Abstract
A new device for measuring the lubricity of drilling fluids for controlling the mechanical friction is developed. This is able to measure mechanical friction at temperatures between room temperature and 200°C and at pressures in the range of atmospheric to 20 000 psi. The effects of lubricants on mechanical friction is outlined. Different types of available test instruments are reviewed. These instruments include both commercial equipment and special designed equipment. In addition, the effect of pressure and temperature as well as their combined effect on the friction coefficient of deionized water, mineral oil and oil-based mud (OBM) have been investigated as initial test of the developed instrument. Our initial results show that friction coefficient increases with pressure increase for the mineral oil and OBM, at 25°C. However, when deionized water was used as lubricant, the friction coefficient decreased when pressure was increased.