ExxonMobil Electrofrac uses a series of fractures created in the oil shale formation.
Preferably these fractures should be longitudinal vertical fractures created from horizontal wells and conducting electricity from the heel to the toe of each heating well.
For conductivity, an electrically-conductive material such as calcined petroleum coke is injected into the wells in fractures, forming a heating element.
Laboratory experiments have demonstrated that electrical continuity is unaffected by kerogen conversion and that hydrocarbons are expelled from heated oil shale even under in situ stress.
The shale oil is extracted by separate dedicated production wells.