This study presents a simplified and accurate procedure for selecting the
rheological model which best fits the rheological properties of a given non-
Newtonian fluid and introduces five new approaches to correct for tool joint
losses from expansion and contraction when hydraulics is calculated. The new
approaches are enlargement and contraction (E&C), equivalent diameter (ED),
two different (2IDs), enlargement and contraction plus equivalent diameter
(E&C+ED), and enlargement and contraction plus two different IDs (E&C+2IDs).
In addition to the Newtonian model, seven major non-Newtonian rheological
models (Bingham plastic, Power law, API, Herschel-Bulkley, Unified, Robertson
and Stiff, and Casson) provide alternatives for selecting the model that most
accurately represents the shear-stress/shear-rate relationship for a given non-
Newtonian fluid.
The project assumes that the model which gives the lowest absolute average
percent error (EAAP) between the measured and calculated shear stresses is the
best one for a given non-Newtonian fluid.
The results are of great importance in achieving correct results for pressure drop
and hydraulics calculations and the results are that the API rheological model (RP 13D) provides, in general, the best prediction of rheological behavior for the
mud samples considered (EAAP=1.51), followed by the Herschel-Bulkley,
Robertson and Stiff, and Unified models. Results also show that corrections with
E&C+2IDs and API hydraulics calculation give a good approximation to
measured pump pressure with 9% of difference between measured and
calculated data.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4334 |
| Date | 30 October 2006 |
| Creators | Viloria Ochoa, Marilyn |
| Contributors | Juvkam-Wold, Hans |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 1961721 bytes, electronic, application/pdf, born digital |
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