Effects of waterborne epoxy resin on the mechanical properties and microstructure of oil-well cement

Abstract

A new type of waterborne epoxy-cement (WEPC) system was developed by adding waterborne epoxy resin (WEP) as an external admixture to cement slurry to solve the problem of cement sheath integrity damage and packing failure caused by easy brittleness of oil well cement stone. We studied the influence of waterborne epoxy resin (WEP) and its curing agent on the mechanical properties and hydration process of oil well cement stone by several testing methods, x-ray diffraction (XRD), fourier transform infrared spectrometer (FTIR), thermo-gravimetric (TG), mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM). The results show that when the curing condition is 70 °C and the proportion of waterborne epoxy resin (WEP) is 10%, the mechanical properties of the waterborne epoxy-cement (WEPC) were the best. Through XRD, FTIR, TG and other methods, it is found that WEP will not affect the hydration products of oil well cement stone. The hydration products are still mainly calcium hydroxide and calcium-silicate-hydrate. The polymer film formed by curing the WEP can connect the hydration product to repair cracks, fill in the pores, and interweave with the hydration products to form a stable network structure to enhance the mechanical strength of the cement stone and improve the matrix structure. The new type of waterborne epoxy-cement system has the potential to improve cement performance and cement quality in wells.

Keywords:

• Polymer
• oil well cement
• waterborne epoxy resin
• mechanism
• microstructure

Acknowledgements

The authors would like to acknowledge the financial support by the National Natural Science Foundation of China [51874254].