Geothermal energy current state and utilization in oilfield, China: An overview

Sustainable development is the critical theme of today's society. The enormous geothermal energy is supposed as renewable resource such as wind, solar and biomass. More significantly, because of its lower emissions of greenhouse gas (CO2), geothermal energy is effective on reducing the catastrophic environmental deterioration. This overview describes the current state and utilization of geothermal energy in oilfield, China. There are many oil-producing wells, with well depth over 3km in oilfield. Moreover, it is economic and sustainable to convert the oil well valueless or abandoned to a geothermal well, which are, therefore, the innate advantages for oilfield to develop geothermal energy. Because the current tectonic stress field is extensional in the eastern sedimentary basin of China, which leads to higher geothermal gradient that is 35–45°C/km so that oilfield distributing on Songliao basin and Bohai Bay basin, such as Huabei, Liaohe, Henan, Daqing, Dagang, Shengli and Jilin, have made great achievement on utilizing geothermal energy. By exploiting the hot water underground, geothermal energy can transform into electric power effectively and make other direct utilization such as extracting heavy oil, heat tracing system, hydrotherm heating, thermal spring and irrigating.