甲基葡萄糖苷的防塌机理研究

以淀粉为原料合成了甲基葡萄糖苷（MEG），考察了MEG对泥页岩分散的抑制作用、对膨润土水化膨胀的抑制性能、对泥页岩膜效率的影响和对钻井液水活度的影响，并在此基础上对MEG的防塌作用机理进行了详细分析，以期达到进一步开发利用MEG的目的。实验结果表明，MEG具有一定的抑制泥页岩水化膨胀、分散的作用，但其抑制作用较弱，远不如无机盐和聚合醇类页岩抑制剂；MEG能大幅度提高泥页岩的膜效率，被25%的MEG溶液饱和后，泥页岩膜效率提高率达200%以上；MEG具有有效降低钻井液水活度的作用，在加量充足的情况下，MEG单独使用或与无机盐复配使用均可将钻井液水活度降到0.85以下。因此，通过提高泥页岩膜效率及降低钻井液水活度，MEG能在钻井液/泥页岩体系间产生有效的渗透压，通过渗透作用降低钻井液中的自由水向地层滤失是MEG稳定井壁的主要作用机理。MEG的防塌性能特点与其分子量和分子结构密切相关。

Study on Anti-sloughing Mechanism of Methyl Glucoside

Methyl glucoside(MEG) is synthesized by mixing corn starch with methnol.The performance of MEG is investigated,including shale dispersion inhibition,bentonite hydration inhibition,and effects on shale membrane efficiency and water activity of drilling fluid. On the basis of the investigation results,the anti-sloughing mechanism of MEG is analyzed in detail,expecting to develop the MEG for better application.Results indicate that MEG can slightly inhibit expansion and dispersion of shale in water,its inhibition is far less than inorganic salts and polyalcohol inhibitors;while MEG can effectively improve shale membrane efficiency,the shale membrane efficiency can be increased by 200% when saturated with 25% MEG;and MEG can decrease the water activity of drilling fluid,below to 0.85 if MEG is added enough in drilling fluid.So through improving shale membrane efficiency and decreasing water activity of drilling fluid,an effective osmosis pressure can be produced between the drilling fluid and shale system which can decrease drilling fluid loss into the formation,so as to realize anti-sloughing.This mechanism is closely related with its molecular weight and molecular structure.