Abstract: A new method for the in-situ conversion of oil shale was introduced i.e.， oil shale in-situ pyrolysis technique by fracturing and nitrogen injection. Electrical heater was put into the heating well and nitrogen was then pumped into the well. As a result， the oil shale layer was pyrolyzed by heated nitrogen. The advantages of the proposed method and the suitable layers were also introduced in comparison with traditional electrical heating and convective heating， and a computer simulation was done for the heating process of nitrogen. The parameters of the heater were optimized and it was confirmed that the length of the electrical heater was 30m and the heat flux was 11kW/m². Finally， based on the suitable thin oil shale layers， it was verified by the computer simulation that the heating time is 80days under the condition that the distance of the heating well and the production well is 15m while the thickness of the oil shale layer is 1.5m. Obviously， the time is shortened compared with traditional electrical heating or convective heating.

Key words: oil shale, gas heater, nitrogen injection, heat transfer simulation, heating time