Today‘s LectureThese powerpoint files were produced for the Earth History class at the Free University Berlin,Department of Geological SciencesThe copyright for texts, graphical elements, and images lies with C. Heubeck, unless otherwisespecified.Download, reproduction and redistribution of theses pages in any form is hereby permitted forprivate, personal, non-commercial, and class-related purposes use as long as the source isidentified.Despite of my efforts, I cannot guarantee the completeness, correctness and actuality of the Reservoirsmaterial.Prof. Christoph HeubeckInstitut für Geologische WissenschaftenFreie Universität BerlinMalteserstr. 74-10012249 BerlinGERMANYph: ++49-(0)30-83870695 fax: ++49-(0)firstname.lastname@example.org http://userpage.fu-berlin.de/~cheubeck/ Today‘s Lecture: Reservoirs What is a Petroleum Reservoir ? • What is a reservoir ? A petroleum reservoir is an accumulation • What types of reservoirs exist ? of oil (and gas) in porous rock. • Why study petroleum reservoirs ? • Three examples • Links and Literature A reservoir is that volume of rock that occurs downdip of a seal and updip of the 100% Sw oil-free level. The HCs in the pores are in pressure- and Sw-equilibrium with the free-water level. 1
Zhanjiajie, Hunan Province The view of your Petroleum Engineer A reservoir is a tank to be drained Why study Petroleum Reservoirs ? Questions you need to answer • What is the most efficient way to empty the tank ? • What do I need to know about its internal structure ? • What obstacles am I likely to encounter ?One of the main objectives of reservoir geology evaluation is toexamine the impact of reservoir heterogeneities on reservoirbehaviour. 3
Levels of Reservoir Heterogeneity How is permeability (k) and porosity (φ) related ? Flow patterns, Grain and Pore Scale drainage efficiency, vertical and lateral sweep efficiency 0.1- 1m k, So/Sw , flow, formation damage 1-10 cm 1- 100 m 0.1-10 mm http://www.creationresearch.org/vacrc/sem02.html Hairy Illite 0.1-10 Rotliegendes- km1-100µ Problem HC volume, Kaolinite areal distribution, play trends Reservoir Heterogeneity Matrix Low Moderate High Wave-dominated delta Delta-front mouth bar Meander belt Barrier core Proximal delta front Fluvially-dominated Low delta Barrier shoreface Tidal deposits Sand-rich shoreface Mud-rich strand plain Back barrier “The geological and reservoir properties of sedimentary rocks depend Vertical Heterogeneity upon an interplay of tectonics, sea level, sediment supply, physical and Eolian Shelf bars Braided stream biological processes of sediment transport and deposition, and climate.” Wave-modified delta Alluvial fans Tide-domainated delta Moderate (distal) Fan delta Lacustrine delta Distal delta front Wave-modified delta (proximal) Basin-floor turbidites Coarse-grained meander belt Back barrier Braid delta Fluvially-dom. delta High Fine-grained meander belt Submarine fans Lateral Heterogeneity 4
Depositional Environments How is permeability (k) and porosity (φ) related ? 10000 DEs take influence Reservoir-Scale: 3-Dimensionality; Heterogeneity Beach through grain size, Barrier Bar sorting, clay content, 1000 mineralogy Tidal Flat Tidal RidgeAir Permeability (mD) 100 10 Navajo Sandstone, Utah Äolische Dünen Lagoon Average and Limits of 1 porosity and Kmax ? φ max ? Swamp permeability K min ? φ min 0,1 0 5 10 15 20 25 30 35 Namib After Nagtegaal, 1978; Porosity (%) modified from Selley, 1998 http://www.bdrg.esci.keele.ac.uk/Staff/mountney/sedimentary_research/sed_research_frames.htm Instructions from a Guru (Bob Sneider) What data are available ? Data Type Use Core (slabbed or oriented) Facies, dep environment Sidewall cores Paleocourrent directions Cuttings Mineralogy, lithology Thin sections Mineralogy, lithology Paleontology (micro, macro, traces), Water depth, dep environment, time Palynology line; pcurrent direction, lithofacies Logs FMS / FMI Pcurrent directions, lithofacies SP,GR Lithology, curve shape analysis Sonic, density, neutron Porosity, curve shape analysis Repeat Formation Tester Pressure (sand body connectedness) 5
How is permeability (k) and porosity (φ) related ?Basin scale Three samples of ~21 % porosity CoreLab Promotionary Material Three samples of Three samples of ~21 % porosity ~21 % porosity CoreLab Promotionary CoreLab Promotionary Material Material 6
Deep-water fan morphology Slope Upper Fan Channels Overbanks Lobes How does depositional Channel- Mouth Bar environment affect reservoir Mid-Fan Lobes properties ? Lobes Lobe Lobes Fringe Basin Plain Lower Fan Example: Model of deep-water fan morphology Reservoir potential of turbidite faciesMutti Layer Lateral Depositional Reservoir Principal Lithology Thickness Continuity Porosity PotentialFacies Environment ms ss cgl 1 10 100 Poor good low high Low high Proximal A Channel B Distal Channel C Lobe D Lobe Fringe E Overbank F Slope G Basin Plain 7
Three Examples •Prudhoe Bay Field, Alaska• Prudhoe Bay Field, Alaska• Seneca Field, Ohio• Pecos Field, Alberta All scanned graphs from articles in John H. Barwis, John G. McPherson, Joseph R.J. Studlick, 1990, Sandstone Petroleum Reservoirs (Casebooks in Earth Sciences): Springer Verlag New York, 582 p. Prudhoe Bay Field, Alaska Prudhoe Bay Field, Alaskahttp://www.arcticphoto.co.uk Permian braid-plain stream http://www.channel6.dk/native/uk/page214.html and gravelly delta deposits 8
Prudhoe Bay Field, Alaska / Salar del Carmen, N Chile Prudhoe Bay Field, Alaska / Sierra de Argomedo, N ChilePrudhoe Bay Field, Alaska / Sierra de Argfomedo, N Chile Prudhoe Bay Field, Alaska Vertical view from bridge, south of Santa Cruz 9
Type log Relationship between petrophysical and geological parameter • Lithology • Permeability • Porosity • Depositional Environment Which facies has the better reservoir quality ? Seneca Gas Field Seneca Gas Field: Log-correlationLower Silurian isopach map (inft) in SE Ohio showing 3 majordepositional lobes 10
Seneca Gas Field: Sand IsopachsSeneca Gas Field: Core sketchesSeneca Gas Field: Sand Isopachs Seneca Gas Field: Sand Isopachs Altwasser (abgeschnittener Mäanderarm) Mäander Gleithang Prallhang Flussaue Gleithang Mäanderhals (zukünftige Abkürzung des Flußlaufs) 11
Seneca Gas Field: Sand Isopachs Seneca Gas Field: Detailed isopach mapping “Birdfoot Delta” geometry Peco Gas Field: Structural Cross section Peco Gas Field: Structure Map Top ReservoirAnticline in footwall of thrust sheet 12
Peco Gas Field: Type log description Peco Gas Field: Stratigraphic cross-section Through Peco A, N Pool Fining-upward fluvial facies Thickness and lateral extent of reservoirPeco Gas Field: Facies, reservoir character Lectura Practica Lectura 9:15-10:45 11:30-13:00 15:15-16:45 Lu Lectura 1 / 2 (Introduction; Lab 2 (Internet Lectura 3 (Geochemistry: Origin of The petroleum system) resources) HC; organic matter, source rocks, accumulation. The "petroleum kitchen") Ma Lectura 4 (porosidad, Lab 4 (Porosity Lectura 6 (The reservoir: Lithology, permeabilidad) calculation) geometry, and facies. Reservoir characterization and management) Mi Lectura 5 (Reservoir Lab 5 (Bound Lectura 7 (Reservoir engineering: petrophysics: capillary water, capillarity Drive mechanisms, phase behavior, pressure, pore-size exercise) production problems, scale distribution, bound water formation etc.) etc.) Ju Lectura 9 (Logging Lab 9 (Logging Lectura 8 (Geophysics in concepts and tools; exercise) exploration and reservoir quantitative evaluation of management) lithology, fluids, and porosity) Vi Lectura 10 (Exploration: Lab 10 (Petro Lectura 11 (Summary: Reserves Hydrocarbon classification Mod) and Resources, unconventional HC) of basins; play types) 13
Links and LiteratureLinks• http://www.ccreservoirs.com/reservoirtypes.htm (3 lists of approx. 300 fields in each category; along with some short description / classification: good enough for a start).Literature• John H. Barwis, John G. McPherson, Joseph R.J. Studlick, 1990, Sandstone Petroleum Reservoirs (Casebooks in Earth Sciences): Springer Verlag New York, 582 p. 14
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