Patent ID: 7568535

Claim:
A method for recovering lost circulation material from spent drilling fluid, the spent drilling fluid containing lost circulation material, drilling fluid, and undesirable solids, the undesirable solids including coarse solids and fine solids, the method comprising: feeding spent drilling fluid to first sizing apparatus, the spent drilling fluid containing lost circulation material, drilling fluid, and undesirable solids, the undesirable solids including coarse solids and fine solids; with the first sizing apparatus separating the stream of spent drilling fluid, producing a first stream of coarse solids, drilling fluid, and lost circulation material and a second stream of drilling fluid and fine solids; providing the first stream to a hydrocyclone; producing with the hydrocyclone an overflow stream and an underflow stream, the overflow stream containing lost circulation material, the underflow stream containing coarse solids, drilling fluid, and fine solids; feeding the overflow stream to second sizing apparatus; the second sizing apparatus producing a primary stream with the lost circulation material, and a secondary stream with drilling fluid and undesirable solids; and returning the primary stream to fluid processing apparatus for re-use in a wellbore operation.