川西北天井山构造泥盆系油砂成矿条件与资源评价

通过对四川盆地油砂资源的全面调查与评价，首次在川西北地区天井山构造下泥盆统平驿铺组的石英砂岩中发现了油砂矿体。根据石油地质及成矿理论对该矿点的成矿条件进行了分析，认为该油砂矿形成过程中可能的烃源岩为早寒武世和早志留世的黑色泥页岩；当进入印支期，烃源岩开始大规模生成液态烃，液态烃通过该期运动形成的逆断层运移至下泥盆统平驿铺组圈闭富集成藏；进入喜山运动，早先形成的油藏抬升暴露、剥蚀而最终形成了目前的油砂矿体。天井山构造泥盆系埋深500 m以上的油砂资源量为5 356.4×10⁴ t。

Oil Sand-Forming Conditions and Evaluation on Resource of Oil Sand in Tianjingshan Structure in Northwest Part of Sichuan Basin

Oil sand in quartz sandstone of the Lower Devonian Pingyipu Formation has been found for the first time in the Tianjingshan structure in the Northwest of Sichuan through detailed surveying and evaluating of oil sand resource in the Sichuan Basin. The authors have analyzed the ore-forming conditions for this mineral occurrence according to oil geology and metallogenic theory. The hydrocarbon source rock of oil sand is likely to be the Early Cambrian and Early Silurian black shales. During the Indosinian orogeny, liquid hydrocarbons were migrated through reverse faults of the Indosinian orogeny and were concentrated in the traps of the Lower Devonian Pingyipu Formation to form oil enriched reservoirs. The reservoirs were uplifted to be exposed and be denuded and were changed into the present oil sands finally during the Himalayan movement. It is calculated that the oil sand resource below 500 meters of the surface in the Tianjingshan structure, based on the calculating method proposed by the new nationwide evaluation program of oil and gas resource, are about 5 356.4×10⁴ t.