Improving microseismic imaging: Role of acquisition, velocity model, and imaging condition

Imaging direct as well as scattered events in microseismic data using inverse scattering theory

“…Unfortunately, this requires the complete knowledge of the velocity and density model; no data-driven approaches exist for predicting multiples in microseismic data. A comparison of reverse-time imaging with smoothed versus true velocity model is shown in Behura et al (2013). The alternative approach is to use all the data and image the scattered arrivals (along with the direct arrivals) such that they focus at the correct hypocenters.…”

“…The source signature can therefore be computed by the application of an imaging condition to the data. A detailed description of the various imaging conditions used in microseismic imaging is given in Behura et al (2013). Here, we use the 2D space-time cross-correlation imaging condition (Behura et al, 2013):…”

“…Figure 3a shows the image of the two microseismic sources obtained using the imaging methodology introduced here. Behura et al (2013) argue that the image of microseismic data should be displayed as a function of space as well as time because the sources can be extended in both space and time. The images in Figure 3 correspond to specific depth slices of the z − x − t image cube.…”

3D passive wavefield imaging using the energy norm

“…Its differences with respect to conventional exploration seismology mainly consist of the absence of a controlled source, but also of distinct array geometries, continuous recording times, and low signal-to-noise ratios (S/Ns), among others. Although the source locations for passive seismic scenario are unknown a priori, one can apply imaging and inversion methods adapted from active source seismic scenarios to generate an image, showing the estimated source location, and/or to reconstruct a 3D earth model, with information about subsurface physical properties (Duncan and Eisner, 2010;Maxwell et al, 2010;Xuan and Sava, 2010;Behura et al, 2013;Blias and Grechka, 2013;Douma and Snieder, 2015;Witten and Shragge, 2015;Bazargani and Snieder, 2016;Shragge, 2017a, 2017b).…”