碳纳米管固井水泥复合材料抗腐蚀及力学性能研究

Research on Corrosion Resistance and Mechanical Properties of Carbon Nanotubes Reinforced Cement-Based Composites

为解决油田地层水在固井水泥中的渗透腐蚀造成套管损坏及环空带压问题,同时优化其力学性能,以纳米材料作为水泥基材料的增强组份,掺加碳纳米管(CNTs)制备了一种碳纳米管固井水泥复合材料。通过非共价键修饰法筛选多种碳纳米管分散剂,从其分散能力和悬浮液的稳定性确定了最优分散剂;研究了碳纳米管固井水泥复合材料的抗压、抗拉力学性能,通过测试强度及孔渗特征变化来对复合材料的抗腐蚀性进行了评价。结果表明,当碳纳米管的掺量为0.03%时,碳纳米管固井水泥复合材料可将水泥石的抗压、抗拉强度分别提高50%、30%以上,其腐蚀60 d的强度衰退和孔隙度增大率均小于5%、渗透率增大率小于1%、有效抑制了有害孔(大于0.1μm)的产生,具有较好的抗腐蚀渗透性能。该水泥复合材料优良的抗腐蚀性、高抗压、高抗拉特性(韧性),对多级缝网压裂水平井开发具有重要的应用价值。

In order to solve problems of casing damage and annular pressure caused by permeation and corrosion of formation water in cement and to optimize mechanical properties,a carbon nanotubes reinforced cement-based composites was prepared by adding carbon nanotubes(CNTs)as reinforcing component of cement-based material.A variety of carbon nanotubes dispersants were screened by non-covalent bond modification and the optimal dispersant was determined from the dispersing ability and suspension stability.The compressive and tensile properties of carbon nanotubes reinforced cement-based composites were studied and the corrosion resistance of the composites was evaluated by testing strength and pore permeability characteristics.The results show that the compressive and tensile strength of cement stone have been increased by more than 50%and 30%respectively when the carbon nanotubes are added in an amount of 0.03%.The increase rate of strength decline and porosity of cement stone are both less than 5%after 60 d corrosion,the increase rate of permeability is less than 1%,the formation of harmful holes(larger than 0.1 um)is effectively inhibited.The composite material has excellent corrosion resistance,high compression and tension resistance,which has an important application for the development of horizontal wells with multistage network fracture.