Numerical Analysis on Casing Deformation During Hydraulic Fracturing of Deep and Tight Volcanic Reservoir

Deep volcanic reservoirs are characterized by tight, low permeability formations that require high fracture pressures to be broken. However, a common issue is the inability to break the formation, leading to potential casing deformation. A casing-cement-formation system was analyzed in this study based on ABAQUS using the finite element method, considering the factors such as well diameter, cement quality, casing grade and wall thickness. The results showed that after changing the well diameter, steel grade and wall thickness of the casing, the mises stress of the casing varied below 30%, indicating that the casing was safe under different working conditions with good quality cement. However, in the condition of poor cement quality, casing deformation may occur in all conditions except when the cement missing angle is small. The stress concentration due to poor cement quality increased the possibility of casing deformation, with the maximum mises stress occurring when the loss angle was between 60° and 120°. In addition, a chart of the safety internal pressure of the casing during hydraulic fracturing has been constructed. This study can serve as a guide for hydraulic fracturing technology in deep tight volcanic rock reservoirs, and offer a reference for selecting casing grades and well thicknesses.