasser Al-Arifi
Received: 7 May 2008 / Accepted: 18 May 2009 / Published online: 5 June 2009
Springer-Verlag 2009
Abstract Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient
electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available
geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of
Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.
3- International Journal of Geophysics
Volume 2014 (2014), Article ID 876180, 11 pages
http://dx.doi.org/10.1155/2014/876180
Research Article
Diacritical Seismic Signatures for Complex Geological Structures: Case Studies from Shushan Basin (Egypt) and Arkoma Basin (USA)
Mohamed I. Abdel-Fattah1 and Hamed A. Alrefaee2
1Geology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
2Geology Department, Faculty of Science, Kafr Elsheikh University, Kafr Elsheikh, Egypt
Received 24 July 2014; Revised 8 October 2014; Accepted 8 October 2014; Published 2 December 2014
Academic Editor: Joerg Schleicher
Copyright © 2014 Mohamed I. Abdel-Fattah and Hamed A. Alrefaee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Seismic reflection techniques show an imperative role in imaging complex geological structures and are becoming more acceptable as data interpreting tools in 2D/3D view. These subsurface geological structures provide complex seismic signature due to their geometrical behavior. Consequently, it is extremely difficult to interpret these seismic sections in terms of subsurface configuration. The main goal of this paper is to introduce seismic attributes as a powerful tool to interpret complex geological structures in different geological settings. In order to image these complex geological features, multiple seismic attributes such as coherence and curvature have been applied to the seismic data generated over the Shushan Basin (Egypt) and Arkoma Basin (USA). Each type of geological structure event usually generates a unique seismic “signature” that we can recognize and identify by using these seismic attributes. In Shushan Basin (Egypt), they provide a framework and constraint during the interpretation and can help prevent mistakes during a 3D structural modeling. In Arkoma Basin (USA), the seismic attributes results provide useful information for broader analyses of the complex structural relations in the region where the Ouachita orogenic belt intersects with the southern Oklahoma aulacogen. Finally, complex geological structures provide dramatically diacritical seismic signatures that can be easily interpreted by collaborating conventional seismic interpretation techniques with multiple seismic attributes.
4- Egyptian Journal of Petroleum
Volume 23, Issue 2, June 2014, Pages 229–245
Open Access
Full Length Article
Agnes high, Western Desert, Egypt: A structural study in view of potential data modelling
A.A. Azab
doi:10.1016/j.ejpe.2014.05.010
Abstract
The spatial relationship between the gravity and magnetic maxima of Agnes horst had been studied utilizing a joint modelling technique. The process depends mainly upon combining the Bouguer and Reduced To north Pole (RTP) aeromagnetic data for constructing 2D/2.5D models of the upper crustal layers. These integrated approaches were accomplished in regional and shallow senses along two profiles, for better obtaining source parameters and finding out the structural style.
Results of the qualitative analysis show that Agnes high gravity and magnetic association is mainly caused by a near surface igneous intrusion of NW orientation. Quantitatively, regional models indicate a normal continental type of crust, which is divided into upper and lower by the Conrad surface (21.5–22 km). The crust–mantle interface lies at 32–33 km meanwhile the magnetic crust reaches a depth of 16 km. Local models reveal that the basement rocks north and south of the Agnes high were offset by some 6–8 km and 3–4.5 km, respectively. Statistically, the area was controlled by two main old trends; the most prevailing WNW to NNW (East African) and the less abundant ENE (Syrian Arc) trends. These two principal trends almost have its doubtless impact on preservation of possible accumulations.
5-GRAVITY AND MAGNETIC METHODOLOGY
ABSTRACT
The Smoke Creek Desert is a large basin about 100 km (60 mi) north of Reno near the California-Nevada border (fig. 1), situated along the northernmost parts of the Walker Lane Belt, a physiographic region defined by diverse topographic expression consisting of northweststriking topographic features and strike-slip faulting. Because geologic and geophysical framework studies play an important role in understanding the hydrogeology of the Smoke Creek Desert, a geophysical effort was undertaken to help determine basin geometry, infer structural
features, and estimate depth to basement. In the northernmost parts of the Smoke Creek Desert basin, along Squaw Creek Valley, geophysical data indicate that the basin is shallow and that granitic rocks are buried at shallow depths throughout the valley. These granitic rocks are faulted and fractured and presumably
permeable, and thus may influence ground-water resources in this area.
The Smoke Creek Desert basin itself is composed of three large oval sub-basins, all of which reach depths to basement of up to about 2 km (1.2 mi). In the central and southern parts of the Smoke Creek Desert basin, magnetic anomalies form three separate and narrow EW-striking features. These features consist of high-amplitude short-wavelength magnetic anomalies and probably reflect Tertiary basalt buried at shallow depth. In the central part of the Smoke Creek Desert basin a prominent EW-striking gravity and magnetic prominence extends from the western margin of the basin to the central part of the basin. Along this ridge, probably composed
of Tertiary basalt, overlying unconsolidated basin-fill deposits are relatively thin (< 400 m). The central part of the Smoke Creek Desert basin is also characterized by the Mid-valley fault, a continuous geologic and geophysical feature striking NS and at least 18-km long, possibly connecting with faults mapped in the Terraced Hills and continuing southward to Pyramid Lake. The Mid-valley fault may represent a lateral (east-west) barrier to ground-water flow. In addition, the Mid-valley fault may also be a conduit for along-strike (north-south) ground-water flow, channeling flow to the southernmost parts of the basin and the discharge areas north of
Sand Pass.
Hoping this will be helpful,
Rafik
Dear Mohammed,
The following publication describe different methods for studying the subsurface structures in a densely desert basin:
1-Journal of Applied Sciences Research, 6(6): 616-636, 2010
© 2010, INSInet Publication (See attached file).
An Integrated Study of Gravity and Magnetic Data on South Sitra Area, Western
Desert, Egypt
1
Saad, M.H. 2
El-Khadragy, A.A. 3
Shabaan, M.M. and 4
Azab, A.
1,4Egyptian Petroleum Research Institute, Naser City, Cairo,
2,3Geology Department, Faculty of Science, Zagazig University, Egypt
Abstract: The potential field data ( Bouguer gravity and total intensity aeromagnetic maps) carried out in the South-Sitra area had been analyzed and integrated with other Geophysical and geological studies to extract information about the regional subsurface structural and tectonic framework of the burried basement rocks, as well as locating promising sites that probably favoring for the hydrocarbon accumulations. The execution of this study was initiated by transformation of the total intensity aeromagnetic data to the Reduced to Pole (RTP) magnetic map. This followed by applying several transformation techniques and various filtering processes through qualitative and quantitative analyses on
both gravity and magnetic data. These techniques include: qualitative interpretation of gravity, total magnetic intensity and RTP magnetic maps. Regional-residual separation was carried out using four methods are: nine-points, least-squares polynomial fitting, second vertical derivative and analytical signal
analysis technique. Surface and subsurface statistical trend analysis was applied on both the surface lineaments of Landsat images to identify the surface structural features, and on gravity and magnetic maps to define the major subsurface tectonic trends of the buried basement rocks. In addition, depths to the basement rocks were estimated by using three empirical methods. The results of qualitative and
quantitative techniques mentioned earlier were integrated together with other geological information to construct a tectonic basement map for the study area. This map is mainly composed of folded basement rocks of alternated synclinal and anticlinal structures cut across the study area in NNW- SSW and ENEWSW
directions. It shows that the Abu Gharadig Basin was divided into two sub-basins; North-Abu Gharadig Basin and South-Abu Gharadig Basin separated by Apollonia-Kattania high. Also, the older NNW-SSE trending structures (folding and faulting) seem to be intersected by a younger set of E-W to ENE trending faults, resulted in large vertical as well as horizontal displacements that complicate the
subsurface situations. The average depth to the basement rocks in the northern basin ranges between 4 and 5.5 km. meanwhile, the average calculated depth along South-Abu Gharadig Basin ranges from 3 km to 4 km. The southwestern area is occupied by the NNW-SSE trending Faghur Basin of Paleozoic age,
with average depth up to 4.9 km. whereas, the depth to the northern anticlinal structure (Gib Afia High) is about 3 km and is considered to be approximately the same depth for the anticlinal uplift in the southeastern part (Cairo-Bahariya uplift).
2-Int J Earth Sci (Geol Rundsch) (2010) 99:1427–1436
DOI 10.1007/s00531-009-0458-9
Integrated geoelectrical survey for groundwater and shallow
subsurface evaluation: case study at Siliyin spring,
El-Fayoum, Egypt
Mohamed Metwaly Æ Gad El-Qady Æ
Usama Massoud Æ Abeer El-Kenawy Æ
Jun Matsushima Æ Nasser Al-Arifi
Received: 7 May 2008 / Accepted: 18 May 2009 / Published online: 5 June 2009
Springer-Verlag 2009
Abstract Siliyin spring is one of the many natural fresh water springs in the Western Desert of Egypt. It is located at the central part of El-Fayoum Delta, which is a potential place for urban developments and touristic activities. Integrated geoelectrical survey was conducted to facilitate mapping the groundwater resources and the shallow subsurface structures in the area. Twenty-eight transient
electromagnetic (TEM) soundings, three vertical electrical soundings (VES) and three electrical resistivity tomography (ERT) profiles were carried out around the Siliyin spring location. The dense cultivation, the rugged topography and the existence of infra structure in the area hindered acquiring more data. The TEM data were inverted jointly with the VES and ERT, and constrained by available
geological information. Based on the inversion results, a set of geoelectrical cross-sections have been constructed. The shallow sand to sandy clay layer that forms the shallow aquifer has been completely mapped underneath and around the spring area. Flowing of water from the Siliyin spring is interconnected with the lateral lithological changes from clay to sand soil. Exploration of the extension of
Siliyin spring zone is recommended. The interpretation emphasizes the importance of integrating the geoelectrical survey with the available geological information to obtain useful, cheap and fast lithological and structural subsurface information.
3- International Journal of Geophysics
Volume 2014 (2014), Article ID 876180, 11 pages
http://dx.doi.org/10.1155/2014/876180
Research Article
Diacritical Seismic Signatures for Complex Geological Structures: Case Studies from Shushan Basin (Egypt) and Arkoma Basin (USA)
Mohamed I. Abdel-Fattah1 and Hamed A. Alrefaee2
1Geology Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
2Geology Department, Faculty of Science, Kafr Elsheikh University, Kafr Elsheikh, Egypt
Received 24 July 2014; Revised 8 October 2014; Accepted 8 October 2014; Published 2 December 2014
Academic Editor: Joerg Schleicher
Copyright © 2014 Mohamed I. Abdel-Fattah and Hamed A. Alrefaee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Seismic reflection techniques show an imperative role in imaging complex geological structures and are becoming more acceptable as data interpreting tools in 2D/3D view. These subsurface geological structures provide complex seismic signature due to their geometrical behavior. Consequently, it is extremely difficult to interpret these seismic sections in terms of subsurface configuration. The main goal of this paper is to introduce seismic attributes as a powerful tool to interpret complex geological structures in different geological settings. In order to image these complex geological features, multiple seismic attributes such as coherence and curvature have been applied to the seismic data generated over the Shushan Basin (Egypt) and Arkoma Basin (USA). Each type of geological structure event usually generates a unique seismic “signature” that we can recognize and identify by using these seismic attributes. In Shushan Basin (Egypt), they provide a framework and constraint during the interpretation and can help prevent mistakes during a 3D structural modeling. In Arkoma Basin (USA), the seismic attributes results provide useful information for broader analyses of the complex structural relations in the region where the Ouachita orogenic belt intersects with the southern Oklahoma aulacogen. Finally, complex geological structures provide dramatically diacritical seismic signatures that can be easily interpreted by collaborating conventional seismic interpretation techniques with multiple seismic attributes.
4- Egyptian Journal of Petroleum
Volume 23, Issue 2, June 2014, Pages 229–245
Open Access
Full Length Article
Agnes high, Western Desert, Egypt: A structural study in view of potential data modelling
A.A. Azab
doi:10.1016/j.ejpe.2014.05.010
Abstract
The spatial relationship between the gravity and magnetic maxima of Agnes horst had been studied utilizing a joint modelling technique. The process depends mainly upon combining the Bouguer and Reduced To north Pole (RTP) aeromagnetic data for constructing 2D/2.5D models of the upper crustal layers. These integrated approaches were accomplished in regional and shallow senses along two profiles, for better obtaining source parameters and finding out the structural style.
Results of the qualitative analysis show that Agnes high gravity and magnetic association is mainly caused by a near surface igneous intrusion of NW orientation. Quantitatively, regional models indicate a normal continental type of crust, which is divided into upper and lower by the Conrad surface (21.5–22 km). The crust–mantle interface lies at 32–33 km meanwhile the magnetic crust reaches a depth of 16 km. Local models reveal that the basement rocks north and south of the Agnes high were offset by some 6–8 km and 3–4.5 km, respectively. Statistically, the area was controlled by two main old trends; the most prevailing WNW to NNW (East African) and the less abundant ENE (Syrian Arc) trends. These two principal trends almost have its doubtless impact on preservation of possible accumulations.
5-GRAVITY AND MAGNETIC METHODOLOGY
ABSTRACT
The Smoke Creek Desert is a large basin about 100 km (60 mi) north of Reno near the California-Nevada border (fig. 1), situated along the northernmost parts of the Walker Lane Belt, a physiographic region defined by diverse topographic expression consisting of northweststriking topographic features and strike-slip faulting. Because geologic and geophysical framework studies play an important role in understanding the hydrogeology of the Smoke Creek Desert, a geophysical effort was undertaken to help determine basin geometry, infer structural
features, and estimate depth to basement. In the northernmost parts of the Smoke Creek Desert basin, along Squaw Creek Valley, geophysical data indicate that the basin is shallow and that granitic rocks are buried at shallow depths throughout the valley. These granitic rocks are faulted and fractured and presumably
permeable, and thus may influence ground-water resources in this area.
The Smoke Creek Desert basin itself is composed of three large oval sub-basins, all of which reach depths to basement of up to about 2 km (1.2 mi). In the central and southern parts of the Smoke Creek Desert basin, magnetic anomalies form three separate and narrow EW-striking features. These features consist of high-amplitude short-wavelength magnetic anomalies and probably reflect Tertiary basalt buried at shallow depth. In the central part of the Smoke Creek Desert basin a prominent EW-striking gravity and magnetic prominence extends from the western margin of the basin to the central part of the basin. Along this ridge, probably composed
of Tertiary basalt, overlying unconsolidated basin-fill deposits are relatively thin (< 400 m). The central part of the Smoke Creek Desert basin is also characterized by the Mid-valley fault, a continuous geologic and geophysical feature striking NS and at least 18-km long, possibly connecting with faults mapped in the Terraced Hills and continuing southward to Pyramid Lake. The Mid-valley fault may represent a lateral (east-west) barrier to ground-water flow. In addition, the Mid-valley fault may also be a conduit for along-strike (north-south) ground-water flow, channeling flow to the southernmost parts of the basin and the discharge areas north of
Sand Pass.
Hoping this will be helpful,
Rafik
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