Patent ID: 7736521

Claim:
Method of filtering and conserving a used oil well fluid containing a viscosifying agent comprising (a) monitoring the viscosity of said fluid, (b) if the viscosity of said fluid is deemed too high to pass through a filter, reducing the viscosity thereof to a value acceptable for filtering, filtering said fluid and recovering said filtered fluid for reuse of at least a portion of said fluid as a well fluid or a well fluid component, (c) if the viscosity of said fluid is deemed too low to be reused, removing water therefrom, thereby obtaining a concentrated fluid, filtering said fluid before or after removing water from it, and recovering said filtered concentrated fluid for reuse of at least a portion of said fluid as a well fluid or a well fluid component, and (d) if the viscosity of said fluid is neither deemed too high to pass through a filter nor too low for said fluid to be reused, filtering said fluid and recovering the filtered fluid thus obtained for reuse of at least a portion of said filtered fluid as a well fluid or a well fluid component.