reservoir characterization of pliocene sand using
Post on 25-Nov-2021
5 Views
Preview:
TRANSCRIPT
Ain Shams University
Faculty of Science
Geophysics Department
Reservoir characterization of Pliocene
sand using quantitative seismic techniques
and well logs at west offshore Nile Delta,
Egypt
A thesis submitted for the degree of Master of Science as a
partial fulfillment for the requirements of Master degree of
Science in Applied Geophysics. By
Esraa Mahmoud Azmy Abdel Hamid B.Sc. in Geology and Geophysics
Faculty of Science – Ain Shams University, 2011
To Geophysics
Department Faculty of
Science
Ain Shams University
Supervised by
Prof. Dr. Said Abdel- Maaboud Aly. Head of Geophysics Department. Faculty of
Science – Ain Shams University
Dr. Azza Mahmoud Abd El-Latif El-Rawy Lecturer of Geophysics
Mr. Maged Mohamed Fahim. Senior Geophysicist- bp Egypt.
Geophysics department – Faculty of Science – Ain Shams University
Cairo – 2015
Note
The present thesis is submitted to faculty of Science, Ain Shams University in partial
fulfillment for the requirements of the Master degree of Science in Geophysics.
Beside the research work materialized in this thesis, the candidate has attended ten post-
graduate courses for one year in the following topics:
1. Geophysical field measurements
2. Numerical analysis and computer programming
3. Elastic wave theory
4. Seismic data acquisition
5. Seismic data processing
6. Seismic data interpretation 7. Seismology
8. Engineering seismology
9. Deep seismic sounding
10. Structure of the earth
She successfully passed the final examinations in these courses.
In fulfillment of the language requirement of the degree, she also passed the final
examination of a course in the English language.
Prof. D. Salah Eldin Abdel Wahab
Mohamed Mousa Head of Geophysics Department
I
Acknowledgments
After thanks to Allah, I would like to thank my direct supervisor
Prof. Dr. Said Abdel- Maaboud Aly, professor of Geophysics, Faculty of
Science, Ain Shams University, for his guidance and his effort
I deeply thank Dr. Azza Mahmoud Abd El-Latif El-Rawy,
Lecturer of Geophysics, Faculty of Science, Ain Shams University, for
sharing with the idea of this study, her effort and leading comments in this
work and reviewing the write up.
Also I deeply thank Mr. Maged Mohamed Fahim, Senior
Geophysist, BP Egypt, for his effort, and his experience and insightful
comments greatly improved the quality of my work.
I would like also to thank BP-Egypt for providing the data and I
deeply thank everyone that helped me to finish my work.
Finally I dedicated this work to my family and I actually thank them
for their patience, support and encouragement.
II
Abstract
Nile Delta is a complex and difficult province for hydrocarbon
exploration, the Pliocene channel prospect is located in the North Alexandria
Block B concession and is a complex, elongated, highly sinuous, deeply
incised, mature Pliocene turbidite channel system that extends 15 Km across
the West Nile Delta. The study area is affected by three main fault trends and
the main sand reservoir is Kafr Elsheik Formation.
3D traditional seismic interpretation was done for identification of the
channel top and base and studying the lateral distribution of the channel. The
Pliocene channel prospect is a complex, elongated, highly sinuous, deeply
incised that extends from NW to SE and it is split into three segments by
NE-SW and E-W faults.
Then, the channel was evaluated by studying the channel
petrophysical parameters to get the net to gross value (NTG) of the reservoir
and getting the value of the GIIP and recoverable resources of the interested
reservoir. X1 Well consists of three pay zones from four sand packages
while X2 Well that consists of one sand package. The GIIP value equal
2.1462*1010 (SCF), and the Recoverable Resources
equal 15.0234*109(SCF). Channel modeling was done to identify the channel and its internal
geometry by using different techniques of attributes such as amplitude
extraction, coherence, spectral decomposition technique and Direct
Hydrocarbon Indicators such as bright, dim and flat spot are clarified within
the channel by the analysis where the north well is brighter than the south
well and the two wells have gas water contact (flat spot) and the dimming
problem within the channel is solved by the modeling.
Amplitude versus offset technique was used to evaluate the Pliocene
channel to get the class type using Rutherford and Wiliam‘s classification
that is class 3 increasing of the amplitude with the offset in the negative
direction and by using EEI technique that discriminate between the lithology
and the fluid where the fluid angle equal 45° and the lithology is
90°. The results of using Extended Elastic Impendence (EEI) technique
showed that EEI is worthy effort to highlight the difference between reservoir
and non-reservoir to identify hydrocarbon area.
List of Contents
Acknowledgments ……………………………………………....I
Abstract……………………………………………………........II
List of Contents………………………………………………..III
List of Tables……………………………………………..…...VII
List of Figures………………………….................................VIII
Chapter one: Introduction……………………….………..…....1 1.1 Location of the Study Area……………………………………………....1 1.2 Aim of Study………………………………………………............……..2
1.3 Available Data…………………………………………………………...3
1.4 Methodology and Techniques ………………………………………..…4
Chapter Two: Regional Geologic Setting…………..………….6 2.1 Introduction………………………………………………………………6 2.2 Regional Stratigraphy………………………………………….………...8
2.2.1 Pre-Miocene Stratigraphy………………………………….….……10
2.2.2 Miocene Stratigraphy…………………………………….…………12 2.2.2.1 Qantara Formation-Early Miocene (Aquitania-Burdigalian)…...12
2.2.2.2 Sidi-Salem Formation (Serravallian-Tortonian)……………..…13
2.2.2.3 Qawasim Formation (Lower Messinian)……………………….13
2.2.2.4 Abu Madi Formation (Upper Messinian)…………………...…..14
2.2.2.5 Rosetta Formation (Messinian)……………………………..….14
2.2.3 Pliocene-Pleistocene Stratigraphy……………………….…...……..15
2.2.3.1 Kafr El Sheikh Formation (Pliocene)……………………….….16
2.2.3.2 El Wastani Formation (Upper Pliocene)………………………..17
2.2.3.3 Mit Ghamr Formation (Pleistocene)…………………………….18
2.2.3.4 Bilqas Formation (Holocene)……………………………..…….18
2.3 Structural Framework of the Nile Delta………………………………...18
2.3.1 NW-SE Temsah Fault Trend…………………………...…….……..21
2.3.2 NE-SW Rosetta Fault Trend………………………………………..22
2.3.3 East-West Coastal Faults…………………………………..……….23
2.3.4 Minor Faul Trends…………………………….……………………23
2.4 Structural Evolution of the study Area……………………………..…..24
2.5 Tectonic History of Offshore Nile Delta……………………………….26
2.5.1 Cratonic sag stage…………………………………………………..28
2.5.2 Rift stage…………………………………………………………....28
2.5.3 Passive margin stage………………………………………………..29
2.5.4 Syrian Arc stage………………………………………………...…..30
2.5.5 Gulf of Suez Rifting and Red Sea Opening Stage………….…..…..32
2.5.6 Tertiary deltaic sedimentation……………………………………...32
2.5.7 Messinian Crisis…………………………………………………….34
2.5.8 Pliocene-Pleistocene Delta Progradation.…………………………..35
2.6 Submarine Fans/Turbidite Systems…………………………………….35
2.6.1 Defining Some Terminology…………………………….…………37
2.6.2 Fine-Grained Turbidite System…………………………………….41
2.6.2.1 Sheet sandstones ……………………………………………….43
2.6.2.2 Canyon and channel-fill sandstones…………………….………44
2.6.2.3 Levee deposits ……………………………………………...…..49
2.6.3 Architectural Hierarchy and Anatomy of Submarine Slope Channel
Complex…………………………………………………………..51
Chapter Three: 3D Seismic Interpretation for Delineation the Pliocene Channel Complex………....55 3.1 Introduction……………………………………………………………..55 3.2 Available Data………………………………………………...………..56
3.2.1 Seismic Data…………………………………………...……….…..56
3.2.1.1 Acquisition Parameters for MAZ Seismic Surveys…………....58
3.2.1.2 Processing Parameters for MAZ Seismic Survey…………..….59
3.3 Data Quality Control (Data Conditioning)……………………………..60 3.3.1 Phase and Polarity of Seismic Data…………………………..……60
3.3.2 Seismic Resolution (Wedge Model)…… …………...…………….63
3.4 Seismic to Well Ties……………………………………………………67
3.4.1 Conditioning, Editing and Analysis of Well logs……………….…68
3.4.2 Data Assessment and Datum Determination………………………68
3.4.3 Wavelet Extraction ………………………………………………68
3.4.4 Synthetic Generation ……………………………………………..69
3.5 Seismic Interpretation……………………………………………..……74
3.5.1 Interpretation of the Pliocene Channel…………………….………75
3.5.1.1 Interpretation of the Top Pliocene Channel…………………....75
3.5.1.2 Interpretation of the Base Pliocene Channel…………………..79
3.5.1.3 Faults Interpretation affecting the Pliocene Channel………..…83
3.5.2 Pliocene Channel Complex Display and Description……………...85
Chapter Four: Petrophysics Analysis………………..……….90 4.1 Introduction…………………………………………………………..….90 4.2 Available Data…………………………………………………………..91
4.3 Evaluation of Petrophysical Properties of the Studied Wells………….95 4.3.1 Determination of Shale Volume …………………………………..96
4.3.2 Determination of Formation Porosity……………………………...97
4.3.2.1 Sonic Porosity …………………………………………………97
4.3.2.2 Density Porosity ……………………………………………….98
4.3.2.3 Neutron Porosity ………………………...…………………….99
4.3.2.4 Combination Neutron-Density logs……………………....….100
4.3.2.4.1 Total Porosity …………………………………….………100
4.3.2.4.2 Effective Porosity ………………………………………..100
4.3.3 Determination of Fluid Saturations ………………………..……100
4.3.3.1 Water Saturations Determination …………………………….101
4.3.3.2 Hydrocarbon Saturations Determination …………………….102
4.4 Determination of Net Pay and Net Reservoir Thicknesses…...……….103
4.5 Lithologic Identification…………………………………………..…...109
4.5.1 Neutron- Density Crossplot……………………………...……….109
4.6 Depositional Model of the Pliocene Channel…………………………114
4.7 Gas In Place and Recoverable Volumes………………………………115
Chapter Five: Seismic Attributes Characterization for
Pliocene Channel …………………………………………….118 5.1 Introduction…………………………………………………………. 118 5.2 Seismic Attributes Classifications………………………………...…..120
5.3 Amplitude Attributes Extraction…………………………………..….121
5.3.1 RMS Amplitude Attribute…………………………………….….122
5.3.2 Maximum Negative Amplitude Attribute…………………..….....122
5.3.3 Channel Internal Geometry Based on Amplitude Variations ……125
5.4 Coherence Attributes Estimation …………………………………..…129
5.4.1 Coherence Algorithms…………………………………………....130
5.5 Spectral Decomposition Attributes Estimation…………….……….....136
5.5.1 Physical Concept of Spectral Decomposition…………………….137
5.5.2 Technical Description and Workflow of Spectral Decomposition.140
5.5.3 Imaging Pliocene Channel Complex by Spectral Decomposition
Attribute Maps..............................................................................145
5.6 Direct Hydrocarbon Indicators (DHI)……………………………..….152
5.6.1 Physical Concept of Direct Hydrocarbon Indicators……….……..154
5.6.2 Direct Hydrocarbon Indicators for Pliocene Channel Complex…..158
5.6.2.1 Bright and Dim Spots Attributes……………………………..159
5.6.2.2 Flat Spot Attribute……………………………………………160
5.6.2.3 Dimming Problem in the Southern Part of the Pliocene Channel
Complex…………………………………………………………164
Chapter Six: Lithology-Fluid Separation Based on AVO and
EEI Modeling………………………………..……………..…169 6.1 Introduction…………………………………………………….….…..169 6.2 Historical and Physical Background of AVO………………………....171
6.2.1 Physical Principles of AVO……………………………………….172
6.2.2 Classification of AVO……………………………………………..176
6.3 Available Data……………………………………………………..….181
6.4 AVO Analysis Workflow……………………………………………..181
6.4.1 Seismic Angle Stacks Conditioning (QC)…………………….…..184
6.4.1.1 Frequency Filtering………………………..………………….184
6.4.1.2 Events Alignment (Trim Statics) ……………………….........185
6.4.1.3 Amplitude Balancing/Scaling………………………………...186
6.4.2 AVO-Response of Gas Sand …………………………………...…187
6.5 Lithology-Fluid Discrimination……………….…………………..…..191
6.5.1 Theoretical Background……………………………………….…..191
6.5.1.1 Elastic Impedance (EI)………………………………..………191
6.5.1.2 Extended Elastic Impedance………………………...………..193
6.5.2 EEI Method for Discriminating between Lithology and Fluids
Anomaly…………………………………………………………………..197
Chapter Seven: Summary and Conclusion…………….…...207
Appendix A …………………………………………………..212
References…………………………………………………….216
Arabic Summary
VII
List of Tables
Table (4.1): The used parameters in calculating shale volume……………..96
Table (4.2): The used parameters in calculating net pay and net reservoir
thicknesses………………………………………………………………...103
Table (4.3): Calculation of average Vsh, Porosity, water saturation and
N/G for X1 well…………………………………………………………....108
Table (4.4): Calculation of average Vsh, Porosity, water saturation and
N/G for X2 well…………………………………………………………….108
Table ( 5.1): Pertrophysical parameters for X1 and X2 wells…………….165
top related