Abstract When a well is shut in for an extended period, the mechanical integrity of the production casing must be verified periodically to ensure there are no leaks in the casing that could lead to potential fluid migration between the producing zone and other formations along the wellbore. Traditionally, these mechanical integrity tests involve moving in a workover rig, tripping production tubing out of the well, setting a mechanical bridge plug above the highest set of perforations, and then pressure testing the casing. This operation is very time- and labor-intensive, with significant safety exposure risks for personnel involved. This paper describes work performed on 83 wells in the DJ Basin where an alternative method, not requiring a workover rig, was used. In this case, conventional cementing equipment was used to pump a Bingham-plastic nonconsolidating sealing material with a high-solid-volume fraction through the tubing to the perforations. This sealing material is a high-quality, quartz-based slurry using an engineered particle-size distribution (PSD) from <100 nm to 2 mm. The specific PSD of the solids in this slurry is designed to maintain pumpability and ensure near-zero permeability once the slurry is in place. The sealing material creates an impermeable barrier across the perforations, which enables the casing to be pressure tested. The operational simplicity of this material offers improvements to both operational efficiency and safety risks. This slurry also poses little to no risk to the environment from an accidental spill or exposure, as it is a purely natural, silica-based product. The silica-based slurry performed successfully, and the resulting mechanical integrity tests were equally successful. This paper explains the state regulations surrounding the mechanical integrity test, a comparison of the advantages seen with the alternative method, a detailed description of the job execution, and a summary of results observed in the cases where this alternate method was used.