An accurate understanding of reservoir conditions and activities benefits every member of the reservoir management team throughout the entire lifecycle of a reservoir. That’s an obvious statement to make, but the reality is that achieving that level of understanding to proactively monitor a reservoir requires the ability to integrate, visualize, and analyze a wide range of subsurface data types. These may include geologic, geophysical, simulation models, drilling logs, completions, wells, production, and near-real-time feeds.
These data are acquired with the aid of various monitoring technologies such as life-of-field seismic (LoFS) systems, and discipline-specific software packages. A reservoir monitoring system that integrates these data and allows reservoir engineers to evaluate production data in the context of changing geologic conditions is an essential tool for maximizing hydrocarbon recovery. A detailed earth model provides the foundation for this evaluation.
Begin With a Detailed Geologic Model
A detailed, 3D geologic model reveals subsurface conditions such as faults, major fault gaps, fault-wedge contours, and other complex geologic structures that can be explored by directly examining the 3D model or via extracted contour maps and cross-sections. These digital representations are critical in assessing volumes, fluid migration, and hydrocarbon entrapment in support of reservoir planning and development, and provide the foundation for an effective reservoir monitoring system.
As a reservoir is developed and produced the geologic model is updated using subsequent seismic surveys and combined with information regarding new wells to help reservoir engineers better understand the effects of individual wells, as well as field-wide production, on reservoir conditions.
Benefits of Leveraging a Reservoir Monitoring System
An Integrated View of Reservoir Performance
An efficient reservoir monitoring system provides reservoir engineers with an integrated view of well and reservoir performance. It allows them to assess the performance of an individual well over time and refine the strategy to improve recovery. Daily production data (pressure, flow, water cut) from the wellhead, combined with observation well data and downhole gauges measuring temperature, bottom hole pressure, and the differential between BHP and WHP, provide near-real-time insight.
Visualizing and analyzing these data in the context of the subsurface environment enables faster detection, isolation, and diagnosis of changes (sudden or gradual) that impact well performance.
Sudden changes in production volume:
- broken pump identified by a drastic drop in daily volume
- reduction in injector well pressure
- collapsed casing brings production to a halt
- surface valve mistakenly closed during routine maintenance
Gradual changes in production volume:
- expansion of the fracture network from nearby well into a production zone
- sand accumulation in strainers, liners, or tubings
- paraffin buildup around completion components
- deformation from compaction in shallow wells
- sucker rod friction abrading casing
A reservoir monitoring system that integrates a wide range of reservoir data helps reservoir management teams with early identification of developing problems, as well as more accurately determine the reasons for sudden production changes.
A Comprehensive Understanding of Changing Reservoir Conditions
A reservoir management system should also allow reservoir teams to evaluate changing conditions as the reservoir is produced and determine effective strategies to improve recovery. By taking advantage of time-lapse seismic data, integrating it with production data, well logs, tracers, horizons, and volumetric data—and animating it over time (4D)—reservoir engineers gain a far better understanding of how well production is impacting subsurface conditions.
With the ability to compare 4D seismic response alongside production data (individual wells, production patterns, and entire fields) engineers can evaluate a wide range of reservoir activities, for example:
- the impact new wells, infills, or sidetracks are having on nearby well production
- the location of previously unrecognized areas of unswept oil
- the migration of gas and water as wells are produced
When a reservoir monitoring system enables reservoir teams to evaluate temporal animations of changing reservoir conditions in response to production, they gain a significantly better understanding of how development decisions impact recovery. This insight, obtained through temporal analysis of reservoir conditions, facilitates better reservoir management and maximized recovery.
When a reservoir monitoring system enables reservoir teams to evaluate temporal animations of changing reservoir conditions in response to production, they gain a significantly better understanding of how development decisions impact recovery.
CoViz 4D: A Critical Component of a Reservoir Monitoring System
An efficient/successful reservoir monitoring system is critical to helping management teams accurately assess opportunities, determine appropriate development strategies, and closely monitor their impact on performance. Data integration, visualization, and analytics software solutions like CoViz 4D enable members of a reservoir team to better understand how the reservoir is evolving and proactively guide its management.