济阳坳陷地温场分布特征

DISTRIBUTION CHARACTERISTICS OF GEOTEMPERATURE FIELD IN JIYANG DEPRESSION,SHANDONG,NORTH CHINA

在整理和分析了 70 3口钻井测温资料的基础上 ,编制了济阳坳陷现今地温梯度分布图、4～ 6km深度的地温分布图和下第三系沙四段顶界面地温分布图 .研究表明 :济阳坳陷的现今地温梯度平均为 35 .5℃ km ,其中沾化、东营、车镇和惠民等 4个主要凹陷地温梯度平均值分别为 36 .1℃ km、35 .5℃ km、35 .4℃ km和 34.6℃ km ,外围的潍北凹陷为 35 .0℃ km .地温和地温梯度分布主要受凸凹相间的构造格局控制 ,与基底埋深有关 ,表现为凸起区高、凹陷区低的特征 .另外 ,济阳坳陷一些地温梯度相对较高的地区与新生代的火山岩分布基本吻合 .盆地基底埋深 ,即盆内凸起凹陷的分布 ,受盆地形成过程中岩石圈伸展控制 ,火山岩的分布也与岩石圈伸展作用有关 ,所以 ,济阳坳陷的地温场分布特征是由构造演化决定的 .研究结果还表明 ,济阳坳陷大部分地区沙四段目前还处在油气液态窗内 .

Based on the analysis of geotemperature data derived from 703 exploration wells in the Jiyang depression of the Shengli oilfield, Shandong, North China, in combination with corresponding geothermal calculations, we present the geothermal field distribution characteristics of this region, which include the plane contour plots of geothermal gradient present day, geotemperature at depths 3km, 4km and 5km, respectively, as well as the top surface of lower Tertiary Es_ 4 formation of Jiyang depression. The results show that the average geothermal gradient present day of the whole Jiyang depression is about 35.5℃/km, the corresponding gradients of its four main sags, i.e. Zhanhua, Dongying, Chezhen and Huimin, are 36.1℃/km, 35.5℃/km, 35.4℃/km, and 34.6℃/km, respectively. While in the Weibei sag, outer flank of the Jiyang depression, it is 35.5℃/km. The distribution of geothermal gradient and geotemperature in the Jiyang depression is mainly governed by its tectonic framework of alternating uplifts and depressions areas. This distribution is also correlated with the basement depth. It is characteristiced by higher temperature in uplifts and lower one in depressions. In addition, those regions of relatively high geothermal gradient are consistent with those of Cenozoic volcanic rocks distribution. The pattern of basement depth of the Jiyang depression, which is also the distributionof uplifts and depressions, is controlled by the lithospheric extension during basin formation. This geodynamic process also accounts for the distribution of volcanic rocks in this region, consequently, the geothermal field characteristics of the Jiyang depression is governed by its tectonic evolution process. In addition, our results also indicate that most of the Es_ 4 formation in the Jiyang depression is still within liquid window of oil and gas.