#
Nomenclature

The table below outlines key nomenclature in Harmony Enterprise.

Variable | Description |
---|---|

a |
Nominal (instantaneous) decline rate |

a_{elf} |
Decline rate at end of linear flow |

a_{f} |
Final nominal (instantaneous) decline rate |

a_{i} |
Initial nominal (instantaneous) decline rate |

a_{lim} |
Limiting nominal (instantaneous) decline rate |

A |
Area |

A_{c} |
Cross-sectional area to flow |

A_{D} |
Areal extent of reservoir |

A_{o} |
Gas-oil pore size distribution index |

A_{SRV} |
Area of stimulated reservoir volume |

A_{w} |
Oil-water pore size distribution index |

AD | Active directory |

AOF | Absolute open flow potential |

APE | Automatic parameter estimation |

API | American Petroleum Institute number |

API | Application programming interface |

AWS | Amazon web services |

b |
Decline exponent |

b_{a,pss} |
Pseudo-steady state constant in the flow equation using material balance pseudo-time (gas) |

b_{Dpss} |
Dimensionless pseudo-steady state constant |

b_{pss} |
Pseudo-steady state constant in the flow equation using material balance time (oil) |

B |
Formation volume factor |

B_{g} |
Formation volume factor for gas |

B_{gd} |
Dry gas formation volume factor, ft3/scf, m3/m3 |

B_{gi} |
Formation volume factor for gas at initial reservoir pressure and temperature |

B_{ginj} |
Formation volume factor for injected gas |

B_{o} |
Formation volume factor for oil, bbl/stb, m3/m3 |

B_{ob} |
Formation volume factor for oil at bubble point |

B_{oi} |
Formation volume factor for oil at initial reservoir pressure and temperature |

B_{w} |
Formation volume factor for water |

B_{wi} |
Formation volume factor for water at initial reservoir pressure and temperature |

B_{winj} |
Formation volume factor for injected water |

BOE | Barrel of oil equivalent |

c |
Compressibility |

c_{d} |
Relative change in pore volume due to desorption of gas |

c_{e} |
Effective compressibility. For oil systems,
includes oil, water, and formation compressibilities. |

c_{ep} |
Relative change in pore volume due to formation and residual fluid expansion |

c_{f} |
Formation / pore compressibility |

c_{f,max} |
Formation compressibility at zero net overburden pressure |

c_{fi} |
Initial formation compressibility |

c_{g} |
Gas compressibility |

c̅_{g} |
Average gas compressibility |

c_{i} |
Initial compressibility |

c_{ma} |
Matrix compressibility |

c_{o} |
Oil compressibility |

c_{t} |
Total compressibility |

c_{̅te} |
Total compressibility at average reservoir pressure including net gas compressibility due to water influx |

c_{ti} |
Total initial compressibility |

c_{T} |
Isothermal compressibility |

c_{T,w} |
Isothermal compressibility of water |

c_{T,wf} |
Isothermal compressibility of gas-free water |

c_{T,wg} |
Isothermal compressibility of gas-saturated water |

c_{ti} |
Total system compressibility at original reservoir pressure |

c_{w} |
Water compressibility |

c_{wip} |
Relative change in pore volume due to water influx and production |

C |
Transfer coefficient related to flow capacity of the formation |

CCA | Custom calculated attributes |

CD |
Storage coefficient |

CDF | Cumulative distribution function |

CDI |
Formation and connate water compressibility d rive index |

CF |
Casing flange (reference point for depth measurements) |

CGR |
Condensate gas ratio, bbl/MMscf, m3/103m3 |

Ca |
Ash content (Langmuir isotherm) |

CA |
Reservoir shape factor |

CaD |
Dimensionless apparent wellbore storage |

CAh |
Shape factor for horizontal wells |

CD |
Dimensionless wellbore storage |

Cg |
Gas content |

C_{g,abdn/CO2} |
Gas content at abandonment pressure or CO2 concentration |

C_{gi} |
Initial gas content |

C_{G} |
Input gas volume fraction |

C_{L} |
Liquid input volume fraction |

C_{m} |
Matrix swelling coefficient |

C_{o} |
Gas-oil entry capillary pressure |

C_{p} |
Mechanical compliance coefficient |

C_{pD} |
Dimensionless storage pressure parameter |

C_{w} |
Oil-water entry capillary pressure. Moisture content. (Langmuir isotherm) |

Cal rate | Calendar rate — does not account for time on production. |

d |
Effective decline rate |

di |
Initial effective decline rate |

d_{lim} |
limiting effective decline rate |

D |
Turbulence factor |

DD % | Drawdown percentage |

DDI |
Depletion drive index |

DLS | Dominion land survey |

DSN | Data source name |

E | Young's modulus of elasticity |

EC2 | Elastic compute cloud by Amazon is a web service that can be used to create virtual machines running various operating systems on the cloud |

EMS | Entitlement Management System (EMS) |

ENERDEQ® | IHS's Energy Information Access & Integration Platform is an information access and integration platform that directly connects you to global energy data |

Entity | A well or scenario. Groups can include various entities (that is, wells and scenarios). |

ESP | Electrical submersible pump |

EOT | End of tubing |

EUR |
Expected ultimate recovery |

E_{avg} |
Average error |

E_{fw} |
Formation expansion factor |

E_{g} |
Gas expansion factor |

E_{gi} |
Gas expansion factor at initial conditions |

E_{L} |
In-situ liquid volume fraction (liquid holdup) |

E_{L0} |
Horizontal liquid holdup |

E_{Lθ} |
Inclined liquid holdup |

E_{o} |
Oil expansion factor |

E_{t} |
Total expansion factor |

f |
Decimal fraction |

f_{c} |
Compressibility modifier |

F |
Reservoir voidage from production |

FMB | Flowing material balance |

Forecast | Used to predict future production |

FP | Flowing pressure |

FSD | Forecast start date |

F_{CD} |
Dimensionless fracture conductivity |

g_{g} |
Geothermal gradient |

G |
Original gas-in-place |

G | Separator gas specific gravity (for fluid properties) |

GHV |
Gross heating value |

GMB | Gas material balance |

GOR |
Producing gas-oil ratio |

GWR | Gas water ratio |

G_{f} |
Free gas-in-place |

G_{inj} |
Cumulative gas injected |

G_{p} |
Cumulative gas production |

G_{pa} |
Additional gas production |

G_{p,n} |
Ultimate recoverable gas |

G_{pn} |
Cumulative gas production at time 'n' |

G_{r} |
Remaining gas |

G_{T} |
Cumulative transferred gas volume in a connected reservoir |

h |
Net pay |

h_{p} |
Perforated interval |

HCPV | Hydrocarbon pore volume |

History matching |
History matching is the process of evaluating your model against known production data (rate and pressure vs. time). For example, in an Analytical model, the inputs are measured sandface pressures and rates, along with a set of fixed parameters like permeability, initial reservoir pressure, saturations, etc. Since a model is just a complex equation that relates pressure to rate, then the measured rates can be applied to a given model in order to synthesize a set of sandface pressures (or vice versa). The history-matching process then consists of changing the model parameters until the synthesized data overlaps the measured data to a reasonable degree. |

I |
Incline rate |

IAM | Identity and access management (for Azure) |

ID | Inner diameter |

IHDC | Information hub direct connect — the Canadian-specific portion of IHS web services |

IPR | Inflow performance relationship |

IWIP |
Initial water-in-place |

j |
Time interval / timestep |

J |
Transfer coefficient |

J_{sat} |
Productivity index. For more information, see Fetkovich-based fit. |

k |
Permeability |

k_{abs} |
Absolute permeability |

k_{aq} |
Aquifer permeability |

k_{e} |
Effective roughness of pipe |

k_{f} |
Fracture permeability |

k_{g} |
Effective permeability of gas |

k_{h} |
Horizontal permeability |

k_{i} |
Initial permeability |

k_{matrix} |
Matrix (outer zone) permeability |

k_{o} |
Effective permeability of oil |

k_{r} |
Pressure-dependent permeability ratio: kr = k / ki |

k_{res} |
Reservoir permeability |

k_{rg} |
Gas-relative permeability |

k_{rgc} |
Gas-relative permeability at residual oil saturation |

k_{rgcw} |
Gas-relative permeability at connate water saturation |

k_{rgro} |
Gas-relative permeability at residual oil saturation |

k_{ro} |
Oil-relative permeability |

k_{rocw} |
Oil-relative permeability at connate water saturation |

k_{rog} |
Oil-relative permeability with respect to gas |

k_{rogc} |
Oil-relative permeability at critical gas saturation |

k_{row} |
Oil-relative permeability with respect to water |

k_{rw} |
Water-relative permeability |

k_{rwgc} |
Water-relative permeability at critical gas saturation |

k_{rwro} |
Water-relative permeability at residual oil saturation |

k_{srv} |
SRV (inner zone) permeability |

k_{v} |
Vertical permeability |

k_{w} |
Effective permeability of water |

k_{x} |
Permeability in the x-direction |

k_{y} |
Permeability in the y-direction |

k_{z} |
Permeability in the z-direction |

KB |
Kelly bushing (reference point for depth measurements) |

L |
Horizontal wellbore length |

L_{D} |
Dimensionless horizontal wellbore length |

L_{e} |
Effective horizontal wellbore length |

LRG | Liquid rich gas |

m |
Slope from the flow equation using material balance time (oil) |

m_{a} |
Slope from the flow equation using material balance pseudo-time (gas) |

M | Mobility ratio (analytical models) (water-drive typecurves) |

MD |
Measured depth (CF or KB) |

MPP |
Mid-point of perforations |

M_{aq} |
Aquifer mobility |

M_{o} |
Molecular weight of stock tank liquid |

M_{res} |
Reservoir mobility |

n |
Moles of gas (ideal g as law equation) |

n_{f} |
Number of fractures |

n_{g} |
Gas exponent |

n_{og} |
Oil-gas system exponent |

n_{ow} |
Oil-water system exponent |

n_{w} |
Water exponent |

N |
Original oil-in-place |

NAD 27 | North American Datum, created in 1927 |

NAD 83 | North American Datum, modified in 1983 |

NGL | Natural gas liquids |

NTS | National topographic (map numbering) system |

N_{p} |
Cumulative oil production |

N_{p,n} |
Ultimate recoverable oil |

N_{VL} |
Liquid velocity number |

ODBC | Open database connectivity |

OCIP | Original condensate-in-place, Mstb, 103m3 |

OCIP_{SRV} |
Original condensate-in-place in a stimulated region, Mstb, 103m3 |

OD | Outer diameter |

ODBC | Open database compliant |

OFIP | Original fluid-in-place |

OGIP |
Original gas-in-place, MMscf, 106m3 |

OGIP_{A} |
Original adsorbed gas-in-place, MMscf, 106m3 |

OGIPF |
Original free gas-in-place, MMscf, 106m3 |

OGIP_{SRV} |
Original gas-in-place in a stimulated region, MMscf, 106m3 |

OMB | Oil material balance |

OOIP |
Original oil-in-place, Mstb, 103m3 |

OOIP_{SRV} |
Original oil-in-place in a stimulated region, Mstb, 103m3 |

OWIP | Original water-in-place, Mstb, 103m3 |

OWIP_{SRV} |
Original water-in-place in a stimulated region, Mstb, 103m3 |

Op Rate | Operated rate — accounts for time on production. |

p |
Pressure |

p̅ |
Average reservoir pressure |

p_{ab} |
Abandonment pressure |

p_{air} |
Air pressure |

p_{aq} |
Aquifer pressure |

p_{aqi} |
Initial aquifer pressure |

p_{bp} |
Bubble point pressure, psi(a), kPa(a) |

p_{c} |
Critical pressure |

(pce)_{go} |
Gas-oil pore entry capillary pressure, psi(a), kPa(a) |

(pce)_{ow} |
Oil-water pore entry capillary pressure, psi(a), kPa(a) |

p_{cgo} |
Gas-oil system capillary pressure, psi(a), kPa(a) |

p_{cow} |
Oil-water system capillary pressure, psi(a), kPa(a) |

p_{d} |
Desorption pressure |

p_{dew} |
Dew point pressure, psi(a), kPa(a) |

p_{D} |
Dimensionless pressure |

p_{Di} |
Dimensionless pressure integral |

p_{Did} |
Dimensionless pressure integral derivative |

p_{e} |
Bulk overburden pressure |

p_{flow} |
Specified flowing pressure |

p_{grd} |
Overburden pressure gradient |

p_{i} |
Initial reservoir pressure |

p_{j} |
Pressure at time "j" |

p_{L} |
Langmuir pressure |

p_{max} |
Maximum pressure |

p_{min} |
Minimum pressure |

p_{n} |
Net overburden pressure |

p_{ni} |
Initial net overburden pressure |

p_{o} |
Oil pressure |

p_{p} |
Pseudo-pressure |

̅p_{p} |
Average pseudo-pressure |

p_{pab} |
Abandonment pseudo-pressure |

̅p_{pab} |
Average abandonment pseudo-pressure |

p_{pi} |
Initial pseudo-pressure |

p_{pwf} |
Wellbore flowing pseudo-pressure |

p_{r} |
Reduced pressure |

̅p_{R} |
Current reservoir pressure |

p_{sp} |
Separator pressure |

p_{sc} |
Pressure at standard conditions (14.65 psia, 101.0 kPa(a)) |

p_{w} |
Water pressure |

p_{wf} |
Sandface flowing pressure |

p_{wff} |
Sandface forecast pressure |

p_{wh} |
Wellhead flowing pressure |

p_{ε} |
Reservoir pressure at 50% matrix strain |

P10 | For each time interval, the P10 point is determined as the value for which 10% of the data points are higher. The production volume for each period is based on the calculated rate, and the cumulative production track is calculated by summing the calculated volumes. The P10 curve can be considered a highly optimistic prediction. |

P50 | For each time interval, the P50 point is determined as the value for which 50% of the data points are higher. The production volume for each period is based on the calculated rate, and the cumulative production track is calculated by summing the calculated volumes. |

P90 | For each time interval, the P90 point is determined as the value for which 90% of the data points are higher. The production volume for each period is based on the calculated rate, and the cumulative production track is calculated by summing the calculated volumes. A line is drawn through each P90 point to obtain the curve. The P90 curve is often considered as a conservative estimate of reserves. |

PI |
Productivity index |

PVT |
Pressure volume temperature |

P_{c} |
Capillary pressure |

P_{OP} |
Operating pressure |

P_{RES} |
Reservoir pressure |

P_{SF} |
Sandface pressure |

q |
Rate |

q̅ |
Average rate |

q_{ab} |
Abandonment rate |

q_{CRIT} |
Critical flow rate |

q_{D} |
Dimensionless rate |

q_{Dd} |
Dimensionless decline rate |

qDde |
Dimensionless decline rate accounting for total pool production |

q_{Dd, integral} |
Dimensionless rate integral |

q_{elf} |
Rate at end of linear flow |

q_{f} |
Final rate (abandonment rate) qf = (number of wells) * (qGas / 6 +qOil); |

q_{g} |
Instantaneous gas rate |

(q_{g})_{f} |
For FMB, URM, and Typecurve: The final abandonment rate for gas |

q_{ginj} |
Injected gas rate |

q_{i} |
Initial rate |

q_{integral} |
Rate integral |

q_{j} |
Rate at time "j" |

q_{MAX} |
Maximum oil rate |

q_{o} |
Instantaneous oil rate |

(q_{o})_{f} |
For FMB, URM, and Typecurve: The final abandonment rate for oil |

q_{OIL} |
Oil rate |

q_{OR} |
Operating rate |

q_{s} |
Gas flow rate from separator |

q_{tot} |
Pool total production rate |

q_{w} |
Instantaneous water rate |

q_{we} |
Rate of water influx |

q_{winj} |
Rate of water injection |

Q |
Cumulative production |

Q_{D} |
Dimensionless cumulative production |

Q_{DA} |
Area-based dimensionless cumulative production |

Q_{Dd} |
Dimensionless cumulative decline production |

Q_{f} |
Final cumulative production |

Q_{g,dry} |
Cumulative surface gas production |

Q_{g,wet} |
Cumulative well stream gas produced at the sandface |

Q_{i} |
Initial cumulative production |

Q_{m} |
Modified cumulative production |

Q_{n} |
Normalized cumulative production |

Q_{tot} |
Pool cumulative production |

r |
Radius |

r_{aq} |
Aquifer exterior radius |

r_{e} |
Reservoir effective radius |

r_{eD} |
Dimensionless effective radius |

r_{o} |
Reservoir outer boundary radius (Water-drive Typecurves and Models) Distance to observation well from active well, for cylindrical reservoirs |

r_{w} |
Wellbore radius |

r_{wa} |
Apparent wellbore radius |

r_{wD} |
Dimensionless wellbore radius |

r_{we} |
Effective wellbore radius |

R |
Ideal gas law constant |

RC | Rate vs cumulative production |

RDP | Remote desktop protocol |

RDS | Relational Database Service created by Amazon |

RF |
Recovery factor |

RR |
Remaining recoverable |

RT | Rate vs time |

R_{p} |
Solution gas-oil ratio based on cumulative oil and gas production |

R_{s} |
Solution gas-oil ratio, scf/bbl, m3/m3 |

R_{sb} |
Solution gas-oil ratio at bubble point |

R_{si} |
Initial solution gas-oil ratio |

R_{sr} |
Reduced solution gas-oil ratio |

R_{sw} |
Gas solubility in water |

R_{v} |
Vaporized oil ratio, bbl/MMscf, m3/103m3 |

s |
Skin |

s_{d} |
Near-wellbore skin damage |

s_{dφ} |
Interporosity skin |

s_{f} |
Fracture face skin |

S |
Salinity of water |

Sandface C | Sandface deliverability coefficient |

Sandface/Wellhead n | Turbulence factor |

SDI |
Segregation (gas cap) Drive Index |

SI | International system of units. For more information, see http://dictionary.reference.com/browse/si+units?s=t |

SL |
Surface losses |

SPE | Society of petroleum engineers |

SQL | Structured query language |

SRV |
Stimulated reservoir volume |

S_{ads} |
Adsorbed gas saturation |

S_{g} |
Gas saturation |

S_{gc} |
Critical gas saturation |

S_{gi} |
Initial gas saturation |

S_{gn} |
Normalized gas saturation |

S_{iw} |
Irreducible water saturation (Relative Permeability Correlations) |

S_{o} |
Oil saturation |

S_{oi} |
Initial oil saturation |

S_{on} |
Normalized oil saturation |

S_{or} |
Residual oil saturation |

S_{org} |
Residual oil saturation to gas |

S_{orw} |
Residual oil saturation to water |

S_{w} |
Water saturation |

S_{wc} |
Critical water saturation (capillary pressure) |

S_{wc} |
Connate water saturation (relative permeability) |

S_{wi} |
Initial water saturation |

S_{wirr} |
Irreducible water saturation (capillary correlations) |

S_{wn} |
Normalized water saturation |

̅S_{w} |
Average water saturation |

t |
Time |

t_{a} |
Pseudo-time |

t_{c} |
Material balance time |

t_{ca} |
Material balance pseudo-time |

t_{cae} |
Total material balance pseudo-time for gas |

t_{ce} |
Total material balance pseudo-time for oil |

t_{co} |
Length of the first time period in material balance time |

t_{D} |
Dimensionless time |

t_{DA} |
Area-based dimensionless time |

t_{Dd} |
Dimensionless decline time |

t_{Dde} |
Dimensionless decline time accounting for total pool production |

t_{Dxf} |
Dimensionless time based on fracture half-length (xf) |

t_{Dye} |
Dimensionless time based on reservoir width (Ye) |

t_{elf} |
Time at end of linear flow |

t_{f} |
Time at start of forecast date |

t_{flow} |
Specified flow time |

t_{j} |
Time at the "jth" time period / timestep |

t_{lim} |
Limiting time |

t_{shut-in} |
Specified shut-in time |

t_{stab} |
Time to stabilization |

T |
Temperature |

TVD |
True vertical depth (CF or KB) |

TPC | Tubing performance curve |

T_{c} |
Critical temperature |

T_{f} |
Formation temperature |

T_{i} |
Initial temperature |

T_{pp} |
Pour point temperature |

T_{r} |
Reduced temperature |

T_{sp} |
Separator temperature |

T_{sc} |
Temperature at standard conditions (60oF/15oC) |

T_{sp} |
Separator temperature |

URM | Unconventional reservoir module |

v_{g} |
Gas velocity |

v_{L} |
In-situ liquid velocity |

v_{m} |
Mixture velocity |

v_{sg} |
Superficial gas velocity |

v_{sl} |
Superficial liquid velocity |

V |
Volume |

VM | Virtual machine |

VR |
Voidage replacement |

VRR |
Voidage replacement ratio |

V_{ACT} |
Actual velocity |

V_{aq} |
Aquifer volume |

V_{CRIT} |
Critical velocity |

V_{ERO} |
Erosional velocity |

V_{HCP} |
Hydrocarbon pore volume |

V_{i} |
Initial volume |

V_{L} |
Langmuir volume |

V_{Li} |
Initial Langmuir volume |

V_{p} |
Pore volume |

V_{R} |
Volatile oil ratio Rock volume |

V_{sc} |
Volume at standard conditions |

V_{T} |
Total volume |

V_{w} |
Wellbore volume |

w_{f} |
Fracture width |

WBS | Well-based security |

WDI |
Water drive index |

WGR | Water gas ratio |

WGS 84 | World Geodetic System, modified in 1984 |

WOR |
Water-oil ratio |

W_{e} |
Water encroachment from aquifer |

W_{ei} |
Initial water encroachment from aquifer |

W_{inj} |
Cumulative water injection |

W_{p} |
Cumulative water production |

x_{e} |
Reservoir length |

x_{eD} |
Dimensionless reservoir length |

x_{f} |
Fracture half-length |

x_{i} |
Half SRV width, or the distance from the fracture to the permeability boundary |

x_{w} |
Active well location in the x-direction |

y |
Distance of investigation at time t |

y_{e} |
Reservoir width |

y_{w} |
Active well location in the y-direction |

y_{e}/y_{w} |
Ratio of reservoir width to well location in the y-direction |

Z |
Gas compressibility factor |

Z** |
Modified gas compressibility factor |

Z̅ |
Average gas compressibility factor |

Z_{ab} |
Compressibility factor at reservoir abandonment pressure |

Z_{i} |
Compressibility factor at initial pressure and temperature |

Zi** |
Modified compressibility factor at initial pressure and temperature |

z_{o} |
Location of observation well from top of zone (z-direction) for rectangular reservoirs |

Z_{sc} |
Compressibility factor at standard conditions |

z_{w} |
Well location in the z-direction (only applicable to horizontal wells) |

α |
Biot's coefficient (Geomechanical Reservoir Models - Dobrynin Correlation) Separation factor / selectivity ratio (Langmuir Isotherm) |

β |
Square root of the anisotropic ratio kh/kv |

β_{D} |
Ratio of total pool production to individual well production |

γ | Permeability modulus (Geomechanical Reservoir Models - Yilmaz & Nur Pressure-Dependent Permeability Correlation)
Dimensionless correlation factor (Geomechanical Reservoir Models - Dobrynin Pressure-Dependent Permeability Correlation) Euler's constant = 0.57721 |

γ_{API} |
Specific gravity of liquid hydrocarbons / condensate in oAPI |

γ_{g} |
Specific gravity of gas |

γ_{g(psp)} |
Specific gravity of gas at separator pressure conditions |

γ_{o} |
Specific gravity of liquid hydrocarbons / condensate |

γ_{t} |
Recombined gas gravity |

γ_{w} |
Specific gravity of water |

∆k |
Change in permeability |

∆p_{f} |
Change in pressure due to friction |

∆p_{HH} |
Change in pressure due to hydrostatic head |

∆Q |
The difference between Q |

∆t |
Forecast duration |

∆V_{d} |
Change in reservoir volume due to desorption of gas |

∆V_{ep} |
Change in reservoir volume due to formation and residual fluid expansion |

∆V_{p} |
Reduction in hydrocarbon pore volume |

∆V_{w} |
Expansion of initial water volume |

∆V_{wip} |
Change in reservoir volume due to water influx and production |

∆X_{o} |
Location of observation well from active well in the x-direction, for rectangular reservoirs |

∆Y_{o} |
Location of observation well from active well in the y-direction, for rectangular reservoirs |

∆Z |
Change in elevation |

ε |
Tensile strain |

ε_{exp} |
Net strain between overburden stress effect and matrix shrinkage as measured experimentally |

ε_{L} |
Langmuir strain |

θ |
Angle of inclination |

θ_{r} |
[(T + 459.67) / 459.67] = relative temperature |

λ |
Interporosity flow coefficient Pore size distribution index (Capillary Correlations - Brooks / Corey) |

λ_{go} |
Gas-oil pore size distribution index |

λ_{ow} |
Oil-water pore size distribution index |

μ |
Viscosity of primary fluid (gas / oil / water) |

µ̅ |
Average viscosity |

μ_{aq} |
Aquifer viscosity |

μ_{g} |
Gas viscosity, cP, mPa.s |

̅μ_{g} |
Viscosity of gas at average pressure |

μ_{i} |
Viscosity at initial reservoir pressure |

μ_{L} |
Liquid viscosity |

μ_{m} |
Mixture viscosity |

μ_{NS} |
No-slip viscosity |

μ_{o} |
Oil viscosity, cP, mPa.s |

μ_{ob} |
Oil viscosity at bubble point |

μ_{od} |
Viscosity of dead oil |

μ_{os} |
Viscosity of saturated oil |

μ_{res} |
Reservoir viscosity |

μ_{w} |
Water viscosity, cP, mPa.s |

ν |
Poisson's ratio |

ξ |
Reduced inverse viscosity |

ρ |
Density |

ρ_{a} |
Apparent density of surface gas |

ρ_{air} |
Air density |

ρ_{ads} |
Density of the adsorbed gas phase |

ρ_{b} |
Bulk density |

ρ_{G} |
Gas density |

ρ_{L} |
Liquid density |

ρ_{m} |
Mixture density |

ρ_{mol} |
Molar density |

ρ_{NS} |
No-slip density |

ρ_{o} |
Oil density |

ρ_{ob} |
Oil density at bubble point |

ρ_{oR} |
Oil density at reservoir conditions |

ρ_{po} |
Pseudo-liquid density at standard conditions |

ρ_{st} |
Stock tank oil density |

ρ_{w} |
Water density |

σ |
Interfacial tension (capillary pressure) |

σ_{i} |
Effective horizontal stress at initial reservoir pressure |

φ |
Porosity |

φ_{i} |
Initial porosity |

φ_{t} |
Total porosity |

Ψ |
Pseudo-pressure |

Ψ̅ |
Pseudo-pressure at average pressure |

Ψ_{i} |
Pseudo-pressure at initial reservoir pressure |

Ψ_{wf} |
Pseudo-pressure at sandface flowing pressure |

ω |
Storativity ratio |