舞阳盐湖盆地地层压力特征与成因机理探讨

CHARACTERISTICS AND GENETIC MECHANISM OF FORMATION PRESSURE IN THE WUYANG SALT-LAKE BASIN

李兰斌 孙家振 陈文礼 扬云飞 李丽贤

LI Lan-bin SUN Jia-zhen CHEN Wen-li YANG Yun-fei LI Li-xian

中国地质大学资源学院, 湖北武汉430074 2. 河南石油勘探局勘探开发研究院, 河南郑州473132

College of Resources, China University of Geosciences, Wuhan, Hubei 430074, China 2. Research Institute of Exploration and Development, Henan Bureau of Petroleum Exploration, Zhengzhou, He'nan 473132, China

本文针对舞阳陆相盐湖盆地盐泥互层的地层结构特殊性,从盆地内异常流体压力分布特征出发,结合盆地埋藏史和热演化史,分析探讨其形成机理。压力计算结果表明盐湖盆地内异常流体压力可分为浅、中、深3套压力封闭体系:浅层为渐变过渡中等异常高压体系;中间盐泥间互发育段为多套低异常高压体系;深部为突变高异常压力体系。异常压力的形成主要与快速沉降造成不均衡压实引起的非渗透性岩层中流体不能排泄出的欠压实作用有关,还与水热增压、有机物转化成烃及构造挤压等有关。

Based on the particularity of stratigraphic structure for the salt-mud interbeds of the Wuyang Continental Salt-lake Basin,the authors discussed the genetic mechanism of anomalous fluid pressure in the basin starting with its destributive characteristics combined with the burial history and thermal evolutionary history of the basin.The calculated results of pressure reveal that the anomalous fluid pressure in the salt-lake basin can be classified into shallow,middle and deep three sets of pressure-sealing systems,that is the gradational and transitional moderately anomalous high pressure system in shallow beds,the mutiple sets of low-degree anomalous high pressure system in middle salt-mud interdeveloping members and the abrupt high-degree anomalous pressure system in deep beds.The formation of anomalous pressure is mainly related to the undercompaction that the fluid in nonpenetrative beds cannot drain off due to non-isostatic compaction result from rapid subsidence.It also has something to do with hydrothermal pressure-enhancement,organic matter converting into hydrocarbon,tectonic compression,etc.

https://doi.org/10.11781/sysydz200003265