摘要：
Nanomaterials have been more and more used in drilling fluids, gaining good results in drilling operation. It has been found in the field application that the nanomaterials always become aggregated as the concentrations increase, making it difficult for the nanomaterials to take effect. Based on the study of the mechanisms of nanomaterial aggregation, a nanomaterial was grafted to render it good dispersity in drilling fluid. The molecules of the nanomaterial have good flexibility and deformability. The molecules of the nanomaterial can be adsorbed on the surface of rocks, thereby enhancing the ability of the nanomaterial to plug micro fractures and fissures. A nanomaterial filter loss reducer has been synthesized to formulate a drilling fluid with other nanomaterial additives, such as lubricant and shale inhibitor. The nanomaterial drilling fluid functions properly at 150 °C, and has properties as follows: API filter loss ≤2.4 mL, HTHP filter loss≤9.8 mL, coefficient of friction≤0.04, percent recovery of permeability of cores ≥ 91％, and percent recovery of drilled cuttings in hot rolling test≥90.5％. Field application has shown that the nanomaterial drilling fluid had good lubricity and reservoirs drilled were effectively protected from being damaged.%针对纳米材料在钻井液中团聚的问题,通过分子设计,改进纳米材料的表面性能,以改性纳米二氧化硅为核,通过接枝柔性聚合物,合成了一种纳米封堵降滤失剂.通过引入强的吸附基团和疏水基团,聚合物分子的亲疏水、氢键等协同作用形成空间的网架结构,使合成的纳米封堵降滤失剂能够以纳米级尺度分散在钻井液中,其在钻井液中纳米级粒度的含量高达59.3％,其不仅具有优异的降滤失性能,同时具有柔性可变形性,还能够吸附在岩石表面,提高纳米材料对微裂缝和小孔隙的封堵能力.以合成的纳米降滤失剂为核心处理剂,并优选出配套的纳米润滑剂、纳米抑制剂,形成纳米钻井液体系.该体系的抗温达150°C,API滤失量在2.4 mL以下、高温高压滤失量在9.8 mL以下、润滑系数不大于0.04,渗透率恢复值不小于91％、目的层井段岩屑回收率≥90.5％.该体系在大港油田枣1510井的应用中表现出良好的润滑性和保护油气层效果.
