Obtaining as accurate as possible an understanding of hydraulic fracture geometry provides many advantages to geologists, geophysicists, and completion engineers as they plan reservoir development. A detailed understanding helps asset teams determine fracking strategies for specific reservoir conditions, evaluate the results of individual frac stages, and continually improve hydraulic fracturing outcomes.
Understanding hydraulic fracture geometry involves the evaluation of complex reservoir properties and forces—such as local and global stress conditions, rock properties, geomechanics, and natural fracture propensity. Combine these properties with decisions regarding fracking fluid, injection rate, pressure, and volume and you’re modeling a very complex process.
The complexities of hydraulic fracture geometry are better understood with the aid of software that integrates and visualizes key data sources such as well image logs, geomechanical models, discrete fracture networks, and microseismic surveys to give completion engineers the information needed to plan and execute optimal frac strategies.
Determine Fracture Orientation
Begin with an analysis of an image log that provides detailed fracture characteristics and fracture corridors local to the borehole. That initial interpretation of fracture orientations is then used to create a rose diagram. Using information from the rose diagram, software tools can then be used to calculate the primary (and possible secondary) stress orientations. From there, stress orientation data can be incorporated into a geomechanical model, visualized and analyzed, and run through multiple realizations to establish property averages that best represent the discrete fracture network.
The combined interpreted image logs and discrete fracture network can contain thousands of fractures in a multitude of orientations, dip and dip direction, with varying degrees of interpretation quality. With 3D visualization capabilities, engineers can highlight specific ranges of dips and dip azimuths to align with the rose diagram.
Visualization also allows reservoir teams to easily review the range of interpretations and filter out poorer quality interpretations to arrive at the best model of a discrete fracture network upon which to develop and refine the completion plan.
Refine Your Understanding of Hydraulic Fracture Geometry
Reservoir teams can further enhance their understanding of hydraulic fracture geometry post-completion by incorporating microseismic surveys into the analysis. Frac treatment, location, perforations, event geometry, magnitude, and stage available in microseismic data can be visualized along with geological and petrophysical data to help reservoir engineers compare the efficacy of the frac strategy against assumptions of the initial discrete fracture network analysis.
Additional insight can be provided by incorporating observation well trajectories and surface and down-hole receiver locations (see image at the top) to provide additional context for hydraulic fracture geometry analysis.
Animate Microseismic Events
An even better approach to understanding the hydraulic fracture geometry of frac treatments is through the 3D animation of microseismic events. With the animation of microseismic time-step data reservoir engineers can:
- observe the developing geologic and petrophysical response to a specific frac treatment;
- learn to what extent primary and secondary fracture orientations have been successfully exploited;
- assess the effectiveness of frac fluid, pressure, volume, and staging sequence; and
- evaluate the potential of well interference with proximity of nearby wells to the events.
With insight gained from the time-step analysis of hydraulic fracture geometry, reservoir engineers can apply these findings to the planning and development of subsequent wells in the reservoir.
CoViz 4D Enables Detailed Understanding of Hydraulic Fracture Geometry
Geologists, geophysicists, well planners, drilling engineers, and completion engineers can enhance their planning and completion efforts with the aid of data integration, visualization, and analytics software. Such software is CoViz 4D which is designed to easily integrate and visualize a wide range of subsurface data to enable engineering teams to better understand the reservoir characteristics.
CoViz 4D combines data sources from seismic surveys, well logs, stress analysis, and geomechanical models to depict discrete fracture networks in context of relevant subsurface conditions. With this level of detailed understanding, engineers can plan completion strategies that take advantage of natural fracture geometry.
With this level of detailed understanding, engineers can plan completion strategies that take advantage of natural fracture geometry.
CoViz 4D can also incorporate microseismic data into the analysis, depicting the development and extent of individual frac stages, as well as animating the entire completion process over time. Analysis of the results of an individual stage gives completion engineers the opportunity to modify successive stages, if necessary, to achieve the desired result.