In situ microemulsions used as spacer fluids

摘要

Nanoemulsions, miniemulsions, microemulsion systems with excess oil or water or both (Winsor III) or single phase microemulsions (Winsor IV) may be formed in situ during hydrocarbon recovery operations after drilling with OBM or SBM using one or more fluid pills. The nanoemulsions, miniemulsions, microemulsion systems with excess oil or water or both or single phase microemulsions remove oil and solids from the well and wellbore surfaces. In one non-limiting embodiment, a single phase microemulsion (SPME) or other in situ-formed fluid may be created from a polar phase, a nonpolar phase, at least one viscosifier, and at least one surfactant.

主权项

1. A method of removing at least a portion of oil-based mud or synthetic-based mud (O/SBM) from a wellbore comprising:
drilling a wellbore with an O/SBM, which drilling forms contaminants and residual oily debris in the wellbore; pumping a fluid pill into the wellbore, where the fluid pill comprises:
at least one surfactant; andwater or brine; forming a Winsor IV microemulsion in situ in the wellbore; and contacting the O/SBM contaminants and residual oily debris with the Winsor IV microemulsion and removing at least a portion of the O/SBM contaminants and residual oily debris contacted with the Winsor IV microemulsion from the wellbore.