Study analyzes causes of corrosion in production tubing

Petroleos Mexicanos launched a study to determine the causes and cures of tubing corrosion in the Chiapas-Tabasco Cretaceous fields of SE Mexico, where oil and associated gas have a high hydrogen sulfide content. The study found that changing the metal composition of the production string to include a higher content of chrome could increase its resistance to chemical attack from hydrogen sulfide and carbon dioxide. Moreover, an organic inhibitor and a bactericide should be mixed with the oil pumped into the annular space. In cases requiring water-base fluids, sodium sulfite and an organic inhibitor should be used for deoxygenation.