Effect of Pressure on the Rheological Properties of Maya Crude Oil

Abstract

At atmospheric pressure, hydrocarbon resources, such as bitumen and Maya and other heavy oils, have been shown to exhibit non-Newtonian behavior at or below typical ambient temperatures. This work is devoted to investigating the effect of pressure on the non-Newtonian rheological properties of Maya crude oil (a commercial heavy oil blend from Mexico). Measurements were performed from 258 to 333 K, using a stress-controlled rheometer, at pressures up to 150 bar and over a broad range of shear rates. Maya crude oil was shown to be a shear-thinning fluid below 313 K exhibiting thixotropy below 293 K, at atmospheric pressure, in a prior work. At fixed temperature, the magnitude of the non-Newtonian behaviors of Maya crude oil appears to increase with increasing pressure, and shear thinning is shown to persist to higher pressures below 313 K. Boundaries of the non-Newtonian region with respect to temperature, pressure, and viscosity are identified and discussed. The thixotropic behavior of Maya crude oil is also shown to persist at higher pressure, and the recovery of the moduli at rest appears to be faster at elevated pressures than at atmospheric pressure.

Basic Fundamentals of Petroleum Rheology and Their Application for the Investigation of Crude Oils of Different Natures

“…The same is true for other heavy oils and bitumens, ,, in which, at low temperatures, there is no crystallization of paraffin waxes or loss of asphaltenes solubility. Besides, it should be noted that the viscosity of heavy oils increases with increasing pressure, the growth of which, however, does not lead to the appearance of a yield stress. , In any case, the non-Newtonian behavior of heavy oils manifests itself poorly and does this only at high shear rates and high pressures and low temperatures ,,, close to the formation temperature of a solid-continuous phase state …”

Modeling of viscoelastic properties of nonpermeable porous rocks saturated with highly viscous fluid at seismic frequencies at the core scale

“…Second, we have assumed here that Maxwell's phenomenological model provides a valid basis for describing the viscoelastic behavior of the saturant. It is not clear that this is the case for the very complex behavior that such “viscous” fluids exhibit during shearing in silicate melts [e.g., Falenty and Webb , ; Green and Cooper , ] or heavy hydrocarbons [e.g., Mortazavi‐Manesh and Shaw , ]. This lack of knowledge with regard to the detailed time‐dependent rheological character of such viscous fluids will continue to be a limiting factor in the applicability of any modeling.…”

“…At the other, highly heavy hydrocarbons saturate both siliclastic and carbonate formations in many sedimentary basins globally. Like silicate melts, the structure and rheology of these fluids is particularly complex [e.g., Mortazavi-Manesh and Shaw, 2016;Behzadfar and Hatzikiriakos, 2013;Bazyleva et al, 2011]. We expect such viscous fluid to influence seismological observations.…”

Pressure Effect on the Rheological Behavior of Waxy Crude Oil with Comb-Type Copolymers Bearing Azobenzene Pendant

“…9,10 As reported in the literature, under high pressure, the oils show persistence and the moduli at rest recover rapidly. 11 It reveals that high pressure not only results in the high viscosity of oils but also leads to typical non-Newtonian behaviors. So far, the cold flowability of oils and the efficacy of chemical additives have been intensively researched at atmospheric pressure, including the rheological properties and the crystallization behaviors of waxes.…”

“…In fact, crude oils are usually stored in the reservoir or transported in pipelines under high pressures. In the case of deep oil spills, the surrounding pressure is of even greater concern. − Due to the limitations of current measuring methods, little work on the flowability of oils at high pressure is reported. , As reported in the literature, under high pressure, the oils show persistence and the moduli at rest recover rapidly . It reveals that high pressure not only results in the high viscosity of oils but also leads to typical non-Newtonian behaviors.…”