A dolomitized shelfedge hardground in the northern Gulf of Mexico

Poppe, Lawrence J.; Circe, R.C.; Vuletich, A.K.

doi:10.1016/0037-0738(90)90004-d

Cited by 7 publications

(1 citation statement)

References 17 publications

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“…The absence of sulfate deposits and intercrystalline cements suggests that dolomitization did not occur according to the evaporative models. Dolomitization along this MFS and along the PSB, which results in impermeable, laterally extensive dolostones, was probably accomplished by slightly modified marine pore waters (Poppe et al, 1990;Tucker, 1993;Sánchez-Román et al, 2009). Dolomitization was likely enhanced by long residence time of the sediments at the seafloor during marine transgression and by bioturbation (Wilkinson, 1991), which could facilitate dolomite nucleation by increasing carbonate alkalinity owing to aerobic and anaerobic decay of organic matter in bioturbation sites (Mazzulo et al, 1995;Bontognali et al, 2010).…”

Section: Diagenesis Along Pb Mfs Ts Psb and Within Tstmentioning

confidence: 99%

Impact of diagenesis on the spatial and temporal distribution of reservoir quality in the Jurassic Arab D and C members, offshore Abu Dhabi oilfield, United Arab Emirates

Morad¹,

Al‐Aasm²,

Nader³

et al. 2012

GeoArabia

107

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This study is based on petrographic examination (optical, scanning electron microscope, cathodo-luminescence, backscattered electron imaging, and fluorescence) of 1,350 thin sections as well as isotopic compositions of carbonates (172 carbon and oxygen and 118 strontium isotopes), microprobe analyses, and fluid inclusion microthermometry of cored Jurassic Arab D and C members from 16 wells in a field from offshore Abu Dhabi, United Arab Emirates. The formation was deposited in a ramp with barrier islands and distal slope setting. Petrographic, stable isotopic and fluid-inclusion analyses have unraveled the impact of diagenesis on reservoir quality of Arab D and C within the framework of depositional facies, sequence stratigraphy, and burial history. Diagenetic processes include cementation by grain rim cement and syntaxial calcite overgrowths, formation of moldic porosity by dissolution of allochems, dolomitization and dolomite cementation, cementation by gypsum and anhydrite, and stylolitization. Partial eogenetic calcite and dolomite cementation has prevented porosity loss in grainstones during burial diagenesis. Dolomitization and sulphate cementation of peritidal mud are suggested to have occurred in an evaporative sabkha setting, whereas dolomitization of subtidal packstones and grainstones was driven by seepage reflux of lagoon brines formed during major falls in relative sea level. Recrystallization of dolomite occurred by hot saline waters (Th 85–100°C; and salinity 14–18 wt% NaCl). Anhydrite and gypsum cements (Th 95–105°C; fluid salinity 16–20 wt% NaCl), were subjected to extensive dissolution, presumably caused by thermal sulfate reduction followed by a major phase of oil emplacement. The last cement recorded was a second phase of anhydrite and gypsum (Th 95–120°C; 16–22 wt% NaCl), which fills fractures associated with faults.

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