A horizontal well plan with ellipsoids of uncertainty displayed along the cross-section of a geologic model is shown with a potential collision with an offset well (in pink). Inset is the traveling cylinder diagram of that potential collision.
With the increase in drilling activities on a global scale, the complexity of managing drilling operations in oil fields is becoming increasingly complex. The knowledge on the exact geospatial location of existing horizontal and directional wellbores has thus become increasingly crucial, especially in determining the proper placement of increased density of wells and the production uncertainties. 3D wellbore visualization has allowed drilling and reservoir engineers and geologists to accurately analyze the uncertainties with the identification of existing well trajectories and examination of planned locations in a simplified and expedited manner.
Determining Uncertainties in Production
The development of assets requires precise knowledge of where the wellbore is spatially located. However, with the increase in drilling activities that minimize adjacent well distance, there is often a need for optimal well placement. Even though it may be easy to locate the well at the surface, it is a difficult task to examine and position the wellbore trajectory, especially for vertical wells. The largest uncertainty comes from the geomagnetic model (BGGM, IGRF, MVHD, etc.), followed by depth uncertainty (drill pipe stretch, wireline stretch, etc.), and finally by tool sensor data (magnetometer, accelerometer, and gyroscopic data). With all of the above, we can derive the MD, inclination, and azimuth. This presents an increased challenge for drilling engineers to analyze these issues to successfully avoid collision and reach the intended target within the reservoir.
The ease of analysis can be achieved with 3D visualization which can accurately depict the reservoir characteristics, subsurface geology, and existing infrastructure at its correct geospatial position. With the integration of seismic, structural, and volumetric data and model for 3D wellbore visualization, geologists, and drilling and reservoir engineers and planners can:
- Determine actual well position and its trajectory in the subsurface.
- Locate nearby wells or conflicting well paths for improved well planning.
- Identify the impact of stratigraphy on drilling.
- Analyze for ideal completion strategy.
- Calculate positional uncertainty ellipsoid and identify target boundary and apply quantifiable rules and warnings.
3D Wellbore Visualization for Improved and Expedited Analysis
3D wellbore visualization along with integrated subsurface and infrastructural data and models allow asset teams to precisely analyze the subsurface anomalies that can impact locating existing wells or planning infill drillings. Visualization capabilities enable accurate identification and quantitative analysis of uncertainty related to horizontal or direction wellbore drilling due to factors including tool limitations and environmental factors inaccuracy in data reading or calculation.
CoViz 4D and WellArchitect facilitate uncertainty visualization along the well path through the integration of the earth model and well plan trajectory for error analysis. These softwares provide engineers with the ability to calculate and display ellipsoids of uncertainty in an interactive platform. These uncertainties are displayed along the well path and is an indication of spatial variation from the actual well position. These softwares also allows creating a 2D/ 3D bubble map of production data. Cumulative production mapped along the wellbores of local offset wells, allows asset teams to see the production status of the wellbore, thus, assisting them to make informed decisions about the further need for well planning and drilling.
Tools for Enhanced Well Planning and Visualization
The powerful capabilities of CoViz 4D can be used in quantitative data analysis for effective well path planning and design. In combination with WellArchitect, the users can easily view the wellbores in their correct geospatial location alongside the relative positional uncertainty, offsets uncertainty, and targets uncertainty to examine the acceptable range of error in well design.
The software platforms allow easy and simplified data integration and analysis for effective 3D wellbore visualization. The precise analysis and evaluation allow drilling and reservoir engineers, geologists, and management to accurately evaluate existing and planned wellbore locations to avoid a potential collision and inaccurate targeting risks.