柴达木盆地红116井区岩性油藏成藏模式探讨

Oil and gas accumulation model of lithologic reservoirs in Hong116,Qaidam Basin

为进一步细化柴达木盆地红柳泉地区成藏过程的研究,针对红116井区下干柴沟组岩性油藏中原油成熟度的差异性,采用生物标志化合物对比、沉积相研究、荧光光谱等方法,对该地区的成藏模式进行了研究。研究结果表明:该区位于下干柴沟组的储层中发育有上部(深度介于3 248至3 252 m)的未熟原油(Ro<0.5%)、中部(深度介于3 328.5至3 334.5 m)的成熟原油(0.8%<Ro<0.9%)和下部(深度介于3 368至3 376 m)的低熟原油(0.5%<Ro<0.7%)3种原油。在沉积砂体质量由下至上逐渐变差及两期成藏的前提条件下,早期的未熟油通过侧向运移至砂体质量最好的下部储层,后因构造变动向上调整至现今位置;晚期形成的低熟油和少量成熟油在密度分异的作用下,致使轻质成熟油聚集在中部储层,中质低熟油聚集在下部储层。

To further sdudy oil and gas accumulation of Hongliuquan Oilfield in Qaidam Baisin, aimed at difference of maturation of Well Hong 116 in Lower Ganchaigou Formation, the model is studied by biomaker comparison, sedimentary facies analysis and fluorescence spectrun. The results illustrate that there are three kinds of crude oil inLower Ganchangou Formation ,which are immature oil at top（ depth from 3 248 m to 3 252 m,Ro 〈0. 5% ） ,mature oil in the middle（depth from 3 328.5 m to 3 334. 5 m,0.8% 〈Ro 〈0.9% ）and low mature oil at bottom（depth from 3 368 m to 3 376 m ,0. 5% 〈Ro 〈0. 7% ）. Under the circumstance of quality of sandstone turning bad from the deep to the shallow and two epi- sodes of hydrocarbon charging, immature oil was charged through lateral migration at first episode and adjusted to the top of the reserviors through diastrophism;much low mature oil and a small quantity of mature oil were charged at second episode and mature oil was charged at middle while low mature oil at bottom because of differentia of density.