A fibre optic probe system was used to measure the profiles of vertical particle velocities in the spout and the fountain of a half‐column and a full‐column spouted bed. In addition, a fibre optic image probe was employed to measure vertical particle velocity profiles in the annulus of the full‐column. In the spout, radial profiles of vertical particle velocities were of near Gaussian distribution. Particle velocities along the spout axis in the half‐column were 30% lower than in the full‐column under identical operating conditions. In the half column, particle velocities adjacent to the front plate were approximately 24% lower than a few millimeters away. The fountain core expanded suddenly near the bed surface and then gradually contracted with height. The model of Grace and Mathur (1978) gave good predictions of fountain heights for the full‐column. In the annulus region, there was a 28% difference between particle velocities adjacent to the column wall and those only 2 mm away. The integrated upward solids mass flow in the spout and the downward solids flow in the annulus matched well at different bed levels.

A fibre optic probe has been used to measure voidage profiles in the fountain, spout and annulus of spouted beds. The voidage in most of the annulus was found to be somewhat higher than the loose‐packed voidage and increased with increasing spouting gas flow rate, contrary to usual assumptions. There is a denser region in the annulus where the voidage was a little lower than the loose‐packed bed voidage. In the core of the fountain, the voidage decreased with height for low spouting gas flow rate, consistent with the model of Grace and Mathur (1978); however, at higher gas flow rate, it first increased with height and then decreased towards the fountain top. The radial profiles of local voidage were roughly parabolic in the lower portion of the spout and blunt in the upper portion.

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Calcium ion contamination in water-based drilling fluids (WBDs) dramatically increases filtration volume loss and worsens rheological properties, especially in high-temperature bore holes. This study demonstrated two types of acrylamide polymers as anti-calcium contamination fluid-loss additives in WBDs, including an amphoteric polymer (ADD) synthesized by 2-acrylamide-2-methylpropanesulfonic acid (AMPS), acrylamide (AM), and diallyl dimethylammonium chloride (DMDAAC) and an anionic polymer (AD) synthesized by AMPS and AM. In transmission electron microscopy (TEM) of sodium bentonite (Na-BT)-based mud under 11.1% CaCl2 contamination and 150 °C hot rolling, a typical “star-net” structure was observed between the ADD and Na-BT layers; however, polymer AD could not form such a net structure. Energy-dispersive spectrometry (EDS) analysis of the Na-BT layer indicated that ADD could greatly decrease the amount of Ca2+ on Na-BT layers in comparison to AD. Accordingly, in an American Petroleum Institute (API) filtration test and a rheological test of Na-BT-based mud with 11.1% CaCl2 contamination after 150 °C hot rolling, Na-BT-based mud with 1.5% ADD could maintain an API filtration volume (FLAPI) as low as 9.6 mL, whereas Na-BT-based mud with 1.5% AD maintained a FLAPI of 36 mL. The rheological properties of Na-BT-based mud also showed that ADD could maintain higher viscosity and shear stress than AD, suggesting that amphoteric polymer ADD was suitable for making WBDs more resistant to calcium contamination and high temperature.

Hydrodynamic measurements were obtained in a half‐column of diameter 0.91 m equipped with a conical base using particles of diameter 3.3 to 6.7mm with operation both as pure spouted beds and in the spout‐fluid bed mode. Comparison of the experimental results for minimum spouting velocity with equations in the literature generally gave unsatisfactory agreement. On the other hand, the correlations of McNab (1972) and Hadžisdmajlović et al. (1983) gave reasonable predictions of spout diameters in spouted and spout‐fluid beds respectively. Hydrodynamic regimes with auxiliary air present were broadly similar to those determined in smaller columns. However, there were substantial dead regimes at the bottom of the column. A finite difference model based on the vector form of the Ergun equation gave good predictions of air flow distribution and longitudinal pressure profiles.

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