Study on Multifrequency Electromagnetic Response of Hydraulic Fracturing Fracture with Proppant: Based on a Forward Model of Short Distance Receiving and Transmitting

Electromagnetic method has become one of the research hotspots of fracturing detection technology in recent years, due to its unique advantages. Based on various advanced electromagnetic modeling and simulation technologies, a large number of scholars have carried out detailed discussion on the signal characteristics of fracture with proppant under different shape parameters. If conditions permit, some researchers have also made real instrument prototype and field test. However, an unusual signal feature has been noticed in our team’s forward modeling of electrical abnormal fracture based on TBC-FEM. In this experimental design, the transmitter is a downhole movable magnetic dipole. When observing the electromagnetic field distribution of the transmitter near the fracture, changing the frequency of the transmitter will lead to different results in the near-field changes. When the transmitter frequency is low, the signal is gradually enhanced as the instrument approaches the fracture under the premise that the receiver and the transmitter are on the same side of fracture. If the frequency of transmitter is increased, the fracture response signal will vary between 1kHz and 10 kHz when the frequency band is higher than 1 kHz, and The trend of fractures response signal curve is opposite. The simulation results show that the expansion thickness of the fracture has a great influence on the abnormal change frequency of the signal. This study will try to find out the correlation between the reason of the signal change and some parameters of the fracture. The engineering application prospect of this study is optimistic. The hypothetical structure of the experimental simulated detection instrument does not need special casing and wellbore structure. In addition, the transmitting and receiving distance is not longer than 1.5 m. The discussion of this problem may obtain a low-cost and easy to implement way to obtain hydraulic fracturing fracture parameters.