Experimental and numerical study on internal pressure load capacity and failure mechanism of CO₂ corroded tubing

With the purpose of researching on the influence of CO₂ injection tubing with corrosion defects to the safety production of CO₂-EOR flooding, experimental tests and finite element simulations were conducted to analyze the failure pressure and stress distribution of P110 pipe with single point corrosion, axial line corrosion and uniform corrosion defects. Metallographic examination was also done to investigate the micro-mechanism of pipe failure. Depending on the experimental results, P110 tubes with corrosion defects mainly ruptured with different sizes of opening. For single point corrosion defects, the injection tubing did not fail when the inner corrosion pressure is 93.9 MPa and the corrosion depth ratio(d/t) is 0.964. For axial line corrosion defects, the higher the failure pressure, the larger the opening was. The result of injection tubing with uniform corrosion defect is contrary to the result of injection tubing with axial line corrosion. In conclusion, the integrity of CO₂ injection tubing is crucial for CO₂ flooding production, in which the defect depth plays a more important role than defect length. DNV RP-F101 model can be a right model to predict failure pressure of all kinds of corrosion defect except single point corrosion.