hi bro 

these both companies lbharat petroleum and oil corporation of india , hindustan petroleum and oil corporate limited are owned partially and runned by the control of the central government and these companies come under PSU's as government made gate as the compulsory criteria for the recuriment so it takes employes only who qualifies and gets a good score in gate only but there will be some small posts which will come under the private employes and you can definetly apply for it and you can work for it so all the best for your future Bro