Microseismic monitoring of hydraulic fracturing generates valuable information that can be used to estimate geometries of fracture networks created during treatment. This provides an important dataset when evaluating development spacing and completion optimization. Assessment of over 50 microseismic surveys in the Midland Basin, spanning three counties, reveals that microseismic can be used to detect variations in hydraulic fracture geometry between landing points and with different completion designs. The development of a systematic workflow allows for the interpretation of microseismic data with a relatively high degree of confidence.
Microseismic surveys are first organized into a comprehensive database together with relevant completion and geologic data for consistent analysis. Microseismic events are analyzed in conjunction with time-series treatment data, allowing insight into whether fracture networks develop uniformly throughout treatment or are concentrated within a specific time window. Looking at microseismic events together with their corresponding fracture stages and perforations also provides valuable insight into perforation efficiency and stress shadowing effects. Microseismic heat maps are then generated for each survey, which illustrate a collective look at the overall event density and fracture geometry for a given well. These maps are used to assign an average fracture half-length, as well as upward and downward height growth for each well. General observations of fracture geometry, such as planar versus complex fracture networks, can also be made by observing event propagation through time together with the associated heat maps. Heat maps aid in identifying not only fracture symmetry around the wellbore, but also fracture barriers that can impede fracture growth. The identification of possible fracture barriers is critical for integration into future development plans.
Utilizing the developed database and workflow allows for correlation between interpreted microseismic fracture properties, landing zones and specific elements of the completion design. This can lead to a better understanding of how changes in geology and completion design affect hydraulic fracture behavior and efficacy.