Basin Analysis

Philip Allen graduated with a Bachelor’s degree in Geology from the University of Wales, Aberystwyth and a PhD from Cambridge University. He held lectureships at Cardiff and Oxford, and professorships at Trinity College Dublin, ETH-Zürich and Imperial College London. He is a process-oriented Earth scientist with particular interests in the interactions and feedbacks between the solid Earth and its ‘exosphere’ through the critical interface of the Earth’s surface.John Allen has over 30 years of experience in the international oil and gas industry as a petroleum geologist, exploration manager, senior exploration advisor, and business strategist with British Petroleum (BP) and BHP Billiton, as well as several years of experience as a non-executive director. He is currently based in Melbourne, Australia.

• Companion website details xPreface to the third edition xiPart 1 The foundations of sedimentary basins 11 Basins in their geodynamic environment 3Summary 31.1 Introduction and rationale 31.2 Compositional zonation of the Earth 61.2.1 Oceanic crust 61.2.2 Continental crust 71.2.3 Mantle 81.3 Rheological zonation of the Earth 81.3.1 Lithosphere 81.3.2 Sub-lithospheric mantle 101.4 Geodynamic background 101.4.1 Plate tectonics, seismicity and deformation 101.4.2 The geoid 121.4.3 Topography and isostasy 141.4.4 Heat flow 141.4.5 Cycles of plate reorganisation 151.5 Classification schemes of sedimentary basins 151.5.1 Basin-forming mechanisms 162 The physical state of the lithosphere 20Summary 202.1 Stress and strain 212.1.1 Stresses in the lithosphere 212.1.2 Strain in the lithosphere 232.1.3 Linear elasticity 252.1.4 Flexure in two dimensions 272.1.5 Flexural isostasy 282.1.6 Effects of temperature and pressure on rock density 292.2 Heat flow 312.2.1 Fundamentals 312.2.2 The geotherm 312.2.3 Radiogenic heat production 332.2.4 Effect of erosion and sediment blanketing on the geotherm 362.2.5 Transient effects of erosion and deposition on the continental geotherm 372.2.6 Effect of variable thermal conductivity 382.2.7 Time-dependent heat conduction: the case of cooling oceanic lithosphere 392.2.8 Convection, the adiabat and mantle viscosity 412.3 Rock rheology and lithospheric strength profiles 432.3.1 Fundamentals on constitutive laws 432.3.2 Rheology of the mantle 442.3.3 Rheology of the continental crust 462.3.4 Strength profi les of the lithosphere 47Part 2 The mechanics of sedimentary basin formation 513 Basins due to lithospheric stretching 53Summary 533.1 Introduction 543.1.1 Basins of the rift–drift suite 543.1.2 Models of continental extension 543.2 Geological and geophysical observations in regions of continental extension 563.2.1 Cratonic basins 563.2.2 Rifts 603.2.3 Failed rifts 673.2.4 Continental rim basins 673.2.5 Proto-oceanic troughs 683.2.6 Passive continental margins 703.3 Uniform stretching of the continental lithosphere 723.3.1 The ‘reference’ uniform stretching model 723.3.2 Uniform stretching at passive continental margins 763.4 Modifications to the uniform stretching model 783.4.1 Protracted periods of rifting 783.4.2 Non-uniform (depth-dependent) stretching 803.4.3 Pure versus simple shear 833.4.4 Elevated asthenospheric temperatures 843.4.5 Magmatic activity 843.4.6 Induced mantle convection 853.4.7 Radiogenic heat production 863.4.8 Flexural compensation 863.4.9 The depth of necking 863.4.10 Phase changes 873.5 A dynamical approach to lithospheric extension 883.5.1 Generalities 883.5.2 Forces on the continental lithosphere 903.5.3 Rheology of the continental lithosphere 923.5.4 Numerical and analogue experiments on strain rate during continental extension 933.6 Estimation of the stretch factor and strain rate history 953.6.1 Estimation of the stretch factor from thermal subsidence history 953.6.2 Estimation of the stretch factor from crustal thickness changes 953.6.3 Estimation of the stretch factor from forward tectonostratigraphic modelling 963.6.4 Inversion of strain rate history from subsidence data 973.6.5 Multiple phases of rifting 974 Basins due to flexure 98Summary 984.1 Basic observations in regions of lithospheric flexure 994.1.1 Ice cap growth and melting 994.1.2 Oceanic seamount chains 1004.1.3 Flexure beneath sediment loads 1014.1.4 Ocean trenches 1034.1.5 Mountain ranges, fold-thrust belts and foreland basins 1044.2 Flexure of the lithosphere: geometry of the deflection 1044.2.1 Deflection of a continuous plate under a point load (2D) or line load (3D) 1044.2.2 Deflection of a broken plate under a line load 1064.2.3 Deflection of a continuous plate under a distributed load 1074.2.4 Bending stresses 1084.3 Flexural rigidity of oceanic and continental lithosphere 1094.3.1 Controls on the flexural rigidity of oceanic lithosphere 1094.3.2 Flexure of the continental lithosphere 1114.4 Lithospheric buckling and in-plane stress 1164.4.1 Theory: linear elasticity 1164.4.2 Lithospheric buckling in nature and in numerical experiments 1174.4.3 Origin of intraplate stresses 1184.5 Orogenic wedges 1184.5.1 Introduction to basins at convergent boundaries 1184.5.2 The velocity field at sites of plate convergence 1204.5.3 Critical taper theory 1204.5.4 Double vergence 1254.5.5 Analogue models 1274.5.6 Numerical approaches to orogenic wedge development 1284.5.7 Low Péclet number intracontinental orogens 1304.5.8 Horizontal in-plane forces during convergent orogenesis 1304.6 Foreland basin systems 1314.6.1 Introduction 1314.6.2 Depositional zones 1324.6.3 Diffusive models of mountain belt erosion and basin deposition 1354.6.4 Coupled tectonic-erosion dynamical models of orogenic wedges 1384.6.5 Modelling aspects of foreland basin stratigraphy 1445 Effects of mantle dynamics 153Summary 1535.1 Fundamentals and observations 1545.1.1 Introduction: mantle dynamics and plate tectonics 1545.1.2 Buoyancy and scaling relationships: introductory theory 1555.1.3 Flow patterns in the mantle 1565.1.4 Seismic tomography 1595.1.5 Plate mode versus plume mode 1595.1.6 The geoid 1625.2 Surface topography and bathymetry produced by mantle fl ow 1645.2.1 Introduction: dynamic topography and buoyancy 1645.2.2 Dynamic topography associated with subducting slabs 1675.2.3 Dynamic topography associated with supercontinental assembly and dispersal 1705.2.4 Dynamic topography associated with small-scale convection 1735.2.5 Pulsing plumes 1755.2.6 Hotspots, coldspots and wetspots 1765.3 Mantle dynamics and magmatic activity 1785.3.1 Melt generation during continental extension 1795.3.2 Large igneous provinces 1805.3.3 The northern North Atlantic and the Iceland plume 1805.3.4 The Afar region, Ethiopia 1805.4 Mantle dynamics and basin development 1815.4.1 Topography, denudation and river drainage 1815.4.2 Cratonic basins 1835.4.3 The history of sea-level change and the fl ooding of continental interiors 1836 Basins associated with strike-slip deformation 188Summary 1886.1 Overview 1896.1.1 Geological, geomorphological and geophysical observations 1896.1.2 Diversity of basins in strike-slip zones 1936.2 The structural pattern of strike-slip fault systems 1946.2.1 Structural features of the principal displacement zone (PDZ) 1946.2.2 Role of oversteps 2006.3 Basins in strike-slip zones 2016.3.1 Geometric properties of pull-apart basins 2016.3.2 Kinematic models for pull-apart basins 2036.3.3 Continuum development from a releasing bend: evolutionary sequence of a pull-apart basin 2066.3.4 Strike-slip deformation and pull-apart basins in obliquely convergent orogens 2076.4 Modelling of pull-apart basins 2096.4.1 Numerical models 2096.4.2 Sandbox experiments: pure strike-slip versus transtension 2156.4.3 Application of model of uniform extension to pull-apart basins 2156.4.4 Pull-apart basin formation and thin-skinned tectonics: the Vienna Basin 2166.5 Characteristic depositional systems 217Part 3 The sedimentary basin-fi ll 2237 The sediment routing system 225Summary 2257.1 The sediment routing system in basin analysis 2267.2 The erosional engine 2277.2.1 Weathering and the regolith 2277.2.2 Terrestrial sediment and solute yields 2337.2.3 BQART equations 2437.2.4 Chemical weathering and global biogeochemical cycles 2467.3 Measurements of erosion rates 2467.3.1 Rock uplift, exhumation and surface uplift 2467.3.2 Point-wise erosion rates from thermochronometers 2477.3.3 Catchment-scale erosion rates from cosmogenic radionuclides 2487.3.4 Catchment erosion rates using low-temperature thermochronometers 2517.3.5 Erosion rates at different temporal and spatial scales 2547.4 Channel-hillslope processes 2567.4.1 Modelling hillslopes 2567.4.2 Bedrock river incision 2597.5 Long-range sediment transport and deposition 2607.5.1 Principles of long-range sediment transport 2607.5.2 Sediment transport in marine segments of the sediment routing system 2637.5.3 Depositional sinks: sediment storage 2657.5.4 Downstream fining 2717.6 Joined-up thinking: teleconnections in source-to-sink systems 2737.6.1 Provenance and tracers; detrital thermochronology 2737.6.2 Mapping of the sediment routing system fairway 2757.6.3 Landscape evolution models and response times 2757.6.4 Interaction of axial and longitudinal drainage 2828 Basin stratigraphy 284Summary 2848.1 A primer on process stratigraphy 2858.1.1 Introduction 2858.1.2 Accommodation, sediment supply and sea level 2858.1.3 Simple 1D forward models from first principles 2868.2 Stratigraphic cycles: definition and recognition 2898.2.1 The hierarchy from beds to megasequences 2898.2.2 Forcing mechanisms 2998.2.3 Unforced cyclicity 3068.3 Dynamical approaches to stratigraphy 3088.3.1 Carbonate stratigraphy 3088.3.2 Siliciclastic stratigraphy 3088.3.3 Shelf-edge and shoreline trajectories; clinoform progradation 3108.4 Landscapes into rock 3158.4.1 Stratigraphic completeness 3158.4.2 Gating models 3188.4.3 Hierarchies and upscaling 3228.4.4 Magnitude-frequency relationships 3249 Subsidence history 326Summary 3269.1 Introduction to subsidence analysis 3279.2 Compressibility and compaction of porous sediments: fundamentals 3279.2.1 Effective stress 3289.2.2 Overpressure 3289.3 Porosity and permeability of sediments and sedimentary rocks 3309.3.1 Measurements of porosity in the subsurface 3319.3.2 Porosity-depth relationships 3339.3.3 Porosity and layer thicknesses during burial 3349.4 Subsidence history and backstripping 3359.4.1 Backstripping techniques 3359.5 Tectonic subsidence signatures 33910 Thermal history 343Summary 34310.1 Introduction 34410.2 Theory: the Arrhenius equation and maturation indices 34410.3 Factors influencing temperatures and paleotemperatures in sedimentary basins 34510.3.1 Effects of thermal conductivity 34510.3.2 Effects of internal heat generation in sediments 34710.3.3 Effects of sedimentation rate and sediment blanketing 34810.3.4 Effects of advective heat transport by fluids 34910.3.5 Effects of surface temperature changes 34910.3.6 Heat flow around salt domes 35010.3.7 Heat flow around fractures 35110.3.8 Heat flows around sills, dykes and underplates 35110.3.9 Thermal effects of delamination 35410.4 Measurements of thermal maturity in sedimentary basins 35410.4.1 Estimation of formation temperature from borehole measurements 35510.4.2 Organic indicators 35510.4.3 Low-temperature thermochronometers 35810.4.4 Mineralogical and geochemical indices 36010.5 Application of thermal maturity measurements 36110.5.1 Vitrinite reflectance (Ro) profiles 36110.5.2 Fission track age-depth relationships 36610.5.3 Quartz cementation 36610.6 Geothermal and paleogeothermal signatures of basin types 367Part 4 Application to petroleum play assessment 37111 Building blocks of the petroleum play 373Summary 37311.1 From basin analysis to play concept 37411.2 The petroleum system and play concept 37411.2.1 Play definition 37411.2.2 The petroleum system 37511.2.3 Definition and mapping of the play fairway 37611.3 The source rock 37911.3.1 The biological origin of petroleum 38011.3.2 Source rock prediction 38411.3.3 Detection and measurement of source rocks 39111.4 The petroleum charge 39311.4.1 Some chemical and physical properties of petroleum 39311.4.2 Petroleum generation 39511.4.3 Primary migration: expulsion from the source rock 39611.4.4 Secondary migration: through carrier bed to trap 39811.4.5 Alteration of petroleum 40111.4.6 Tertiary migration: leakage to surface 40211.5 The reservoir 40211.5.1 Introduction 40311.5.2 Reservoir properties: porosity and permeability 40411.5.3 Primary or depositional factors affecting reservoir quality 40411.5.4 Diagenetic changes to reservoir rocks 40611.5.5 Reservoir architecture and heterogeneity 40811.5.6 Carbonate reservoir quality in relation to sea-level change 41011.5.7 Models for clay mineral early diagenesis in sandstone reservoirs 41311.5.8 Fractures 41311.6 The regional topseal 41511.6.1 The mechanics of sealing 41611.6.2 Factors affecting caprock effectiveness 41611.6.3 The depositional settings of caprocks 41711.7 The trap 41911.7.1 Introduction: trap classification 41911.7.2 Structural traps 42011.7.3 Stratigraphic traps 43011.7.4 Intrusive traps: injectites 43211.7.5 Hydrodynamic traps 43311.7.6 Timing of trap formation 43311.8 Global distribution of petroleum resources 43412 Classic and unconventional plays 436Summary 43612.1 Classic petroleum plays 43712.1.1 Introduction 43712.1.2 Niger Delta 43712.1.3 Campos Basin, Brazil 43912.1.4 Santos Basin pre-salt play, Brazil 44012.1.5 Northwest Shelf, Australia (Dampier sub-basin) 44112.2 Unconventional petroleum plays 44212.2.1 Introduction 44212.2.2 Tight gas 44312.2.3 Shale gas 44412.2.4 Coal seam gas 44512.2.5 Gas hydrates 44512.2.6 Oil sands and heavy oil 44612.3 Geosequestration: an emerging application 449Appendices: derivations and practical exercises 4551 Rock density as a function of depth 4572 Airy isostatic balance 4593 Deviatoric stress at the edge of a continental block 4614 Lateral buoyancy forces in the lithosphere 4635 Derivation of flexural rigidity and the general flexure equation 4656 Flexural isostasy 4687 The 1D heat conduction equation 4708 Derivation of the continental geotherm 4729 Radiogenic heat production 47310 Surface heat fl ow and the radiogenic contribution 47511 Radiogenic heat production of various rock types 47712 Effects of erosion and deposition on the geotherm 47913 Effects of variable radiogenic heating and thermal conductivity on the geotherm in the basin-fill 48114 The mantle adiabat and peridotite solidus 48515 Lithospheric strength envelopes 48716 Rift zones: strain rate, extension velocity and bulk strain 49017 The ‘reference’ uniform extension model 49218 Boundary conditions for lithospheric stretching 49419 Subsidence as a function of the stretch factor 49620 Inversion of the stretch factor from thermal subsidence data 49721 Calculation of the instantaneous syn-rift subsidence 49922 The transient temperature solution 50123 Heat fl ow during uniform stretching using a Fourier series 50324 The stretch factor for extension along crustal faults 50525 Protracted rifting times during continental extension 50726 Lithospheric extension and melting 50827 Igneous underplating – an isostatic balance 50928 Uniform stretching at passive margins 51029 Flexure of continuous and broken plates 51130 The time scale of flexural isostatic rebound or subsidence 51331 Flexural rigidity derived from uplifted lake paleoshorelines 51532 Deflection under a distributed load – Jordan (1981) solution 51633 Deflection under a distributed load – numerical solution of Wangen (2010) 51734 Deflection under a periodic distributed load 51935 Flexural unloading from a distributed load – the cantilever effect 52036 Bending from multiple loads: the Hellenides and Apennines in central Italy–Albania 52237 Flexural profiles, subsidence history and the flexural forebulge unconformity 52438 Bending stresses in an elastic plate 52539 In-plane forces and surface topography during orogenesis 52740 The onset of convection 52941 A global predictor for sediment discharge: the BQART equations 53042 Modelling hillslopes 53243 The sediment continuity (Exner) equation 53444 Use of the stream power rule 53545 Effects of tectonic uplift on stream longitudinal profiles 53746 Estimation of the uplift rate from an area-slope analysis 53947 Uplift history from stream profiles characterised by knickpoint migration 54048 Sediment deposition using the heat equation 54149 Axial versus transverse drainage 54250 Downstream fining of gravel 54551 Sinusoidal eustatic change superimposed on background tectonic subsidence 54652 Isostatic effects of absolute sea-level change 54753 Sea-level change resulting from sedimentation 54854 The consolidation line 54955 Relation between porosity and permeability – the Kozeny-Carman relationship 55056 Decompaction 55157 Backstripping 55558 From decompaction to thermal history 55659 Advective heat transport by fluids 56260 Heat flow in fractured rock 563References 564Index 603