New to 4D: data auditing service, training, and strategic planning 

4D auditing

NOJV

NOJV partners expressed concern that they were being asked to approve financial and technical decisions based on an incomplete understanding of the operator’s 4D seismic work.

M&A

A client inherited a large amount of poorly documented 4D data accompanying their company’s acquisition of a mature asset. They lacked the internal expertise to thoroughly understand their data and how to make best use of it.

Complex data history

An operator inherited an enormous, poorly archived seismic database. 4D seismic typically involves the generation of a multitude of datasets, and the client was unclear which where the correct datasets to proceed with.

Challenging Data

Quantitative interpretation requires data that has been optimally processed to remove noise while retaining amplitude information across all angle ranges. A client was concerned with the noise level in their 4D data and how this was negatively impacting the value of information.

4D auditing

NOJV

NOJV partners expressed concern that they were being asked to approve financial and technical decisions based on an incomplete understanding of the operator’s 4D seismic work.

M&A

A client inherited a large amount of poorly documented 4D data accompanying their company’s acquisition of a mature asset. They lacked the internal expertise to thoroughly understand their data and how to make best use of it.

Complex data history

An operator inherited an enormous, poorly archived seismic database. 4D seismic typically involves the generation of a multitude of datasets, and the client was unclear which where the correct datasets to proceed with.

Challenging Data

Quantitative interpretation requires data that has been optimally processed to remove noise while retaining amplitude information across all angle ranges. A client was concerned with the noise level in their 4D data and how this was negatively impacting the value of information.

iRes-Geo Data Auditing Service

Seismic data QC should always be performed prior to the commissioning of further data re-processing . This enables the reprocessing to be targeted and optimised so as to reduce costs and increase OE. iRes-Geo have successfully completed a number of projects identifying noise, noise sources and other issues relating to acquisition and the original processing workflow.

The Impact of Poor 4D Data

Quality Poor 4D data quality has a number of negative effects on a 4D program, but fundamentally it impacts confidence in the resulting interpretation. iRes-Geo’s partner, PSS-Geo, specialises in the post – stack removal of noise and preservation of signal, whether the noise be coherent or incoherent, ghosts, multiples or acquisition footprint.

iRes-Geo Data Auditing Service

Seismic data QC should always be performed prior to the commissioning of further data re-processing . This enables the reprocessing to be targeted and optimised so as to reduce costs and increase OE. iRes-Geo have successfully completed a number of projects identifying noise, noise sources and other issues relating to acquisition and the original processing workflow.

The Impact of Poor 4D Data

Quality Poor 4D data quality has a number of negative effects on a 4D program, but fundamentally it impacts confidence in the resulting interpretation. iRes-Geo’s partner, PSS-Geo, specialises in the post – stack removal of noise and preservation of signal, whether the noise be coherent or incoherent, ghosts, multiples or acquisition footprint.

Cross equalisation Deep – Dive

  • Check through the time-lapse processing history and equalisation history
  • Fine tuning of: Time- shift, Phase, Frequency spectrum, Amplitude cross – equalisation

Q. Has the Spectral Content / Phase / Amplitude Balancing been optimally performed?

A. If so, anomalies noted in the difference cube will be related to pressure / saturation changes. If not, the anomalies seen will not be ‘real’.

Q. Is 4D Seismic quality maintained across the entire angle range?

A. If so, Quantitative Interpretation of observed 4D anomalies can proceed. If not, the values of parameters derived from QI will be incorrect.

Q. Has the optimal approach to time – shift removal been implemented?

The typical convolution approach can introduce noise to the difference cube (see right). The appropriate time – shift removal algorithm must be selected on a case by case basis.

time-shift

Cross equalisation Deep – Dive

  • Check through the time-lapse processing history and equalisation history
  • Fine tuning of: Time- shift, Phase, Frequency spectrum, Amplitude cross – equalisation

Q. Has the Spectral Content / Phase / Amplitude Balancing been optimally performed?

A. If so, anomalies noted in the difference cube will be related to pressure / saturation changes. If not, the anomalies seen will not be ‘real’.

Q. Is 4D Seismic quality maintained across the entire angle range?

A. If so, Quantitative Interpretation of observed 4D anomalies can proceed. If not, the values of parameters derived from QI will be incorrect.

Q. Has the optimal approach to time – shift removal been implemented?

The typical convolution approach can introduce noise to the difference cube (see right). The appropriate time – shift removal algorithm must be selected on a case by case basis.

time-shift
noise

Removing Coherent 4D Noise:

iRes-Geo together with our seismic data processing partner PSS – Geo specialises in the removal of noise in the Post–migration domain, using specially designed filters.

  • Acquisition noise
  • Multiples
  • Ghosts
  • 4D broadband de-noising / de-multiple / Swell / angle mute
  • Angle stack quality control and optimisation for quantitative input
  • Post-migration re-equalisation

Removing Coherent 4D Noise:

iRes-Geo together with our seismic data processing partner PSS – Geo specialises in the removal of noise in the Post–migration domain, using specially designed filters.

  • Acquisition noise
  • Multiples
  • Ghosts
  • 4D broadband de-noising / de-multiple / Swell / angle mute
  • Angle stack quality control and optimisation for quantitative input
  • Post-migration re-equalisation
noise

Leveraging RE to Optimise 4D Interpretability

As important same as well tie to 3D seismic, the reservoir engineering and production data (RE data) is the hard control for 4D data quality. 4D signals that do not make RE sense are either geophysical or acquisition related noise, that should be detected and excluded. iRes-Geo has proprietary workflow to independently convert the conventional available RE data, e.g. tracer, water breaking through timing, RST, salinity etc., into 4D seismic confidence matrix, which will help the client to work with even the most noisy time-lapse seismic dataset, to make sense of the changes in the subsurface reservoir .

4D interpretation

Leveraging RE to Optimise 4D Interpretability

As important same as well tie to 3D seismic, the reservoir engineering and production data (RE data) is the hard control for 4D data quality. 4D signals that do not make RE sense are either geophysical or acquisition related noise, that should be detected and excluded. iRes-Geo has proprietary workflow to independently convert the conventional available RE data, e.g. tracer, water breaking through timing, RST, salinity etc., into 4D seismic confidence matrix, which will help the client to work with even the most noisy time-lapse seismic dataset, to make sense of the changes in the subsurface reservoir .

4D interpretation