Research Progress of Cementing Fluids to Improve the Interfacial Bonding Quality Under Oil-Based Drilling Fluids

The interfacial bonding strength is an important factor affecting the cementing quality, which is directly related to the safety production, resource development efficiency, economic benefits and ecological environment protection of the oilfield. Affected by the development trend of unconventional oil and gas reservoirs, oil-based drilling fluids are widely used in complex deep wells and horizontal wells. Limited by wellbore conditions, displacement rate of preflush fluids, cementing construction technology, etc., the residual oil-based drilling fluids on the interface cannot achieve ideal displacement and cleaning, which seriously affects the strength development and interlayer isolation quality of the cement sheath, leading an adverse impact on the long-term integrity of the well. Based on the contamination mechanism of oil-based drilling fluids and cement slurry, this paper reviews the research progress of improving the cementation quality of cementing interface under oil-based drilling fluids. It can be seen that at present, adding surfactants to the preflush fluids system to improve the wettability of the interface to improve the removing rate of the mud cake is still the main treatment method. On this basis, the introduction of emulsification technology and nano-functional materials can effectively improve the degreasing effect. In addition, it has become a new development trend to explore ways to relieve oil-based drilling fluids contamination from the perspective of cement slurry. The introduction of surfactants, nanomaterials and adsorbent materials into the cement slurry can effectively improve the bonding strength of cementing interface, ensure the safety of cementing construction and improve the quality of cementing.