Abstract: Disclosed herein are various embodiments of methods and systems for optimizing the analysis of the source locations of microseismic sources, comprising recording microseismic data using patches of sensors. Each patch contains multiple sensors, arranged as a grid or a line segment. This approach uses fewer sensors and can cover a larger area than previous techniques for acquiring microseismic data. The data recorded in this way can be filtered using directional filters, such that each patch may be targeted at a specific point in the subsurface. The microseismic source-scanning algorithm benefits from having data filtered to include directional signals only from pairs of patch locations and subsurface locations. This produces an improved estimate of the locations of microseismic events. The patches may be disposed about a horizontal well bore, and aligned such that directional filtering enhances data from hydraulic fracturing operations in the wellbore.

Abstract: Disclosed herein are various embodiments of methods and systems for optimizing signals generated by microseismic sources, comprising recording microseismic data using patches of geophones, filtering the data to impart a directionality to the data, and performing a source scan to determine the times and locations of microseismic events. The subsurface is divided into a voxel grid that is further subdivided into subgrids. Using a filter designed for each patch-subgrid pair, only data arriving within a predetermined angle of incidence are input to the source scan, thus reducing noise, and enhancing the quality and accuracy of the identified microseismic events. The method is also applicable to data previously recorded with sensor grids or other arrays such as star arrays.

Abstract: Disclosed herein are various embodiments of methods and systems for optimizing the analysis of the source locations of microseismic sources, comprising recording microseismic data using patches of sensors. Each patch contains multiple sensors, arranged as a grid or a line segment. This approach uses fewer sensors and can cove r a larger area than previous techniques for acquiring microseismic data. The data recorded in this way can be filtered using directional filters, such that each patch may be targeted at a specific point in the subsurface. The microseismic source-scanning algorithm benefits from having data filtered to include directional signals only from pairs of patch locations and subsurface locations. This produces an improved estimate of the locations of microseismic events. The patches may be disposed about a horizontal well bore, and aligned such that directional filtering enhances data from hydraulic fracturing operations in the wellbore.

Abstract: Disclosed herein are various embodiments of discriminating between small microseismic events and false events comprising identifying candidate events, and creating sub-stacks of the microseismic data traces. Analysis of the sub-stacks shows distinct differences between real microseismic events and false events created by noise bursts. Further discrimination between real and false events is achieved by visual or automated analysis of the reverberations and patterns of polarity reversal associated with real microseismic events, which are more clearly visible in the sub-stacks than in the raw microseismic data. The methods described herein are applicable to surface, downhole and buried array microseismic data.

Abstract: Disclosed herein are various embodiments of methods and systems for optimizing signals generated by microseismic sources, comprising recording microseismic data using patches of geophones, filtering the data to impart a directionality to the data, and performing a source scan to determine the times and locations of microseismic events. The subsurface is divided into a voxel grid that is further subdivided into subgrids. Using a filter designed for each patch-subgrid pair, only data arriving within a predetermined angle of incidence are input to the source scan, thus reducing noise, and enhancing the quality and accuracy of the identified microseismic events. The method is also applicable to data previously recorded with sensor grids or other arrays such as star arrays.