Synthesis, characterisation and application of seat-healing material in oil weir cement for healing microcracks

Microcracks can occur in oil well cement, which can lead to regional isolation and casing corrosion or even serious damage to the well. Self-healing cement is therefore of great interest for oil well applications. In this work, a self-healing material (called YW) was prepared by catalytic synthesis of a double-proton acid and characterised by Fourier transform infrared spectroscopy. The self-healing performance of cement with different additions of YW was evaluated in terms of permeability and compressive strength. The self-healing mechanism was analysed using pore structure analysis, scanning electron microscopy and energy dispersive spectroscopy. The results revealed that YW can significantly improve the compressive strength of cement and reduce its permeability. It can also continue to complex calcium hydroxide to generate insoluble acicular substances, so unhydrated cement particles can continue to hydrate to generate hydrated calcium silicate gel and calcium hydroxide.