Viscosity of water and hydrocarbon changes with micro-crevice thickness

•Viscosity of fluid in micro-crevice increases as thickness of the micro-crevice decreases.•Viscosity increasing of fluids in small micro-crevice is correlated to energy decay and energy dissipation rate of the measuring system.•Viscosity of the fluid in small micro-crevice is affected by solid surface and fluid molecule structure.

Viscosity of C10, C12, C14, C16 and water in micro-crevice of 100–1500 μm was measured with a proprietary micro-crevice viscometer that was developed earlier in our laboratory. The viscosity was calculated based on a newly proposed model for fluid in the scale of micro-crevice stated above. The results of the study show that the viscosity of the fluids in small micro-crevice increases as the thickness of the micro-crevice decreases at low shear rate(1.34–9.07 s−1). The viscosity of the fluids is correlated to energy decay and dissipation rate of measuring system. When h < hdis, C10, C12, C14, C16 and water in small micro-crevice become dilatant fluid, therefore, η, Edec, Edis-rate and τ of the fluids increase as h decreased. Due to hdis of C10, C12, C14 and C16 is increased with increasing molecular mass, and hdis of water which is a polar molecule is bigger than that of C16 which is a non-polar molecule, the properties of fluid in small micro-crevice are not only affected by solid surface but also by fluid molecular structure.

Graphical abstractViscosity of water and hydrocarbons vs h at 25 °C.Due to effect of solid surface and fluid molecule structure the viscosity of fluid in micro-crevice increases as thickness of the micro-crevice decreases.Figure optionsDownload full-size imageDownload as PowerPoint slide