Engineers and geoscientists know more than anyone about the challenges associated with complex reservoir characterization, especially in systems such as unconventionals, carbonates, and sands. Continuous monitoring entails the provision of new data which must be assimilated with existing information to achieve a full analytical profile of the reservoir in question. What’s needed is a visual aid that combines old and new data in a crisp visual format that’s accessible to all team members.
The ability to integrate petrophysical and geological data within a single geospatial framing would allow users to understand shifting dynamics within complex reservoir systems. With the ability to cross-plot and visualize the changes in data over time (4D), analysts can find potential obstacles that could hamper development and make a correlation between wells that wouldn’t have been available without the use of data integration.
The Role of 4D in Data Visualization
Data integration is paramount to complex reservoir characterization, but the addition of 4D capabilities allows analysts to obtain a clearer view of subsurface variations and how they change over time. Quality seismic responses are helpful, but a seismic grid combined with other vital subsurface datasets gives a more resolute dynamic profile of the reservoir, regardless of its complexity.
CoViz 4D, an integrated software solution created by Dynamic Graphics, Inc., offers the visualization and analysis of multidisciplinary data. Its 4D capabilities are especially useful if analysts are dealing with a complicated reservoir structure and flow patterns with a constant stream of varied and mass data, as the 4D addition enhances the seismic history match and improves the reservoir flow models based on understanding of pressure and fluid variations over time.
CoViz 4D fosters the following:
- the tracking of fluid and pressure fluctuations at a subsurface level
- better understanding to improve well placement and well positioning plans
- the increased likelihood of discovering bypassed reserves
In terms of detailed resolution, leveraging CoViz 4D also increases the chance that users can find precarious anomalies that may lead to pressure or fluid disturbances. For example, if a team finds a gas kick that leads to a well control issue in a shale reservoir, to obtain a more comprehensive understanding of the problem, team members would need to compare 4D seismic data to the original survey taken before production began and another post-production survey to trace the root of the gas kick.
With the ability to filter, and compare, grid differences, CoViz 4D can display areas of increased pressure as a possible source. The addition of seismic grid differences, well logs, and wellpaths in a 4D visual scope can alert team members to an existing problem or indicate that a quality seismic survey is needed to view the obstacles with additional clarity.
CoViz 4D allows asset teams to visualize all relevant data in a comprehensive viewing environment instead of relying on low-resolution surveys to make decisions that may fail to identify anomalies and potential risk or potential.
The Role of 4D in Data Analysis
4D visualization is also useful when comparing predicted simulation with on-the-ground events. For instance, if a team discovers a discontinuity between a seismic response and a reservoir simulation model in an offshore oil field, the combination of reservoir simulation data with time-lapse geophysical data can pinpoint the problem and allow them to craft a proper solution to address the issue. With CoViz 4D, the team could trace the root of the discrepancy in the following ways:
- take a series of temporal animation shots over a certain period
- analyze subsurface data including seismic surveys, prediction models, amplitude variations of reservoir sands, and well event data to ensure a reservoir is performing as expected.
- compare a baseline survey to an updated seismic survey
The comparisons between new and old surveys are especially paramount, as they can expose anomalies that are the root cause of disconnects between the simulation and the production data. Such comparisons could reveal deviations in the form of high-pressure disturbances or water injection issues in the upper parts of a reservoir, which are not reflected in the associated predictive reservoir models.
CoViz 4D can be used to expose unforeseen challenges, such as a pressure dip stemming from a gas breakout—all revealed by analysis of the time-lapse seismic response. With all of this evidence gathered, a team can conclude, for example, that injector perforations in upper sands underwent a blockage, causing water injection complications in lower zones and unexpectedly higher water rates in the upper zone. With the ability to integrate and analyze data in CoViz 4D, asset teams can implement the necessary adjustments and optimize oilfield production.
Complex Reservoir Characterization with CoViz 4D
The key to a thorough understanding of complex reservoir conditions is integrated 4D data, across a range of disciplines, that allows users to draw connections and find potential sources of contention. The inclusion of 4D fosters the necessary visual and analytical tools to help teams make the right decisions on the field. With merged data and high-resolution visuals, team members understand well conditions faster and pinpoint anomalies earlier.
Complex reservoir characterization using static low-resolution surveys can mask aberrations and hide detailed aspects of subsurface dynamics and well conditions.
Complex reservoir characterization using static low-resolution surveys can mask aberrations and hide detailed aspects of subsurface dynamics and well conditions. However, CoViz 4D has the necessary capabilities to merge multi-disciplinary data into a central system, where geoscientists and engineers can better understand the data. With a cohesive team dynamic, diverse disciplines can more confidently understand and contribute detailed analysis to ensure the quick identification of any issues and, therefore, achieve optimum production.