Joint marine electromagnetic (EM) and seismic interpretations are widely used for offshore gas hydrate and petroleum exploration to produce improved estimates of lithology and fluids and to decrease the risk of low gas saturation. However, joint data acquisition is not commonly employed. Current marine EM data acquisition depends on an ocean bottom electromagnetic receiver (OBEM), and current seismic exploration methods use seismometers. Joint simultaneous data acquisition can decrease costs and improve efficiency, but conventional independent data receivers have several drawbacks, including a large size, high costs, position errors, and low operational efficiencies. To address these limitations, we developed a compact ocean bottom electromagnetic receiver and seismometer (OBEMS). Based on existing ocean bottom E-field receiver (OBE) specifications, including low noise levels, low power consumption, and low time drift errors, we integrated two induction coils for the magnetic sensor and a three-axis omnidirectional geophone for the seismic sensor to assemble an ultra-short baseline (USBL) transponder as the position sensor, which improved position accuracy and operational efficiency while reducing field data acquisition costs. The resulting OBEMS has a noise level of 0.1 nV m^−1 rt^−1 (Hz) at 1 Hz in the E-field, 0.1 pT rt^−1 (Hz) at 1 Hz in the B-field, and a 30 d battery lifetime. This device also supports a Wi-Fi interface for the configuration of data acquisition parameters and data download. Offshore acquisition was performed to evaluate the system's field performance during offshore gas hydrate exploration. The OBEMS operated effectively throughout the operation and field testing. Therefore, the OBEMS can function as a low-cost, compact, and highly efficient joint data acquisition method.

中文翻译：

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紧凑的海底电磁接收器和地震仪

联合的海洋电磁（EM）和地震解释被广泛用于海上天然气水合物和石油勘探，以产生改进的岩性和流体估计，并降低低天然气饱和度的风险。但是，联合数据采集并不普遍。当前的海洋EM数据采集取决于海底电磁接收器（OBEM），并且当前的地震勘探方法使用地震仪。联合同时进行的数据采集可以降低成本并提高效率，但是常规的独立数据接收器具有多个缺点，包括尺寸大，成本高，位置误差大和操作效率低。为了解决这些限制，我们开发了紧凑型海底电磁接收器和地震仪（OBEMS）。基于现有海底E场接收器（OBE）规范，包括低噪声水平，低功耗和低时间漂移误差，我们集成了两个用于磁传感器的感应线圈和一个用于地震传感器的三轴全向地震检波器，以组装超短基线（USBL）应答器作为位置传感器，可提高位置精度和操作效率，同时降低现场数据采集成本。所产生的OBEMS的噪声水平为0.1？nV？m ^？1？rt ^{???? 1}（Hz）在1？Hz处。E场，在B中的¹ ° Hz处为0.1°pTΔrtrt≤1 （Hz）场，并具有30？d的电池寿命。该设备还支持Wi-Fi接口，用于配置数据采集参数和数据下载。在海上天然气水合物勘探期间，进行了海上采油以评估系统的现场性能。OBEMS在整个操作和现场测试中均有效运行。因此，OBEMS可以用作低成本，紧凑且高效的联合数据采集方法。