Monitoring Water Flood Front Movement by Propagating High Frequency Pulses Through Subsurface Transmission Lines

Abstract

This manuscript describes a novel approach to monitor water flood front movement using Proximity Sensing in conjunction with contrast agents. Our technique exploits the presence of resistive layers between reservoirs, which act as a transmission line for electromagnetic signals, to achieve increased propagation range. This work focuses on numerical simulations to evaluate the potential of this approach to monitor water movement in the reservoir under different conditions. A series of 2D axisymmetric numerical simulations were conducted to assess the potential of Proximity Sensing to monitor moving fronts of labeled brine as well as to detect isolated pockets of brine labeled with contrast agents. The study was conducted using layered models that resemble a resistive seal bounded by reservoirs saturated with brine or brine and contrast agents. The effect of magnetic permeability (μ) on signal travel time and amplitude is reported and compared to the effect of electric permittivity (ε). The results show that Proximity Sensing is a suitable technique to detect changes in the μ of reservoirs adjacent to resistive seals. Therefore, our approach can be used in combination with contrast agents, such as Magnetic NanoMappers, to monitor water flood front movement in the reservoir. In addition, this technique can be used to detect isolated pockets of labeled brine, which suggests that injection of slugs of labeled water would be enough for field applications. The observed effect of μ on signal travel time is similar to the trend observed when the electric permittivity of the bounding reservoirs is changed. A significant difference is that increasing μ of the bounding reservoirs appears to reduce signal amplitude while increasing ε has the opposite effect. This result was unexpected and requires further simulations and experimentation to validate this behavior. Proximity Sensing offers a novel approach to address the challenge of electromagnetic propagation in conductive media and paves the way for the development of refined techniques that provide reservoir saturation and water flood front monitoring capabilities with greater resolution.