Casing leaks are a common issue in the oil and gas industry that might lead to severe production problems. Corrosive fluids often cause casing leaks, as well as prolonged exposure to corrosive gases, casing fractures under pressure, or casing wear from extended periods of drilling work. While drilling, the cementing process is done between the formation and the casing or between two casings to provide zonal isolation and well protection. If the cementing process is done poorly, a well barrier can fail, and cracks and micro-fractures can appear, allowing corrosive fluids to migrate. This can slowly corrode tubing and casing over time. Another possibility for casing corrosion to occur is from fluids flowing inside the wellbore, leading to the same consequences. Thus, casing leaks must be detected early to prevent these losses, which can result in substantial expenses. This master¿s thesis is focused on casing leak remediation by using conventional and ultrafine cement, as well as epoxy resin. Each fluid was tested according to API standards, and later, the injectivity tests were done for that fluid in the casing leak setup, which was developed in the previous master¿s thesis. Upon completing the API and the injectivity tests for one fluid, the data was analyzed, and the next fluid was tested. As a reference point, injectivity tests for water were also conducted. The injectivity tests of cement and epoxy resin were done using three different internal tubing diameters, which include 4,572 mm, 1,753 mm, and 0,774 mm. The results of the experiments demonstrated that all fluids successfully passed through 4,572 mm internal tubing diameter without problems. The injectivity tests for the 1,753 mm internal tubing diameter showed the influence of solids inside the liquid, with the conventional cement slurry starting to plug and the pressure spikes starting to appear. Other fluids passed through successfully without issues. The injectivity tests for 0,774 mm indicated that only solid-free liquids like epoxy resin can guarantee a successful casing leak remediation. However, due to the high cost of epoxy resin, an attempt should be first made with the ultrafine cement slurry.