Abstract:

In the CO₂ flooding environment, puncture occurs frequently in the gathering and transportation pipeline network composed of carbon steel pipelines. So it is of great significance to reduce corrosion and maintenance costs by using reinforced plastic non-metallic pipes instead of some metal pipes. Corrosion immersion experiments are conducted to study the changes of permeability, expansion and mechanical properties of swelling and mechanical properties of flexible composite pipes and aramid glass steel pipes under high salinity and CO₂ content with immersion periods. The results show that as the immersion periods increases, the permeability and expansion rate of the two non-metallic materials increase, but the tensile strength decreases. Among them, aramid glass steel pipe has higher permeability, relatively smaller expansion rate, and higher tensile strength. The flexible composite pipe has the smaller permeability, a relatively larger expansion rate, and the smaller tensile strength. After the strength check relay on the changed mechanical properties, both materials can meet the gathering and transportation pressure requirements of 3 MPa. Based on the experimental results, the maximum allowable pressure for different pipeline specifications is calculated.

Key words: high salinity, CO₂ flooding, non-metallic pipe, tensile strength, corrosion resistance