4) {+45} ChevBob decides to use a largely solids-free water-based solution of the highly soluble potassium formate (KCOOH) salt for drilling a reservoir interval with alternating sand-shale formations. The required initial mud weight is 11 ppg. KCOOH solubility data is given in the table enclosed with the Equations sheets. Answer the following questions: a) {+10} Do KCOOH brine solutions follow ideal mixing rules? Explain your answer. Also briefly explain the difference between ideal and non-ideal mixing. b) {+10} What is the required weight percentage (wt%) of KCOOH to generate the required density, and what mass (Ibm) of KCOOH will need to be added to a barrel of freshwater (with a density of 1.0 SG) to achieve the required density? c) {10} What will be the concentration of KCOOH in ppm and in mg/L? d) {15} As already indicated in problem (3), there is a chance that higher-than-expected pore pressures are encountered in the gas reservoir, in which case the mud needs to be weighted up quickly from 11.0 ppg to 12.5 ppg. This can be done with addition of 4.8 SG MicroMax (Manganese Tetroxide, Mn304, an insoluble compound). To maintain optimum viscosity, 1 gal of water needs to be added for every 100 Ibm of Mn304 added. For 600 bbl limited volume, calculate how much fluid (in bbl) will need to be discarded (to be recycled) and how much MicroMax (in Ibm) and water (in bbl) needs to be added to achieve the required 12.5 ppg density.