Abstract: Methods and apparatus for interferometric seismic imaging and creation of a high-resolution three-dimensional seismic volume in proximity to a wellbore are described. In contrast to current methods that deliver positions of microseismic events using a small fraction of the microseismic wavefield, the present invention provides for the analysis of a full microseismic wavefield. In a preferred embodiment, the method includes creating a planar image slice and/or corridor between the location of one or more microseismic events and one or several sensor arrays to produce a multitude of azimuthally orientated planar image slices and/or corridors. The method further includes adding the planar image slice and/or corridor contributions to create a single three-dimensional volume for analysis and rendering.

Abstract: The present disclosure describes semiconductor external cavity laser with wide bandwidth frequency modulation capabilities. The laser is preferably packaged in a standard form-factor package, such as a 14-pin butterfly package. The front end of the cavity comprises an integrated planar circuit (e.g., silica-on-silicon planar lightwave circuit with Bragg gratings), and the “back facet” of the laser is implemented as a high-reflection (HR) coated LiNbO3 phase tuning section in the double pass configuration. AC-voltage signal applied to the electrodes of phase tuning section modulates a refractive index of the propagating TE-polarization mode of external cavity and produces frequency modulation. Such frequency modulation is not associated with any thermal behavior of the gain element included in the external cavity laser, and has a negligible phase delay over a wide bandwidth.

Abstract: The present invention relates to distributed acoustic sensing using fiber-optic system. More particularly, the present invention describes use of frequency pulse labeling techniques and wavelength pulse labeling techniques for providing high bandwidth acoustic sensing in applications such as infrastructure monitoring. In one embodiment, a segmented sensing fiber is used with corresponding circulators in an architecture that controls the interrogation of each segment of the fiber. In another embodiment, a single continuous length of sensing fiber is used, but a plurality of pulse sequences with different wavelengths are used to interrogate. In both configurations, heterodyne beat frequency components are rejected by a processing scheme, resulting in a simple direct measurement of baseband phase information.