以取自尼日利亚上贝努埃地槽Gongola盆地Kolmani-1井的样品为基础,对其放射性热产量进行了估算,并对放射性热产量对沉积物生油气潜力的影响进行了分析。研究采用精确标定的碘化钠伽马射线检测系统,对不同层组的38块样品（取样间隔73.2 m,包括砂岩、页岩、含煤页岩、砂质页岩、泥质砂岩）进行了40K、238U及232Th的放射性分析。研究结果表明,沉积物中放射性元素的放射性浓度存在显著变化,40K浓度最高;沉积物放射性热产量为228.44~1 412.82 pW/kg;Kolmani-1井砂岩和砂质页岩属于低热产量沉积物,含煤页岩、页岩及泥质砂岩属于中热产量沉积物,潜在烃源岩（页岩和含煤页岩层段）的放射性热产量值主要位于中热产量范围（750~1500 pW/kg）,同时具有生成液态烃和气态烃的能力。此外,沉积物的放射性热量约占盆地总地表热通量的10.9%~20.9%,沉积物的放射性热量是总地表热通量的重要组成部分,应将其纳入盆地的热模拟。图3表3参21
OYEBANJO O M
,
AJAYI T R
,
TCHOKOSSA P
. 尼日利亚Gongola盆地地层放射性热产量与生烃潜力[J]. 石油勘探与开发, 2016
, 43(3)
: 411
-416
.
DOI: 10.11698/PED.2016.03.11
Samples taken from Well Kolmani-1 in the Gongola Basin in the Upper Benue Trough of Nigeria were studied to estimate the radiogenic heat generated and to analyze the possible impact of radiogenic heat on hydrocarbon generation potential of the sediments. Thirty-eight samples taken from the different formations at intervals of 73.2 m including sand, shale, coaly shale, sandy shale, and shaly sand were analyzed for 40K, 238U, and 232Th using the well calibrated NaI (Tl) Gamma Ray detector System. The results showed that the activity concentrations of the radio-nuclides varied significantly within the sediments. The 40K concentrations were the highest. The radiogenic heat produced ranges widely from 228.44 pW/kg to 1 412.82 pW/kg. In Well Kolmani-1, sands and sandy shale are low heat production sediments, while the shale, coaly shale and silty sands are medium heat production sediments, the potential source rock (shale and coaly shale) medium in heat production (750 pW/kg to 1 500 pW/kg), can produce liquid and gaseous hydrocarbons. It is estimated that the radiogenic heat from the sediments contributed about 10.9% to 20.9% to the total surface heat flux in the basin. Therefore, the radiogenic heat generated by the sediments contributed significantly to the total surface heat flux, and should be taken into consideration in the simulation of basin thermal evolution.
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