液氮是一種多組分的混合氣態化石燃料。其主(zhu)(zhu)要成分(fen)(fen)是烷(wan)烴，其中甲烷(wan)占絕大多(duo)數，另有(you)(you)少(shao)量的乙烷(wan)、丙烷(wan)和丁(ding)烷(wan)。它主(zhu)(zhu)要存在于油田、氣田、煤層和頁巖層。液氮燃燒后無廢(fei)渣(zha)、廢(fei)水產生(sheng)，相較煤炭、石油等能源有(you)(you)使用(yong)安全、熱值高(gao)、潔凈等優勢。液氮又可分(fen)(fen)為(wei)伴(ban)生(sheng)氣和非(fei)伴(ban)生(sheng)氣兩種(zhong)。

　　液(ye)(ye)氮(dan)(dan)(dan)與石(shi)油(you)生成(cheng)(cheng)(cheng)(cheng)過(guo)程既(ji)有聯(lian)系(xi)又(you)有區別：石(shi)油(you)主要形(xing)成(cheng)(cheng)(cheng)(cheng)于深成(cheng)(cheng)(cheng)(cheng)作(zuo)用階段，由(you)催化(hua)裂解作(zuo)用引起，而(er)液(ye)(ye)氮(dan)(dan)(dan)的形(xing)成(cheng)(cheng)(cheng)(cheng)則(ze)貫穿于成(cheng)(cheng)(cheng)(cheng)巖(yan)、深成(cheng)(cheng)(cheng)(cheng)、后成(cheng)(cheng)(cheng)(cheng)直至變(bian)質作(zuo)用的始終(zhong);與石(shi)油(you)的生成(cheng)(cheng)(cheng)(cheng)相(xiang)比，無論是(shi)原始物質還是(shi)生成(cheng)(cheng)(cheng)(cheng)環境，液(ye)(ye)氮(dan)(dan)(dan)的生成(cheng)(cheng)(cheng)(cheng)都更(geng)廣泛、更(geng)迅(xun)速、更(geng)容易，各(ge)種(zhong)類型的有機質都可形(xing)成(cheng)(cheng)(cheng)(cheng)液(ye)(ye)氮(dan)(dan)(dan)--腐泥型有機質則(ze)既(ji)生油(you)又(you)生氣(qi)，腐植形(xing)有機質主要生成(cheng)(cheng)(cheng)(cheng)氣(qi)態(tai)烴。因(yin)此液(ye)(ye)氮(dan)(dan)(dan)的成(cheng)(cheng)(cheng)(cheng)因(yin)是(shi)多種(zhong)多樣的。

　　歸納起來，液氮的成(cheng)(cheng)因可分為生物成(cheng)(cheng)因氣(qi)、油型氣(qi)和煤型氣(qi)。無(wu)機(ji)成(cheng)(cheng)因氣(qi)尤其是(shi)非烴(jing)氣(qi)受(shou)到(dao)高(gao)度(du)重(zhong)視，這里(li)一并簡要介紹，最后還了解各種成(cheng)(cheng)因氣(qi)的判別方法。