Crosswell Magnetic Sensing of Superparamagnetic Nanoparticles for Subsurface Applications

Abstract

Stable dispersions of superparamagnetic nanoparticles that are already in use in biomedicine as image-enhancing agents also have potential use in subsurface applications. Surface-coated nanoparticles are capable of flowing through micron-sized pores across long distances in a reservoir, with modest retention in rock. These particles change the magnetic permeability of the flooded region, and thus one can use them to enhance images of the flood. In this paper, we model the propagation of a "ferrofluid" slug in a reservoir and its response to a crosswell magnetic tomography system.This approach to monitoring fluid movement within a reservoir is built on established electromagnetic (EM) conductivity-monitoring technology. In this work, however, we investigate the contrast between injected and resident fluids when they have different magnetic permeabilities. Specifically, we highlight the magnetic response at low frequency to the magnetic excitations generated by a vertical magnetic dipole source positioned at the injection well. At these frequencies, the induction effect is small, the casing effect is manageable, the crosswell response originates purely from the magnetic contrast in the formation, and changes in fluid conductivities are irrelevant.The sensitivity of the measurements to the magnetic slug is highest when the slug is closest to the source or receivers and lower when the slug is midway in the interwell region. At low frequencies, the magnetic response of the ferrofluid slug is largely independent of frequency. As expected for the conductive slug, the sensitivity of the inductive measurements is negligible at low frequencies whereas significant levels of detectability result at higher frequencies. We demonstrate sensitivity to the vertical boundaries of the slug by shifting the vertical position of the excitation source relative to the magnetic slug. The slug geometry plays a key role in determining the magnetic response. With a fixed volume of ferrofluid, there is an optimum slug geometry that results in the maximum magnetic response. Hydrodynamic dispersion of the slug has negligible effect on the magnetic response during early stages of the waterflood. As the slug travels farther into the formation, however, dispersion reduces the concentration of nanoparticles, and the spatial contributions of the magnetic measurements are more diffuse. We illustrate how these low-frequency excitation behaviors are consistent with the quasistatic magnetic dipole physics. The fact that the progress of the magnetic slug can be detected at very early stages of the flood, that the traveling slug's vertical boundaries can be identified at low frequencies, and that the magnetic nanoparticles can be sensed well before the actual arrival of the slug at the observer well provide significant value of the use of the magnetic-contrast agents in crosswell EM tomography.

Viscosity reduction of extra heavy crude oil by magnetite nanoparticle-based ferrofluids

“…Ferrofluids are stable dispersions of magnetic nanoparticles in the presence of surfactant in determined carrier fluid (Kothari et al, 2010). In the oil and gas industry, ferrofluids have been used in various applications such as improved flow surfactants in EOR processes (Cocuzza et al, 2011), imaging of fractures (Sengupta, 2012), corrosion inhibitors (Rahmani et al, 2014), and mobilization of residual crude oil by viscosifying displacement fluid and reducing interfacial tension (Matteo et al, 2012;Soares et al, 2014). One of the greatest advantages of ferrofluids is that in the presence of an external field, the magnetic moments of each nanoparticle in the ferrofluid will align along a preferential direction according to the applied field, keeping the mechanical behavior of fluids and allowing to control its flow by convenience through the manipulation of the magnetic effort (Kothari et al, 2010; Saint-Martin de Abreu Soares, 2015).…”

Synergy between Sugar‐Based Anionic‐Nonionic Surfactants and Ag‐TiO2 Nanohybrids for Enhanced Oil Recovery

“…The wettability reversal phenomenon of the GDA/Ag-TiO 2 sample was more obvious, which could be described as the spontaneous "wedge spread" of NP layered structures in the confined three-phase contact region of the wedge film increasing the contact angle change versus surfactant alone (Bera and Mandal, 2015). In addition, the adsorption of NP (Rahmani and Bryant, 2015).…”

A State-of-the-Art Review of Nanoparticles Application in Petroleum with a Focus on Enhanced Oil Recovery

“…Real-time oil reservoir evaluation with two-dimensional detection technology [23] Magnetic NP Detect flood front, fluid contact, hydrocarbon bypass and fracture [24] Superparamagnetic NP Cross well magnetic sensor for tracking flood front [25] Drilling & Completion…”

“…Magnetic NPs for detecting flood front and oil-water interfaces have been studied, and the result showed the capability of travel-time tomography to detect magnetic NPs in different media, which was a big step in the utilization of magnetic nanosensors [24]. Similarly, Rahmani et al [25] successfully employed superparamagnetic NP for tracking floodfront using a crosswell magnetic sensing method. The most recent advance in the use of nanotechnology in oil and gas exploration is the utilization of reservoir nano-robots by Liu et al [50], who successfully tested a nano detection device which integrates a reservoir sensor, a micro-dynamic system, and micro-signal transmission.…”