Multi‐scale data integration in Crosswell EM imaging and interpretation

Alumbaugh, David; Donadille, Jean Marc; Gao, Guang; Levesque, Cyrille; Nalonnil, Ajay; Reynolds, Lawrence P.; Wilt, Michael; Zhang, Ping

doi:10.1190/1.3064060

Cited by 4 publications

(1 citation statement)

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“…However, for copper ore detection, numerous single-well loggings are required to obtain the distribution of the target, resulting in enormous cost. The crosswell electromagnetic (EM) method is an important geophysical exploration method that extends the research scope of traditional single-well logging and can obtain the formation conductivity distribution over a large area between wells [6]. This method is widely used for reservoir characterization, flood monitoring, oil and gas identification, and mineral exploration [7]- [10].…”

Section: Introductionmentioning

confidence: 99%

Long-Distance Crosswell EM Logging of Copper Ore Using Borehole-Surface Current Injection in Slim Holes

Dang

Zhao

Guo

et al. 2022

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Crosswell electromagnetic (EM) methods are widely used in subsurface geophysical prospecting because they can achieve more effective long-distance detection than single-well methods. However, a large-diameter borehole is required to increase the magnetic moment of the magnetic dipole source. For the long-distance detection of copper ores, which is usually performed in slim holes, we present a borehole-surface currentinjection-based crosswell EM logging method. Considering the cost of deploying casing, we inject a low-frequency AC directly into the ground, and converging current is formed around lowresistance anomalies in the formation. Then, the distribution of the anomalies can be inferred by detecting the low-frequency alternating magnetic field of the converging current in the receiver well. Moreover, to further improve the detection performance, we design a placement scheme for the grounding electrode for multianomaly crosswell detection based on the Gauss-Newton inversion algorithm, where the EM responses for different grounding electrode locations are analyzed. Field experiments are conducted using two slim open holes spaced approximately 1000 m apart for the detection of two copper ores. Through the processing and interpretation of measured EM signals, the conductivity imaging results of the crosswell EM method indicate that the measured distribution of anomalies is consistent with prior knowledge obtained from numerous single-well loggings, demonstrating the feasibility of the proposed application for long-distance crosswell EM logging in slim open holes.

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Section: Introductionmentioning

confidence: 99%

Long-Distance Crosswell EM Logging of Copper Ore Using Borehole-Surface Current Injection in Slim Holes

Dang

Zhao

Guo

et al. 2022

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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A modeling comparison of two crosswell EM systems for water flood monitoring in horizontal wells

Kaputerko

Alumbaugh

Levesque

2009

SEG Technical Program Expanded Abstracts 2009

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Crosswell Magnetic Sensing of Superparamagnetic Nanoparticles for Subsurface Applications

Rahmani

Bryant

Huh

et al. 2013

Day 2 Tue, October 01, 2013

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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-size pores across long distances in a reservoir, with modest retention in rock. These particles change the magnetic permeability of the flooded region, and thus can be used 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 (less than 100 Hz) 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 (below 100 Hz in our assumed model), 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 while significant levels of detectability result at frequencies above 100 Hz. 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. Given a fixed volume of ferrofluid and considering several candidate formations for test pilot design, there is an optimum layer thickness which 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 quasi-static 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, provides significant value of using the magnetic contrast agents in crosswell EM tomography.

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Multi‐scale data integration in Crosswell EM imaging and interpretation

Cited by 4 publications

References 0 publications

Long-Distance Crosswell EM Logging of Copper Ore Using Borehole-Surface Current Injection in Slim Holes

Long-Distance Crosswell EM Logging of Copper Ore Using Borehole-Surface Current Injection in Slim Holes

A modeling comparison of two crosswell EM systems for water flood monitoring in horizontal wells

Crosswell Magnetic Sensing of Superparamagnetic Nanoparticles for Subsurface Applications

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