Scholars' Mine Doctoral Dissertations Student Theses and Dissertations Fall 2017 Geophysical interpretation and static reservoir modeling of structurally complex reservoir, RG oil field area, Sirte Basin, Libya Abdalla A. Abdelnabi Follow this and additional works at: https://scholarsmine.mst.edu/doctoral_dissertations Part of the Geology Commons, and the Geophysics and Seismology Commons Department: Geosciences and Geological and Petroleum Engineering Recommended Citation Abdelnabi, Abdalla A., "Geophysical interpretation and static reservoir modeling of structurally complex reservoir, RG oil field area, Sirte Basin, Libya" (2017). Doctoral Dissertations. 2753. https://scholarsmine.mst.edu/doctoral_dissertations/2753 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. GEOPHYSICAL INTERPRETATION AND STATIC RESERVOIR MODELING OF STRUCTURALLY COMPLEX RESERVOIR, RG OIL FIELD AREA, SIRTE BASIN, LIBYA by ABDALLA ALI ABDELNABI A DISSERTATION Presented to the Faculty of the Graduate School of the MISSOURI UNIVERSITY OF SCIENCE AND TECHNOLOGY In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY in GEOLOGY AND GEOPHYSICS 2017 Approved by: Kelly Liu, Advisor Stephen Gao Mingzhen Wei Ralph E. Flori Jawad Rustum 2017 Abdalla Ali Abdelnabi All Rights Reserved iii PUBLICATION DISSERTATION OPTION This dissertation has been prepared in the form of four papers for publication as follows: Pages 3-46 have been published at Society of Exploration Geophysics (SEG, 2016) and being finalized for submission to interpretation Journal- Society of Exploration Geophysics (SEG). Pages 47-65 have been published at Society of Exploration Geophysics (SEG, 2017) and be finalized for submission to interpretation Journal- Society of Exploration Geophysics (SEG). iv ABSTRACT Cambrian-Ordovician and Upper Cretaceous reservoir formations are found in the central western Sirte Basin, the main oil producing region in the Sirte Basin, Libya. As a result of changes in sedimentary environments and structural activities, a number of irregularities in reservoir continuity have developed, which negatively affected the overall performance of the reservoir. Effective simulation of such complex reservoirs can be achieved by integrating geophysical, geological, and petrophysical data to construct a reliable full-field static model, which has the potential to simulate the vertical and lateral variations in the reservoir formations. In this study, 2D and 3D seismic data acquired in the central western Sirte Basin are used to construct a fault and structural model which is an important component of the static model. The median filter and spectral whitening are applied to enhance the data quality and remove noise resulted from acquisition and processing effects. Spectel whitening is used to enhance the resolution of the data while mediam filter is used as noise filter. Coherence and curvature attributes are used to delineate faults and fracture zones. Coherence adequately detect major faults and minor faults. Most positive and most negative curvatures are used to define upthow and downthrow faults blocks. Curvatures attributes are also used to define fracture zones in reservoir formations. The most common fracture zone are identified in the northwest and southeast in the Cambrian-Ordovician reservoir formation in the study area.Well data are incorporated with core data to construct a property model that integrates a range of reservoir properties including facies, porosity, permeability, and net-to-gross ratio. A fine- scale geo-cellular model is created by integrating the fault, structural, and property models for the entire field. v ACKNOWLEDGMENTS First, I must express my special sincere gratitude to my advisors, Dr. Kelly Liu and Dr. Stephen Gao, for guiding and teaching me over the past four years. They provided me with an excellent learning environment and it has been a great pleasure to work with them. I want to extend my appreciation to my advisory committee members, Dr. Jawad Rustum, Dr. Mingzhen Wei and Dr. Ralph E. Flori for the time and advice they provided when reviewing my dissertation. I would like to express my gratitude to the staff of Geosciences and Geological and Petroleum Engineering Department for all the assistance over the past several years. I want to thank my colleagues of the geophysics group for their help. I am grateful for my parent, my brothers, and my sisters. They offered continuous support and encouragement. Last but not least, I would like to thank my wife. She always believed in me and helped me during my study. I cannot accomplish my doctoral dissertation without her understanding, support, encouragement, and constant love. vi TABLE OF CONTENTS Page PUBLICATION DISSERTATION OPTION ................................................................... iii ABSTRACT ....................................................................................................................... iv ACKNOWLEDGMENTS .................................................................................................. v LIST OF ILLUSTRATIONS ............................................................................................. ix LIST OF TABLES ........................................................................................................... xiii NOMENCLATURE ........................................................................................................ xiv SECTION 1. INTRODUCTION .................................................................................. 1 PAPER I. A FULL FIELD STATIC MODEL OF THE RG-OIL FIELD, CENTRAL SIRTE BASIN, LIBYA ........................................................ 3 ABSTRACT ................................................................................................ 3 1. INTRODUCTION................................................................................... 4 2. GEOLOGICAL SETTING ..................................................................... 7 3. DATA ...................................................................................................... 9 4. METHODS ........................................................................................... 11 4.1 SEISMIC HORIZON AND FAULT INTERPRETATION ... 11 4.2. PETROPHYSICS .................................................................. 12 5. RESULTS AND DISCUSSIONS ......................................................... 17 5.1. FAULT MODELING ............................................................ 17 5.2. STRUCTURAL INTERPRETATION .................................. 17 vii 5.3. STRUCTURAL MODELING ............................................... 19 5.4. UPSCALING WELL LOGS.................................................. 19 5.5. PROPERTY MODELING ..................................................... 31 5.6. FACIES MODELING ........................................................... 31 5.7. POROSITY AND PERMEABILITY MODELING .............. 32 5.8. NET-TO-GROSS (NTG) RATIO .......................................... 38 5.9. VOLUMETRIC ESTIMATION ............................................ 38 6. CONCLUSIONS ................................................................................... 41 ACKNOWLEDGMENTS ........................................................................ 42 REFERENCES ......................................................................................... 42 II. SEISMIC ATTRIBUTES AIDED FAULT DETECTION AND ENHANCEMENT IN THE SIRTE BASIN, LIBYA .......................... 47 SUMMARY .............................................................................................. 47 1. INTRODUCTION................................................................................. 48 2. DATA, METHODOLOGY, AND RESULTS ...................................... 50 2.1. DATA CONDITIONING ...................................................... 50 2.2. SIMILARITY OR COHERENCE ATTRIBUTES ................ 57 2.3. CURVATURE ATTRIBUTES .............................................. 58 2.4. FAULT INTERPRETATION AND FAULTS VISUALIZATION………………………………………….62 3. CONCLUSIONS ................................................................................... 64 ACKNOWLEDGMENTS ........................................................................ 64 REFERENCES ......................................................................................... 64 viii SECTION 2. CONCLUSIONS ................................................................................... 66 VITA ................................................................................................................................. 68 ix LIST OF ILLUSTRATIONS Figure Page PAPER I 1. Location map of the study area showing the sedimentary basins in Libya including the Ghadames, Murzuq, Kufra, and Sirte basins. ................................... 5 2. A stratigraphic-lithologic column of the central Sirte Basin .......................................... 6 3. Model development workflow showing the process of integrated geology, geophysics, and petrophysics data to construct a full field static reservoir model of the RG-oil field using all the available data such seismic, well log, and core description data. ......................................................................................