Reservoir monitoring using permanent sources and vertical receiver antennae

Meunier, J.; Huguet, F.; Meynier, P.

doi:10.1190/1.1815724

Cited by 5 publications

(1 citation statement)

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“…Whereas in most cases the focus has been on the changes of fluids within a given volume (e.g. Meunier et al 2000), another parameter is often neglected—the change in pressure; recently, however, even such an experiment has been described (Haney et al 2004, 2005). New algorithms and advanced imaging techniques have been developed to quantify the changes within reservoirs such as, for instance, variations of the seismic impedance (Lumley 1995, 2001; Jack 2001).…”

Section: Introductionmentioning

confidence: 99%

Pressure-dependent seismic reflection amplitude changes in crystalline crust: lessons learned at the Continental Deep Drilling Site (KTB)

Beilecke

Bram

Buske

2010

Geophysical Journal International

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S U M M A R YWe conducted an active seismic experiment aimed at measuring changes in seismic reflection amplitudes as a consequence of fresh water injection and corresponding pressure changes at the German Continental Deep Drilling site (KTB). The injection took place at the bottom of the 4-km-deep pilot borehole in the SE2 fault zone in crystalline rock units between the springs of 2004 and 2005. Prior to the experiment, theoretical calculations indicated a possible increase in the compressional wave reflection coefficient as a result of an injection-induced reduction of the seismic velocities within the fault zone.Despite good repeatability of the emitted source signals, the experiment suffered from missing the clear reflection signals expected from the fault zone with regard to seismic data from past experiments. Applying various data-processing steps did not enhance the signals enough to obtain clear reflections or even pressure-dependent reflection amplitude changes. The signal-to-noise ratio remains smaller than the effects under observation. Provided that reflections are present in the data, the error bar of the recorded signals is of the order of 100 per cent. Therefore, we conclude that the experiment was not successful in seismically measuring pressure variations. However, important lessons for land seismic time-lapse measurements in crystalline environments have been learned: (i) The source should be capable of emitting frequencies below 30 Hz. (ii) The detector array setup proved to be partly questionable because in a scattering environment like the crystalline rocks at the KTB site, the incidence of a plane wave precondition might be violated for high-frequency signals. (iii) Near-surface variations of elastic properties likely influence seismic monitoring. (iv) Using a step function, that is a first-order pressure discontinuity, to model the subsurface pressure build-up, is very likely too simple an approach.

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Section: Introductionmentioning

confidence: 99%