جستجوی مقالات مرتبط با کلیدواژه « south pars » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

South Pars gas field which is the host of largest gas reserves in the world is located on Iran- Qatar border line in Persian Gulf waters. Main reservoir rocks of this field are the Permo-Triassic Upper Dalan member and Kangan formation. Lithology of this succession is predominantly carbonate and composed of limestone and dolomite. Dolomitization is one of the most important diagenetic features. In addition to, dolomitization has mainly affected this succession and changed reservoir parameters and pore network characterizations. In this study, some reservoir properties and pore network parameters; such as, porosity, permeability, pore size and pore throat size of limestone and dolomite units have been evaluated and compared. The results show that Dolomite units, despite of lower porosity and smaller pores have higher permeability and subsequently better reservoir quality than limestone units. This is due to larger pore throats in dolomites and then the pores are connected together with larger pore throats.

The main application of sequence stratigraphy is recognition of reservoir and non-reservoir intervals in hydrocarbon- bearing formations. So, it is very important to construct a suitable sequence stratigraphic-based model reservoir zonation schem. The transgressive-regressive model is comprehensively used for this purpose. Sequence stratigraphy of Kangan and upper Dalan formations in South Pars Gas Field has been done based on the EXXON model in this study. Four 3rd order sequences were determined; each sequence contains LST, TST and HST. In Kangan sequences (KS1 and KS2) and lower sequence of upper Dalan Formation (UDS2), the reservoir quality changes similarly. The LST has low reservoir quality due to the high anhydrite content while TST has good reservoir properties. The HST is not a good reservoir again with considerable anhydrite content. In the upper sequence of upper Dalan Formation, there is a reverse order. Regarding the considerable relative sea-level fall at the end Permian time, the anhydrite content is high in TST, while UDS1-HST has good reservoir quality due to dissolution influenced by meteoric water. Results of this study show that the applied model has a considerable ability for carbonate reservoirs zonation.

Correlation means comparison of hydrocarbons with each other or with hydrocarbons from a source rock for genetical relations using geochemical analyses. For this propose generally, biomarkers and isotopical analyses are used. In this study, an extensive geochemical analyes such as Rock-Eval pyrolysis, Bitumen extraction and fractionatios, biomarkers and isotpical analyses were carried out on core rock samples collected from Shaly-Carbonate layers of Kangan Formation of wells B and C in South Pars Gas field. Rock-Eval pyrlysis and biomarkers analysis results reveal that the kerogen of samples were type II and III, indicating marine organic matter with a little terrestrial input. Chromatograms of saturate fraction of samples show no biodegradation alterations. The organic matter of these samples were derived from source rock(s), with clastic-semicarbonate lithology which deposited under anoxic to subanoxic depositional environment. The samples collected from well C, showing poor to moderate genetic potential and samples of well B has poor genetic potential. Maturity level of kerogen of both samples are in early oil generation zone (late diagenesis to early catagsnesis). Samples from well B showing slightly higher maturity level compare with that of well C. Well B samples show paraffinic-naphthenic and naphthenic hydrocarbon characterestics, were as the organic matter of well C, with paraffinic-naphthenic and paraffinic hydrocarbon properties. In spite of similarity of fingerprints and chemical characterization between wells C and B, it seems shally- carbonate layers of Kangan Formation is responsible for a negligible amount of hydrocarbon production. These layers act as a low quality source rock with poor potantiality.