DRILLING FLUID ADDITIVE

摘要

The invention relates to methods for sealing fractures in drilled formations by defining a seal in the formation 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 chips. In a particular arrangement, the fibres may comprise wood fibres such teakwood fiber and the chips may comprise woodchips. In another arrangement, the lost circulation material is an acid soluble material that may comprise calcium carbonate flakes. The lost circulation material may be biodegrdable and may also comprise nut shells. Moreover, the invention also provides for a lost circulation pill and the methods for sealing fractures that extend into a formation from a borehole.