الفهرس 
CHAPTER I INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 138 |  |  |
| | | from | 138 | | |
Abstract
The discovery of the Al Baraka oil field in Komombo basin, Upper Egypt in 2007 represents a huge leap in oil exploration in Egypt because it is considered the first oil field discovered in the far most south of the Western Desert, where all oil discoveries were made in the northern part of the Western Desert due to the presence of large sedimentary basins. The South Valley Egyptian Petroleum Holding Company (GANOPE) is the company that undertook all exploration studies as well as managing this oil field discovered in the Al-Baraka area. The company actively participates in oil and gas discoveries and production activities in Upper Egypt by maintaining the competitive advantage to attract direct investments within the framework of various franchise agreements.
Al Baraka basin is located within the El-Gallaba plain in the Komombo basin. It is bounded from the west by a calcareous plateau and from the east by the Nile valley. The studied area (430.16km2) including the Al Baraka basin and the surrounding parts is characterized by arid climatic conditions. The area is covered with different sediments (fluvial and aeolian) which mainly consist of sand, a mix of gravel/sand, and gravel.
The stratigraphic section of the Komombo basin is represented by non-marine and shallow marine sequences deposited during the Cretaceous. This section is dominated by clastic sediments (sandstone, siltstone, claystone, and shale). The Cretaceous succession in the Komombo basin concession generally consists of six formations from the top to the base; Dakhla, Quseir, Taref, Maghrabi, Sabaya, Abu Ballas, and Six Hills Fms. Six-Hills Fm. is subdivided into seven members from base to top (A, B, C, D, E, F, and G). These members are the main source rock especially B member which is made up of dark shale rich in organic matter. This sequence can be described in terms of Late Jurassic, Cretaceous, and Paleocene succession.
Komombo basin is located within an old flat plain of the Nile Valley. The exposures near the Nile are shown by a NW-fault ridge of Upper Cretaceous rocks and are tightly correlated to the exposures in the eastern bank of the Nile. This basin is considered an extensional rift basin, which appears to be a half-graben. Probably, this basin was developed from an extensional stress regime that originated in Central and North Africa with the opening of the South Atlantic. This process started from the Late Jurassic–Early Cretaceous age and terminated in the Late Cretaceous by the Syrian Arc inversion in southern Egypt.
The most significant sandstone reservoir rocks are found in the strata of the Lower Cretaceous age, especially the Neocomian to Aptian (Abu Ballas and SixHills formations), in which the major discoveries have existed. There are many structure traps resulted from the effect of faulting which is considered the good potential for oil.
Generally, the key elements of petroleum systems are the source rocks, reservoir rocks, traps, and seals. These elements in the Al Baraka basin were detected and determined from the interpretation of petrophysical and seismic reflection data. Each of these elements was evaluated in a particular way to determine the potential of the system in Al Baraka.
The major objectives of this study are to integrate geological and geophysical data to build a detailed reservoir characterization model including a 3D reservoir property model. This building model is aimed to improve reservoir management, reserve estimation, understand the structure features, and improve production.
The well logging data was taken from four drilled wells: Al Baraka-2, Al Baraka-14 (Cg 78-14), Al Baraka-4 (Cg 78-4), and West Al Baraka-2 (Cf 78-3). These data were used to determined petrophysical parameters and find hydrocarbon zones in the area. The seismic data included 10 inlines (dip lines) running NW and NNW directions, and 5 crosslines (strike lines) oriented in the NE direction. These data were used to understand the geological settings of the field, define large-scale geological structures, and define cap rock, seal rock, and source rock with the structural model. 3D property models were constructed to determine; facies, porosity, permeability, water saturation, and net–to–gross ratio.
Based on the correlation and integration of both well logging and seismic data the following conclusions can be reached:
1. Petrophysical analysis of well-logging data reveals that Al Baraka wells consist of three types of lithology: sand, shale, and siltstone in the form of sand shale interbedding.
2. Two hydrocarbon-bearing reservoirs were detected in the Lower Cretaceous SixHills Fm; 1) S-E zone in the AB-4 well, and 2) S-D zone in the AB-14well. While seven hydrocarbon-bearing zones (R1, R2, R3, R4, R5, R6, and R7) were detected in West AB-2 well. These zones are made up of sand and their depths range from 1965ft to 3852ft in Abu Ballas and SixHills formations. They have moderate to good porosity (14.2% to 23.5%), the low effect of shale distribution (20% to 8.5%), and average hydrocarbon saturation (29% to 70%) with high movability. Also, there is a reservoir (S-F) zone in AB-2 well that is not potential for hydrocarbon due to the high amount of water saturation present. The zones R2, R4, and R5 in West AB-2 well comparatively having a high thickness, porosity, and hydrocarbon saturation than others (AB-4 and AB-14well). These detected zones are potential for oil production than others.
3. The constructed cross-plots reflect that the main lithologic type of the delineated reservoirs is shaly sandstone to sandstone. The dimensions of shaly sediments decrease gradually and are partly dispersed. The identified reservoirs are characterized with moderate to good porosity, low values of water saturation indicating a high proportion of hydrocarbon, and having a high movability index. So, these reservoirs are considered the potential for accumulation of commercial oil.
4. The careful inspection of the 3D structural model and cross-sections indicate the presence of two normal faults NNW-SSE to NW and NE to ENE directions. The NW-SE trend is the dominant one, creating a major half-graben system with NE dip direction.
5. The 3D static model for the studied area is characterized by six main segments bounded by major faults and five-zone with layers. where the northeastern part of the area is considered as the depocenter area.
6. The 3D facies models reveal the presence of three types of facies; sandstones, shale, and siltstones distributed within the area. SixHills (D), and (C) have high lateral and vertical distributions of sand bodies in the northeastern and the central parts of the area. Also, the property models show that SixHills (D) and (C) are characterized by low shale volume, high effective porosity, high permeability, and low water saturation at the northeastern and central parts of the study area.
7. The new potential area (promising) is located in the northeastern and central parts of the studied area, especially in SixHills (D) and (C) formations. This is related to the high accumulation of sediments characterized by sand bodies, low shale, high porosity, high permeability, and low water saturation values.