During leakoff tests (LOTS) in shallow marine sediments, casing shoe failure may be caused by cement channeling at pressures lower than the rock-fracture pressure. Pressure required for leakoff behind the cement can be determined from contact stress between cement and well-bore. Contact stress develops during cement setting as a result of volumetric changes in the annulus. Changes in cementing and drilling practices can increase casing shoe integrity and reduce the need for cement squeeze operations. The full-length paper presents a mathematical model of contact stress around the casing shoe based on cement volume reduction and compensation from casing string elongation, cement compressibility, and wellbore shrinkage. The study identifies two factors directly related to drilling technology that control critical pressure of cement channeling: contact stress at the casing shoe and drilling fluid invasion of rock around the casing shoe.