通过岩心、薄片等资料的研究表明,塔里木盆地塔中卡塔克1区块—顺西区块奥陶系储层中的沥青主要分布于孔隙(粒内、粒间、晶间、晶内)和裂隙中,其次分布于缝合线中.根据沥青的荧光颜色,可将其分为油质沥青、胶质沥青、沥青质沥青和碳质沥青等四种类型,其中油质沥青和碳质沥青分布最为普遍.储层沥青的形成期次可大致区分出早期不发荧光和晚期发荧光两期,两期之间的切割或包裹关系较为明显.沥青反射率高的碳质沥青可能是早期沥青历经长期热演化或遭受热事件的产物,沥青反射率低的发荧光沥青可能是晚期油气充注后的产物.

It is known that an amount of bitumen is distributed in Ordovician reservoirs in the northwest of central Tarim Basin. The analysis of the drilling cores and thin-sections from Katake-1 area to Shunxi area shows that the reservoir bitumen commonly exists within various pores (such as intragranular, intergranular, intracrystal and intercrystal pores) and fissures, as well as sutures. According to the fluorescent color, the reservoir bitumen can be divided into 4 kinds, oily bitumen, gel-bitumen, residual bituminous bitumen and carbonaceous bitumen, in which the oily bitumen and carbonaceous bitumen are common. The Ordovician bitumen probably formed during two periods, the early-forming one without fluorescence and the late-forming one with fluorescence, depended on the evident crosscutting or packing between the two periods. It is believed that the carbonaceous bitumen with high Rb values probably is the product that derives from the early-forming bitumen that suffered from long term thermal evolution, and the fluorescent carbonaceous bitumen with low Rb values probably is the late product after hydrocarbon charging in the reservoir.