Post on 07-Feb-2016
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Lunch & Learning: Basic Concept for Reservoir Simulation
Niu Yuqiang
2 Initials04/22/23
Overview
What you should know
•Basic hydrocarbon geology
What you can learn
•Formation property•Formation fluid property•Field production datasetTool you need
•Eyes ears and hearts
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Oil and Gas Wells
GASGAS
OILOILWATERWATER
sandstone gradessandstone gradesto clay sedimentto clay sediment
sandstonesandstonepinch outpinch out
lithological
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Multiwell Plots
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RTPM-GREAT Reservoir Definition
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What we shall know
• Lithology (reservoir rock?)• Resistivity (HC,water,both?)• Porosity (how much HC?)• What type of HC
• Formation mech. properties• Permeability / cap pressure• Shape of the structure• Geological information• Geothermal• Unconventional applications
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Porosity - Definition
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Porosity (Continued)
A rock can be made up of small grains or large grains but have the same porosity
Porosity depends on grain packing, not the grain size
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Oolites and Oomoldic Porosity
Freedman/Sander, 1978
Ooids Oolitic limestone withoomoldic porosity
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Pore-Space Classification
Total porosity, t =
Effective porosity, e =
VolumeBulkSpacePoreTotal
VolumeBulkSpacePorectedInterconne
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PermeabilityPermeability is a measure of the ease with which fluids can flow through a formation.
Note: To be permeable, a rock must have some interconnected pores, capillaries, or fractures. Hence, there exists some rough relationship between porosity and permeability. Greater permeability, in general, corresponds to greater porosity, but this is not an absolute rule.
Shale and some sands have high porosity but the grains are small that the paths available for the movement of fluid are quite restricted and tortuous; thus their permeabilities may be very low.
Limestone may be composed of a dense rock broken by a few small fractures of great extent. The porosity can be low but the permeability of a fracture can be enormous.
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Darcy’s experiment
Water Tank
Rock Core with u
Height, H
Flow out, Q
Q=-K A / u * dp / L
dp = rou*g*H
Length, L
Area, A
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Relative Permeability
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Saturation Definitions
HydrocarbonWater
*Sw*(1-Sw)
(1-)
*Sw=amount of water per unit volume*(1-Sw)=amount of hydrocarbon per unit volume
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SaturationThe saturation of a formation represents the amount of a given fluid present in the pore
space.
The porosity logs react to the pore space.The resistivity logs react to the fluids in the pore space.The combination of the two measurements gives the saturation
Matrix
water
oil
Sw = Swirr + Sw"free"
So = Soresidual + So"free"
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Invasion
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Archie’s Equation
n
t
mw
wR
RaS
Water saturation, fraction
wSResistivity of formation water, -mwR
Resistivity of uninvaded formation, -m
tRPorosity, fraction
Empirical constant (usually near unity) a
Saturation exponent (also usually near 2)
n Cementation exponent (usually near 2)
m
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Formation Structure
Tops
Layer
zone
Faults
Boundary
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Formation
TopsLayerZoneDzDznetFaultsBoundaryPermeabilityPorosity
Fluid Property
Relative permeabilitySaturationDensity, Gravity (API)ViscosityFormation Volume factor
Compressibility
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Production Dataset
Time
Oil Production Rate
Water Production Rate
Gas Production Rate
Other Operation
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What is Reservoir
Trapped HC; One pressure gradient
How to define Reservoir
GeologyFluid
How to simulate Reservoir
Production data
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Eclipse Data For Simulation (Continued)
RUNSPECTITLE THIS LINE IS A RUN TITLEDIMENS 9 9 1 /OILWATERFIELDTABDIMS 1 1 20 2 1 20 /WELLDIMS 2 1 1 2 /START 1 'JAN' 1983 /
GRID DX 81*50 /PERMX 81*50.0 /EQUALSPERMX 130 206 206 205 205 1 1 /PERMX 130 205 207 206 206 1 1 /PERMX 130 206 206 207 207 1 1 //COPYDX DY /PERMX PERMY / PERMX PERMZ //
DZ 81*50.0 /TOPS 81*5000.0 /PORO 81*0.3 /RPTGRID1 1 1 1 1 0 0 0 /
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Eclipse Data For Simulation (Continued)
PROPS SWFN .25 .0 4.0 .7 1.0 .0/SOF2 .3000 .0000 .7500 1.0000/PVDO-- VF Vis .0 1.0 2.0 8000.0 .92 2.0/
ROCK 5000.0 .30E-05 /DENSITY 52.0000 64.0000 .04400 /PVTW .0 1.0 3.03E-06 .65 /REGIONS SATNUM 81*1 /SOLUTION EQUIL4000 4000 5028 0 0 0 0 0 0 /
SUMMARY FWIPFOIPFOPRWBHP/FWCTFPR
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Eclipse Data For Simulation (Continued)
SCHEDULE RPTSCHED 1 0 1 0 0 0 1 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 /WELSPECS'P' 'G' 5 5 4000 'OIL' //COMPDAT'P' 5 5 1 1 'OPEN' 0 1000000 1* 1* 0.0 //
WCONHIST 'P' OPEN LRAT 0 50 0 / /TSTEP50*0.1/ WCONHIST 'P' OPEN LRAT 0 0 0 / /TSTEP50*1/ WCONHIST 'P' OPEN LRAT 0 50 0 / /END