During this first Quarter of the Project, a team of five individuals was formed to characterize aphron drilling fluids, with the ultimate objectives to gain acceptance for this novel technology and decrease the costs of drilling mature and multiple-pressure formations in oil and gas wells. Aphron drilling fluids are very high low-shear-rate viscosity fluids laden with specially designed microbubbles, or ''aphrons.'' The focus of the Project is to develop some understanding of the aphron structure and how aphrons and base fluid behave under downhole conditions. Four tasks were begun during this Quarter. All of these focus on the behavior of aphrons: (a) Aphron Visualization - to evaluate various methods of measuring bubble size distribution, especially Acoustic Bubble Spectroscopy (ABS), in aphron drilling fluids at elevated pressure; (b) Fluid Density - to investigate the effects of pressure, temperature and chemical composition on the survivability of aphrons; (c) Aphron Air Diffusivity - to determine the rate of loss of air from aphrons during pressurization; and (d) Pressure Transmissibility - to determine whether aphron networks (similar to foams) in fractures and pore networks reduce fracture propagation. The project team installed laboratory facilities and purchased most of the equipment required to carry out the …