1 An Introduction Basin Analysis [PDF]

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UTP Department of Geosciences



QBB 3023 Basin Analysis



1 Sedimentary Basins by



1. Associate Professor Dr Abdul Hadi Abd Rahman 2. Awalludin Harun Department of Geosciences, Faculty of Geosciences and Petroleum Engineering Universiti Teknologi PETRONAS



Awalludin Bin Harun 1. 2.



BSc. (Applied Geology), University of Malaya, 1982. MSc. Micropalaeontology, University College London, 1989



Working for PETRONAS for a total of 29 years. - 18 years in PETRONAS Research - 7 years in Petroleum Management Unit - 4 years in PCSB



Learning Outcomes • At the end of this course, students should be able to: • Explain and write on the theories of basin formation, and the



methodology used to classify sedimentary basins in terms of driving mechanisms and structural style, • Describe and evaluate the structural style, subsidence history and evolution of the main types of sedimentary basin (rifts, passive margins, strike-slip, foreland/thrust-top) as well as gravity and salt tectonics, • evaluate controls of sediment generation, transport and deposition and use sequence stratigraphy to analyze sedimentary successions • prepare and present an oral presentation on a basin analysis / petroleum system topics



Course Content 1. Introduction 2. Basin formation mechanisms 3. Classification of sedimentary basins 4. Sedimentary basin fill – sequence stratigraphy 5. Basin fill styles 6. Subsidence analysis



Lecture Outline 1. Introduction 2. Mechanisms of Basin Formation 3. Basin Classification 4. Global examples 5. Summary



Timetable Thursday:



10 – 12, Lecture at 21-02-12



Monday:



10 – 12, Lab 02 at 14-01-02B



Thursday:



10 – 12, Lab 01 at 14-01-02B



Examination Coursework:



50%



Assignment, Test, Lab work, quizzes



Final Exam:



50%



1 Introduction  Basin analysis - Study of sedimentary



rocks to determine:  Subsidence history  Stratigraphic architecture  Paleogeographic evolution



 Tools:  Geology (outcrops, wireline logs, core)  Geophysics (seismic, gravity, aeromagnetic)  Computers (modeling, data analysis)



1 Introduction What is a basin?  Repository / storage for sediment  Formed by crustal subsidence relative to surrounding



areas  Surrounding areas sometimes uplifted  Many different shapes, sizes and mechanisms of formation • Areas of the earth where there is a net sedimentation, or in the



fossil (ancient) record of such areas • Zones of pronounced subsidence where sediment can



accumulate. The larger the thickness of sediments and longer the accumulation has taken place, the more interesting to the oil companies the basin becomes.



Example of a basin.



1 Introduction Zonation of the Earth – Composition Crust



Mantle Core



Solid Earth Crust (5-70 km): Most abundant elements are silicon (Si) and oxygen (O)



Mantle (2900 km): Most abundant elements are magnesium (Mg), oxygen (O) and silicon (Si)



Core: Composed mainly of iron (Fe), with some nickel (Ni), lighter elements Inner core is solid, outer core is liquid



Look at the outer layers of the solid Earth: Upper mantle & crust = lithosphere



Three mechanical layers of the crust and mantle: •Lithosphere (crust and upper mantle, about 100 km thick) is strong and brittle •Asthenosphere (mantle, 100-660 km) is plastic and deformable – it contains a small amount of molten rock or magma. •Mesosphere (>660 km) is strong, but not brittle



1 Introduction Zonation of the Upper Earth – Rheology  Lithosphere  Rigid outer shell  Crust and upper mantle



 Asthenosphere  Weaker than lithosphere  Flows (plastic deformation)



1 Introduction  Zonation of the Upper Earth – Rheology Vertical motions (subsidence, uplift) in sedimentary basins are primarily in response to deformation of lithosphere and asthenosphere



1 Introduction



1 Introduction  Plate motions  Plate-plate interactions can generate vertical crustal



movements  Examination of basins according to their positions with respect to plate boundaries and plate-plate interactions may explain how basins form  “Wilson Cycle” – opening and closing of ocean basins – a conceptual framework



1



Introduction



Three types of plate boundaries:  Divergent – plates moving apart  Mid-ocean ridges, rifts



 Convergent – plates moving towards each other



 Subduction zones  Conservative – plates move parallel to each other



 Strike-slip systems



Divergent Plate Boundary



• Usually start within continents — grows to become ocean basin