辽河油田冷118井上部油藏原油两期注入史

A History of Twophasefilling of Crude Oil in the UpperReservoir of Well Leng 118

辽河油田西部凹陷冷东断裂带冷１１８井沙三段上部油藏中原油样品的地球化学分析表明，该油藏原油具降解和未降解的双重特征：①正构烷烃和类异戊二烯烃类的气相色谱分布没有遭受微生物降解的迹象；②饱和烃馏分气相色谱的总体分布显示甾类及五环三萜类相对丰度远高于正异构烷烃；③ＧＣ／ＭＳ检出了相当丰富的２５降藿烷系列。这种降解和未降解的特征处于同一原油样品之中的现象，表明该油藏至少存在两期原油注入的历史：即早期注入油藏的原油遭受到严重的微生物降解作用后，又有未受微生物降解的原油注入该油藏。

Geochemical analyses of crude oil trapped in the sandstone reservoir of the upper Es3 formation,well Leng 118 located in the Lengdong structural zone,Liaohe western depression show that i) the GC of n and isoalkanes in the oil do not have the characteristics of biodegradation;ii) Steranes and triterpanes are abnormally abundant in the saturated hydrocarbon fraction;and iii) high abundence of 17α(H)25norhopanes was detected in the oil.The characteristics of both biodegraded and nonbiodegraded oil are shown in the same reservoir.It may be indicated that the reservoir has a history of twophasefilling of crude oils,ie.earlier oil emplaced in the reservoir was severely biodegraded,and then the later nonbiodegraded oil filled the same reservoir.