Patent ID: 6457588
Filing Date: 2002-10-01
Classification: B01D,B07B,E21B

Abstract:
A method for separating fluid and fibrous lost circulation material from a mixture of fluid, drilled cuttings and fibrous lost circulation material, the method comprisingintroducing the mixture onto a screen assembly that is vibrating for passage of the fluid and fibrous lost circulation material through the screen assembly and for separation from the mixture of drilled cuttings, the screen assembly comprising at least two layers of screening material one on top of the other and including at least a first layer over a second layer, each layer having screen mesh with rectangular openings as viewed from above, the first layer having first rectangular openings, and the second layer having second rectangular openings, each of the first rectangular openings having a first width and a first length, and each of the second rectangular openings having a second width and a second length, the ratio of the first length to the first width ranging between 1.55 and 2.00, the ratio of the second length to the second width ranging between 1.55 and 2.00, the ratio of the first length to the second width ranging between 0.95 and 1.05, and the lengths of the first rectangular openings are parallel to lengths of the second rectangular openings.