Why were the refineries shut down?

Why did half of the Romanian refineries close? In 1997 I dealt with the oil industry as a government expert in the Reform Council. The Arpechim, Onești, Dărmănești, Astra, Surplacul de Barcău and Steaua Română de la Câmpina refineries were closed. Why did we lose 6 of the 10 refineries we left communism with?
In this film I am not talking about corruption, but about the objective factors that led to this result.