摘要
壳质组的荧光性是评价煤化作用程度和油源岩成熟度的补充标准.它在石油勘探中,可以用来评价腐泥型干酪根的成熟度,并且只适用于石油消亡线之前的成熟度评价.其荧光性是随成熟度而变化的.
The fluorescence of exinite can be used as an additional indicator to eval-uate coalification level and source rock maturity. The method is especially important when there is no or too few vitrinite to measure its reflectance in samples. For example, ancient strata (before Devonian) and sapropelic kerogen are made up of mainly exinites, and very little or even no vitrinite, but the exinite can be clearly recognizable only under fluorescent light. lts fluorescent intensity is influenced by maturity. Therefore, it is very important to apply the exinite fluorescence to evaluating maturities of ancient oil source rock and sapropelic kerogen.
Fluorescence of exinite means the three following parameters: 1) fluorescent intensity of 546nm; 2) distribution characteristics of fluorescent spectrum: exinite is excited with long wave UV (365nm), it emits a continued light spectrum, with the maximum value not clear, within 400-700nm of wavelength(visi-ble light). The spectrum is delineated with both wavelength (Amax) at maximum intensity and Red-Green quotient (Q), i. e. Q is the ratio of fluorescent intensity of 650nm to that of 500nm; 3) change of fluorescent intensity, i. e. the changes in fluorescent intensity of 546nm when continuously irradiating a sample. The increase of intensity is called positive change, and the opposite is negative change. If the intensity first weakens and then increases, it is a posi-tive-negative change (mixed change).
In the petroleum explorations, the measurement of exinite fluorescence is only suitable for evaluating maturity not beyond oil dead line. In the immature stage, the fluorescent intensity rapidly decreases and jumps from negative to positive value. The max ranges from 500nm to 560-580nm. In the oil jump I , the fluorescent intensity begins to turn another way and becomes positive; max is at 640mn (orange light); Q value speedily increases and bituminite seeps begin to appear. In the maturation stage (oil window), the fluorescent inteasity gradually decreases and changes from positive to positive-negative, then to mixed and negative; max ranges between 640nm and 670nm; Q value gradually increases. In the oil jump II (oil dead line), the fluorescence disap-pears.
We ought to choose alginite grains to do the fluorescence measurements.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
1989年第2期101-108,共8页
Marine Geology & Quaternary Geology
