The oil-wetting agent concentration has an effect similar to that of emulsifier concentration on the PV and this effect is used for its optimization. As with emulsifier, slight overtreatment with oil-wetting agent is better than undertreatment. Barite was used as the weighting agent because of its low cost. A base fluid with the lowest viscosity was chosen. Critical Mud Properties Mud Weight.
Mud weight is most critical because of the small drilling window.
In the past, a constant mud weight was maintained at the flowline irrespective of flowline temperature. In the Shearwater project, a standard temperature was defined and used to correlate surface mud weight with equivalent downhole mud weight. Surface mud weight was controlled by a temperature vs. mud weight chart. Therefore, every effort was made to minimize the PV in mud-formula optimization. A validated hydraulics program was used to calculate mud weight, optimum rheology, pump rate, and tripping procedures.