中文摘要：

为解决钻井过程中的泥页岩井壁失稳问题,选取了重均分子量为6×10^4g/mol的超支化聚乙烯亚胺（HPEI）作为水基钻井液页岩抑制剂,通过膨润土造浆实验、线性膨胀实验和泥页岩热滚回收实验对其泥页岩抑制性能进行了评价,通过红外光谱表征、X-射线衍射实验以及热重分析对其抑制机理进行了分析。结果表明,HPEI对膨润土水化膨胀有良好的抑制作用,20%膨润土在1.5%HPEI溶液中造浆后的动切力仅为0.5 Pa,膨润土在3%HPEI溶液的膨胀高度较蒸馏水中减少了67%;溶液的pH值越低,HPEI的质子化程度越高,对膨润土水化分散的抑制性能越好。HPEI抑制黏土水化膨胀的机理为：HPEI分子进入黏土层间,通过静电引力和氢键的共同作用减弱黏土水化分散,其疏水结构阻止水分子进入黏土层间,抑制膨润土晶层膨胀。

英文摘要：

In order to solve the problem of wellbore instability in drilling process, the hyper-branched polyethyleneimine （HPEI） with weight average molecular weight of 6×10^4g/mol was selected as a shale inhibitor for water-based drilling fluid. The inhibitive performance on shale of HPEI was evaluated via bentonite inhibition texts, linear swelling experiment and shale hot aging recovery experiment. The inhibition mechanism of HPEI was analyzed by means of infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The results showed that HPEI exhibited excellent inhibitive property on the hydration expansion of shale. The yield point of suspension with 20% bentonite in 1.5% HPEI solution were only 0.5 Pa. The swelling hight of bentonite in 3% HPEI solution reduced by 67% than that in distilled water. The lower the pH value of solution, the higher the protonation degree of HPEI and the better effect of inhibition on the dispersion of bentonite were. The mechanism of HPEI inhibiting clay hydration expansion was described as follows. The HPEI molecules entered the clay layers and weakened the clay hydration through the common role of electrostatic attraction and hydrogen bonding. The hydrophobic structure of HPEI prevented water molecules from entering the clay lay- ers and suppressed the expansion of bentonite crystal layer.