Pre-, syn- and post-tectonic diagenetic evolution of a carbonate reservoir: A case study of the lower cretaceous Fahlian formation in the Dezful Embayment, Zagros foldbelt, SW Iran

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F23%3A73622941" target="_blank" >RIV/61989592:15310/23:73622941 - isvavai.cz</a>

Výsledek na webu

<a href="https://onlinelibrary.wiley.com/doi/epdf/10.1111/jpg.12846" target="_blank" >https://onlinelibrary.wiley.com/doi/epdf/10.1111/jpg.12846</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1111/jpg.12846" target="_blank" >10.1111/jpg.12846</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Pre-, syn- and post-tectonic diagenetic evolution of a carbonate reservoir: A case study of the lower cretaceous Fahlian formation in the Dezful Embayment, Zagros foldbelt, SW Iran

Popis výsledku v původním jazyce

Lower Cretaceous carbonates of the Fahliyan Formation form prolific reservoir rocks at oilfields in the Dezful Embayment, central Zagros fold-thrust belt, SW Iran. The carbonates have undergone significant diagenetic alteration in phases which can in general be linked to the pre-, syn- and post-tectonic evolution of the fold-thrust belt. This paper investigates the impact of diagenetic processes on the reservoir quality of the carbonates using integrated petrographic, geochemical and sedimentological analyses of subsurface and outcrop samples of the formation. Diagenetic alterations include:(i) pre-tectonic eogenesis in the marine and shallow-burial realm, which resulted in micritization of allochems and cementation by equant and isopachous calcite rims and framboidal pyrite together with limited dolomitization and dissolution of metastable bioclasts. The isotopic compositions of micrite and early calcite cement depart from postulated values of Lower Cretaceous marine carbonates, signifying early stabilization of precursor metastable carbonate minerals and the possible effects of the incursion of meteoric waters and/or increasing burial temperatures;(ii) mesogenesis during the subsequent syn-tectonic phase, which included Late Cretaceous ophiolite obduction at the northern margin of the Arabian Plate and the later Zagros orogeny in the Miocene-Pliocene. Diagenetic modifications included the emplacement of hydrocarbons, the development of stylolites and fractures, and the precipitation of saddle dolomite, replacive rhombic dolomite, discrete pyrite, microcrystalline quartz, kaolin and anhydrite. The average stable isotope compositions of saddle dolomite (delta 18O: -6.9 parts per thousand +/- .9 and delta 13C 0.5 parts per thousand +/- 1.6, respectively) also reflects the influence of high temprature basinal fluids;and (iii) &quot;late&quot; (telogenetic, post-tectonic) uplift-related modification starting in the Pliocene, when the incursion of meteoric waters resulted in the formation of vugs, the calcitization of dolomite, and cementation by fracture-filling blocky calcite. The negative delta 18O and delta 13C stable isotope values (average: -5.5 parts per thousand +/- 1.5; and -3.6 parts per thousand +/- 5.9, respectively) of late blocky calcite cement suggest the incursion of meteoric water into the system.This study demonstrates that diagenetic processes in carbonates in the Fahliyan Formation, which exerted a significant control on the distribution of secondary porosity, can be related to the tectonic evolution of the central Zagros fold-thrust belt. Thus, constraining the diagenetic history of carbonate successions within the context of their wider tectonic evolution is important for the prediction of the spatial and temporal distribution of reservoir quality.

Název v anglickém jazyce

Pre-, syn- and post-tectonic diagenetic evolution of a carbonate reservoir: A case study of the lower cretaceous Fahlian formation in the Dezful Embayment, Zagros foldbelt, SW Iran

Popis výsledku anglicky

Lower Cretaceous carbonates of the Fahliyan Formation form prolific reservoir rocks at oilfields in the Dezful Embayment, central Zagros fold-thrust belt, SW Iran. The carbonates have undergone significant diagenetic alteration in phases which can in general be linked to the pre-, syn- and post-tectonic evolution of the fold-thrust belt. This paper investigates the impact of diagenetic processes on the reservoir quality of the carbonates using integrated petrographic, geochemical and sedimentological analyses of subsurface and outcrop samples of the formation. Diagenetic alterations include:(i) pre-tectonic eogenesis in the marine and shallow-burial realm, which resulted in micritization of allochems and cementation by equant and isopachous calcite rims and framboidal pyrite together with limited dolomitization and dissolution of metastable bioclasts. The isotopic compositions of micrite and early calcite cement depart from postulated values of Lower Cretaceous marine carbonates, signifying early stabilization of precursor metastable carbonate minerals and the possible effects of the incursion of meteoric waters and/or increasing burial temperatures;(ii) mesogenesis during the subsequent syn-tectonic phase, which included Late Cretaceous ophiolite obduction at the northern margin of the Arabian Plate and the later Zagros orogeny in the Miocene-Pliocene. Diagenetic modifications included the emplacement of hydrocarbons, the development of stylolites and fractures, and the precipitation of saddle dolomite, replacive rhombic dolomite, discrete pyrite, microcrystalline quartz, kaolin and anhydrite. The average stable isotope compositions of saddle dolomite (delta 18O: -6.9 parts per thousand +/- .9 and delta 13C 0.5 parts per thousand +/- 1.6, respectively) also reflects the influence of high temprature basinal fluids;and (iii) &quot;late&quot; (telogenetic, post-tectonic) uplift-related modification starting in the Pliocene, when the incursion of meteoric waters resulted in the formation of vugs, the calcitization of dolomite, and cementation by fracture-filling blocky calcite. The negative delta 18O and delta 13C stable isotope values (average: -5.5 parts per thousand +/- 1.5; and -3.6 parts per thousand +/- 5.9, respectively) of late blocky calcite cement suggest the incursion of meteoric water into the system.This study demonstrates that diagenetic processes in carbonates in the Fahliyan Formation, which exerted a significant control on the distribution of secondary porosity, can be related to the tectonic evolution of the central Zagros fold-thrust belt. Thus, constraining the diagenetic history of carbonate successions within the context of their wider tectonic evolution is important for the prediction of the spatial and temporal distribution of reservoir quality.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Petroleum Geology

ISSN

0141-6421

e-ISSN

1747-5457

Svazek periodika

46

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

22

Strana od-do

441-462

Kód UT WoS článku

001076993400002

EID výsledku v databázi Scopus

2-s2.0-85172671738