Abstract:
This research focuses on the sedimentological and petrographical analyses on Core-1 intervals (447.46m – 456.00m) and Core-2 intervals (515.00m – 545.33m) at X well, Y Basin, Sudan.
The sedimentological investigations such as scanning electron microscope and X-Ray Diffraction analyses were carried out at reservoir beds from the above mentioned two core intervals with total length of 19.63m, apart from the preserved intervals, at X well.
In addition to that, significant quantities of Kaolinite and some amounts of iron oxide as authigenic minerals were detected in most of the investigated reservoir beds. The clay mineral analysis (XRD) revealed that the studied strata are essentially composed of kaolinite with few amounts of chlorite, illite, smectite and mixed layer clay minerals.
The vertical arrangements of the studied two core facies sequences retrieved from X well logs; suggest deposition in both fluvial (braided and meandering) and deltaic distal channels’ depositional environments. Moreover, the higher amounts of the kaolinite in the studied core; suggest most probably intensity of chemical weathering and leaching processes under warm humid climate. The increase of the authigenic kaolinite clay minerals and iron oxides minerals in the studied reservoir sand beds contribute towards decrease of the reservoir porosity at the studied well. On the other hand, Partial dissolution of feldspars and mica during the digenesis produce a fair to good reservoir at some depths of X well.
