Hole Cleaning Index Calculator
Calculate the Carrying Capacity Index (CCI), critical transport velocity, and cuttings transport efficiency. Identify risk zones for cuttings beds in deviated wells.
Input Parameters
CCI = MW × AV × YP / 400,000
Transport Ratio = AV / Critical_Transport_Velocity
CCI
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Transport Ratio
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Critical Velocity
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Annular Area
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Assessment & Recommendations
CCI & Transport Ratio vs. Hole Angle
Shows how hole cleaning difficulty changes with inclination. The 30-60° range is the most challenging for cuttings transport.
How this was calculated
CCI (Carrying Capacity Index): CCI = MW x AV x YP / 400,000. Values > 1.0 indicate good cuttings transport; < 0.5 indicates poor transport and likely cuttings accumulation.
Critical transport velocity: Estimated minimum annular velocity for cuttings transport, adjusted for hole angle. Higher angles (30-60 deg) require higher velocities due to cuttings bed formation tendency.
Angle correction: A sinusoidal correction factor peaks around 45 deg inclination, where cuttings beds are most difficult to remove because gravity and fluid flow are at their worst combined angle.
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Book a free strategy call →Understanding Hole Cleaning in Drilling
Hole cleaning is the process of removing drill cuttings from the wellbore annulus. Inadequate hole cleaning leads to pack-offs, stuck pipe, excessive torque and drag, poor cement jobs, and increased non-productive time (NPT). The problem is significantly more challenging in deviated and horizontal wells where gravity causes cuttings to settle on the low side of the hole, forming cuttings beds.
The Carrying Capacity Index (CCI) is a practical field metric that combines the three most important factors for cuttings transport: mud weight (buoyancy), annular velocity (drag force), and yield point (suspension ability). While simplified, CCI correlates well with field observations and is widely used for quick assessments.
The critical angle range of 30-60 degrees from vertical is where hole cleaning is most difficult. At these angles, cuttings slide down the low side of the hole faster than the fluid can carry them up, forming stationary beds that grow over time. Below 30 degrees, gravity helps move cuttings upward. Above 60 degrees, cuttings beds tend to be more stable and can be managed with periodic wiper trips and high flow rates.
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