Perforation Friction Calculator
Calculate perforation friction pressure, velocity per perforation, hydraulic horsepower loss, and design limited entry completions.
Input Parameters
ΔPperf = 0.2369 × ρ × Q² / (n² × Cd² × d4)
HHP = ΔP × Q / 40.8 | vperf = Q / (n × Aperf)
Perforation Friction
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Velocity per Perf
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Hydraulic HP Loss
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Rate per Perf
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Limited Entry: Perfs Needed
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Erosion Risk
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Perforation Friction vs Number of Perforations
How this was calculated
Equation: dP = 0.2369 * rho * Q^2 / (n^2 * Cd^2 * d^4). Where: dP = perforation friction (psi), rho = fluid density (ppg), Q = pump rate (bbl/min), n = number of perfs, Cd = discharge coefficient, d = perf diameter (in).
Discharge coefficient: Cd accounts for entrance effects. New perfs: 0.95. Slightly eroded: 0.89. Heavily eroded: 0.60-0.70. Proppant-eroded perfs have lower Cd initially, then increase as they erode open.
Limited entry: By reducing the number of perforations, you increase perf friction to force uniform fluid distribution across multiple zones. Target perf friction is typically 300-700 psi for effective diversion.
Erosion risk: When velocity exceeds ~100 ft/s, perf erosion becomes significant with sand-laden fluids, increasing Cd and reducing friction over the course of the treatment.
HHP: Hydraulic horsepower = dP * Q / 40.8. This is the power wasted pushing fluid through perforations.
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Book a free strategy call →Understanding Perforation Friction in Hydraulic Fracturing
Perforation friction is the pressure drop that occurs as fluid is forced through the small openings (perforations) in the casing and cement. This pressure loss is proportional to the square of the flow rate and inversely proportional to the square of the number of perforations and the fourth power of the perforation diameter.
In conventional completions with many perforations, perf friction is typically a small component of the total treating pressure. However, in limited entry designs, the number of perforations is deliberately reduced to create sufficient friction to divert fluid uniformly across multiple zones with different stress profiles. A typical target of 300-700 psi of perf friction ensures that all clusters receive fluid, even if closure stress varies by several hundred psi between clusters.
Perf erosion is a critical consideration: as sand-laden fluid passes through perforations at high velocity, the perforation diameter increases over time, reducing friction and potentially defeating the limited entry strategy. Monitoring treating pressure for declining perf friction signatures is essential for diagnosing erosion during a treatment.
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