Visualization of Fluid-Loss Polymers in Drilling-Mud Filter Cakes

Summary The appearance of fluid-loss polymers in freeze-dried drilling-mud filter cakes was studied with scanning-electron-microscope (SEM) photography. Three fluid-loss polymers were studied: starch, polyanionic cellulose (PAC), and a high-temperature- (HT)-stable, sulfonated polymer. The effects of electrolyte contamination (NaCl, CaCl2, and MgCl2) and temperature (200 to 350°F) on the appearance of the fluid-loss polymers were also studied. A correlation between API filtrate and polymer appearance was sought.