Composition comprising a nanometer film structured reservoir protecting agent and a water block preventing agent, and drilling fluid containing the same and use thereof for drilling in low-permeability reservoirs

摘要

The present invention relates to the petroleum drilling field and discloses a reservoir protecting agent composition comprising a structured nanometer film reservoir protecting agent and a water block preventing agent, a drilling fluid containing the same and use thereof for drilling in low-permeability reservoirs. The reservoir protecting agent composition comprises a structured nanometer film reservoir protecting agent and a water block preventing agent, wherein the structured nanometer film reservoir protecting agent comprises montmorillonite laminas, structural units represented by formula (1) and structural units represented by formula (2),; wherein each of R₁, R₂, R₃, R₄ and R₅ is independently selected from H, C₁-C₄ alkyl and C₁-C₄ alkoxy, R₆ is C₁-C₆ alkylene. The present invention further provides a drilling fluid that contains the reservoir protecting agent composition according to the present invention. The drilling fluid that contains the reservoir protecting agent composition according to the present invention exhibits favorable rheology property, temperature-tolerant property, anti-collapse performance and reservoir protection property when used for drilling in low-permeability reservoirs.