What is EOR in Petroleum Engineering?

EOR= End Of Run

EOR is the abbreviation of Enhanced oil Recovery. In most cases the60% of the oil and gas reserves remian unproduced after the normal production. To produce that60% of the reserves of oil and gas, engineers uses different techniques called Primary, secondary and tertiary technique to produce those oil from subsrface to surface. these techniques might be water flooding, gas injection or bacterial injection in reservoirs.

 EOR= enhance oil recovery  thats means enhance the techinques to  get oil  when  encountored problems   when the porosity is decreace to diagenatic process  then define this problems and solve depend on the type of the diagenatic if the calcite cement close the pore then used hydrocloric  acid 

EOR= End Of Run ( the end of Cycle in reforming catalyst for ex

What motivated me to answer is the weird answers I've found here.Yet the best answer was from Mr Zia Ur Rahman but he gave a wrong number about the produced ratio after EOR, the recovery ratio of the produced oil never reached100% and I don't think that it will. In gas reservoirs the recovery is very high comparing to the oil reservoirs due to the gas physical properties. However the most effective EOR method is the thermal recovery then comes the chemical methods. MEOR or Microbial EOR which Mr ZIA called bacterial is used also but it's not at the top of the list, another mistake is considering water injection is an EOR method because it's a secondary oil recovery method, unless if he meant injection of water alternatively with gas which is called WAG. Still there are other EOR methods like electrical EOR which is relatively new and it gave promising values in the tested fields but I still think is the best way till now is the thermal because it succeeded worldwide. About the other answers they are all way far from the truth...what Miss Mrwa explained is called well stimulation not EOR and it happens in the drilled path vicinity and it has nothing to do with the EOR because this is a well issue and EOR is a field issue. Thanks all and please don't stimulate me to drill for you because I am going to need a long time to recover (smile). Petroleum Engineer