裂谷盆地复杂地温场精细表征方法

Methods for Detailed Characterization of Geothermal Fields in Complex Rift Basin

刘钧 杨希濮 徐伟 杨小丽 房磊

LIU Jun YANG Xipu XU Wei YANG Xiaoli FANG Lei

中海油研究总院, 北京 朝阳 100028

CNOOC Research Institute, Ghaoyang, Beijing 100028, China

东非裂谷盆地地温场复杂，特别是E油田内部地温梯度存在很大差异，影响了油藏流体性质和开发策略。深入分析油田测试资料后认为，地温梯度在平面上呈分区性，垂向上呈分段性，常规研究方法难于刻画此特征，基于此，探索了一种能精细表征油田内部地温场差异的方法——分区分段回归法。利用该方法对E油田复杂地温场进行了精细表征。结果显示，浅层地温梯度平均为6.10℃/（100 m），平面上由南往北呈减小趋势；深部地温梯度平均为1.53℃/（100 m），平面上由南往北呈增大趋势。沉积是平面地温梯度产生差异的主要因素。

The geothermal field of rift basins in East Africa are highly complex. In particular, the geothermal gradients within Oilfield E are highly variable, which affects the characteristics of reservoir fluids and the oilfield's development strategies. A detailed analysis of the measurements taken from the oilfield revealed that the geothermal gradients displayed zoning in the horizontal plane and segmentation in the vertical axis, which is difficult to visualize using conventional research methods. Hence, we explored a method termed as zoned-segmented regression that is capable of characterizing the geothermal field variations of an oilfield in detail. This method was used to perform a detailed characterization of complex geothermals in Oilfield E. The results indicate that the average geothermal gradients in shallow ground layers is 6.10℃/(100 m), and the geothermal gradients decreases towards the northern part of the research area. The average geothermal gradients in deep-lying sections is 1.53℃/(100 m), and increases towards the north instead. Sedimentation was found to be the main factor determining the development of variations in geothermal gradients in the horizontal plane.

10.11885/j.issn.1674-5086.2016.08.26.02