A Review on Current Situation of Groundwater Pollution from Shale Oil and Gas Extraction

Abstract:

The extraction of shale oil and gas produces a large number of waste materials that are generally discharged into the groundwater environment， causing contamination of groundwater which threatens human health. First， the distribution and storage mechanism of shale oil and gas， as well as the extraction technologies， which include oil shale retorting， horizontal drilling， and hydraulic fracturing， are introduced. Then， various events that may cause groundwater pollution and the main sources of contamination in the extraction processes， which consist of preparations， drilling and fracturing， and capture of shale oil and gas， are summarized. Afterwards， three types of groundwater pollutants caused by shale oil and gas exploitation， which are organic contaminants， heavy metals， and radioactive material， are discussed， and the characteristics of groundwater contamination are expounded. Finally， the prospect of groundwater pollution research in the exploitation of shale oil and gas is proposed from the perspectives of technological improvement and waste treatment.

Key words:shale oil;shale gas;groundwater pollution;hydraulic fracturing;horizontal drilling