▎ 摘　　要

NOVELTY - Drilling a wellbore in a formation (4), comprises: introducing a drilling fluid (16) which comprises graphite into the formation; and activating the drilling fluid to convert at least some of the graphite to graphene within fractures in the formation. USE - The method is useful for: drilling a well bore in a formation; and drilling of depleted reservoirs. ADVANTAGE - The method provides: full control during drilling operations; is simple, cost-effective and environmentally friendly; and graphene, which is able to block pores in rocks more effectively than additives which have a spherical geometry, where the flexibility of graphene sheets permits a slight deformation under pressure which results in sealing of the graphene sheets around pore edges. DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of drilling a well bore in which a section of a depleted formation is drilled. Formation (4) Drill string (8) Drill bit (10) Induced fractures (12) Drilling fluid (16)