Abstract Lost circulation (LC), commonly encountered during oilwell drilling and cementing, can be a costly problem that increases non-productive time. LC is especially concerning in high permeability reservoir sections. When LC occurs during cementing, poor annular coverage and cement fall back may occur which results in an undesired top of cement and the need for remediation. Described herein is the use of a new tailored spacer fluid system engineered to effectively mitigate LC or seepage losses while preparing the wellbore to receive cement. Ecopetrol S.A, the National Oil Company in Colombia was concerned about cementing production liners in highly permeable, depleted sandstone sections of a formation. The challenges included permeabilities from 7-8 Darcy, lost circulation events, and unacceptable hydraulic seals according to cement evaluation logs resulting in remedial operations. Managed Pressure Drilling (MPD) was an initial solution. As part of the best cementing practices to meet this objective, designing and tailoring of the spacer needs to be taken into consideration. Optimum tuning allows the cement to cover zones of interest and reduce contamination such that the cement properties can develop and bond with the formation in an efficient way. A new spacer system was designed to optimize cementing jobs, the tailored spacer system utilizes additive synergies to help prevent LC in porous or fractured formations and enable control of rheological hierarchy and wellbore fluid displacement efficiency. Use of the new cement spacer system with the tailored approach enabled flawless execution per the job design. The spacer exhibited excellent rheological behavior to meet and maintain hierarchy requirements. Cement was circulated to the top of the liner. After performing the cementing operation, LC was not observed. Cement bond log (CBL) and variable density log (VDL) results confirmed zonal isolation objectives were achieved. Operations with previous wells in the same field required remedial squeeze jobs to complete. In this case, the Tailored Cement Spacer System helped eliminate the need for remediation, allowing a significant cost saving opportunity on these wells. The new spacer system successfully employed in high permeability formations in cementing operations in Colombia allowed savings for the operator and helped improve barrier dependability.