Abstract Abu-Shaybah Formation is located on the coastal of the Meditrranean sea South of Ghanimah North West of Libya, between Tripoli and Al Khumes, about 100 km East of Tripoli. It lies on the eastern end of Jabel Nafusa flank. Abu Shaybah Formation Ghanimah area of Late Triasic age, consists of sandstone. The sedimentary structure in the lower most part from studied outcrops reflect NW paleocurrent direction indicating that Jabel Nafusa uplift poorly effect the study area. The upper part of studied succession changing in pallaeocurrent dirction to NE due to Jabel Nafusa uplifting. The extreme changing of paleocurrent direction and paleoslope direction to East due to continuous increase in Jabel Nafusa uplift, direction of vertical joints in Wadi Qirrim presented from NW to SE dirction. The rocks of Abu Shaybah Formation analyzed using differnt kinds of technique, Polrized Microscpe, XRF, SEM techniques. The study of sedimentary texture (grain size, roundness, sorting, and sphiricity) and sedimentary structures showed that Abu Shaybah Formation outcrops deposited in response to two fining upword cycles, formed mainly in Braided Stream Rivers with some effects of meandering. The sequences of Abu Shaybah Formation outcrops that exposed in Wadi Qirrim have been identified on many types of sedimentary facies associated with given sedimentary stucture as, Planar cross bedding, Convolute bedding, Trouph cross bedding, Ripple bedding, Shrinkage cracks, Plant rootlets, Concretions, Unconformity, Channels, Massive bedding, Laminated bedding, and the results which located on the grain size of quartz also loacted on the grain size of heavy minerals like tormaline, zircon and reutile.
سليم معمر قجوم (2009)

Abstract This study covers the Fields producting from the Gialo Formation a reservoir which is composed of Limestone and Dolomitic-Limestone and consists mainly of highly altered Nummulitic Packstone. This study was achieved through three parts of study including a petrographic study, petrophysical study of reservoir properties from core analysis and borehole logs. The general geological framework was obtained from petrographical study of thirty six thin sections, 129 representative core plug data and logs from 5 different wells are utilized to better understanding the petrophysical framework of the formation. The plots correlating petrophsical parameters and the frequency histograms suggested the presence of distinctive reservoir trends. These discriminations were also represented in Winland porosity- permeability cross plots resulted in clusters for different port-size that are responsible for different flow characteristics. Linear and multiple regression were used for the study of each unit. The permeability models were constructed and their reliabilies were compared by the regression coefficients for predictions in un-cored well. The combination of all data revealed the worst ranked reservoir quality corresponded to moldic and intergranular pore types, which occurred mainly in the Bioclastic Wackstone facies. The highest ranked reservoir quality corresponded to intragranular and intergranular which occurred mainly in the Nummulitic Packstone Facies.
وردة الشوشان (2010)

Abstract The sandstone of Upper Ordovician Mamuminyat Formation represents part of stratigraphic column in Murzuq Basin, south west Libya. It is the primary reservoir target in the basin, soursed and caped by Lower Silurian Tanezzuft Shale (Sola, 2000). The Mammuniyat reservoir in Murzuq Basin is characterized by lateral and vertical variation of petrophysical properties duo to lateral change of depositional environment and the digenetic effect on the formation load various facies deposition quality. The Concession NC174 is discovered in 1997 by Lasmo Grand Maghreb Limited then On the 26th October 2003 the development drilling campaign started by MOG till thepresent time. The El feel field is the major discovery in NC174. Porosity range is 16-18% and permeability some hundreds millidarcys. The Net thickness/Gross thickness ratio varies from 20% to 95% with an average value of 70%. The sedimentary fill in the Murzuq basin is mainly Paleozoic to Mesozoic in age and reaches a thickness of about 4000 meters in the depocenter. The sedimentary sequence is punctuated by several regional unconformities corresponding to successive tectonic activity phases. In the area of NC174, the tectonic phases developed anticlines and fault bounded anticlines generally super-imposed and re-actived through time. The resulting structural style is characterized mainly by poli-history sub-vertical reverse faults with different directions (N-S, NNW-SSE and NNE-SSW), these faults bound most of the prospects apparently superimposed on subtle anticlines oriented SSWNNE along which the culminations are aligne.
خالد مسعود الزوام (2014)