钻井液用可降解聚合物暂堵剂的研制OA北大核心

Biodegradable polyester temporary plugging agents(TPAs)have good degradability and low damage to reservoirs,but the disadvantages,which include low thermal stability,low strength of the plugging layers formed and high production cost etc.,make it difficult for them to be widely used.To satisfy the requirements for TPAs to work at elevated temperatures,a new biodegradable TPA is developed.This new TPA is prepared by melt blending polybutylene terephthalate(PBT),which has slower hydrolysis rate,and polyamide 6(PA6),and an epoxy chain extender ADR is added to improve the compatibility of the melt blending materials.The new TPA has better thermal stability and forms plugging layers of higher strength.Experimental results show that the new TPA has better degradability,in a NaOH solution(pH=10)at 120-150℃,percent weight loss of the new TPA after 20-60 d is greater than 80%.When the ratio of PBT and PA6 in the melt blending system is 70%PBT/30%PA6,and into the melt blending system add 1.5%ADR,the compressive strength of the new TPA can be 91 MPa,after degrading at 150℃for 16 h the compressive strength is still greater than 70 MPa.This new TPA has good compatibility with drilling fluids and excellent plugging performance,and after degrading at 120℃for 14 d,the residual compressive strength of the plugging layer is 2 MPa.