Input Panels > Sensitivities Panels

IPR Sensitivities

This dialog allows the user to select sensitivity parameters which can be varied to evaluate the effect of changes in the system. When appropriate, selections which are not applicable (i.e. gravel pack permeability when no Gravel Pack is defined) are not shown in the list of available sensitivities.

Inputs Sensitivities IPR

Reservoir & Completion Sensitivities:

Reservoir pressure (psia): The reservoir pressure to be used for all defined zones. The program currently allows the definition of multiple zones but requires that the reservoir pressure be the same for each one. This option is best for depletion studies and is always valid but should be used carefully when flowrates are defined, since the IPR curve will attempt to recognize all the data.

Permeability: The permeability of the first layer or the layer of interest. A future version of the program will include variable permeabilities for each layer.

Perforation Density (SPF): The perforation density as defined in the completion dialog. The net perforation density should be entered here. This option is unavailable when no completion is defined.

Perforation Diameter (in): The perforation diameter as defined in the completion dialog. This parameter is most important in gravel pack completions. This option is unavailable when no completion is defined.

Perforation Penetration(in): The length of the perforation tunnel as defined in the cased hole completion dialog . This option is unavailable when a gravel pack completion is defined and the flow length is defined instead.

Flow Length (in): The gravel pack flow length as defined in the gravel pack completion dialog. This option is valid only for gravel pack completions.

Water Cut : This is the only sensitivity that affects both the IPR and hydraulics (multiphase) calculations since the fluids produced are also the fluids in the wellbore, tubing and flowline. If this option is selected, it defines both the hydraulic and IPR sensitivities. It is not valid if test data was supplied, if the well is dry gas, or if a multiphase sensitivity has already been selected.

Skin: The skin factor used in the IPR calculations. It is helpful in estimating the impact of stimulation operations.

Other IPR Sensitivities

Back Pressure C factor

Perforation Efficiency

Fluid Level 1

Fluid Level 2

Back Pressure N factor

Productivity Index

Bottom Hole Test Pressure 2

Stabilized Pressure

Ramey D factor

Flow Rate 1

Flow Rate 2

Test Rate 1

Test Rate 2

Stabilized Rate

Skin Factor

Constant PI Reservoir Pressure

Reservoir Pressure

Net Thickness

Drainage Radius

Reservoir Permeability

Wellbore Radius

Formation Mechanical Skin

Zonal Water Cut

Permeability in the axis of the Hwell

Permeability in the perp to axis of the Hwell

Horizontal Well Drainage area

Distance from heel end of drainage to heel

Distance from heel end of drainage to toe

Length of side along Hwell axis

Distance in from side to Hwell axis

Length of side perp to Hwell axis

Distance from top of Hwell area

Fracture Length

Porosity

Producing Time

Total Compressibility

Fracture Width

Fracture Conductivity

Gravel Permeability

Perforation Diameter

Perforation Tunnel Length

Perforation Interval

Shot Density

Completion Permeability

Completion Thickness

Test Rate 1

Bottom Hole Test Pressure 1

Test Rate 2

Bottom Hole Test Pressure 2

Shut-in Pressure

PVT Sensitivities:

API Gravity

FVF Correlation

GOR Correlation

Oil Viscosity Correlation

Kuparuk Depth

Oil Formation Volume Factor

Gas-Oil Ratio

Solution GOR Correlation

Liquid Yield

Bubble Point Pressure

V&B Reference Pressure

Gas Specific Gravity

Specific Gravity of Free Gas

Specific Gravity of Solution Gas

Oil Specific Gravity

Water Specific Gravity

Surface Tension

V&B Reference Temperature

Gas Viscosity

Liquid Viscosity

Water Cut

Z Factor

Kuparuk Zone Option

Combined Sensitivities:

Water Cut (fraction): Since the water cut affects both the IPR and tubing hydraulics, it is run as a combined sensitivity. Selecting this option will turn off all other sensitivities.