珠江口盆地珠三坳陷有机包裹体特征及其在含油气系统研究中的应用(英文)

Organic inclusion and its application on petroleum system in Zhu Ⅲ Depression, Pearl River Mouth Basin, China

根据对珠江口盆地珠三坳陷有机包裹体均一温度、盐度、荧光光谱、红外光谱、激光拉曼探针、同位素和生物标志化合物测试结果的分析 ,认为 :①文昌A凹陷和琼海凸起的珠海组和珠江组储集岩的两期有机包裹体中 ,第一期充填于石英碎屑内部或边缘的次生孔隙 (均一温度为 12 0～ 14 0℃ ) ,第二期主要充填于石英裂隙中 (均一温度为 15 0～ 170℃ ) ,反映两期油气运移时的古水体特征不同 ,包裹体中的烃类主要来自恩平组 ;②文昌B凹陷只有一期有机包裹体 ,充填于次生孔隙和裂隙中 (均一温度为12 0～ 14 0℃ ) ,包裹体中的烃类主要来自文昌组 ,油气运移时的古水体介质与文昌A凹陷不同。通过有机包裹体研究 ,认为油气运移时间文昌A凹陷油气系统为中渐新世至第四纪 ;文昌B凹陷油气系统为早中新世到第四纪 ,主要通过不整合和斜坡底砂岩沿鼻状构造脊侧向运移 ,并沿断层垂向运移 ;琼海凸起是被两个含油气系统夹持的鼻状古凸起 ,油气运移时间为晚渐新世至第四纪 ,油气主要来自文昌A凹陷油气系统 ,是油气勘探的有利地区。

Abundant organic inclusions with different characteristics of filling were discovered from the reservoir rocks of Zhuhai and Zhujiang Formation in Zhu ⅢDepression. The organic inclusions in Wenchang Sag A and Qionghai Uplift can be divided into two phases that represent two main periods of oil and gas migration. The Phase I organic inclusions filled in the secondary pores of the inner or edge of the detrital quartz grains, with the homogenization temperature ranging from 120℃ to 140℃. The Phase II organic inclusions filled in the crack of detrital quartz grains or overgrowths on the quartz, with the homogenization temperature ranging from 150℃ to 170℃. There is only one phase of organic inclusions occurred in Wenchang Sag B, indicating only one period of oil and gas migration. The organic inclusions filled in the secondary pore and crack, with its temperature varying from 120℃ to 140℃. The measurement of homogenization temperature of organic inclusions can be used to calculate the paleo-geothermal gradient. With the paleo-geothermal gradient, the buried depths for oil/gas migration have been calculated and the time for peak oil/gas migration is inferred at Middle Oligocene to Quaternary. This paper analyzes the experimental test results of the homogenization temperature, salinity, fluorescence spectrometry, micro-Fourier transform infrared spectrometry, laser Raman microprobe, isotope and biomarker from the organic inclusions. It is suggested that the hydrocarbons within organic inclusions in Wenchang Sag A and Qionghai Uplift come from Enping Formation, and that in Wenchang Sag B from Wenchang Formation. The ancient water between Wenchang Sag A and B has different characteristics. In result, the characteristic and distribution of petroleum system in Zhu Ⅲ depression are further understood.