甲基葡萄糖甙钻井液抑制机理研究

STUDY ON INHIBITING MECHANISM OF MEG DRILLING FLUID

甲基葡萄糖甙所携带的羟基(-OH),对页岩有强烈的吸附作用,所携带的甲基(-CH3)使吸附后的甲基葡萄糖甙,具有半透膜的作用。用分光光度计,测定了甲基葡萄糖甙溶液对膨润土的吸附量。甲基葡萄糖甙与无机盐复配后,会进一步提高其吸附能力;用X射线衍射法,测定了甲基葡萄糖甙处理前后蒙脱石的晶层间距,结果表明,处理后的蒙脱石进入的水量少,水化膨胀小;用自行研制的页岩膜效率评价仪,测定了甲基葡萄糖甙处理前后岩心的膜效率,结果表明,处理后的膜效率提高,这是甲基葡萄糖甙在页岩表面吸附形成半透膜的结果。根据甲基葡萄糖甙的抑制机理,为强水敏的郑斜41井设计了以甲基葡萄糖甙为主处理剂的钻井液配方,应用效果证明,甲基葡萄糖甙钻井液体系具有优良的抑制和防塌作用。

MEG has hydroxy (-OH), which has strong adsorptive action on shale. Also, MEG has methyl (-CH), which makes the MEG become semi-permeable diaphragm after adsorbing. With spectrophotometer, the MEG adsorptive capacity to bentonite is measured. The MEG adsorptive capacity will be improved after mixing MEG with inorganic salt. With X-ray diffraction method, the crystal interface of montmorillonit is measured before and after the montmorillonit is treated with MEG. The results show the montmorillonit absorbs less water and have less hydration expansion after treatment. With the self-made shale film effect evaluator, the film effect of cores is measured before and after treating by MEG. The results show the film effect is improved after the treatment, which is the result of that MEG is adsorbed at the shale surface to form a semi-permeable diaphragm. According to the inhibiting mechanism of MEG, the drilling fluid formula taking MEG as the key additive is designed for the well Zheng-X 41 that has strong water sensitivity. As indicates by application, the MEG drilling fluid system has good effects of inhibition and collapse control.