The hydrocarbon reservoir at the time of discovery is the product of a seismic survey and a collection of appraisal wells. Use of various techniques to examine the seismic (AVO analysis for example) allows the identification of anomalous reflectivity that may relate to the presence of hydrocarbons and their locations. Subsequent seismic surveys are known as time lapse or 4D. They can be used to detect changes in the reservoir over time. Detailed interpretation of the time lapse signal in terms of fluid flow can identify barriers and allow the estimation of sweep efficiency in the reservoir compartments. 4D seismic will provide the details necessary to manage the asset. Allowing for accurate asset planning, optimizing infill drilling, managing injection/production strategies, calculating remaining reserves and ensuring the appropriate infrastructure is available to ensure the uninterrupted production into the future.
Seismic and Reservoir Data: Key Components of the Big Picture
Evolving Reservoir Characterization and Modeling
The reservoir is a dynamic entity. Production causes reservoir pressures to change, the fluid saturation changes as wells get drilled and fluids are produced. At any time we want to take into consideration the state of the reservoir by displaying simulation models that show the previous match of production to history, in combination with 4D seismic surveys that confirm or deny the correctness of the reservoir engineer’s models. Only CoViz 4D has the ability to scroll through the time domain. This unique ability allows data types to link across time, providing insight to the behavior of dissimilar data as the reservoir evolves during its production phase.
The Value of 4D Seismic Visualized With Reservoir Models
When visualized together in DGI’s CoViz 4D, reservoir models and 4D seismic data provide a powerful analytical tool in helping geophysicists and engineers understand the current and future performance of a producing field. Information provided by 4D seismic data is critical in understanding fluid flow within the reservoir. Accurate reservoir characterization and modeling give engineers the ability to predict reservoir behavior using data collected during its production lifetime and factoring in future production strategies.
The value of 4D seismic now extends beyond identifying optimal production zones or bypassed oil. When combined and visualized with reservoir models, it becomes an essential tool for quantitative reservoir management, enabling geophysicists and reservoir and production engineers to:
- determine why certain wells are producing while others are underperforming in comparison to the predicted output of reservoir simulation models.
- accurately identify the extent and characteristics of depleted and unswept zones.
update or fine-tune reservoir simulation models per changes observed in recent seismic studies to more accurately forecast production. - identify the likelihood of potential problems such as increased water cut and subsidence.
By using 4D seismic analysis to adjust reservoir models, engineers gain a better understanding of a reservoir’s dynamic behavior and can recommend appropriate strategies to increase the recovery factor of a reservoir or extend production for a few years to maximize return on investment.
CoViz 4D Facilitates Visualization
CoViz 4D, a data visualization analytics software from Dynamic Graphics, Inc., gives geologists, geophysicists, and reservoir engineers the ability to easily access and combine all relevant data associated with subsurface environments. Powerful analytic capabilities enable users to explore data relationships, analyze the accuracy of depth conversion of 3D seismic, and visualize seismic well ties and velocity models to facilitate decisions that positively impact profit and reduce operational risk. To learn more about CoViz 4D, contact our team.