بررسي پتانسيل هيدروكربورزايي و محيط انبايش سازند كژدمي در ميدان نفتي نوروز، شمال غرب خليج فارس

Petroleum potential evaluation and sedimentary environment of the Kazhdumi Formation in Nowrouz oil filed, northwest Persian Gulf

For petroleum potential evaluation of the Khazhdumi Formation in Nowrouz oil field north west of the Persian Gulf 59 ditch cutting samples obtained from two wells were investigated through petrographic and geochemical studies. Petrographical studies resulted in characterization and separation of four palynofacies. Palynofacies I (PF-1) containing 95-100 percent phytoclast and kerogen type III was recorded only in well 1. In palynofacies II (PF-2) values of phytoclast respect to previous palynofacies decreased and were in the range of 70-90 percent and included kerogen type III. This palynofacies contain majority of samples. Palynophacies III (PF-3) was composed of 40-50 percent phytoclast and 50-60 percent AOM and kerogen type III. Palynofacies IV (PF-4) included higher amount of AOM (in the range 65-80 percent) and kerogen type II. In the differentiated palynofacieses marine element were rarely observed. High values of dark AOM in the studied samples showed the domination of oxic conditions. The Ol/HI ratios obtained from Rock-Evel pyrolysis showed the region between restrictions CD and D which confirmed rather oxic continental to marine environments. Also plotting hydrogen index values versus total organic carbons (TOC) a series of regressive and oxic conditions was concluded. Plotting data on Tysonʹs ternary diagrams and Van kervelen geochemical diagrams indicated that the kerogen is of type III, potentialy poor to fair in terms of hydrocarbon generation and type of petroleum is mainly gas except for a few samples are fairly oil-generative. In well number 1 sample were on the boundary of immature and mature and in threshold of entrance to mature stage while in well 2 the samples were in early mature stage and or were in entrance threshold to this stage.