A method includes conveying a casing cutting tool into the wellbore lined with at least one casing string and cement, and stroking the casing cutting tool over a predetermined axial length of the wellbore while ejecting fluid from one or more nozzles in the casing cutting tool and thereby forming a plurality of longitudinal cuts through the casing string and cement. The casing cutting tool is then rotated about its longitudinal axis at two or more axially offset locations along the predetermined axial length while ejecting fluid from nozzles and thereby forming a plurality of axially offset transverse cuts in the casing string and the cement. The longitudinal cuts and axially offset transverse cuts form wedges in the wellbore, and the wedges are dislodged from the wellbore to expose formation rock along the predetermined axial length.