US 11,926,789 B2
Additives for wellbore cleaning and fluid displacement
Dorianne Castillo, Houston, TX (US); Erna Kakadjian, The Woodlands, TX (US); and Saniya Syed, Houston, TX (US)
Assigned to Baker Hughes Oilfield Operations LLC, Houston, TX (US)
Filed by Baker Hughes Oilfield Operations LLC, Houston, TX (US)
Filed on Jul. 22, 2021, as Appl. No. 17/383,267.
Prior Publication US 2023/0022139 A1, Jan. 26, 2023
Int. Cl. C09K 8/524 (2006.01); C09K 8/035 (2006.01); C09K 8/536 (2006.01)
CPC C09K 8/524 (2013.01) [C09K 8/035 (2013.01); C09K 8/536 (2013.01); C09K 2208/30 (2013.01)] 4 Claims
 
1. A solid weighting agent-free, brine-based viscosified pill formulation for displacement or removal of a drilling fluid, the formulation comprising:
about 80 vol. % to about 95 vol. % viscosified brine; and
about 5 vol. % to about 20 vol % of a surfactant-solvent blend comprising:
about 5 wt. % to about 40 wt. % of at least one non-ionic surfactant;
about 5 wt. % to about 20 wt. % of at least one polyglycerol ester;
about 20 wt. % to about 60 wt. % of at least one co-solvent;
about 20 wt. % to about 25 wt. % water; and
about 1 wt. % to about 15 wt. % of at least one hydrophobic solvent, wherein the at least one hydrophobic solvent is an olefinic ester; and
where the formulation contains no solid weighting agents, and does not form a microemulsion.