Ven-Fyber Coarse™ is a premium blend of micronized, surface-modified organic fibers for the prevention and remediation of whole fluid losses in drilling fluid applications. Ven-Fyber Coarse™ is field proven around the world for the prevention of moderate, severe & whole fluid losses. Ven-Fyber Coarse™ is composed of a blend of differing types of surface modified micronized cellulosic fibers. The differing types and sizes of the source materials provide excellent bridging and matting of thief zones in the near well-bore formation for effective sealing and prevention of whole fluid losses.