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Abstract Successful cementing operations in oil wells are critical to achieving zonal isolation, preventing costly remedial operations, and avoiding hydrocarbon production losses. Several challenges may arise prior to successful cementing, including the effective removal of non-aqueous drilling fluids (NAF) and managing naturally fractured formations, which can lead to induced losses. This study presents field applications of an engineered sequence of spacers comprising Newtonian and weighted fluids, formulated with environmentally friendly particles. These spacers are designed to scour the wellbore and shield the formation, mitigating losses and enhancing cement bonding. Common industry practice to remove NAF includes the use of surfactant and solvents to modify the wettability of the annular surfaces in cement spacers with higher rheological properties to displace the drilling fluid and prepare the casing and formation surfaces for the cement slurry placement. On some occasions, this practice is not sufficient, resulting in poor or average cement coverage, increasing the overall cost of the drilled well, potential HSE incidents and loss of production. Based on laboratory testing, a train of cementing spacers including non-aqueous chemical wash, scouring and wellbore shielding spacers has been successfully implemented in the field. Laboratory tests has been applied to evaluate the cement spacers performance for mud removal and plugging efficiency under the different mud types and up to 3,000 microns plugging capability. Conventional cement spacers show lower performance in the laboratory tests results when tested on field drilling fluid samples. The scouring spacer consistently achieves cleaning efficiency above 92%. The wellbore shielding spacer has been tested to ensure fluids compatibility, stability and plugging efficiency up to 3,000 microns. This train of spacers has been field tested on different field cementing operations in sections where NAF is present. In all the applications the cement slurry has achieved the cement top, and cement bond logging demonstrated in all cases zonal isolation improvement. This train of spacers also has been proven on narrow annular restrictions, such as liner hangers without increasing the friction pressures based on acquired pumping pressures. This engineered spacer train is easy to deploy and can be deployed with conventional surface equipment and is compatible with NAF, Newtonian fluids, surfactant / solvents and cement slurries. Industry best practices such as wellbore centralization, fluids friction hierarchy design and fit for purpose cement slurry design are part of the engineering design approach. The scouring and wellbore shielding spacer can be utilized to improve mud removal and cement bonding through its mechanical action and the shearing effect, effectively removing gelled mud from the walls of the casing and plugging formation pores up to 3,000 microns. The wellbore shielding spacer increase the operating window by limiting the pressure transmission to the formation. Both technologies are rated up to 350°F circulating bottom hole temperature.