油砂组分遥感光谱响应特征及意义

基于油砂组分的吸收光谱物理响应机理,通过对比矿物基团平均吸收深度,建立主要蚀变矿物ASTER多光谱遥感数据异常提取模式以识别油砂分布.研究表明,与传统的烃类微渗漏遥感研究手段相比,该模式可以更有效地指示油砂的分布.利用油砂组分基团光谱平均吸收深度与孔隙度及渗透率进行相关分析,研究了油砂光谱与所处地质背景环境中储层物性之间的关联关系.结果表明,表征粘土矿物含量的粘土基团吸收深度与孔渗值呈负相关关系,指示含油性的烃类基团吸收深度与孔渗值呈显著正相关关系.

Characteristics of spectral response of oil sand components and their significance

Oil-bearing sands are a mixture of clay mineral,bitumen (an array of various hydrocarbon), quartz grains, water and minor accessory minerals. A number of analytical techniques have been applied to study the complex nature of such oil sands. The laboratory-derived reflectance spectra of oil sands show an abundance of diagnostic absorption features in the 350~2500 nm wavelength range. Discrete absorption bands due to clay mineral, ferrous mineral, carbonate and hydrocarbon appear at well-defined wavelengths. The phases are present in the oil sand, except quartz, which display distinct absorption bands that are potentially resolvable. The intensities and wavelength positions of spectra could provide information on the physical and chemical properties of various phases. The most prominent regions which are indicative of hydrocarbon absorption bands are near 1700 nm and between 2200 and 2600 nm, respectively. These spectral ranges are dominated by various C-H stretching overtones and combination bands. Absorption bands in the 2200 nm regions are most useful for identifying the presence and types of clay minerals with Al-OH.Based on the absorption spectra of physical response mechanism of the components of oil sands, the patterns of ASTER imagery anomalies extracted from the main alteration minerals were established by comparing the average absorption depth of the mineral groups. These patterns could be filtered to produce a lot of interference information and may more effectively indicate the distribution of oil sand compared with conventional tools with hydrocarbon microseepage of remote sensing. The correlation analysis was made to absorption depth of groups and porosity and permeability, then the relationship between the spectra of oil sands and reservoir quality from geological background environment was studied. The results show that the absorption depth of clay mineral group which characterizes clay mineral content is negatively correlated with poroperm values and absorption depth of hydrocarbon groups which characterizes petroliferous properties is positively related with poroperm values. This research proves that the field spectral characteristics of oil sand components may guide using the imagery data to detect the distribution of favorable areas for oil sands and provide an approach to in-depth study the petrophysical properties by establishing the relationship between the spectra of oil sands and poroperm values.