Analysis and evaluation for oil zone washed by water

It is well known that T₃ Chang 2 oil zone exists widely in Ordos basin,they contain industrial oil and some water.The T₃ Chang 2 of Zhouhe country of Zhidan county is very different from that of other regions: accor ding to chemical exploration and rock core and interpretation,the oil zone is good,but its out put is poor.Sands distribute widely in these oil well and its thickness is large.The article analyzes clearly the "three-good and one-poor" phenomenon.