An innovative apparatus and computer implemented methods to obtain values for a set of scalars corresponding to each force and displacement, which may be obtained from acoustical signals captured by sensors of a drill bit while drilling, in a material of known mechanical properties, such as a cement from casing the well, such that the application and use of the scalars in relation to measurements of the mechanics while drilling, such as the acceleration of the bit and motion of the bit captured by sensors such as accelerometers, allow for absolute values of mechanical rock properties to be obtained in rock formations, being drilled through, with otherwise unknown mechanical properties prior to drilling.

The present disclosure includes a method including determining a spatial region for analysis and selecting a segment of time for analysis, analyzing and correcting a plurality of traces from a plurality of receivers using an iterative non-linear inversion algorithm, wherein each iteration of the non-linear algorithm corrects the plurality of traces using at least one set of parameters defining a microseismic event, determining whether a final stack value of the plurality of traces corrected based on the at least one set of parameters of a final iteration of the iterative non-linear inversion algorithm exceeds a predetermined threshold and upon a determination that the final stack value exceeds the predetermined threshold, detecting a microseismic event defined by the at least one set of parameters of final iteration. The present disclosure also includes associated systems and computer-readable media.

A method for evaluating and optimizing complex fractures, in one non-limiting example far-field complex fractures, in subterranean shale reservoirs significantly simplifies how to generate far-field fractures and their treatment designs to increase or optimize complexity. The process gives information on how much complexity is generated for a given reservoir versus distance from the wellbore under known fracturing parameters, such as rate, volume and viscosity. The method allows the evaluation of the performance of diversion materials and processes by determining the amount of fracture volume generated off of primary fractures, including far-field secondary fracture volumes. The methodology utilizes fracture hit times, volumes, pressures and similar parameters from injecting fracturing fluid from a first primary lateral wellbore to create fractures and record fracture hit times, pressures and volumes from a diagnostic lateral wellbore in the same interval.

Methods and mediums for estimating stimulated reservoir volumes are disclosed. Some method embodiments may include obtaining microseismic event data acquired during a hydraulic fracturing treatment of the formation, the data including event location and at least one additional attribute for each microseismic event within the formation; filtering the microseismic events based on the at least one additional attribute; determining a density of filtered microseismic events; weighting the filtered microseismic events based on the density; and determining a stimulated reservoir volume estimate based on filtered and weighted microseismic events.

Uncertainty of microseismic monitoring results can be reduced to improve hydraulic fracture modeling. A computing device can use a fracture model to determine a predicted geometry of a hydraulic fracture in a subterranean formation based on properties of a fracturing fluid that is introduced into the subterranean formation. An uncertainty index of the predicted geometry of the hydraulic fracture can be determined based on an uncertainty value of the predicted geometry and a trend of uncertainty values. When the injection flow rate of the fracturing fluid is less than a maximum flow rate, it can be increased from an initial injection flow rate to an increased injection flow rate in response to determining the uncertainty index exceeds a pre-set maximum.

A well system includes a fiber optic cable positionable downhole along a length of a wellbore and a reflectometer communicatively coupleable to the fiber optic cable. The reflectometer detects and locates a microseismic event using strain detected in reflected optical signals received from the fiber optic cable. Further, the reflectometer computes a set of spectra for waveforms of the microseismic event. Additionally, the reflectometer aggregates each spectrum from the set of spectra that meet an acceptance threshold to generate an aggregate spectrum. Furthermore, the reflectometer applies a fault source model to the aggregate spectrum to determine a magnitude of the microseismic event.

In accordance with some embodiments of the present disclosure, a method of modeling a downhole drilling tool is disclosed. The method may include obtaining microseismic data corresponding to a treatment of a subterranean region, the microseismic data including a microseismic event time for each of a plurality of microseismic events, and a microseismic event location for each of the plurality of microseismic events. The method may additionally include calculating a plurality of fracture planes based upon the microseismic event times, and calculating a closed boundary enclosing a first subset of the plurality of fracture planes. The method may further include identifying a microseismic supported stimulated reservoir volume (μSRN) for the treatment based on the closed boundary.

A method can include receiving acoustic emission data for acoustic emissions originating in a formation, performing a moment tensor analysis of the data, thereby yielding acoustic emission source parameters, determining at least one acoustic emission source parameter angle having a highest number of associated acoustic emission events, and calculating an in situ stress parameter, based on the acoustic emission source parameter angle. A system can include multiple sensors that sense acoustic emissions originating in a formation, and a computer including a computer readable medium having instructions that cause a processor to perform a moment tensor analysis of the data and yield acoustic emission source parameters, determine at least one acoustic emission source parameter angle having a highest number of associated acoustic emission events, and calculate an in situ stress parameter, based on the acoustic emission source parameter angle.

The combination of one or more 3-component microseismic sensors deployed into a wellbore adjacent a microseismic event and a linear array of distributed fiber optic acoustic sensors deployed uphole thereof provides two sets of data for establishing noise-free signals for locating the microseismic event in the formation about the wellbore. The distributed fiber optic signals monitor noise transmitted along coiled tubing used to pump a completion operation or as a result of the fluid flowing through the casing or coiled tubing, or along wireline used to deploy the microseismic sensors. The noise is mapped and extrapolated for estimating noise at the 3-component sensors. The estimated noise is removed from the 3-component sensor data for producing clean signals representing the location of the microseismic events.

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.