Hydrothermal dolomitization of the Bekhme formation (Upper Cretaceous), Zagros Basin, Kurdistan Region of Iraq: Record of oil migration and degradation

Pervasive early diagenetic dolomitization, subsequent hydrothermal alteration, and late stage hydrocarbon accumulation in a Middle Triassic carbonate sequence (Szeged Basin, SE Hungary)

“…Hydrothermal dolomitization induced by compressional tectonism is also a well-documented phenomenon (e.g., Ronchi et al, 2012;Sirat et al, 2016;Mansurbeg et al, 2016;Dong et al, 2017); however, in contrast with our interpretation, in the most cases the hydrothermal fluids are identified as basinal brines or mixed magmatic and formational waters.…”

“…The latest pore-filling phases are calcite, quartz, and Cd-3 dolomite, that postdate all the matrix phases and Cd-2 cement, but their timing relative to each other is uncertain. Among these phases, the calcite is most probably meteoric in origin, as it is documented from similar lithologies and geological settings (e.g., Nader et al, 2004;Gomez-Rivas et al, 2014;Sirat et al, 2016;Mansurbeg et al, 2016;Guo et al, 2016;Dong et al, 2017). The observed cathodoluminescence zonation of calcite crystals (Fig.…”

“…The western part of the B-B′ cross-section is based on the interpreted seismic sections of Tari (1999) and Matenco and Radivojević (2012), that are located close to the studied area. Davies and Smith, 2006;Gomez-Rivas et al, 2014;Sirat et al, 2016;Hips et al, 2016;Mansurbeg et al, 2016;Guo et al, 2016;Dong et al, 2017).…”

Diagenetic evolution of lower Jurassic platform carbonates flanking the Tazoult salt wall (Central High Atlas, Morocco)

“…On the other hand, the relatively depleted δ 18 O values (from −7.45 to −5.13‰ VPDB ) suggests formation from relatively high temperature fluids (Allan & Wiggins, ; Spötl & Pitman, ). In this regard, saddle dolomite is considered to precipitate from hot basinal, frequently hydrothermal, fluids (Davies & Smith, ; Mansurbeg et al, ; Morad, Nader, Morad, Al Darmaki, & Hellevang, ), with temperatures above 60°C (Spötl & Pitman, ). Therefore, the most probable scenario is that RD3 and SD1 formed from light carbon and high temperature Mg‐rich fluids expelled from the Zawyat Ahançal Group sediments or the Pliensbachian basinal marls, which are in lateral contact with the Pliensbachian platform carbonates, using faults, fractures and the margin of the Tazoult salt wall as major conduits (Figure ).…”

Comparison of the diagenetic and reservoir quality evolution between the anticline crest and flank of an Upper Jurassic carbonate gas reservoir, Abu Dhabi, United Arab Emirates

“…Shift in the chemistry of formation waters from Mg-rich to Ca-rich can be constrained by using T mice and apparent eutectic temperatures of carbonate cements. The T mice (-24.4 and -17.8°C) and apparent eutectic temperatures (-58 to -50°C) of fluid inclusions in blocky calcite (C5) indicate that the brines were highly saline (19.2-25.2 wt% NaCl eq) and contained other salts than NaCl, possibly CaCl 2 (Oakes et al, 1990, Goldstein andReynolds, 1994 Merino and Canals, 2011;Mansurbeg et al, 2016;Sirat et al, 2016).…”