Abstract: Disclosed are various embodiments of methods, devices and systems for performing a microseismic survey. According to some embodiments, microseismic signals are detected at seismic sensor stations deployed in two sets of seismic sensor lines, the seismic sensor lines within each set being substantially parallel to one another and the two sets of seismic sensor lines being mutually orthogonal. According to other embodiments, microseismic signals are detected at seismic sensor stations deployed in a hexagonal pattern. Such sensor geometries offer advantages over linear or radial arrays, including noise reduction, data acquisition flexibility as new wells are added to the survey area, and an improved distribution of data points above points in the subsurface.

Abstract: Disclosed are various embodiments of methods and systems for a 3D seismic data acquisition array, comprising: a first plurality of receiver positions, substantially equally spaced along a first plurality of substantially parallel and substantially equally spaced receiver lines; a second plurality of receiver positions, substantially equally spaced along a second plurality of substantially parallel and substantially equally spaced receiver lines, wherein the receiver lines in the second plurality of receiver lines are substantially orthogonal to the receiver lines in the first plurality of receiver lines; a plurality of source positions, the source positions being located along a plurality of substantially parallel and substantially equally spaced source lines that are substantially parallel to one of the diagonals of the rectangles formed by the first plurality of receiver lines and the second plurality of receiver lines.

Abstract: Disclosed are various embodiments of methods, devices and systems for performing a microseismic survey. According to some embodiments, microseismic signals are detected at seismic sensor stations deployed in two sets of seismic sensor lines, the seismic sensor lines within each set being substantially parallel to one another and the two sets of seismic sensor lines being mutually orthogonal. According to other embodiments, microseismic signals are detected at seismic sensor stations deployed in a hexagonal pattern. Such sensor geometries offer advantages over linear or radial arrays, including noise reduction, data acquisition flexibility as new wells are added to the survey area, and an improved distribution of data points above points in the subsurface.

Abstract: Segmenting the spectral distribution of overlapped vibratory signals improves the efficiency of data acquisition while providing reduced harmonic distortion in the time zones of interest. Two identical sweep segments are used. Each sweep segment includes an earlier low frequency sweep and a later high frequency sweep, the individual sweeps having substantially no overlap in frequency except for tapering. The high frequency sweep in each pair starts before the end of the low frequency sweep with an overlap in time that is selected to avoid harmonics from the low frequency sweep. Correlation of the recorded signal separately with the low frequency sweep and the high frequency sweep gives data sets in which individual portions of the desired data are recoverable with the harmonic distortion largely separated from the desired data. The individual portions of the desired data are then spliced to give a broadband response of the earth.