松辽盆地中央拗陷带青山口组玄武岩与油气分布的关系

RELATIONSHIP BETWEEN THE INJECTED BASALT IN QINGSHANKOU FORMATION AND OIL/GAS IN ZHONGYANG DEPRESSION, SONGLIAO BASIN

韩广玲 赵洪涛 边吉

Han Guangling Zhao Hongtao Bian Wen

吉林油田探勘开发研究院

Jilin Research Institute of Petroleum Exploration and Development, MInistry of Petroleum Industry

通过对乾124井岩屑、测井和地震、重力、磁法资料及金6井等有关成果,对中央坳陷带的玄武岩岩性、产状及其与构造和油气的关系进行了探讨。认为在青山口组沉积中晚期,沿松辽壳断裂断续有中心式玄武岩的喷溢或贯入,其喷溢过程形成的牵引构造和冷却阶段的差异压实构造,为油气聚集和油气藏形成提供了良好前提,它能局部提高源岩的成熟度而无破坏影响,含油气盆地中的玄武岩分布区是油气勘探中值得重视的新领域。

The Cretaceous Qingshankou Formation of Songhuajiang Group comprises the main source rocks of Songliao Basin. It is proved that basalts have been injected into this formation in Qianan and Taikang areas of the central depression zone. The authors of this paper approach to the relationship between the distributive characters of the basalt and oil/gas. It is considered that axial injection and eruption of the basalt occurred along the heigh-tened Moho discontinuity of the basin during the late sedimentation stage of Qingshankou Formation. The seismic waves have rather high velocity in the basalt area and constitute dune reflective configurations. The logging curves in the basalt area are characterized by "one high and three lows". Generally speaking, drag structures related to the basalt eruption would develop beneath the basalt body while primary structures related to the dune configuration and differential compaction would develop above the basalt body. Therefore, such an area would be favourable for the traps of oil/gas. In addition, gentle baking of the source rocks by the basalt eruption and injection would improve the prospect for oil/gas exploration.

https://doi.org/10.11781/sysydz198803248