沉积基准面在层序划分对比及地层岩性油气藏预测中的应用

APPLICATION OF DEPOSITIONAL BASE-LEVEL CONCEPT IN SEQUENCE STRATIGRAPHIC DIVISION, CORRELATION AND LITHO-STRATIGRAPHIC TRAPS PREDICTION

曹颖辉 池英柳 薛良清 王洪江

CAO Ying-hui CHI Ying-liu XUE Liang-qing WANG Hong-jiang

中国石油 勘探开发研究院, 北京 100083 2. 石化管理干部学院, 北京 100101

Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China 2. Management Institute, SINOPEC, Beijing 100101, China

沉积基准面旋回变化控制着陆相层序地层的形成与演化。与海相盆地相比,陆相盆地的沉积基准面既不是海平面也不是湖平面,而是相当于河流平衡剖面的一个抽象界面。在沉积基准面旋回中,不同位置的可容纳空间大小的不同,致使沉积物在不同相域内进行体积分配,从而导致了地层堆积样式、旋回厚度的变化。这些变化正是层序划分对比的标志。依据沉积基准面旋回中沉积物的体积分配原理,高分辨率层序地层对比应当是有时岩石与岩石、有时岩石与界面、有时界面与界面的对比,而不是岩性对比和等厚度对比。沉积基准面旋回变化过程中,可容纳空间大小变化的差异与不同体系域的生储盖层发育以及地层不整合面、岩性尖灭线的分布之间存在密切关系。这为地层-岩性油气藏预测提供了科学依据。该文以松辽盆地为例,具体阐述了砂岩透镜体岩性油气藏、砂岩上倾尖灭油气藏、断层岩性油气藏以及地层超覆、地层不整合遮挡油气藏的形成与分布。

Depositional base-level cycle controls the development and evolution of sequence stratigraphy.Different from that in sea basin,the depositional base-level in continental basin is not sea-level or lake-level but river depositional equilibrium profile.During depositional base-level cycles,the sediment volume into different facies varies correspondence with its accommodation and that leads to the variation of sediment stacking patterns and symmetries of stratigraphic cycles.This provides scientific basis for sequence division and correlation.Correct chronostratigraphic correlation should be that of rocks to rocks,rocks to surfaces or surfaces to surfaces according to sediment volumetric partition.During depositional base-level cycles,the variation of accommodation controls the development of source rock,reservoir rock and cap rock in different system tracts and the forming of unconformity and various litho-pinch out. This is the basis of strata-lithologic traps prediction.In this paper,taking Songliao basin as an example,five principal types strata-lithologic traps and their particular formation conditions and distribution were analysed in the basin.

https://doi.org/10.11781/sysydz200201036