Small scale experiments of CO₂ boiling liquid expanding vapor explosion in injection pipes

CO₂ injection to enhance oil recovery (CO₂-EOR), which can both sequester CO₂ and increase crude oil supply, is now widely used all over the world. According to the prediction of international energy agency (IEA) in 2008, the potential ability of enhancing oil recovery for CO₂-EOR is about 1600×10⁸-3000×10⁸ barrels, which will make a positive contribution to the sustainable development of oil and gas. However, CO₂ injection pipes in deep wells are often suffering acid corrosion, by which the structural integrity of steel was destroyed. Thus, boiling liquid expanding vapor explosion (BLEVE) accident is more than likely to happen for CO₂ injection pipes with high operating pressure. This paper gives a short description of CO₂ BLEVE and presents results from preliminary, small scale experiments of CO₂ BLEVE in injection pipes. The results indicated that CO₂ undergone special decompression behavior during injection and the rapid phase transitions in BLEVE were different from gas explosions. But tremendous amounts of energy could also be released during BLEVE of this nonflammable pressurized liquefied gas (PLG) in P110 injection pipe, which made the burst pressure be more than 50 MPa and the pipes blasted in several fragments. The geometrical parameters of corrosion defect in injection pipe were extremely important to BLEVE and the final burst pressure.