الفهرس 
CHAPTER 1 INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
offshore.
The Latitude and Longitude of Nile Delta is 30º54’N and 31º7’E respectively.
The Nile Delta is locate sedimentary build up began in the Miocene time with a very thick section of Late Tertiary – Quaternary sediments indicating a rapid and continuous deposition in a gradually subsiding basin. This section consists mainly of shale with sandstone intercalations.
Sapphire Field (study area) lies within the West Delta Deep Marine (WDDM) Concession on the north-western margin of the Nile Delta cone The bathymetry of the area, indicates that, the water depth at Sapphire study area ranges from 500-1200m represented by shelf slope to deep marine and then to an ultra-deep marine on the extreme north of the study area
The Lower Pliocene Sapphire reservoirs were deposited during the Early Pliocene age within the basal part of Kafr El Sheikh Formation and comprise gas/condensates .
The first drilled well in Sapphire field area was Esso- NDOA-1 exploration well in year 1975 to test the Pliocene/ Miocene sections in the NDOA faulted anticline . The well penetrated Sapphire sand units that were water-bearing as it was penetrated in a down dip position of the NDOA structure and below the regional hydrocarbon water contact.
Sapphire Field includes all areas that lie to the north of the main NDOA fault. Recent well also proved the continuity of some sapphire reservoir units to the south of the main NDOA fault.
The materials used in this study include collection and description of the complete log sets from ten wells in the study area, including the composite, Gamma Ray (GR), Self Potential (SP), Caliper, Deep and Shallow Laterolog resistivities (LLD, LLS), Micro-Spherically Focused log (MSFL), Photoelectric factor (PEF), and porosity tools (Density, Neutron, and Sonic), In the form of (LAS Format).
A review of the available previous geological and geophysical studies as well as internal reports of oil companies is helpful to study the general.
TechLog computer programs for the quantitative estimations of the subsurface sequence have been used; Also Petrel Software has been used for mapping purpose.
Reviews of the available previous geological and geophysical studies as well as internal reports of oil companies are helpful to study the general stratigraphic column of the Nile Delta with special emphasis on the study field.
The Sapphire field was discovered by the Sapphire-1 Exploration well in 2000. The field is locating at the eastern portion of the West Delta Deep Marine concession (west to Scarab-Saffron, Serpent and Simian discoveries).
Stratigraphic column of the Nile Delta is ranging in age from Mesozoic to recent, Is represented by the Tineh Formation of Late Oligocene/Early Miocene, which consists of very thick series of marine to fluvio-marine shale and sandstone interbeds, The Qantara Formation has been dated as Early Miocene, It is equivalent to the Moghra Formation in the Western Desert. The formation is delineated overlying the Tineh/Dabaa formations (Late Oligocene) and underlying the Sidi Salim Formation.
The Qantara Formation is made up of calcareous shale with sandstone and limestone streaks that deposited in a variety of coastal littoral to inner sub-littoral environment and it may rank to a coastal lagoon one,
The Qawasim Formation Tortonian – Messinian in age forms an angular unconformity over the Sidi Salim Formation. Early Miocene represented by the Abu Madi Formation, Early to Late Pliocene is represented by the Kafr El Sheikh Formation that started with the deposition of the Early Pliocene sediments during marine flooding, The Late Pliocene to Early Pleistocene is represented by El Wastani Formation that was deposited as a regressive sequence after a starvation event of the Kafr El Sheikh Formation, The Late Pliocene to Early Pleistocene is represented by El Wastani Formation that was deposited as a regressive sequence after a starvation event of the Kafr El Sheikh Formation and Pleistocene – Holocene Age is represented by; the Mit Ghamr and Bilqas formations.
Sapphire channel lies at the base of the El Wastani Formation at a similar level to the many slope channels laying in the same play in the offshore Nile Delta area, Sapphire is a combination stratigraphic/structural feature with dip-closure along the northern and southern margins and stratigraphic closure (channel margin pinch-out) along the whole length of the reservoir. El Wastani Formation claystones form the seal to the Sapphire field. The Sapphire field comprises a number of deep marine channels constrained within a SW/NE trending Rosetta fault and the ENE-WSW trending NDOA anticline.
Sapphire Field includes all areas that lie to the north of the main NDOA fault (Fig.4). Recent well also proved the continuity of some sapphire reservoir units to the south of the main NDOA fault.
The Nile delta subdivided into two subprovinces by a faulted hinge line oriented WNW to ESE located at Kafr El Sheikh Latitude city. This hinge line is known as the faulted flexure that is separates the south delta province from the north delta plain basin, Tthis hinge is the most significant structural feature of the Nile Delta region and is known as the faulted flexure. It separates the Southern ridge from the Northern Delta basin. The different structural trends are East- Northeast of Late Cretaceous to Eocene age and those Syrian arc folds
The Nile cone is a recent phenomenon when compared with other major deltas; The Nile Delta can be subdivided into the following structural sedimentary provinces (A) The South Delta province, a continuation of Western Desert stratigraphic sequences and structure, The North Delta basin, The Nile cone and The Levant platform.
Well logging: Explain how the program (TeckLog) worked, explain available data for this study, explain equation that are generally used to measure properties petro physical and explain equation that we used in the current study. Was the work of some examples of some wells in the study area, such as raw data and corrected, the methods used to calculate the volume of the shale and the methods used to calculate the
porosity, as well as to determine the water saturation and hydrocarbon saturation and explain method in which calculating the volume of the shale.
Reservoir Evaluation: A comprehensive formation evaluation was carried out for the Late Pliocene Sapphire Channel, section encountered in the ten selected wells in the study area. Reservoir evaluation, that represents the main task in the present work, is conducted to evaluate the petro physical parameters needed for formation evaluation. It includes, the determination of the volume of shale, porosities (total, secondary and effective), lithological composition (shale and sand) and fluid saturation (water and, oil, gas,) for the studied members using the TechLog for the quantitative estimations of the subsurface sequence. The output results are presented, zone-wise, in two vertical cross plots, of the same depth scale, for each well.
The first cross plot illustrates the corrected log data and the second one is a litho-saturation cross plot. Determine the contact between gas zone and water zone (GWC) can be easily recognized from the relation between the neutron, density and the response of resistivity logs in each well. Moreover, a number of Neutron-Density cross plots, Neutron-Sonic cross plots, and M-N cross plots relationships have been constructed to help identification type of the lithology, the value of the porosity and in addition to the gas and clay effect, Results of well log analysis were used in the evaluation of hydrocarbon potential in the study area.
from log analysis and interpretation Sapphire Channel can be divided into two main unit, a thick unit of sandstone ranges between (78m to 115m thickness) and a small unit in the base of the channel (10m to 25m thickness) mainly silty and shaly staff, the sand stone unit in varying in thickness relative to the core of the channel hence the wells in close to core of the channel has more sandstone thickness than the wells far from the channel core.
The petro physical parameters computation and results of the reservoir rocks are represented by a number of isoperimetric maps, which include: volume of shale, total porosity, effective porosity, water saturation, hydrocarbon saturation, reservoir and net pay thicknesses. These maps had been interpreted as a follows:
a) The volume of shale ranging in values from minimum value of (10.6 %) in Sapphire De well to maximum value of (38.3 %) in Sapphire Dd well. Generally the shale content distribution decreases in the core of the channel and increase toward the levee of the channel.
b) The total porosities analyses Shows variation in porosity values from minimum value (25 %) at Sapphire 2 well to maximum value (30 %) at Sapphire De well, shows an increase in the total porosity from levee of the channel to the core of the channel along the axis of the channel. While the highest valve of total porosity is concentrated among the axis of the channel. While the effective Porosity Distribution Map of the Sapphire channel shows minimum value of (10.6 %) in Sapphire Db well and maximum value of (18.3 %) in Sapphire Da well, generally the effective porosity is increasing from edge of the channel toward core of the channel along the channel axis of the channel
c) The water saturations show minimum value of (38.2 %) in Sapphire 3 well to maximum value of (64.3 %) in Sapphire Dc well. Generally the water saturation distribution increases from core of the channel toward the edge of the channel along the channel core. While the hydrocarbon saturation shows traditionally a reverse pattern to that of the water saturation. It varies between 36 % and 62%.
The Hydrocarbon Potentialities of the study area can be discussed by integrating the lithological, petro physical, fluid Parameters and hydrocarbon generation factors affecting on the investigated area which are achieved from the comprehensive analyses processes. Consequently, maps are constructed for the studied channel. These maps are based on pay zone thickness, hydrocarbon saturation, some reservoir petro physical parameters such as effective porosity and volume of shale. These maps are helpful for the future developing of the study area and a guide for the future appraisal and Development plan.
The Hydrocarbon Potential map of the Sapphire channel reveals that the core of the channel is the optimize sites for development and production from the channel where the levee part of the channel is promising sites for future development where it has high potential for gas bearing in the thin bedding part which is thick and wide and has good hydrocarbon saturation and good porosity specially the gas has high mobility which gives good opportunity for recovery. CHAPTER 5 SUMMARY AND CONCLUSION
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Recommendations
- In this kind of reservoir which is characterized by high present of shale in all intervals including a thick sand intervals also has not compacted and soft sediments SP, and Sonic log is not recommended in formation evaluation hence no clear deflection between sand and shale so need to focus more in the other tool in evaluation.
- In sand shale reservoir the volume of the shale is important factor and has direct impact on the formation evaluation so new logging technology like Magnetic Resonance help to determine the shale content and amount of irreducible water as well.
- More attention should be given to thin bed analysis, in sand shale reservoir is much important and adds more reserve so should take in consideration by applying the newly developed technology.
-Recommend strongly open hole production to recover the gas bearing thin bedded in the levee part.
-Drilling more wells to in the channel where it still has a good gas potentiality to be recovered.