Analyzing the Facies, Sedimentary Environment, Sequence Stratigraphy and Diagenetic Processes of Kangan Formation in Kish Gas Field (Kish Well#3)

摘要

Background/Objectives: Although many studies have investigated the reservoir formations in Dahrom group including Kangan formation, but most of these studies have been concerned to other hydrocarbon fields. Regarding the great reservoir importance of Kangan formation in Kish Gas field, therefore, it is important to examine these rich gas-condensate reservoirs. This study aims to restore the sedimentation condition and the conditions governing the sedimentary basins during that period (lower Triassic) and detect the factors affecting the reservoir quality. Methods: To determine facies, sedimentary environment, sequence stratigraphy and identify the most important diagenetic processes occurring in the evaporate-carbonate depositions of Kangan Formation in Kish Gas Field, a sample of 510 microscopic thin sections were collected out of the core extracted from Kish Well#3 and considered by polarizan microscope. Results: Detailed petrographic investigation and well log analysis of the Kangan Formation in Kish gas field led to the recognition of arid tidalflat (A), back barrier lagoon (B) and barrier/shoal (C) facies belts related to an inner part of a homoclinal ramp platform. The Kangan Formation is mainly composed of dolomite, dolomitic limestone with shale and anhydrite. This formation has been affected by several diagenetic processes which played a significant role in improving reservoir quality. Conclusions: Vertical facies changes and cycle stacking patterns demonstrate that the Kangan Formation consists of four depositional sequences of the Third-order in the Kish Well#3, each consisting of transgressive and highstand systems tracts.