▎ 摘　　要

Wellbore instability frequently occurs in shale formation when water-based drilling fluids (WBDFs) are used. To mitigate and avoid the wellbore instability of shale formation, graphene oxide (GO) was used to plug the nanosized pores, to inhibit water invasion into shale, and to prevent clay minerals of shale swelling. The GO was prepared and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The linear swelling tests, filtration experiments, imbibition tests and uniaxial compressive strength measurements were conducted to systematically evaluate the protection of GO sheets on shale. Meanwhile, other commonly used shale inhibitors and nanomaterials (nano-silica) were compared with the GO. The results indicated that GO exhibited an improved performance on preventing clay minerals from swelling, plugging nano-sized and micron-sized pores, inhibiting water invasion into the interior of the shale core, and maintaining the shale strength, compared to the commonly used inhibitors. The GO sheets form the large and unbroken film to protect the shale, and the soft and flexible GO sheets can easily deform to plug and fill the different shapes of shale pores. Therefore, GO displays great potential to protect and stabilize shale in WBDFs.