Carbonate Reservoirs - Porosity Evolution and Diagenesis in a Sequence Stratigraphic Framework

GeoArabia ◽  
2010 ◽  
Vol 15 (2) ◽  
pp. 91-156 ◽  
Author(s):  
Bastian Koehrer ◽  
Michael Zeller ◽  
Thomas Aigner ◽  
Michael Poeppelreiter ◽  
Paul Milroy ◽  
...  

ABSTRACT The Middle Permian to Lower Triassic Khuff Formation is one of the most important reservoir intervals in the Middle East. This study presents a sequence stratigraphic analysis of the Khuff Formation of a well-exposed outcrop in the Oman Mountains, which may provide a reference section for correlations across the entire Middle East. On the Saiq Plateau of the Al Jabal al-Akhdar, the Permian Upper Saiq Formation is time-equivalent to the Lower and Middle Khuff Formation (K5–K3 reservoir units in Oman). The Permian section is dominated by graded skeletal and peloidal packstones and cross-bedded grainstones with a diverse marine fauna. The Lower Mahil Member (Induan Stage), time-equivalent to the Upper Khuff Formation (K2–K1 reservoir units in Oman), is dominated by grainstones composed of microbially-coated intra-clasts and ooids. In general, the studied outcrop is characterized by a very high percentage of grain-dominated textures representing storm-dominated shoal to foreshoal deposits of a paleogeographically more distal portion of the Khuff carbonate ramp. A sequence-stratigraphic analysis was carried out by integrating lithostratigraphic marker beds, facies cycles, bio- and chemostratigraphy. The investigated outcrop section was subdivided into six third-order sequences, named KS 6 to KS 1. KS 6–KS 5 are interpreted to correspond to the Murgabian to Midian (ca. Wordian to Capitanian) stages. KS 4-Lower KS 2 correspond to the Dzhulfian (Wuchiapingian) to Dorashamian (Changhsingian) stages. Upper KS 2–KS 1 represent the Triassic Induan stage. Each of the six sequences was further subdivided into fourth-order cycle sets and fifth-order cycles. The documentation of this outcrop may contribute to a better regional understanding of the Khuff Formation on the Arabian Platform.


2017 ◽  
Vol 4 (1) ◽  
pp. 85 ◽  
Author(s):  
Zhipeng Lin ◽  
Le Chen ◽  
Jingfu Shan ◽  
Tan Zhang ◽  
Qianjun Sun ◽  
...  

Currently, the recognition and research on the classification of fluvial types mainly focus on the description and results of a series of indicators, such as the plane shape and sediment characteristics. However, there is limited literacy about how to demonstrate the fluvial types from the depositional process, especially less on sequence model of inland fluvial. Thus, this paper aims o propose a new kind of sequence stratigraphic framework, which is able to reflect the fluvial processes under the perspective of sequence stratigraphy. Accordingly, we use the principle of concrete analysis for concrete problems by comprehensively summing up the previous classification schemes of river types. With the research method of sedimentation process, new fluvial systems tracts for fluvial are presented here, including four parts: low fluvial system tract (LFST), advancing fluvial system tract (AFST), flooding fluvial system tract (FFST), receding fluvial system tract (RFST). Moreover, these could be applied to tackle the problem of the traditional division of fluvial. Various rivers have the different characteristics of systems tracts, then this may play a vital role in the discrimination of meandering river, braided river, anastomosing river and branched river. This study embodies the philosophical thought of Process Sedimentology and may contribute to revealing the deposition process of the fluvial system more profoundly from the aspect of genetic mechanism and evolution course. Most importantly, the fluvial classification system is definitely improved from the description stage to a complete rational stage.


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