Identify re-development concepts to enhance Abu Roash “C” oil reservoir productivity Sitra Area, Abu Gharadig Basin, Western Desert, Egypt

• Main Authors: H. Salama, M. Darwish, M. Wahdan, A. El-Batal
• Format: Article
• Language: English
• Published: Elsevier 2017-06-01
• Series: Egyptian Journal of Petroleum
• Subjects: Facies modeling; Depositional model; Reservoir characterization; Redevelopment concepts; Enhance oil productivity
• Online Access: http://www.sciencedirect.com/science/article/pii/S1110062116300125

This study includes a new understanding of the depositional model of Abu Roash “C” Member deposited in Sitra Field in Abu Gharadig Basin during Turonian time, and illustrates the major affecting factors that control the behavior of this reservoir and consequently offer a great opportunity for Sitra field’s future development activities through a new methodology to maximize the field’s ultimate recovery. The Sitra development lease is located in north Western Desert and occupies the central western part of Abu Gharadig Basin and covers the southern extension of Badr El-din Petroleum Company (BAPETCO) leases with an area of 322.4 km2. Sitra Area is divided into several structural closures; the main producing one is the Sitra 8 block in which 39 wells were drilled since 1993. Various data from these wells were evaluated to construct the depositional facies models for the Abu Roash “C” reservoir. The log analyses have been integrated with the core descriptions, and ditch cutting data to interpret the depositional facies model that controlled the reservoir characteristics. In Sitra Area the Abu Roash “C” Member exhibits all of the characteristics of the Shallow Marine-Tidal dominated estuaries which are linked to the south with a fluvio-marine environment, the tide-dominated estuaries are represented in tidal channels and tidal flat facies, march deposits, and distributary mouth bars. The best reservoir rock in the Abu Roash “C” Member was deposited as distributary channel fill/Mouth bars that cut through the underlying strata. Two major parasequences were identified, the first lower one was developed during a shallowing upward sequence represented by shale/sand intercalations into which the main Abu Roash “C” reservoir sand bodies are included, and reached its end by the appearance of a laterally extended coal marker nearly one meter thick. This parasequence was deposited subsequently to a falling sea level phase which occurred after the deposition of Abu Roash “D” limestone. The succeeding parasequence (deepening upward) reached its maximum flooding surface (MFS) by the deposition of the widely extensive shale marker being rich in pelagic Pelecypod shells. The resultant stratigraphic units consist of: genetically related depositional cycles (3 cycles) and their components of facies sequences (5 facies types), each cycle has its own distribution, facies classification and reservoir characteristics.