Acoustic Zoom Inc
685 St. Thomas Line
Canada A1L 3V2
The principle of operation of the multi-pipe sound source design is founded on generating a highly efficient frequency-controlled source based on a tunable, high-Q underwater set of acoustic organ-pipe resonators. The system contains a digitally synthesized signal generator controlled by high-precision and low power consumption hybrid Rubidium atomic clock.
The Acoustic Zoom method focuses on achieving detailed seismic characterization at high resolution within subtle complex stratigraphic and/or volumetric geometries. Typically, seismic exploration of overconsolidated shale zones has involved long offset data acquisition seismic spreads that have only delivered low spatial resolving powers generally noted to have not been capable of imaging the internal structure of the targeted reservoir. This inability to resolve, for instance, the shale-sand transitions is owed to the fact that these facies are often elastically comparable, thus no major impedance contrast can be observed within the resolution cells of the seismic data collected.
In contrast to current long offset data acquisition, the AZ approach as expressed in the first pilot is to employ the Acoustic Zoom®’s innovative data acquisition approach to deliver a more comprehensive dataset with increased dynamic range, to better characterise the subtle impedance boundaries between varying shale based strata. This is made possible by delivering intensively stacked high frequency vibroseis energy deployed in a tight acoustic lens pattern that focuses source energy to complement the associated star-configured receiver array deployment. The larger receiver array pattern then functions such that all of the seismic energy reflected back from the earth’s structure to the receiver array is captured, especially the diffused energy, and is available for image processing.
This is a major difference between the Acoustic Zoom® technique and that of conventional seismic imaging, which uses only the specular reflected energy to form the image of the geology. Indeed, conventional migration seismic data processing techniques and/or inversion protocols discriminate against the diffuse, non-specular backscattered energy. In many instances, the very detail of the geological structure that is being imaged is too small (sub-wavelength scale) for a strong specular reflection to be built up and the detail in the reservoir is thus not resolvable. It is in these very small but often strong diffused non-specular reflections that the true character of unconventional reservoir geology can be revealed. This essentially is what the Acoustic Zoom beam-steering receiver and high frequency high-fidelity source transmissions can capture and beam-form into.
Acoustic Zoom Test Pilot Site - The Eagle Ford, Austin TX
Loading of Acoustic Zooms Marine Source onto a vessel
Our design is founded on using a multiplicity of unique resonant cavity optimized pipes in which broadband frequencies can be swept. The novelty of our device is designed for geophysical mapping applications of the seabed. The source is typically applied in a stationary manner on the seabed during data acquisition (it however can be towed). This is specifically for supporting high-resolution exploratory seismic imaging.
The source applies advanced array focusing techniques combined with chirp-excited signals repeatedly over an extended period of time to increase the high-end frequencies available for seismic imaging. It delivers a broadband range of seismic frequencies not seen in current art, delivering the 40 – 300 Hz through its resonant tubes. The individual elements of the device are each designed to provide an incremental signal-to-noise increase that, when combined, will exceed anelastic and scattering attenuation and allow observation of the high frequencies. The frequency increase will provide a commensurate increase in resolution that will be beneficial to a variety of exploration problems.
Reducing and managing the impact of oil exploration on marine life has been an increasing focus of oil and gas producers, and seismic sound source levels are now being regulated.
Developments are under way to deliver increasingly benign seismic signals within environmentally sensitive waterways and marine mammal habitats. Seismic airgun surveys such as those used in the exploration of oil and gas deposits underneath the ocean floor produce loud, sharp impulses that propagate over large areas, and the resulting reverberation increases noise levels substantially. Exploration surveys often last for months and the noise they produce is becoming pervasive in the ocean and is potentially dangerous to flora and fauna found therein.
Our development in 2013 delivered a marine seismic approach that provides a much quieter and less harmful broad bandwidth directional source device and system for seabed imaging and delivers long-duration swept frequency signals. This is in direct contrast with the explosive short-duration high-energy signals dispense by current seismic sources such as airguns, waterguns, exploder sleeve devices, and large electrostrictive transmitter types.
By design, Acoustic Zoom® accentuates the rich content of the non-specular backscatter energy directly probing underlying geophysical properties of the earth; conventional migration accentuates specular reflecting from ambiguous impedance changes in the subsurface. Acoustic Zoom® reconstructs the complementary components of recorded energy that 3D seismic rejects as incoherent noise.
Non-specular returns detected by Acoustic Zoom® have significantly lower coherent background interference because coherent interference is highly attenuated due to the narrow beamwidth of the receiver array and Acoustic Zoom's® beamformer method further suppresses coherent interference through the firms' proprietary adaptive classification and filtering of specular energy using singular value decomposition (SVD) and advanced eigen-structure methods.
Acoustic Zoom reconstructs the complementary components of recorded energy that 3D seismic rejects as incoherent noise Non-specular returns detected by AZ have significantly lower coherent background interference because coherent interference is highly attenuated due to the narrow beamwidth of the receiver array, and Acoustic Zoom’s beamformer method further suppresses coherent interference through the firm’s proprietary adaptive classification and filtering of specular energy using singular value decomposition (SVD) and advanced eigen-structure methods.
A strategic over-consolidated Eagle Ford shale formation (unconventional reservoir) was targeted, which is considered to be a rich structure with vast entrapped gas and condensate potential in the region of San Antonio, Texas.
The AZ data acquisition in this pilot was designed to capture the subtle reservoir features which cannot easily be imaged through the capture of standard long offset, wide-azimuth seismic data, even when very high source location density and high multi-fold data are acquired.
Acoustic Zoom's patent-protected technologies allows for focused, high-resolution seismic detail associated with the diffused and/or diffracted character in areas of geological interest, while conventional seismic provides a broader, lower-resolution image with marginal focusing ability to resolve subtle complex discontinuities in formations such as caused by fractures.
Acoustic Zoom® Seismic is a novel seismic exploration/exploitation technique adapted from sonar applications. The method is complementary to 3D seismic imaging, enabling high resolution imaging of geological structures within the seismic volume using beam-forming and beam-steering techniques. The approach utilizes purpose-designed steerable phased arrays, analogous to the arrays used in radio astronomy, for both the source and receiver arrays.
Learn more about our Seismic Technology for free in the latest in-depth review featured in the Journal of Natural Gas Science and Engineering. Read the PDF here.
Learn why Marine Technology Magazine has labelled the Acoustic Zoom Marine Source "The Future of Offshore Exploration". Find the article here.