查干凹陷现今地温场研究及其油气地质意义

Present geothermal fields of Chagan Sag and its oil and gas geological significance

邓已寻 2 左银辉2 3 郝情情⁴ 李中超 5 李新军² 高霞² 李仁甫² 徐深谋²

中国地质大学（北京）能源学院，北京 100083 中国石化中原油田分公司勘探开发科学研究院，河南 濮阳 457001 中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249 中国冶金地质总局矿产资源研究院，北京 100025 成都理工大学沉积地质研究院，四川 成都 610059

查干凹陷是银-额盆地最具油气勘探潜力的凹陷，文中应用9口井的测温资料，计算了查干凹陷的地温梯度、大地热流，分析了查干凹陷地温梯度平面分布特征。研究结果表明：查干凹陷具有稳定区域的中等地温型地温场特征，其平均地温梯度为3.36 °C/100 m，平均估算大地热流为54.04 mW/m²；凹陷地温梯度的分布呈现毛敦次凸最高，东部次凹次之，西部次凹最低的特征；其分布与基底埋深相关，还与查干凹陷区巨厚沉积盖层和凹陷四周凸起之间产生的“热折射”效应作用有关。另外，查干凹陷烃源岩的成熟度受古地温影响。研究成果为查干凹陷及银-额盆地其他凹陷的烃源岩生烃评价提供了地温资料。

Chagan Sag has the most potential of oil and gas exploration in Yingen-Ejinaqi Basin. The geothermal gradient distribution map was drawn by calculating the present geothermal gradients of 9 wells and the terrestrial heat flow value was estimated. The results show that Chagan Sag has the characteristics of middle temperature field in the stable area, with an average thermal gradient value of 3.36 °C/100 m and an average terrestrial heat flow value of 54.04 mW/m². The geothermal gradient distribution generally shows the highest value in the Maodun Subsag, the middle value in the eastern subsag and the lowest value in the western subsag. The geothermal gradient distribution is not only associated with the basement depth, but also associated with the thermal refraction effects between the huge sedimentary cover in the sags and the uplifts around the sags. In addition, the maturity of source rock is controlled by paleotemperature. This study can provide the geothermal data for evaluating the hydrocarbon generation of source rock in Chagan Sag and other sags in Yingen-Ejinaqi Basin.

10.6056/dkyqt201203003