Numerical modeling of surface-to-borehole electromagnetic surveys for monitoring thermal enhanced oil recovery

Spies, Brian R.; Greaves, Robert J.

doi:10.1016/0016-7142(91)90038-e

Cited by 11 publications

(4 citation statements)

References 25 publications

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“…Wilt et al (1991) demonstrated, in an oilfield experiment, that cross-hole EM measurements made between boreholes spaced 100 m apart can be repeated to better than 1% of the field amplitude. The numerical model study by Spies and Greaves (1991) showed that, using a borehole-to-surface configuration, it is possible to detect the changes in resistivity associated with the progress of an enhanced oil recovery (EOR) processs.…”

Section: Introductionmentioning

confidence: 99%

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models¹

Sasaki

Matsuo²,

Yokoi

1994

Geophysical Prospecting

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We describe a least-squares inversion approach to estimating the subsurface resistivity structure from cross-hole or borehole-to-surface electromagnetic data. It is assumed that the resistivity distribution is symmetric about the axis of a borehole and that vertical magnetic dipoles are located on the borehole axis. The receivers are placed either in another borehole or on the earth's surface. T h e inversion scheme uses the finite-element and smoothness-constrained least-squares methods. The computational effort required to obtain partial derivatives is reduced considerably by using the reciprocity principle. Numerical simulations show that the reconstructions are generally in good agreement with the true structures when the assumption of an axisymmetric earth structure holds. An example involving the breakdown of this assumption, which can be obtained by interchanging the source and receiver boreholes, suggests that the inversion result may also be useful for locating a general 3D anomaly although artifacts are present.

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Section: Introductionmentioning

confidence: 99%

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models¹

Sasaki

Matsuo²,

Yokoi

1994

Geophysical Prospecting

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“…Ithas beenestablished that atlow ternperaturcs up toabout200 degrees thercsistivities ofrocks and saturating fluid have similar temperature d_-_)cndcncc: theincrease inconductivity withincreasing temperature up toabout200oC (Llera etal., 1990).Thisiscausedby anincreased mobility ofions withtheincrease oftemperature (Senand Goode, 1992). (Mansure, 1990;Spies and Greaves, 1991), indicate that the conductivity of the steaming zone can increase by a factor between 5 to 8 from its presteaming values. This increase is caused by the fact that, although the steam itself is resistive, only between of 60% to 80% of the steam actually enters the medium.…”

Section: II Range Of Conductivity Variationsmentioning

confidence: 99%

The crosswell electromagnetic response of layered media

Deszcz-Pan

1994

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Crosswell electromagnetic measurements are a promising new geophysical technique for mapping subsurface electrical conductivity. Because the conductivity of sedimentary rocks depends on the conductivity of the fluid that fills the rock pores, the variations in conductivity can provide information about the subsurface distribution of water, oil or steam. In this work the fields from a low frequency vertical magnetic dipole have been examined from the specific point of view of their application to the determination of the conductivity of a layered medium. Since it was established that the sensitivity of the fields to the conductivity distribution is higher when the source and the receiver axe located inside the medium they were placed inside two separate boreholes. The range of penetration of such a crosswell system for typical earth resistivities and for currently available transmitter and receiver technologies was found to be up to 1000 meters so problems in ground water and petroleum reservoir characteristics can be practically examined. The parameters that affect the conductivity estimates have been assessed using a whole-space approximation to simulate the conditions around the boreholes. It was established that the sensitivity of the fields to the variations in conductivity depends on the transmitter-receiver geometry and that the regions where fields change sign or vary rapidly with distance are subject to large errors caused by the possible misplacement of the transmitter with respect to the receiver. An analysis of the behavior of the magnetic fields at the boundary between two half-spaces showed that the horizontal magnetic field component, I-lp, and the vertical derivative of a vertical component, 8Hz/SZ, are more sensitive to conductivity variations than Hz. The analysis of derivatives led to the concept of measuring the conductivity directly using a second vertical derivative of Hz. Conductivity prof'des interpreted from field data using this technique reproduced accurately the electrical logs for a test site near Devine, Texas.

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“…Published reports have shown that the resistivity typically decreases from 35 to more than 80% after steam injection (Mansure and Meldau, 1990;Ranganayaki et al, 1992;Spies and Greaves, 1990). This decrease occurs because temperature increases and because the high-resistivity oil is replaced by the lower-resistivity steam and water injectate mixture.…”

Section: P3 Determine a New Pointmentioning

confidence: 99%

Supporting technology for enhanced oil recovery for thermal processes

Reid¹,

Bolivar²

1997

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Numerical modeling of surface-to-borehole electromagnetic surveys for monitoring thermal enhanced oil recovery

Cited by 11 publications

References 25 publications

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models¹

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models¹

The crosswell electromagnetic response of layered media

Supporting technology for enhanced oil recovery for thermal processes

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Numerical modeling of surface-to-borehole electromagnetic surveys for monitoring thermal enhanced oil recovery

Cited by 11 publications

References 25 publications

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models1

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models1

The crosswell electromagnetic response of layered media

Supporting technology for enhanced oil recovery for thermal processes

Contact Info

Product

Resources

About

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models¹

Resistivity inversion of cross‐hole and borehole‐to‐surface EM data using axially symmetric models¹