济阳坳陷上地壳速度结构与地热相关性研究

济阳坳陷及周边地区位于华北板块东部,是板内伸展沉积构造。目前研究区水热型地热资源开发利用程度较高,但上地壳热源传导机制研究较少,济阳坳陷及周边地区的高分辨率三维地壳速度结构有助于探讨该区热源富集规律。利用双差层析成像方法,获得了研究区三维地壳的速度结构,通过与地温场特征比对分析,认为上地壳速度结构与深部热源传导规律密切相关。根据反演结果,发现聊考-齐广断裂西北0～5km深度存在大规模低速层,这与区域厚度较大的沉积地层有关;聊城东部、埕宁隆起等区域表现为明显的高速异常,隆起区地温增温率明显高于凹陷区,这与储层下部地层导热能力有关;东营地区10km以下速度普遍较高,下地壳热流值贡献稳定;燕山晚期以来鲁中南部隆起对研究区地壳的拖拽拉伸是济阳坳陷内地热田最直接的构造影响因素,形成的多组地堑构造是水热型沉积盆地地热田边界的重要控制因素。

Correlation between Velocity Structure of Upper Crust and Geothermal Energy in Jiyang Depression

Jiyang depression and its surrounding area are located in the east of North China plate. They are extensional sedimentary structures in the plate. At present, development and utilization of hydrothermal geothermal resources in the research area is relatively high, but the study on the conduction mechanism of the upper crust heat source is less. High resolution threedimensional crustal velocity structure in Jiyang depression and its surrounding areas is helpful to explore the law of heat source enrichment in the area. The velocity structure of the threedimensional crust in the study area is obtained by using double difference tomographic method. Through comparison and analysis on characteristics of geothermal field, it is concluded that velocity structure of the upper crust is closely related to the conduction law of deep heat source. According to the inversion results, it is found that there are large scale low velocity layers in the northwest of Liaokao-Qiguang fault, which is related to the sedimentary strata with large regional thickness; High speed anomalies are obvious in eastern Liaocheng and Chengning uplift, and the temperature increase rate of uplift area is higher than that in the depression area, which is related to thermal conductivity of the lower strata of the reservoir. The velocity below 10km in Dongying area is generally high, and the contribution of the heat flow value of the lower crust is stable. The drag and pull of the crust in the study area by the uplift in the south central part of Shandong province since late Yanshan period is the most direct structural factor of thermal field in the inner part of Jiyang depression. The formation of multi group graben structure is an important control factor of geothermal field boundary in hydrothermal sedimentary basin.