Wang Zhi, Jia Deli, Sun Fuchao, Chen Qiang, Zhu Shijia, Wang Quanbin
Research Institute of Petroleum Exploration and Development, Beijing, 100083, China.
Sci Rep. 2024 Aug 29;14(1):20093. doi: 10.1038/s41598-024-71011-3.
Over recent years, as digitalization and intelligence in oil wellbore have increased, so have the stricter requirements for wireless communication technology in terms of distance, accuracy, and portability. As a result, it's necessary to rely on more advanced and efficient wireless communication technologies to meet the industry's needs. However, traditional communication technologies such as cables and optical fibers have inherent shortcomings in construction, data interpretation, and cost. ELF electromagnetic waves are an ideal solution for communication in complex wellbore conditions due to long-distance communication and strong penetration capabilities, making it a highly effective option. Based on the theory of network splitting, this paper establishes a polygonal multiple-delays uncertainty coupled complex network model of ELF electromagnetic waves propagating through the casing in layered media and designs a controller, including expressions for the intensity of the magnetic and electric fields in different directions, and the propagation and distribution characteristics in different media. We determined that the optimal transmitting frequency of ELF electromagnetic waves under general conditions is 12.7 Hz. Based on field experiments, we verified that ELF electromagnetic waves can enable wireless wellbore communication within 1500 m without relays. We also analyzed the impact of casing thread deformation on ELF electromagnetic wave propagation due to high-temperature and high-pressure environments. We used simulation experiments to solve the distribution relationship between the electric and magnetic fields of the solenoids through casing and strata, as well as the coupling coefficients between the transmitting and receiving solenoids, and explore how different transmitting frequencies affect the efficiency of signal propagation. Both theories and experiments have verified the correctness of the model, and have also demonstrated the reliability and continuity of using ELF electromagnetic waves to achieve wireless wellbore communication, which provides a theoretical basis and feasibility for subsequent engineering applications.
近年来，随着油井数字化和智能化程度的提高，对无线通信技术在距离、精度和便携性方面的要求也越来越严格。因此，有必要依靠更先进、高效的无线通信技术来满足行业需求。然而，传统的通信技术，如电缆和光纤，在施工、数据解读和成本方面存在固有缺陷。极低频（ELF）电磁波由于具有远距离通信和强穿透能力，是复杂井筒条件下通信的理想解决方案，使其成为一种高效的选择。基于网络分裂理论，本文建立了极低频电磁波在分层介质中通过套管传播的多边形多延迟不确定性耦合复杂网络模型，并设计了一个控制器，包括不同方向上电场和磁场强度的表达式，以及在不同介质中的传播和分布特性。我们确定了一般条件下极低频电磁波的最佳发射频率为12.7赫兹。基于现场实验，我们验证了极低频电磁波无需中继即可在1500米范围内实现无线井筒通信。我们还分析了高温高压环境下套管螺纹变形对极低频电磁波传播的影响。我们通过模拟实验求解了螺线管通过套管和地层的电场和磁场分布关系，以及发射和接收螺线管之间的耦合系数，并探讨了不同发射频率如何影响信号传播效率。理论和实验都验证了模型的正确性，也证明了使用极低频电磁波实现无线井筒通信的可靠性和连续性，为后续工程应用提供了理论依据和可行性。
