Abstract: Design method for hydraulic fracturing of a reservoir is presented that maximize well production rates and minimize proppant flowback. The method comprises employing computer simulators that analyze a fracturing treatment design in the context of well properties, reservoir properties, fluids and proppants, and calculates a critical filtration velocity for a proppant pack. If the fluid flow velocity in the fracture exceeds the critical filtration velocity, there is a risk for proppant flowback. The method is applicable to wells that have not yet been fractured, as well as those that have previously undergone a fracturing treatment.

Abstract: Acoustic signals sent by a logging tool disposed in a borehole are detected by receivers located on the logging tool. Time domain representations of the detected acoustic signals are converted into frequency domain representations. Then at least one frequency range is selected and the detected acoustic signals corresponding to each selected frequency range are filtered. Eigenvectors for the filtered data for each selected frequency range are computed and dependence of the eigenvectors on the frequency is obtained. System for processing acoustic signals comprises a computer in communication with the logging tool and a set of instructions executable by the computer.

Abstract: Method for processing acoustic waveforms comprises acquiring acoustic waveforms in a borehole traversing a subterranean formation and transforming at least a portion of the acoustic waveforms to produce frequency domain signals. Then model dispersion curves, modes spectrum or waveforms are generated based on an anisotropic borehole-formation model having a set of anisotropic and geometrical borehole-formation parameters and by specifying governing equations and computational mesh based functional basis. The frequency-domain signals are back-propagating using the model dispersion curves to correct dispersiveness of the signals and coherence of the back-propagated signals is calculated. Alternatively the difference between the measured and the model dispersion curves is determined.

Abstract: A method for processing acoustic waveforms comprises acquiring acoustic waveforms in a borehole traversing a subterranean formation and transforming at least a portion of the acoustic waveforms to produce frequency domain signals. Then model dispersion curves are generated based on an anisotropic borehole-formation model having a set of anisotropic borehole-formation parameters. The frequency-domain signals are back-propagating using the model dispersion curves to correct dispersiveness of the signals and coherence of the back-propagated signals is calculated. Alternatively the difference between the measured and the model dispersion curves is determined. Model parameters are iteratively adjusted until the coherence reaches a maximum or exceeds a selected value, or alternatively until the difference between the measured and the model dispersion curves becomes minimal or is reduced to below a selected value. Then at least a portion of the set of anisotropic borehole-formation parameters is obtained.