Abstract

The study of normal geomagnetic background fields is the premise and basis for obtaining local geomagnetic anomalies caused by changes in underground pressure during gas injection and extraction in an underground gas storage (UGS) area. Measurements of the total magnetic field in an array consisting of sixty-three stations were acquired at a UGS and its surrounding areas. We completed field measurements at the stations using proton precession magnetometers (PPMs) with a sensitivity of 0.15 nT @ 1 Hz in April 2017 and March 2018. The geomagnetic background field model of the UGS area is calculated using the Taylor polynomial fitting method based on the data of all measured stations. A fourth-order Taylor polynomial model is appropriate for the UGS area according to a comprehensive comparative analysis of the mean square error and boundary distortion effect. The geomagnetic field distribution in the core area of the UGS can be better described by enlarging the network of repeat stations. The results provide a reference model for extracting the variations in the local magnetic field (LMF) caused by the underground pressure variations in the UGS area.

中文翻译：

---

地下储气库地磁场的泰勒多项式模型

摘要

正常地磁背景场的研究是获得地下储气库（UGS）区域注气和抽采过程中地下压力变化引起的局部地磁异常的前提和基础。在UGS及其周围地区采集了由63个站组成的阵列中的总磁场的测量值。我们于2017年4月和2018年3月使用质子旋进磁力计（PPM）在0.15 nT @ 1 Hz的灵敏度下完成了站点的实地测量。UGS地区的地磁背景场模型是根据基于所有测量站的数据。根据对均方误差和边界失真效应的综合比较分析，四阶泰勒多项式模型适用于UGS区域。通过扩大中继站的网络，可以更好地描述UGS核心区域的地磁场分布。该结果为提取由UGS地区地下压力变化引起的局部磁场（LMF）变化提供了参考模型。