| CPC C09K 8/32 (2013.01) [C09K 8/032 (2013.01); E21B 21/08 (2013.01)] | 6 Claims |

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1. A method for performing a drilling operation employing pressurized mudcap drilling (PMCD) techniques using a hollow glass bead (HGB) fluid, comprising:
providing an HGB fluid with a density of 3.5 pounds per gallon (ppg) to 6.0 ppg by suitably mixing the following combination of constituents:
a base oil;
an oil viscosifying agent comprising a hydrogenated polyisoprene (HPI) star polymer;
hollow glass beads (HGBs);
an organophilic clay;
a clay activator comprising an oil-soluble, polar material;
a surfactant comprising a silicone block copolymer; and
a liquid oil-soluble hydrogen sulfide (H2S) scavenger;
drilling a wellbore through a reservoir using a drill bit arranged at an end of a drill string, wherein an annulus is defined between the drill string and an inner wall of the wellbore;
closing the annulus;
pressurizing the annulus by introducing the HGB fluid into the annulus; and
pumping a sacrificial fluid through the drill string with the HGB fluid placed in the annulus.
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