Chevron is currently experimenting with new technology to extract more oil from its oldest fields, some of which have been in decline since the 1970s. Well, it’s not exactly new technology – it’s steam. The heat of steam injected into the old fields, which still hold as much as fifty percent of their original oil deposits, loosens and liquefies oil trapped in rock and shale for easier extraction. The company uses new, very sensitive electronic sensors to control where and how much steam is used.