Dolomitization and Hypogenic Dissolution of the Eocene Avanah Formation, Iraqi Kurdistan

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989592%3A15310%2F25%3A73633921" target="_blank" >RIV/61989592:15310/25:73633921 - isvavai.cz</a>

Výsledek na webu

<a href="https://aro.koyauniversity.org/index.php/aro/article/view/2333/497" target="_blank" >https://aro.koyauniversity.org/index.php/aro/article/view/2333/497</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.14500/aro.12333" target="_blank" >10.14500/aro.12333</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Dolomitization and Hypogenic Dissolution of the Eocene Avanah Formation, Iraqi Kurdistan

Popis výsledku v původním jazyce

This study constrains the mechanism of extensive dolomitization and its impact on reservoir quality of the shallow-water marine ramp carbonates of the Avanah Formation (Eocene), Iraqi Kurdistan. The presence of shoal deposits, which semi-isolate a lagoon water body from the open marine, suggests that dolomitization was by seepage reflux of brines. Nevertheless, the absence of eogenetic gypsum/anhydrite in the dolostones succession indicates that the dolomitizing fluids were mesohaline/penesaline brines formed during cycles of relative sea level (RSL) fall. Dolomitization resulted in the formation of abundant intercrystalline and moldic/vuggy pores. Restriction of dolomitization and related reservoir quality improvement to the lower part of the formation is attributed to an overall 3rd order fall in the RSL. Conversely, the lack of dolomitization in the upper part of the formation is attributed to deposition during 3rd order marine transgression, which prevented severe restriction and evaporation of the inner ramp and, consequently, inhibited the development of dolomitizing brines. It is suggested that hypogenic dissolution (karstification) by upward flow of aggressive fluids along faults and fractures during the Zagros Orogeny caused dissolution and considerable porosity and permeability improvement of the dolostones. A greater extent of dolostones dissolution in the flanks, which was accompanied by calcite cementation, compared to the crest, reflects the role of oil emplacement in the retardation of diagenetic reactions.

Název v anglickém jazyce

Dolomitization and Hypogenic Dissolution of the Eocene Avanah Formation, Iraqi Kurdistan

Popis výsledku anglicky

This study constrains the mechanism of extensive dolomitization and its impact on reservoir quality of the shallow-water marine ramp carbonates of the Avanah Formation (Eocene), Iraqi Kurdistan. The presence of shoal deposits, which semi-isolate a lagoon water body from the open marine, suggests that dolomitization was by seepage reflux of brines. Nevertheless, the absence of eogenetic gypsum/anhydrite in the dolostones succession indicates that the dolomitizing fluids were mesohaline/penesaline brines formed during cycles of relative sea level (RSL) fall. Dolomitization resulted in the formation of abundant intercrystalline and moldic/vuggy pores. Restriction of dolomitization and related reservoir quality improvement to the lower part of the formation is attributed to an overall 3rd order fall in the RSL. Conversely, the lack of dolomitization in the upper part of the formation is attributed to deposition during 3rd order marine transgression, which prevented severe restriction and evaporation of the inner ramp and, consequently, inhibited the development of dolomitizing brines. It is suggested that hypogenic dissolution (karstification) by upward flow of aggressive fluids along faults and fractures during the Zagros Orogeny caused dissolution and considerable porosity and permeability improvement of the dolostones. A greater extent of dolostones dissolution in the flanks, which was accompanied by calcite cementation, compared to the crest, reflects the role of oil emplacement in the retardation of diagenetic reactions.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

N - Vyzkumna aktivita podporovana z neverejnych zdroju

Rok uplatnění

2025

Kód důvěrnosti údajů

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

Název periodika

ARO-The Scientific Journal of Koya University

ISSN

2307-549X

e-ISSN

2410-9355

Svazek periodika

13

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

IQ - Irácká republika

Počet stran výsledku

13

Strana od-do

202-214

Kód UT WoS článku

001589101800002

EID výsledku v databázi Scopus

2-s2.0-105023554417