Drilling fluid additive

摘要

The invention relates to methods for sealing pores and/or fractures in drilled formations by defining a seal in the fracture including a matrix of lost circulation material delivered through a pill of drilling fluid additive. The invention also relates to a drilling fluid additive comprising the lost circulation material that comprises fibres and acid-soluble flakes. In a particular arrangement, the fibres may comprise wood fibres such teakwood fiber. In an arrangement, the acid soluble flakes may comprise calcium carbonate flakes. Moreover, the invention also provides for a lost circulation pill, a drilling fluid and methods for treating a borehole that extends into a formation to define an impermeable layer that include a matrix of the lost circulation material.