Middle Miocene normal faulting along the Tobe Thrust in western Shikoku.

Abstract The purpose of this study is to evaluate the reservoir geomechanics and stress path values of the depleted Miocene sandstone reservoirs of the Badri field, Gulf of Suez Basin, in order to understand the production-induced normal faulting potential in these depleted reservoirs. We interpreted the magnitudes of pore pressure (PP), vertical stress (Sv), and minimum horizontal stress (Shmin) of the syn-rift and post-rift sedimentary sequences encountered in the studied field, as well as we validated the geomechanical characteristics with subsurface measurements (i.e. leak-off test (LOT), and modular dynamic tests) (MDT). Stress path (ΔPP/ΔShmin) was modeled considering a pore pressure-horizontal stress coupling in an uniaxial compaction environment. Due to prolonged production, The Middle Miocene Hammam Faraun (HF) and Kareem reservoirs have been depleted by 950-1000 PSI and 1070-1200 PSI, respectively, with current 0.27-0.30 PSI/feet PP gradients as interpreted from initial and latest downhole measurements. Following the poroelastic approach, reduction in Shmin is assessed and reservoir stress paths values of 0.54 and 0.59 are inferred in the HF and Kareem sandstones, respectively. As a result, the current rate of depletion for both Miocene reservoirs indicates that reservoir conditions are stable in terms of production-induced normal faulting. Although future production years should be paid more attention. Accelerated depletion rate could have compelled the reservoirs stress path values to the critical level, resulting in depletion-induced reservoir instability. The operator could benefit from stress path analysis in future planning of infill well drilling and production rate optimization without causing reservoir damage or instability.

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Les grands traits d'une structure nouvelle proposee pour le massif de Sainte-Victoire

BSGF - Earth Sciences Bulletin ◽

10.2113/gssgfbull.s7-vi.4.545 ◽

1964 ◽

Vol S7-VI (4) ◽

pp. 545-553 ◽

Cited By ~ 2

Author(s):

Fernand Touraine

Keyword(s):

Upper Cretaceous ◽

Middle Miocene ◽

Middle Eocene ◽

Normal Faulting ◽

The South ◽

Southern France ◽

Western Margin ◽

Thrust Faulting ◽

Differential Movement

Abstract The Sainte-Victoire mountain in southern France has been considered the overturned southern limb of the Vauvenargues anticline, but the structure east of the Delubre fault is complicated by an oblique fold. The western margin is concealed by transgressive Tortonian (middle Miocene) beds covering the plateau of Beaumettes. The anticline probably is upper Cretaceous. Folding was renewed in the upper Lutetian (middle Eocene), and resulted in overturning and thrust faulting of the south limb. Subsequent normal faulting compartmented the mass, resulting in selective differential movement of blocks as horsts and grabens. The term piano keys structure is given to this type of structure.

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Mineralogy of the Au-Ag mineralization from the Finsterort and Anton vein system, Štiavnické vrchy Mts. (Slovakia)

Bulletin Mineralogie Petrologie ◽

10.46861/bmp.29.255 ◽

2021 ◽

Vol 29 (2) ◽

pp. 255-269

Author(s):

Jozef Vlasáč ◽

Martin Chovan ◽

Rastislav Vojtko ◽

Peter Žitňan ◽

Tomáš Mikuš

Keyword(s):

Middle Miocene ◽

Precious Metals ◽

Central Zone ◽

Strike Slip ◽

Normal Faults ◽

Normal Faulting ◽

Vein System ◽

Štiavnica Stratovolcano ◽

Dextral Strike Slip ◽

Strike Slip Movement

The Finsterort and Anton vein system is located in the central zone of the Middle Miocene Štiavnica Stratovolcano between Vyhne and Hodruša-Hámre villages. The vein system contains several partial veins and veinlets and has generally NNE - SSW strike with moderate to steep eastward dip. Kinematics of the veins is characterised by older dextral strike-slip movement replaced by younger normal faulting. The mineralization is associated with the normal faults and the veins contain interesting paragenesis of Au-Ag bearing minerals. Minerals of precious metals are represented by argentotetrahedrite-(Zn) and rozhdestvenskayaite-(Zn), Au-Ag alloys, members of polybasite-pearceite and pyrargyrite-proustite solid solutions, acanthite and uytenbogaardtite. Au-Ag mineralization is accompanied by older paragenesis comprising mainly pyrite, galena, sphalerite and chalcopyrite. Besides quartz, carbonates (calcite, siderite and dolomite) are the main gangue minerals.

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