Seismic Physical Modeling Research Articles

Time-lapse 3-D seismic physical modelling

Seismic physical modelling is used to study the effects ofseismic wave propagation in isotropic and anisotropic media, and to improve methods of data acquisition, processing and interpretation. Until recently, the use of unconsolidated sands for seismic physical models had been unsuccessful due to the lack of control or understanding of the natural variations that occur throughout the models. Our research has allowed many of the drawbacks to be overcome.The use of sands allows fluids to be incorporated into the models for the first time, providing a much more realistic analogue of hydrocarbon reservoirs, and presents an opportunity to expand the role of seismic physical modelling. The computer controlled modelling system allows repeatable acquisition, which makes it an ideal environment to study some of the time variant characteristics of reservoirs that occur with production. This is demonstrated with a model whereby the migration of kerosene and air is monitored with time-lapse surveys. Time-lapse 3-D (or 4-D) seismic is becoming increasingly important in the management of hydrocarbon production, yet there is a lack of model data to support some of the fundamental conclusions being made. Subtle anomalies on difference sections may in fact be artefacts of the different acquisition footprints or manufactured from the complex data processing that is necessary to allow comparison of legacy data sets.The ability to perfectly repeat data acquisition on sand models bypasses these problems such that any anomalies seen on difference sections can be directly attributed to changes that have occurred within the model. The development of TL3-D seismic physical models will also provide a number of other advantages, which are:Inexpensive, real seismic data.The absence of complications from seasonal or climate factors.Rapid data turn around in a matter of days, rather than having to revisit an area years later.Potential to control the changes within the model and compare the seismic interpretations against the known changes.The ability to deliberately change acquisition parameters to test the effect on the resultant seismic difference sections

ABSTRACT: Fluid flow monitoring with seismic physical models

ABSTRACT: Fluid flow monitoring with seismic physical models

THE SEISMIC EXPRESSION OF THREE-DIMENSIONAL SANDBOX MODELS

Analogue sandbox models provide cheap, concise data and allow the evolution of geological structures to be observed under controlled conditions in a laboratory. Seismic physical modelling is used to study the effects of seismic wave propagation in isotropic and anisotropic media and to improve methods of data acquisition, processing and interpretation. These two independent geological modelling techniques have been linked for the first time, to combine and expand the existing benefits of each method.Seismic physical modelling to date has employed solid models, constructed with pre-determined structures built into the model. Previous attempts to adapt this technology to unconsolidated materials failed due to the severe energy attenuation of seismic waves in cohesionless grain matrices, and excessive signal scatter due to scaling limitations of the geological feature size to wavelength ratio. This paper presents our research to overcome these problems and thereby allow the successful seismic imaging of sandbox models.A number of techniques have been developed to combine these two independent modelling methods and results show that it is possible to image several layers within the models, demonstrating the potential to interpret complex geological structures within such models. For seismic modelling, the main advantages are that the seismic data collected from these models contain natural variation that cannot be built into solid models, which results in a more realistic image, and the cost and construction time of the models are also dramatically reduced. For sandbox modelling, the recording of seismic data over them allows far more detailed interpretation of the structures than previously possible and also allows direct comparison with field data for the first time, to substantiate or negate an existing interpretation.