Analyze drilling fluid behavior with fast rheology calculations. Compare plastic viscosity, yield point, and flow trends. Export clean reports for field checks and engineering reviews.
The chart helps compare the two measured points used in the viscosity estimate.
Plastic viscosity for drilling fluid is commonly estimated from Fann viscometer dial readings using the Bingham plastic model:
Plastic Viscosity (PV) = θ600 − θ300
Where θ600 is the 600 RPM dial reading and θ300 is the 300 RPM dial reading.
Related indicators often reviewed with PV are:
PV reflects internal friction caused mainly by solids concentration, solids shape, and base fluid viscosity. A higher PV often signals greater pump pressure demand and reduced hydraulic efficiency.
These example records show how plastic viscosity changes across different drilling fluid samples.
| Sample | 600 RPM | 300 RPM | PV (cP) | AV (cP) | YP |
|---|---|---|---|---|---|
| Sample A | 68 | 42 | 26 | 21 | 16 |
| Sample B | 74 | 48 | 26 | 24 | 22 |
| Sample C | 63 | 39 | 24 | 19.5 | 15 |
| Sample D | 81 | 51 | 30 | 25.5 | 21 |
| Sample E | 59 | 36 | 23 | 18 | 13 |
Plastic viscosity represents resistance caused by internal friction within the fluid. In drilling applications, it often reflects solids concentration, base fluid thickness, and how easily the mud can circulate through the system.
Those two standard viscometer readings provide a quick field estimate under the Bingham plastic assumption. Their difference gives a practical plastic viscosity value without requiring full rheological curve fitting.
There is no universal best value. Acceptable plastic viscosity depends on hole size, solids content, hydraulics, and mud program goals. Lower values improve pumpability, while excessively low values may indicate weak carrying support.
Yes. It calculates yield point using the common relation YP = θ300 − PV. Reviewing PV and YP together gives a more complete picture of drilling fluid carrying capacity and flow behavior.
No. Plastic viscosity measures internal friction effects, while apparent viscosity is a broader effective viscosity at a selected shear condition. Both are useful, but they describe different aspects of drilling mud performance.
A sudden rise can result from higher drilled solids, poor solids control, contamination, increased weighting material, or fluid chemistry changes. Temperature shifts and measurement issues can also contribute to abnormal readings.
Yes, with caution. The calculator follows a simple two-point Bingham style estimate. It works best where that assumption is reasonable. Complex non-Newtonian fluids may require broader rheological testing.
CSV export saves a structured data file for spreadsheet analysis. PDF export uses the browser print dialog to generate a clean report that includes the visible result summary, graph section, and reference content.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.