Following an inter-well tracer study for their field, an onshore group was given the results of the study in the format of spreadsheets and 2D charts. The spreadsheet data were particularly difficult to interpret and the group felt a 3D/4D visualization of the tracer results was critical to fully understand them. Furthermore, the group wanted to integrate the tracer data with other field data that could potentially help with the tracer interpretation, including offset well trajectories, well logs, property models, microseismic data and horizon surfaces.
The group knew that CoViz® 4D could integrate numerous data types in a temporally aware environment and they worked with technical support staff to automate bringing their tracer data into the software. The directionality (from source to producer) of the tracer data enabled the creation of vectors representing the communication between the wells. The tracer source stage was tied to the X,Y,Z location of that stage along the well and pointed to the nearest location on the receiver well trajectory (along with the time the tracer was recorded). Other tracer data, like flowback and cumulatives were tied only to a single stage indicated by their measured depth ranges. The vector representations of the tracer data were customized so that the arrowhead on the vector was scaled to represent the amount of tracer received, with a larger arrow indicating a larger slug, thus creating an easy to interpret visual.
Figure 1. Animation of tracer data showing source well (well_13) and offset well tracer arrivals. Arrowheads are scaled to show relative tracer amounts received.
By integrating the well trajectory locations with the dynamic tracer data, the well and fracture relationships became apparent. The group extended the workflow, incorporating multiple types of visualization for the tracer data. For the flowback tracers, 3D animating towers were pinned to each source stage so the rates could easily be seen increasing or decreasing with each sample date. Cumulative flowback towers (which continued to grow as the tracer was sampled returning to the source well) showed which areas were sealed off from large fracture systems. Cumulative directional tracers were shown as an ellipse symbol that continued to grow over time and highlighted the most used pathways for fluids.
Figure 2. Tracer flowback data shown as green and blue (cumulative) towers. Cumulative ellipse symbols highlight optimal fluid pathways. Monthly gas, oil and water production towers also shown.
Microseismic data were also available and when integrated with the tracer data in the CoViz 4D environment, patterns began to emerge. A strong correlation between low microseismic areas and low tracer flowback lead the group to conclude that the frac job did not open up enough permeability for good fluid flow. And areas where high microseismic activity coincided with low tracer production were likely areas where the fractures did not connect, or the fractures closed very quickly upon fluid production.
Figure 3. Integration of microseismic data with tracer flowback data.
The ability to visualize the tracer data in 3D and 4D, and integrate the tracer data with well trajectories, microseismic and other critical information, enabled the onshore group to fully investigate and understand their tracer results. The easy to interpret symbols and time varying displays within CoViz 4D greatly simplified the comprehension of an otherwise complex and overwhelming data set.
