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Title: Rheology of oil-base muds

Conference ·
OSTI ID:7159582

The rheological behaviour of invert emulsion muds has been studied at pressures up to 1000 bar and temperatures up to 140/sup 0/C. Rheological parameters were calculated for the Bingham, Herschel-Bulkley and Casson rheological models. The Herschel-Bulkley and Casson models both give good fits to the experimental rheograms. The Casson model is more reliable for extrapolation purposes than the Herschel-Bulkley model. A pair of two similar exponential expressions were found to be able to model the pressure and temperature behaviour of the two parameters of the Casson model. The expressions, which are based on the relation for pure liquids derived theoretically, contain temperature dependent pressure coefficients. The simplifications inherent in the temperature and pressure model are discussed in the light of the temperature and pressure behaviour of the viscosity of common base oils and their constituent hydrocarbons. Field application of the model requires measurement of the rheology of the mud at two or more temperatures and knowledge of the pressure coefficients relating the behaviour of the plastic viscosity to that of the yield point, or the Casson high shear viscosity to that of the Casson yield stress. Pressure measurements or other information are then not required. Applications can be based on Casson or Bingham rheological measurements. The relationships between the parameters of the Casson and Binham models are discussed.

Research Organization:
Schlumberger Cambridge Research
OSTI ID:
7159582
Report Number(s):
CONF-861080-
Resource Relation:
Conference: Society of Petroleum Engineers annual technical conference and exhibition, New Orleans, LA, USA, 5 Oct 1986
Country of Publication:
United States
Language:
English