▎ 摘　　要

NOVELTY - Drilling fluid loss reducing agent comprises 54-67 wt.% starch grafted acrylamide, 10-13 wt.% calcium carbonate, 12-17 wt.% clay, 10-15 wt.% sodium alginate and 0.5-1 wt.% graphene oxide. USE - Used as drilling fluid loss reducing agent. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing drilling fluid loss reducing agent comprising (1) preparing starch graft acrylamide, (2) mixing the calcium carbonate and clay, crushing and grinding; after grinding, the grain diameter is less than or equal to 0.150 mm, mixing with the starch grafted acrylamide prepared in step (1) uniformly to obtain the mixture, (3) uniformly mixing the sodium alginate and graphene oxide, adding the mixture in the step (2), finally stirring and mixing uniformly.