Tectonics
Zahra Tavazo; Ebrahim Gholami; Hossien Motamedi; Bahman Soleimany
Abstract
Numerous mechanisms are active during folding in folded-thrust belts, such as the role of salt movement, the role of multiple detachments in sedimentary cover, interference between different phases of deformation, and the role of basement during folding. The performance of these mechanisms plays an important ...
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Numerous mechanisms are active during folding in folded-thrust belts, such as the role of salt movement, the role of multiple detachments in sedimentary cover, interference between different phases of deformation, and the role of basement during folding. The performance of these mechanisms plays an important role in the formation of different structures and geological features in geological units and folds geometry. In this research, such structures have been introduced and studied in Takhteh, Nahreh and Kuh-e-Lar anticlines in the north of Fars Paleo-High during field observations and measurement of geometric features of anticlines such as Aspect ratio, axial distance and half wavelength. These structures mainly include growth strata, geometry of tectonic synchronous strata, structures associated with shallow detachment such as rabbit ear structures, faults that are themselves structures that control the geometry and kinematics of structures, and sulfur springs that related to faults and rheology of exposed formations. The present study shows that the anticlines have an aspect ratio less than ten and are part of the detachment folds in which the detachment horizons have played a role and have a dextral arrangement. The formation of these anticlines occurred at the same time, which will be connected to each other, and these anticlines are associated with basement faults. The location of these anticlines is suitable for the presence of hydrocarbons but the basement fault in the southern flank of Takhteh anticline may affect the reservoir. The presence of water gaps and wind gaps in the region is a sign of uplift and activity of the region.
Kh. Hashemi; B. Oveisi; A. Saeedi
Abstract
Young deformations and folds are one of the impressive characteristics of Zagros simple folded belt. The studied structure is Hormud fault-related fold which is situated in the coastal Fars and the southward of Lar town. In order to illustrate the geometry of the studied structure and its kinematic relationship ...
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Young deformations and folds are one of the impressive characteristics of Zagros simple folded belt. The studied structure is Hormud fault-related fold which is situated in the coastal Fars and the southward of Lar town. In order to illustrate the geometry of the studied structure and its kinematic relationship with north and south structures, a structural cross section with ~27 km length from NE to SW was prepared. This study showed that Hormud anticline has been formed in the footwall of Lar fault, synchronous with kinematic reorganization in the core of Lar anticline and increasing horizontal stresses. Interpretation of crustal young deformations in the vicinity of the footwall of Lar fault indicates that Hormud anticline is growing in the form of a constant limb length detachment fold. Estimation of relative shortening rate (0.9± 0.2) for south limb of Hormud anticline is showing its fast growth in the form of a rocket fold which was associated by fast propagation of Hormud fault toward the surface. As a consequence of this process, kinematic model of Hormud anticline changes from a constant limb length detachment fold to a shear fault bend fold. Estimations predict 0.7 ± 0.1 mm/yr relative uplift rate for young Hormud anticline in its crest.
Mehran Arian; R. Mohammadian
Abstract
Marun oil field is situated on the eastern part of Dezful Embayment zone (Zagros).Aghajari Formation is cropping out on the surface. Asmari formation, Bangestan and Khami Groups are the Main reservoirs in this field. Asmari formation with six reservoirs layers is the most important reservoir. Dolomitic ...
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Marun oil field is situated on the eastern part of Dezful Embayment zone (Zagros).Aghajari Formation is cropping out on the surface. Asmari formation, Bangestan and Khami Groups are the Main reservoirs in this field. Asmari formation with six reservoirs layers is the most important reservoir. Dolomitic carbonates are dominant lithology in the 1,2,3layers and so, fracture density is high, especially in the first layer(90% Dolomite).Increasing of shale and Marle Layers in the 4,5,6 layers caused to decreasing of brittle property and fracture density is low. According to this research, Marun Anticline is a fault (thrust) related fold with faulted Detachment Fold mechanism. Two major fractures system in the Marun oil field could be recognized which are regional fractures (with east-west trending) and local fractures (fold and bending related fractures). The main fractured sectors, Marun Anticline are being seen in the southern limb and the eastern part of northern limb by curvature investigation (by Differential and Graphical methods).The results of Isopermeability, RFT, PI maps are consistable with the results of fracture study in order to identification of fractured sectors in the Marun Anticline
