Method of removing an invert emulsion filter cake after the drilling process using a single phase microemulsion

A method for open hole completion comprising:

• drilling to total depth with an invert emulsion drilling fluid, which fluid comprises acid-soluble weighting agents and forming a filter cake of the weighting agents;
• making a trip into a casing above an open hole;
• running back a work string into the open hole to the bottom;
• pumping a base oil spacer to scour an external filter cake in the wellbore;
• pumping a viscosified, weighted push pill comprising at least the invert emulsion drilling fluid;
• pumping a solids-free invert emulsion drilling fluid into the open hole and the casing above the open hole;
• picking up the work string to a casing shoe;
• screening the solids in the drilling fluid to a size that will not plug completion screens;
• pulling the work string out of the casing above the open hole to the surface;
• running a completion screen to the bottom of the hole;
• tripping out of the hole with the work string;
• running in the hole with a packer, ball valve, wash pipe and setting packer;
• spotting a single phase microemulsion soak solution in the open hole and into the casing above the open hole, where the single phase microemulsion soak solution comprises a single phase microemulsion;
• displacing above packer assembly the single phase microemulsion;
• checking leak-off;
• allowing the single phase microemulsion to penetrate filter cake without circulating the well;
• and
• preparing to inject water or produce hydrocarbons.

A method of removing a majority of water-in-oil invert emulsion and filter cake particles from a hydrocarbon reservoir wellbore comprising:

• drilling a wellbore in a hydrocarbon reservoir with an invert emulsion drilling fluid;
• forming a filter cake of water-in-oil invert emulsion and bridging particles over at least part of the wellbore;
• pumping into the wellbore a single phase microemulsion gravel pack carrier brine having:
• sized gravel, and
• placing a gravel pack into the wellbore;
• incorporating the invert emulsion into the single phase microemulsion by solubilization without circulating the well;
• changing the wettability of the filter cake particles from oil-wet to water-wet allowing the single phase microemulsion to contact the filter cake for a time as a soak solution;
• and
• removing a majority of the filter cake particles.