Drilling Engineering Lab Report

Lab Report: DRILLING FLUID (MUD) DENSITY Objective: The aim of this experiment is to determine the mud density, specific gravity and hydrostatic pressure gradient for water-based-mud, WBM (Drilling fluid) using the OFITE mud balance. Theory: Drilling fluids are used during the drilling of boreholes, either for oil wells or water boles holes. One of the major functions of a drilling fluid includes providing hydrostatic pressure to prevent formation fluids from entering the wellbore. To ensure that the hydrostatic pressure balances out with formation pressure and that the wellbore is stable, the mud density has to be taken into consideration. Higher formation pressure require higher mud density (this can be achieved by adding more barite to the drilling fluid) and vice versa. Using an incorrect drilling fluid (in terms of its mud density), can result in a formation damage thereby leading to a well blowout. Equipment and Materials: The mud density is determined using the mud balance shown in Fig. 1. This 4-scale instrument provides an accurate way to measure some parameters which are: Fig. 1 * Density in ppg and pcf * Specific gravity * Pressure gradient in PSI/1000ft) The balance uses the cantilever design (fixed somewhere on the lever arm). The cup is attached to one end and the counter weight on the other end. The lever arm is calibrated, the rider also acts as a counterweight and there is a level glass to determine when the instrument is balanced. A thermometer is also required to measure the temperature of the drilling fluid to be tested. Procedure: The instrument was wiped down and then place in the carrying case. * The temperature of the first drilling fluid (water) was noted down * The mud cup got filled up with the drilling fluid and covered. It got wiped down due to the overflowing liquid from the sides and the opening on the lid. This overflowing shows that the trapped gas/air bubbles, if any, have been expelled and the cup is properly full. * The rider is then moved on the arm to find the equilibrium position i. e. when the bubble in the level glass is in the middle. * The readings are then taken. The cup is rinsed out and wiped down, ready for the next drilling fluid. * The procedure is repeated again, to find the details of the drilling fluid and all results are recorded in a table. Table of Results: | WATER| MUD SAMPLE| Temperature, ? | 19. 60| 17. 00| Specific Gravity | 1. 00| 1. 04| Density, lbm/ft3 (pcf)| 62. 00| 65. 00| Density, lbm/gal (ppg)| 8. 30| 8. 70| Density, Kg/m3| 1000. 00| 1043. 00| Pressure gradient, psi/1000ft| 430. 00| 455. 00| Mud gradient = 8. 7 x 0. 052 = 0. 45 psi/ft Density in g/cm3= 8. 7/8. 345 = 1. 04 g/cm3