4D seismic feasibility study: The importance of anisotropy and hysteresis

2018 ◽  
Vol 37 (9) ◽  
pp. 688-698 ◽  
Author(s):  
Michinori Asaka ◽  
Mu Luo ◽  
Takashi Yamatani ◽  
Ayato Kato ◽  
Keita Yoshimatsu ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Rock Physics ◽  
Forward Modeling ◽  
Seismic Signal ◽  
Stress Sensitivity ◽  
Propagation Direction ◽  
Velocity Measurements ◽  
Velocity Anisotropy ◽  
Measurement Direction ◽  
4D Seismic

Core velocity measurements are an essential part of any 4D seismic feasibility study. During recently conducted core velocity measurements, we found some interesting results regarding velocity anisotropy and hysteresis. These findings include: (1) the stress sensitivity of velocity varies depending on the propagation direction, (2) velocities measured during loading have a significantly larger stress sensitivity than those measured during unloading, and (3) horizontal effective stress has a noticeable impact on velocity anisotropy. We conducted rock physics analysis and 1D seismic forward modeling, incorporating velocity anisotropy, and found that the estimated 4D seismic signal is largely affected by velocity anisotropy and hysteresis. These findings suggest the importance of considering the velocity measurement direction and the nature of the stress change to obtain a realistic 4D seismic signal. Neglecting these considerations may lead to a significantly underestimated or overestimated modeled seismic response.

Pressure and saturation inversion of 4D seismic data by rock physics forward modeling

2002 ◽  
Author(s):  
Steve Cole ◽  
David Lumley ◽  
Mark Meadows ◽  
Ali Tura
Keyword(s):  
Seismic Data ◽  
Rock Physics ◽  
Forward Modeling ◽  
4D Seismic

Impact of Reservoir Pressure Changes on 4D Seismic Responses in Carbonates: Special Rock Physics Core Study

2007 ◽  
Author(s):  
William L. Soroka ◽  
Taha Al-Dayyani ◽  
Christian J. Strohmenger ◽  
Hafez H. Hafez ◽  
Mahfoud Salah Al-Jenaibi
Keyword(s):  
Rock Physics ◽  
Reservoir Pressure ◽  
Seismic Responses ◽  
Core Study ◽  
Pressure Changes ◽  
4D Seismic

scholarly journals Time-Lapse Seismic Monitoring of Onshore Reservoirs in Niger Delta, Field ‘K’ as a Case Study

2017 ◽  
Vol 1 (1) ◽  
pp. 23-27 ◽  
Author(s):  
A. Ogbamikhumi ◽  
T. Tralagba ◽  
E. E. Osagiede
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Niger Delta ◽  
Rock Physics ◽  
Time Lapse ◽  
Seismic Survey ◽  
Impedance Change ◽  
Data Set ◽  
Reservoir Fluid ◽  
4D Seismic

Field ‘K’ is a mature field in the coastal swamp onshore Niger delta, which has been producing since 1960. As a huge producing field with some potential for further sustainable production, field monitoring is therefore important in the identification of areas of unproduced hydrocarbon. This can be achieved by comparing production data with the corresponding changes in acoustic impedance observed in the maps generated from base survey (initial 3D seismic) and monitor seismic survey (4D seismic) across the field. This will enable the 4D seismic data set to be used for mapping reservoir details such as advancing water front and un-swept zones. The availability of good quality onshore time-lapse seismic data for Field ‘K’ acquired in 1987 and 2002 provided the opportunity to evaluate the effect of changes in reservoir fluid saturations on time-lapse amplitudes. Rock physics modelling and fluid substitution studies on well logs were carried out, and acoustic impedance change in the reservoir was estimated to be in the range of 0.25% to about 8%. Changes in reservoir fluid saturations were confirmed with time-lapse amplitudes within the crest area of the reservoir structure where reservoir porosity is 0.25%. In this paper, we demonstrated the use of repeat Seismic to delineate swept zones and areas hit with water override in a producing onshore reservoir.

scholarly journals Quantitative seismic interpretation of the Lower Cretaceous reservoirs in the Valdemar Field, Danish North Sea

2021 ◽  
pp. petgeo2021-016
Author(s):  
K. Bredesen ◽  
M. Lorentzen ◽  
L. Nielsen ◽  
K. Mosegaard
Keyword(s):  
Lower Cretaceous ◽  
Water Saturation ◽  
Rock Physics ◽  
Seismic Signal ◽  
Seismic Interpretation ◽  
Reservoir Quality ◽  
Well Log ◽  
Field Development ◽  
Attribute Analysis ◽  
Complex Geology

A quantitative seismic interpretation study is presented for the Lower Cretaceous Tuxen reservoir in the Valdemar Field, which is associated with heterogeneous and complex geology. Our objective is to better outline the reservoir quality variations of the Tuxen reservoir across the Valdemar Field. Seismic pre-stack data and well logs from two appraisal wells forms the basis of this study. The workflow used includes seismic and rock physics forward modelling, attribute analysis, a coloured inversion and a Bayesian pre-stack inversion for litho-fluid classification. Based on log data, the rock physics properties of the Tuxen interval reveals that the seismic signal is more governed by porosity than water saturation changes at near-offset (or small-angle). The coloured and Bayesian inversion results were generally consistent with well-log observations at the reservoir level and conformed to interpreted horizons. Although the available data has some limitations and the geological setting is complex, the results implied more promising reservoir quality in some areas than others. Hence, the results may offer useful information for delineating the best reservoir zones for further field development and selecting appropriate production strategies.

On the Analysis of the Activation Volume

1976 ◽  
Vol 31 (7) ◽  
pp. 728-730
Author(s):  
A. S. Rrausz
Keyword(s):  
Temperature Dependence ◽  
Activation Volume ◽  
Stress Sensitivity ◽  
Dislocation Climb ◽  
Rate Theory ◽  
Dislocation Mobility ◽  
Velocity Measurements ◽  
Temperature Dependent ◽  
Measured Stress ◽  
Similar Dependence

Abstract The stress and temperature dependence of the activation volume is often explained by a similar dependence of the measured stress sensitivity. This explanation cannot be reconciled with the nonconservative motion of jogs, with dislocation climb, nor with the intersection mechanism. It is in contradiction with the results obtained in direct dislocation velocity measurements as well. It is now shown that when the backward movement of the dislocations is taken into consideration an explanation, consistent with the rate theory and with the dislocation mobility observations, can be developed. The analysis shows that with constant activation volume the stress sensitivity is stress and temperature dependent, in agreement with the corresponding measurements and mechanisms.

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