ACTIVITY 3: Density of a drilling fluid and its role in well bore stability (30 minutes) Lecture recap: The density of mud (commonly referred to as mud weight) is the parameter that can keep the borehole open. Insufficient mud density (weight) can cause borehole instability and borehole collapse. The mud density provides sufficient hydrostatic pressure which can result in stability of borehole. The required bottom-hole pressure at this depth to keep the wellbore stable is 58 MPa. The mud is made up of water, 2 kg of polymer per m of water, and barite. The barite will be suspended by the mud. Densities: Barite - 4200 kg/m3, Polymer - 2000 kg/m' and Water - 1000 kg/m3 The drilling depth (km) can be found from inserting your initials into the Excel worksheet below (double-click to open Excel): Initial #1 Initial #2 depth (km) r k 4.52 (a) Calculate the required mud weight (density, kg.m) to ensure wellbore stability, showing your working. (b) Calculate the mass of barite (tonnes) required to make up the mud, if the available water is 1000 m3. Show your working