Horizontal Well Dimensionless Pressure Drop Calculator
Enter area-based dimensionless time, horizontal shape factor, lateral length in feet and drainage area in square feet to return dimensionless pressure drop.
Enter area-based dimensionless time, horizontal shape factor, lateral length in feet and drainage area in square feet to return dimensionless pressure drop.
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Calculation context and source notes
Evaluate the implemented horizontal-well pressure expression from area-based dimensionless time, drainage area, lateral length and horizontal shape factor. The result is dimensionless pressure drop, not a pressure in psi or a productivity index.
Use this reference to check the arithmetic of the cited bounded-reservoir expression. Since 4(L/2)^2 equals L^2, the first logarithm uses A/L^2. Keep A in square feet when L is in feet and obtain dimensionless time and shape factor from a compatible model rather than assuming the defaults describe a field case.
Solves for
P_D (dimensionless)
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Formula, variables, and sourceFormula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns P_D = 1.68803 dimensionless. Defaults demonstrate the implementation; they are not recommended field values.
0.1
30
2000
27878400
Input definitions
t_DA
dimensionlessDimensionless Time Based on Drainage Area
C_Ah
dimensionlessHorizontal Well Shape Factor
L
ftHorizontal Well Length
A
ft^2Drainage Area
Output definitions
P_D
Wellbore Dimensionless Pressure Drop
t_DA
Dimensionless Time Based on Drainage Area
C_Ah
Horizontal Well Shape Factor
A
Drainage Area
Engineering use, assumptions, and limits
Use this reference to check the arithmetic of the cited bounded-reservoir expression. Since 4(L/2)^2 equals L^2, the first logarithm uses A/L^2. Keep A in square feet when L is in feet and obtain dimensionless time and shape factor from a compatible model rather than assuming the defaults describe a field case.
Assumptions
- Dimensionless time and the horizontal shape factor are supplied on the basis of the cited pressure expression.
- Drainage area and lateral length use compatible area and length units; both logarithm arguments must be positive.
Limitations
- The calculator does not establish when the reservoir reaches pseudosteady-state flow or derive the horizontal shape factor.
- A dimensionless result cannot be interpreted as psi without a compatible dimensional pressure conversion; this is not the Joshi steady-state productivity-index calculator.
Common mistakes
- Entering acres for A while leaving the lateral length in feet; one acre must be converted to 43,560 square feet.
- Using base-10 logarithms instead of the natural logarithms in the expression.
- Entering elapsed hours as area-based dimensionless time or substituting an unrelated shape factor.
Frequently asked questions
What inputs does the Pseudosteady-State Dimensionless Pressure Drop for Horizontal Well calculator need?
The calculation uses Dimensionless Time Based on Drainage Area (t_DA), Horizontal Well Shape Factor (C_Ah), Horizontal Well Length (L), Drainage Area (A). Enter values on the units shown beside each field.
What result does this calculator return?
The primary result is wellbore dimensionless pressure drop in dimensionless. The formula section shows the declared relationship, variables, and a reproducible default calculation.
What should I check before using the result?
Confirm the unit basis, source applicability, and input quality. The calculator does not establish when the reservoir reaches pseudosteady-state flow or derive the horizontal shape factor. Entering acres for A while leaving the lateral length in feet; one acre must be converted to 43,560 square feet.
Source and record status
Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.
Joshi, S. D. Horizontal Well Technology, PennWell Publishing Company, Chapter 7, Page 216.
Open source reference