Abstract:

With the development of drilling techniques and oil-gas exploration, deep hydrocarbon exploration has gained more and more attention and may become an important fungible field for rising reserves. Analysis on the data of drilling and oil-gas geology of deep wells over 7 000 m in depth shows that the low limit of depth range for generation of deep hydrocarbon is possibly large, and there still exists the hydrocarbon-generation potential for the high mature source rocks. The low limit of preservation depth for the effective reservoir can shift downward, and the fractured reservoir is predominant. The oil-gas pools mainly include the earlier accumulation-later deep burying pattern, the later accumulation pattern after deeply burying and the multi-stage charging pattern. The earlier accumulation pattern can restrain the shrink of rock porosity during the deep burying process. The fractured reservoir is predominant and more developed near the fault belts, when the burial depth is more than 6 000 m. Faults connected with the deep source rocks are usually the important migration pathways for the later oil accumulation. The hydrocarbon enrichment degree near the fault belts is very high. The multi-stage hydrocarbon charging and strong charging processes can often improve the reserve abundance. The hydrocarbon resource in the strata beyond 7 000 m in depth is of considerable potential in the basins in central and western China.

Key words: deep hydrocarbon accumulation, source rocks, hydrocarbon-generation potential, reservoir pattern, oil and gas exploration potential, basins in the central and western China

摘要：

随着油气钻探技术的提高和勘探工作的不断深入,深层油气勘探愈来愈被重视,深层将可能成为未来储量增长的重要接替领域。对中国7000m以下深井的钻探资料和深层油气地质资料分析表明,烃源岩的生烃深度下限范围可能较大,高过熟阶段的烃源岩生烃潜力依然存在。深部各类有效储集体的保存深度下限可能下移,以发育裂缝型储集体为主,油气藏类型主要包括早期成藏-后期深埋型、储层深埋后晚期成藏型和多期充注成藏型。早期成藏可以抑制深埋过程中岩石孔隙的萎缩,埋深大于6000m的油藏以裂缝型储集体占优势,断裂带附近裂缝型储集体更为发育,断裂通常是晚期成藏型油气藏的重要输导通道。断裂带附近油气富集程度较高,油气多期充注作用和强烈充注作用往往能提高油气藏的储量丰度。因此,中国中、西部盆地7000m以下层系成藏条件较好,油气资源潜力可观。

关键词: 深层油气成藏, 烃源岩, 生烃潜力, 油藏类型, 油气勘探潜力, 中国中、西部盆地