Cementing is a major step in the construction and sealing of hydrocarbon wells. During the life cycle of the well, cement is prone to cracking due to a change in downhole conditions. This research investigates the use of micro-sized crosslinked polymer gel as a sealant material to mitigate cracked cement sheaths. Two experimental setups were designed to investigate water leakage through cement. The impact of polymer gel strength on the gel's ability to seal cement cracks was investigated using four gel strengths, including 500 pa, 1200 pa, 1450 pa, and 2440 pa. The impact of the width of the cement crack was also investigated using 0.5, 2, 3.2, and 6.75 mm. Results showed that the polymer gel propagated across fractures like a piston with no gravity effect and with angle with gravity effect. Blocking efficiency to water flow is controllable, and it can be increased if a high strength polymer gel is selected. To the authors' knowledge, very little experimental work has been conducted to investigate the use of crosslinked micro-gel in cement zonal isolation. This study can provide the oil and gas industry with a better understanding of the materials to use in improving cement zonal isolation and thus reduce the impact of cement failure.