应用定量颗粒荧光技术研究塔中地区志留系古油藏分布特征

Application of Quantitative Grain Fluorescence Technique in Study of Silurian Palaeo-Oil Pools Distribution in the Center Tarim Basin

引进定量颗粒荧光技术,研究了塔里木盆地塔中隆起志留系的油藏分布特征,着重探讨了古油藏叠合连片分布的可能性。结果表明,塔中地区的志留系在晚期成藏过程中没有形成过叠合连片的大规模的可动油气藏,而只在局部构造上形成规模较小的、独立的油气藏。塔中4和塔中17井柯坪塔格组上一亚段在地质时期都曾成过藏,但均遭破坏;塔中117井柯坪塔格组上三亚段和塔中31井柯坪塔格组上一亚段仅在后期充注过程中有油气聚集成藏;塔参1井在第一期油气充注过程中曾形成过较大的古油藏,而晚期充注过程中则未聚集成藏。研究还表明,志留系储层是好的输导层,地质时期中有烃类运移通过。中央断垒带为油气运移、聚集的主要路径和有利场所,在下一步的志留系勘探中应给予高度重视。

Quantitative grain fluorescence technique is for the first time applied in study of Silurian palaeo-oil pools distribution in the Central Tarim Basin. Much attention was put on discussion of possi bility of vertical superposition and horizontal continuity of small pools to form a large-scale palaeo-oil pool. The results show that there weren＇t large-scale moveable oil pools superposed and connected with same palaeo-oil-water contact, While all the small oil pools distributed separately in the single local structures. In geological periods, oil pools were formed in the 1st sub-member of upper member of Kepingtage Formation in well-Tazhong 4 and well-Tazhong 17 areas, but they were destroyed later on. In the 3rd sub-member of this upper member in well-Tazhong 117 area and the 1st sub member in well- Tazhong 31 area, oil pools were only formed in the later oil accumulation stage. In the 1st sub-member in Tacan 1 well area, a large pool came into being in the first oil accumulation stage, but without oil charging in later stages. The results also indicate that Silurian reservoirs are good for oil ＆ gas migra-tion so that plenty hydrocarbons migrated through them in geological stages. The central fault belt in the Tazhong uplift are thought to be the favorable locations for oil accumulation, so it should be taken into consideration in future Silurian exploration.