Method and system for analyzing a target region under a surface using generated noise

Abstract

This invention discloses a method, system, and computer-readable medium for determining one or more land properties of a target area beneath a surface, comprising: inserting a seismic sensor into the target area beneath the surface; generating a noise signal; outputting noise at the surface or outputting noise incident on the surface by a noise source based on the generated noise signal to generate seismic waves in the target area; receiving a response signal indicating the generated seismic waves measured by the seismic sensor; and determining one or more land properties of the target area based on the received response signal. This invention extracts insights from geographic data and further relates to improvements in sustainability and environmental development: together we create a safe and livable world.

Description

Technical Field

[0001] This invention relates to methods and systems for analyzing target areas beneath a surface using generated noise. More specifically, this invention relates to a method and system for determining one or more land properties of a target area beneath a surface based on generated noise signals emitted by a noise source at or incident on the surface. This invention extracts insights from geographic data and further relates to improvements in sustainability and environmental development: together we create a safe and livable world. Background Technology

[0002] There is a widespread and ongoing need to improve data acquisition in subsurface surveys. Determining subsurface characteristics is crucial for identifying objects beneath the surface and for identifying soil properties such as soil type, density, moisture content, and shear modulus, which can be used for foundation planning and / or management. Subsurface information can be used for, for example, site characterization of infrastructure projects and foundation calculations. For such applications, it is essential to generate a comprehensive understanding of the subsurface in an efficient and accurate manner.

[0003] One method for conducting such tests is commonly known as the seismic cone penetration test (SCPT). SCPT is a geotechnical engineering method that combines the standard cone penetration test (CPT) with in-situ measurements of seismic wave velocity, the speed at which seismic waves travel through a material. Seismic wave velocity is a key parameter used to determine the properties of soil in a volume of interest. SCPT is used in geotechnical engineering field investigations to assess the physical properties of soils, including stiffness and shear strength.

[0004] During SCPT, a cone penetrometer equipped with seismic sensors is driven into a target area in the ground, and a pulse source (such as a hammer or, typically, an air gun in a marine environment) generates seismic waves in the target area. The seismic waves generated by the pulse source are measured by the seismic sensors to determine the seismic wave velocity. Typically, a cone penetrometer consists of two seismic sensors spaced at a fixed distance. The seismic waves generated by the pulse source are measured simultaneously at two depths. The seismic wave velocity within the depth range is then determined by calculating the propagation time difference between the two receivers.

[0005] Another method for performing such tests is often called vertical seismic profiling (VSP). Vertical seismic profiling is a geophysical method commonly used in the oil and gas industry, measuring seismic wave velocities by deploying an array of seismic sensors in a vertical borehole or well. A pulse source, such as a hammer or, typically, an air gun in a marine environment, is used to generate seismic waves in a target area for detection by the seismic sensor array in the vertical borehole or well. VSPs can take various forms, examples including zero-offset VSPs, where the pulse source is located at the top of the well or borehole, and walkaway VSPs, where the pulse source is gradually moved away from the well or borehole while data is being acquired. VSP data can be processed in two ways: 1) by inverting the propagation time of the direct wave path from the pulse source to the seismic sensor array, or 2) by imaging the seismic energy reflected from changes in soil properties. VSP data can also be used to correlate surface seismic data with in-situ seismic measurements. This is often done to convert the data from time to depth, or to calibrate seismic properties obtained from seismic inversion using seismic reflection methods (i.e., to provide a background velocity model).

[0006] Both SCPT and VSP are types of in-situ seismic wave velocity measurement tests. These tests require the use of impulse noise sources, such as hammers or air guns. Impulse sources release acoustic energy into their environment (e.g., in bodies of water) for a very short time and can produce high sound pressure levels. They have limited control over frequency content, repeatability, and the pressure levels released. They can also be harmful to wildlife and the environment, for example, disturbing local animal populations and creating a negative environmental footprint. Air guns, hammers, and other impulse sources can cause destructive effects such as injury, hearing loss, and behavioral changes in the surrounding environment.

[0007] Therefore, it is necessary to improve the in-situ seismic wave velocity measurement and testing to avoid the above-mentioned shortcomings. Summary of the Invention

[0008] The concepts introduced in this overview will be described in more detail in the detailed description. It should not be used to identify essential features of the claimed subject matter, nor should it be used to limit the scope of the claimed subject matter.

[0009] According to a first aspect of this disclosure, a method is provided for determining one or more land properties of a target area beneath a surface, the method comprising: In some implementations, the method includes inserting a seismic sensor into the target area beneath the surface. In some implementations, the method further includes generating a noise signal. In some implementations, the method further includes outputting noise at the surface by a noise source or outputting noise incident on the surface, and generating seismic waves in the target area based on the generated noise signal. In some implementations, the method further includes receiving a response signal indicating the generated seismic waves measured by the seismic sensor. In some implementations, the method further includes determining one or more land properties of the target area based on the received response signal.

[0010] Advantageously, one or more land properties of a target area can be determined based on seismic wave measurements generated using a noise source that produces the output noise signal, avoiding the drawbacks associated with the use of pulse sources. The ability to determine the land properties of such a target area without using pulse noise sources such as air guns offers numerous advantages. Compared to existing invasive field analysis methods and methods utilizing pulse noise sources, it is simpler, faster, cheaper, less energy-intensive, and has less impact on the local environment and wildlife. This is because no pulse noise stimulation is required. Furthermore, and crucially, the disclosed method is both accurate and reliable, making it a practical and technically attractive technique. Due to its low-impact characteristics, the disclosed method is particularly suitable for use in marine environments.

[0011] Advantageously, using a signal generated from the output of a noise source can improve the accuracy and precision of land characterization compared to using a pulse noise source (such as an air gun). Pulse sources release acoustic energy in a very short time, and they have limited control over frequency content, repeatability, and the pressure level released. These problems are solved by using a signal generated from the output of a noise source.

[0012] Furthermore, the generated noise signal from the noise source output can further improve the analysis of land properties in subsurface target areas. As will be discussed further in this paper, seismic wave propagation is affected by subsurface physical properties. Noise from pulse sources may be limited in frequency range and / or content at specific frequencies. Therefore, this can negatively impact the quality of extracted seismic wave information, thus negatively affecting the determination of land properties at specific depths. By utilizing the generated noise signal from the noise source output, the frequency content of the generated noise can be controlled, meaning that land properties can be determined more efficiently within the depth range of interest. Moreover, utilizing the generated noise signal from the noise source output can improve the quality (e.g., accuracy and precision) of land property determination by providing control over the intensity, location, frequency profile, duration, and noise profile of the noise output from the noise source, which will be discussed further in this paper. Finally, utilizing the generated noise signal from the noise source output allows for better control over the frequency, intensity, and sound pressure level used in geotechnical imaging. This helps generate signals with lower amplitudes than pulse sources such as air guns, reducing the environmental impact of the geotechnical imaging process.

[0013] In some implementations, the noise source can be a vibration noise source, such as a loudspeaker. Using a vibration noise source allows for better control of the frequency, intensity, and sound pressure level used in geotechnical imaging. This helps generate signals with lower amplitudes than pulse sources such as air guns, reducing the environmental impact of the geotechnical imaging process. Examples of vibration noise sources that can be used in the systems and methods described herein include transducers and low-frequency electrodynamic sound projectors.

[0014] Environmental noise, or seismic environmental noise, can be generated by one or more environmental sources. These sources can be natural (i.e., naturally occurring vibrations) or cultural (i.e., vibrations from human activities). For example, environmental sources may include ocean (e.g., tidal or wave noise), wind, industry, industrial machinery, vehicles such as cars or trains, and human noise (e.g., footsteps).

[0015] This method includes a noise source that generates noise that is similar to, identical to, or has the same characteristics as environmental noise generated by an environmental source. Specifically, such a noise source can be included as part of the method disclosed herein to generate noise that is received / measured by a receiver (interchangeably referred to herein as a sensor or seismic sensor—a seismic sensor may have multiple seismic sensor elements, each configured to detect seismic waves). As will be further discussed herein, generating noise similar to environmental noise has less impact on the local environment and wildlife compared to more invasive methods and methods utilizing impulse noise sources (such as air guns). Simultaneously, such a noise source can be used to supplement existing environmental noise, enabling a better determination of one or more land properties in a target area beneath the Earth's surface. The noise source is configured to output noise based on the generated noise signal. The noise output by the noise source is referred to herein as "generated noise."

[0016] In some implementations, the receiver used in the method of the present invention can be a seismograph, an accelerometer (such as a vertical or triaxial accelerometer), a particle velocity sensor, a fiber-optic sensor, a seismograph, a vibration sensor, a pressure sensor, a hydrophone and / or a transducer, or an array of any of these types of receivers. In some implementations, the receiver can collect data over a considerable period of time. For example, generated noise can be continuously measured over a period of five days. This longer recording time allows for sufficient extraction of seismic wave information from the noise recorded on or near the surface of the target area. The recording time required to obtain sufficient extraction of seismic wave information depends on the quality and quantity of the noise measured by the receiver. In cases where seismic wave information is insufficient, a longer recording time can be used to compensate for this by combining the seismic wave information to generate a stronger signal. Advantageously, using the generated noise signal output from the noise source can provide sufficient seismic wave information without the need for extended recording time. In fact, in most cases, combining the use of the generated noise signal output from the noise source can reduce the time required to obtain sufficient surface wave information extraction. Therefore, operational efficiency can be improved, i.e., more effective use of time, human resources, and hardware resources, while minimizing disturbance / impact on the local environment, wildlife, and community.

[0017] Those skilled in the art will understand that the noise source used in the method of the present invention can be any device capable of generating vibration. In some implementations, the noise source can output noise over a long period of time.

[0018] Each response signal can indicate the P-wave and / or S-wave caused by the generated noise.

[0019] In some implementations, the method may also include, for example, outputting one or more land properties of the target area to the user via a user device.

[0020] In some implementations, the method further includes receiving an additional response signal indicating a generated seismic wave measured by a seismic sensor at a location different from the location where the response signal is received (e.g., a vertically offset location). The method further includes: cross-correlating or deconvolving the response signal and the additional response signal; and performing an inversion using the cross-correlating or deconvolved response signal and the additional response signal to generate a two-dimensional "2D" or three-dimensional "3D" model of the target area regarding one or more land properties.

[0021] In some implementations, the response signal and another response signal are simultaneously measured by the vertical offset seismic sensor element of the seismic sensor.

[0022] In some implementations, response signals and additional response signals are measured sequentially by moving the seismic sensor between two locations for each measurement.

[0023] In some implementations, the step of cross-correlating the response signal and / or other response signals includes cross-correlating the response signal with the output noise and / or cross-correlating other response signals with the output noise.

[0024] In some implementations, the step of determining one or more land properties of a target area based on the received response signal includes using the received response signal to determine a vertical seismic profile (VSP).

[0025] In some implementations, the step of determining one or more land properties of a target area based on the received response signal includes performing a seismic cone penetration test (SCPT) using the received response signal.

[0026] In some implementations, the noise signal is generated using a pseudo-random binary sequence. Advantageously, pseudo-random binary sequences are deterministic and can be generated efficiently using simple low-level hardware implementations. Furthermore, using pseudo-random binary sequences can shorten data acquisition time, thus enabling efficient use of time and hardware resources. Additionally, pseudo-random binary sequences possess acoustic properties similar to white noise, which has the advantage of reducing the impact / interference on the environment and wildlife.

[0027] In some implementations, the pseudo-random binary sequence is at least one of a maximum-length sequence, a Gold sequence, or a Kasami sequence. In some implementations, any pseudo-random binary sequence with properties similar to noise, such as white noise or noise of other colors, can be used. In some implementations, any combination of the aforementioned pseudo-random binary sequences can be used to generate a noise signal.

[0028] In some implementations, a random number generator is used to generate noise signals.

[0029] In some implementations, the noise signal is output at an intensity that is based on, matches, equal to, or audibly equal to the average intensity of the ambient noise measured at the seismic sensor. This allows the noise source to output a noise signal at an intensity that minimizes disturbance / impact on the local environment and wildlife. Output noise .

[0030] In some implementations, the noise signal output by the noise source is limited to a threshold output level. In some implementations, the threshold output level can be the average intensity of ambient noise in all directions across the noise profile, or in some implementations, it can be the average intensity of the ambient noise received at the seismic sensor. However, as will be discussed further herein, the threshold output level can be any suitable threshold, such as the highest recorded ambient noise, based on environmental standards / regulations, etc. In some implementations, the threshold output level can include one or more threshold output sub-levels based on one or more frequency values ​​or frequency ranges of the generated noise / noise signal.

[0031] In some implementations, the noise signal is generated to contain frequency content within a specific frequency range of 30-200 Hz. This frequency has been found to be helpful in generating S-waves in the target region.

[0032] In some implementations, the noise signal is generated to contain frequency content within a specific frequency range of 30-1000 Hz. This frequency has been found to be helpful in generating P-waves in the target area.

[0033] In some implementations, the noise signal is modulated to a specific frequency range, such as the range described above. In some implementations, the noise signal is filtered to attenuate frequencies outside the specific frequency range (e.g., the range described above). By filtering the noise signal to attenuate frequencies outside the specific frequency range, similar to the modulation of the noise signal described above, the noise signal can be controlled to increase the noise energy / intensity at a specific frequency or frequency range. Advantageously, this ensures that the noise signal includes the frequency content required to generate P-waves and / or S-waves for geotechnical imaging within the target area.

[0034] In some implementations, the noise source comprises multiple noise sources. In some implementations, a second noise source may be provided at a different location from the first noise source. In some implementations, the second noise source comprises multiple noise sources. Advantageously, by including noise sources comprising multiple noise sources, the accuracy and precision of land use determination can be further improved, as will be discussed further herein.

[0035] In some implementations, multiple noise sources are configured to output noise signals sequentially. By having multiple noise sources output noise signals sequentially (i.e., one at a time, following a predetermined order or, in some implementations, a random order), this ensures that the output noise signals are uncorrelated with each other because they do not overlap in time. This makes it possible to efficiently determine Green's function and can reduce data acquisition time. Therefore, even if each of the multiple noise sources outputs the same noise signal, there is no correlation between the noise sources.

[0036] In some implementations, the noise signal output at each of the multiple noise sources is different. That is, the noise signal output by each of the multiple noise sources is different from each other. Advantageously, enabling each of the multiple noise sources to output noise based on a different noise signal can provide an output of noise that is similar to, analogous to, or shares characteristics with the ambient noise.

[0037] In some implementations, the different noise signals output at each of the multiple noise sources are uncorrelated with each other.

[0038] In some implementations, one or more land properties may include one or more elastic properties of the target area, such as shear velocity Vs. Extracting the shear velocity of the target area provides valuable insights into the land properties of the target area, such as the small strain shear modulus of the target area. This enables engineers to identify weak zones in the target area below the surface, or lateral variations in the geology.

[0039] As useful background information, the shear velocity Vs is the speed at which the shear wave travels through the material and is controlled by the material's shear modulus. The relationship between shear velocity and shear modulus G is given by... Defined as , where ρ is the density of the material. Therefore, the measurement of Vs provides valuable insight into the soil properties of the subsurface area. The small strain shear modulus (Gmax) is also important in foundation design, where Gmax = Shear modulus is a measure of a material's elastic shear stiffness and represents the deformation of a solid when subjected to a force parallel to one of its surfaces and an opposing force on its opposite surface. Such forces and their effects on subsurface land volumes are important parameters studied before and during the design of land-based and offshore building and infrastructure projects. To determine the shear modulus of a volume, the shear velocity Vs needs to be determined. This, in turn, gives an indication of the stiffness of the subsurface material and its ability to support structures extending above and / or through the volume. In the context of land studies, two types of waves are typically distinguished: P-waves and S-waves. In P-waves, particles in the volume oscillate in the direction of wave propagation, causing compression and decompression of the land as the wave propagates through it. Meanwhile, S-waves are shear waves, in which particles oscillate in a direction perpendicular to the wave propagation direction.

[0040] In some implementations, the processing steps may include processing the first and / or second response signals to emphasize the representation of the received noise. In other words, emphasizing the broadband characteristics of the received noise. For example, by eliminating the instrument response and / or filtering out large amplitudes. Such large amplitudes may be caused by (undesired) signals from the earthquake. Advantageously, this prevents large amplitude events from overwhelming the generated noise (and ambient noise, if present) response of interest.

[0041] In some implementations, the step of inserting a seismic sensor into the target area includes pushing the seismic sensor into the target area.

[0042] In some implementations, the step of inserting a seismic sensor into the target area includes drilling a hole in the target area and inserting the seismic sensor into the hole.

[0043] In some implementations, the seismic sensor includes at least two vertically offset seismic sensor elements.

[0044] In some implementations, the seismic sensor includes at least one of the following: a pressure sensor, a seismograph, a hydrophone, an accelerometer (such as a vertical or triaxial accelerometer), a particle velocity sensor, a fiber-optic sensor, a seismograph, a vibration sensor, and / or a transducer.

[0045] In some implementations, the seismic sensor includes a seismic cone penetrator.

[0046] In some implementations, the seismic cone penetrator includes at least three seismic sensor elements.

[0047] In some implementations, the noise source is connected to at least one of the following: a structure on the surface; and a vehicle on the surface, such as a truck or tracked vehicle.

[0048] In some implementations, the noise source is in direct contact with the surface.

[0049] In some implementations, the surface is the surface of a bed of water.

[0050] In some implementations, the seismic sensor is coupled to the vessel, for example, via a push rod distributed from the vessel. In some implementations, the vessel includes a drive mechanism for driving the push rod into the target area. In some implementations, a device for drilling a borehole is included.

[0051] In some implementations, the noise source is connected to one of the following: a structure on the bed of the water body; and a vehicle on or in the water body, such as a ship, USV, or ROV.

[0052] In some implementations, the noise source is connected to the tow cable of a vehicle on or in the water.

[0053] In some implementations, the noise source and the seismic sensor are connected to the same vehicle.

[0054] In some implementations, the step of outputting noise from a noise source based on a noise signal, wherein the noise source is located in the water body, includes generating pressure waves in the water body that are incident on the surface of the bed of the water body.

[0055] In some implementations, pressure waves are incident on the surface of the water bed at an angle ranging from 10 to 40 degrees, optionally at an angle of 30 degrees. This angle has been found to optimize the generation of P-waves and / or S-waves at the surface and in the target region.

[0056] In some implementations, the noise source includes an array of noise sources configured to form a noise beam incident on the surface of the bed of the water body. This enhances the generation of P-waves and / or S-waves at the surface and in the target region.

[0057] In some implementations, the noise beam is incident on the surface of the water bed at an angle ranging from 10 to 40 degrees, optionally at an angle of 30 degrees. This angle has been found to optimize the generation of P-waves and / or S-waves at the surface and in the target region.

[0058] In some implementations, the response signal and / or additional response signals include P-waves and / or S-waves generated by the output noise in the target region.

[0059] In some implementations, the noise source moves relative to the surface of the bed of the water body.

[0060] In some implementations, motion correction is applied to the response signal and / or other response signals to account for the movement of the noise source relative to the surface of the bed in the water body. Using motion correction to account for the relative movement of the noise source improves the accuracy of the method.

[0061] According to another aspect, a program product is provided, which includes instructions that, when executed by a computer, cause the computer to perform the method according to any of the preceding claims.

[0062] According to another aspect, a system is provided, comprising: one or more processors; and one or more memories having computer-readable instructions stored thereon configured to cause the one or more processors to perform operations including steps of the method of the first aspect or any of the methods described herein.

[0063] According to another aspect, a computer-readable medium is provided, which includes instructions that, when executed by a computer, cause the computer to perform the method of the first aspect or any of the methods described herein.

[0064] According to another aspect, a system is provided, comprising: a noise source, a seismic sensor, one or more processors; and one or more memories storing computer-readable instructions thereon, the computer-readable instructions being configured to cause the one or more processors to perform operations to control the system thereby performing the steps of the first aspect or any of the methods described herein.

[0065] According to another aspect, a system is provided, comprising: a noise source, a seismic sensor, and a vehicle, wherein the seismic sensor is coupled to the vehicle. In some implementations, the noise source is coupled to another vehicle on or in a body of water. In some implementations, the noise source is coupled to the same vehicle as a first receiver and / or a second receiver. In some implementations, the vehicle and / or the other vehicle is a ship, an unmanned surface vessel (USV), or a remotely operated vehicle (ROV). In some implementations, the system further includes one or more processors; and one or more memories storing computer-readable instructions configured to cause the one or more processors to perform operations to control the system thereby performing the steps of the first aspect or any of the methods described herein. Attached Figure Description

[0066] To describe how the above and other advantages and features of this disclosure can be obtained, the principles briefly described above will be described in more detail with reference to specific embodiments shown in the accompanying drawings. It should be understood that these drawings depict only exemplary implementations of this disclosure and should not be considered as limiting its scope. The principles herein are described and explained with additional specificity and detail using the drawings, wherein: Figure 1 An example system for determining one or more land properties of a target area beneath a surface is shown; Figure 2 The method for determining one or more land properties of a target area is shown; and Figure 3 This is a block diagram of one implementation of a computing device that can be used to perform the methods described herein.

[0067] Throughout the specification and drawings, the same reference numerals denote the same features. Detailed Implementation

[0068] The following description of certain embodiments of the invention is given by way of example only and with reference to the accompanying drawings.

[0069] Various implementations and examples of this disclosure are discussed in detail below. While specific implementations and examples are discussed, it should be understood that this is for illustrative purposes only. Those skilled in the art will recognize that other components and configurations can be used without departing from the spirit and scope of this disclosure. Therefore, the following descriptions and figures are illustrative and should not be construed as limiting. Many specific details are described to provide a thorough understanding of this disclosure. However, in some cases, well-known or conventional details are omitted to avoid obscuring the description. In this disclosure, references to implementations or examples may be references to the same implementation or example, or any other implementation or example. Thus, such references refer to at least one implementation or example herein.

[0070] The terms used in this specification generally have their common meaning in the art, in the context of this disclosure, and in the specific context in which each term is used. Alternative languages ​​and synonyms may be used for any one or more terms discussed herein, and it should not be particularly emphasized whether terms are elaborated or discussed herein. In some cases, synonyms for certain terms will be provided. The use of one or more synonyms does not preclude the use of other synonyms. Examples used anywhere in this specification, including examples of any terms discussed herein, are illustrative only and are not intended to further limit the scope and meaning of this disclosure or any example terms. Similarly, this disclosure is not limited to the various implementations given in this specification. Unless otherwise stated, references to numerical ranges or values ​​“between” two values ​​should be interpreted as including the endpoints of those ranges.

[0071] A method for determining one or more land properties of a target area beneath a surface will now be described. (The following is in conjunction with...) Figure 2 A more detailed explanation of the method is provided. In short, the method involves inserting a seismic sensor into a target area beneath a surface, generating a noise signal, having a noise source output noise at the surface or output noise incident on the surface based on the generated noise signal to generate seismic waves in the target area, receiving a response signal indicating the generated seismic waves measured by the seismic sensor, and determining one or more land properties of the target area based on the received response signal. This provides valuable insights into the composition of the target area. In turn, this can be used to influence subsequent field surveys and construction decisions in onshore or offshore environments, as will be described below.

[0072] This method is an in-situ seismic wave velocity measurement test, and in some implementations, it can follow the conventional processing steps in SCPT and VSP. The key difference lies in generating a noise signal and having a noise source output noise based on the generated noise signal to generate seismic waves in the target area.

[0073] Using generated noise eliminates the need for impulse noise sources such as hammers or air guns. Impulse sources release acoustic energy into their environment (e.g., in bodies of water) for a very short time and can produce high sound pressure levels. They have limited control over frequency content, repeatability, and the pressure levels released. They can also be harmful to wildlife and the environment, for example, disturbing local fauna and creating a negative environmental footprint. Air guns, hammers, and other impulse sources can cause destructive effects such as injury, hearing loss, and behavioral changes in the surrounding environment. The use of generated noise addresses each of these problems, which will be explained below.

[0074] Environmental noise is generated by various environmental sources. These sources are divided into two categories: natural and cultural. Natural sources refer to naturally occurring vibrations caused by the ocean or wind. Cultural sources originate from human activities, such as industry, industrial machinery, vehicles like cars or trains, power lines, and human noise.

[0075] The generated noise is based on a generated noise signal and is output by a noise source at or near the surface of the target area. In some implementations, the generated noise is similar to, identical to, or has the same characteristics as the ambient noise generated by an environmental source. In this way, the environmental impact and other harmful effects of the generated noise can be mitigated compared to pulse sources.

[0076] More specifically, each response signal of this method is measured by a seismic sensor. The response signal indicates the amplitude of the generated noise transmitted from the noise source through the ground and measured by the seismic sensor, which will be explained below. In particular, seismic waves, such as P-waves and S-waves, can be measured. Seismic waves can be generated by cultural or natural processes occurring at or near the surface (i.e., environmental noise), or they can be generated by generated noise output from one or more noise sources.

[0077] Seismic sensors may include one or more of the following: seismographs, accelerometers (e.g., vertical or triaxial accelerometers), particle velocity sensors, fiber-optic sensors, seismographs, pressure sensors, vibration sensors, hydrophones and / or transducers, or arrays of any of these types of sensors.

[0078] A noise source can be any device capable of generating vibrations through one or more media. In some implementations, the noise source can output noise over a long period of time. In some implementations, the noise source is a vibratory noise source or vibrator (used interchangeably herein) that is electromagnetically, hydraulically, or otherwise driven to generate vibrations. In some implementations, the noise source is a loudspeaker, woofer, subwoofer, buzzer (e.g., piezoelectric), tweeter, or any other device capable of producing sound, vibration, or seismic activity. In some implementations, the noise source is a combination of one or more of the above devices. The noise source can be placed on or near the surface of the target area, but in some implementations, the noise source can be placed at a distance from the target area.

[0079] Vibration noise sources can emit any type of acoustic signal, including chirps, sweeps, and pseudo-random sequences (e.g., maximum-length sequences). These signals can be tuned to be "as quiet as possible." This means that the sound pressure level of the generated signal can be as close as possible to the measured ambient noise level (the sound level already present in the environment), but high enough to ensure the minimum required signal-to-noise ratio for processing. This avoids releasing excess acoustic energy into the environment.

[0080] Advantageously, the vibration noise source generates an acoustic signal that is repeatable and frequency-controllable, thus producing a suitable noise signal. Using the vibration noise source, P-waves and S-waves can be generated in the target area to allow in-situ measurement of seismic velocities by generating noise within the frequency bandwidth required for P-wave or S-wave generation. This method can also be used to enhance the correlation between in-situ and surface seismic measurements, contributing to a more accurate and comprehensive analysis of subsurface geological characteristics. Controlling the frequency content of the noise source allows the generated noise to be emitted in a manner matching the desired vertical spatial resolution. This is beneficial when surface seismic data (i.e., data associated with seismic waves detected at the surface) is correlated with in-situ measurements of seismic wave velocities (e.g., SCPT or VSP data). Ensuring they have the same frequency bandwidth, and thus the same vertical resolution, makes it easier to achieve correlation between in-situ and surface seismic measurements.

[0081] Figure 1 An example system for determining one or more land properties of a target area beneath a surface is shown. This system can be used to perform the methods described above, as well as in conjunction with the following... Figure 2 Related methods. Figure 1 The image shows a first vehicle 102 and a second vehicle 108 on water body 110. A remotely operated vehicle (ROV) 104 has been deployed by the first vehicle 102 and operates within water body 110. A noise source 106 is connected to the ROV 104 for use in the subsurface volume 118 within the bed of water body 110 (as per [reference]). Figure 2 The method described guides generated noise 114 at the surface 112 of the bed of water body 110 above the target area (subsurface volume and target area can be used interchangeably). The generated noise 114 generates seismic waves 120 in the subsurface volume 118. A seabed frame 134 is located on the surface 112. The seabed frame includes a drive mechanism 116 for driving a push rod 130 distributed by the second vehicle 108 into the subsurface volume 118. An additional noise source 132 is provided on the seabed frame 134 for guiding noise (not shown) at the surface 112 to generate seismic waves 120 in the subsurface volume 118. In some implementations, only one of the noise source 106 and the additional noise source 132 is provided.

[0082] Seismic sensor 128 is located at the end of push rod 130 for measuring seismic waves 120 generated by any one or both of noise sources 106 and 132. Seismic sensor 128 includes a first seismic sensor element 122 offset perpendicularly to the second seismic sensor element 124. At its distal end, seismic sensor 128 includes a cone penetrator 126.

[0083] The generated noise 114, produced by any one or both of noise sources 106 and 132, influences the surface 112 of the water body 110 bed, generating a seismic wave 120 in the subsurface volume 118. This seismic wave 120 is detected by a seismic sensor 128 within the subsurface volume 118. Example seismic waves 120 include P-waves and S-waves, which can be used for high-resolution sediment characterization. P-waves excited in the water body 110 can convert to S-waves at the surface 112 of the water body 110 bed or at any interface where the elastic properties of the soil change (e.g., sedimentary layers). These different conversion modes can be recorded by the seismic sensor 128. This process will be described with reference to... Figure 2 To provide a more detailed description.

[0084] Figure 1 The first vehicle 102 can be any suitable vehicle or vessel located on or within the body of water 110, including unmanned surface vessels (USVs) or remotely operated vehicles (ROVs). The first vehicle 102 can be controlled by an operator located at the first vehicle 102 or at a remote operations center (not shown). The first vehicle 102 can also be autonomously controlled.

[0085] Figure 1 The ROV 104 can be controlled from the first vehicle 102, for example, via a cable (such as...). Figure 1 (as shown) or via wireless communication (not shown). In another example, ROV 104 can be controlled by an operator located at the first vehicle 102 or at a remote operations center (not shown).

[0086] Any one or both of noise sources 106 and 132 may be a device capable of generating vibrations through one or more media. In some implementations, noise sources 106 and 132 may output generated noise 114 over a long period of time. In some implementations, any one or both of noise sources 106 and 132 are vibration noise sources or vibrators (used interchangeably herein) that are electromagnetically, hydraulically, or otherwise driven to generate vibrations. In some implementations, any one or both of noise sources 106 and 132 are loudspeakers, woofers, subwoofers, buzzers (e.g., piezoelectric), tweeters, or any other device capable of generating sound, vibration, or seismic activity. In some implementations, any one or both of noise sources 106 and 132 are combinations of one or more of the aforementioned devices. One or both of noise sources 106 and 132 may be placed on or near the surface 112 of the underground volume 118, but in some implementations, one or both of noise sources 106 or 132 may be located at a certain distance from the underground volume 118.

[0087] Figure 1 The noise source 106 can be a noise source array (such as...) Figure 1 As shown below, the nature of the noise source will be discussed in more detail. The position and orientation of the noise source 106 can be changed by controlling the movement of the ROV 104. In an alternative example, the noise source 106 can be directly connected to the first vehicle 102, for example, by a tow cable. The noise source 106 is capable of generating noise 114 in the form of pressure waves incident on the surface 112 in the water body 110.

[0088] In some implementations, it is possible to Figure 1 The system provides multiple ROVs 104, each with a corresponding noise source 106.

[0089] In some implementations, the noise source 106 may be attached to a structure (not shown) on the surface 112 of the bed of the water body 110, rather than to the ROV 104 or the first vehicle 102.

[0090] Figure 1 Another noise source 132 is disposed on the seabed frame 134. Like noise source 106, the other noise source 132 may be an array of noise sources. This other noise source 132 is capable of generating noise in the form of pressure waves incident on the surface 112 in the water body 110.

[0091] Figure 1The second vehicle 108 can be any suitable vehicle or vessel located on or within the water body 110, including a USV or ROV. The second vehicle 108 can be controlled by an operator located at the second vehicle 108 or at a remote operations center (not shown). The second vehicle 108 can also be autonomously controlled. The second vehicle 108 is configured to distribute push rod 130 when push rod 130 is inserted into the ground.

[0092] In some implementations, the push rod 130 is mounted on the second vehicle 108 in a coiled configuration, and when the push rod 130 is deployed, a drive mechanism drives the push rod 130 into the underground volume 118. In some implementations, the push rod 130 is a segmented push rod, wherein the segments of the push rod are screwed together or otherwise connected when the push rod is inserted into the ground.

[0093] Figure 1 The seabed frame 134 is located on the surface 112 of the bed of the water body 110. In some implementations, the seabed frame 134 is lowered onto the surface 112 by a second vehicle 108.

[0094] The seabed frame includes a drive mechanism 116 for driving the push rod 130 into the subsurface volume when the push rod 130 is distributed by the second vehicle 108. Alternatively, the drive mechanism 116 may be located on the second vehicle 108. Any suitable drive mechanism may be used for this purpose.

[0095] Seismic sensor 128, located at the end of push rod 130, is used to measure seismic waves 120 generated by any one or both of noise sources 106 and 132. Seismic sensor 128 includes a first seismic sensor element 122 vertically offset from the second seismic sensor element 124. This vertical offset allows seismic waves generated by the pulse source to be measured simultaneously at two depths. The seismic wave velocity within the depth range is then determined by calculating the propagation time difference between the first seismic sensor element 122 and the second seismic sensor element 124.

[0096] Seismic sensor elements 122 and 124 are configured to detect seismic waves 120 generated by any one or both of noise sources 106 and 133. Any one or both of seismic sensor elements 122 and 124 may include at least one of a pressure sensor, a seismograph, a hydrophone, an accelerometer (e.g., a vertical or triaxial accelerometer), a particle velocity sensor, a fiber-optic sensor, a seismograph, a vibration sensor, and / or a transducer. In some implementations, seismic sensor 128 is configured to perform a standard seismic cone penetration test (SCPT).

[0097] In some implementations, the seismic sensor 128 includes three or more seismic sensor elements.

[0098] At its distal end, the seismic sensor 128 includes a cone penetrator 126. The cone penetrator 126 can be configured to perform a cone penetration test of SCPT. In some implementations, the seismic sensor 128 may be provided without the cone penetrator 126.

[0099] although Figure 1 The example system includes a pusher 130 that can be driven into a subsurface volume 118 to perform, for example, SCPT, but the system can alternatively be configured to deploy a seismic sensor array in a vertical borehole or well, such as in a vertical seismic profile (VSP) type application. In such an exemplary implementation, the second vehicle 108 may include means for drilling a borehole and / or means for deploying a seismic sensor array within the borehole. Such a seismic sensor array includes similarly vertically offset seismic sensor elements, such as seismic sensor elements 122 and 124. They may have the same characteristics as seismic sensor elements 122 and 124 described herein.

[0100] although Figure 1 The example systems described herein are set in a marine environment, but it is understood that the example implementations described herein are not limited to marine environments. These components can also be provided in terrestrial environments. For example, components disposed on the first vehicle 102 and the second vehicle 108 can be disposed on equivalent land-based components, such as land-based or air-based vehicles and / or structures. More specifically, noise source 106 can be disposed on a structure on a surface or on a vehicle on a surface, such as a truck or tracked vehicle. Devices for distributing pushrods and driving them into the ground can be disposed on a structure on a surface or on a vehicle on a surface, such as a truck or tracked vehicle.

[0101] This also applies to example systems configured to deploy seismic sensor arrays in vertical boreholes or wells, such as in vertical seismic profile (VSP) type applications. The components of this system can similarly be located on land.

[0102] Figure 2 The diagram shows the methods used to determine the target area (such as...). Figure 1 An exemplary method 200 for determining one or more land properties (subsurface volume 118). Method 500 may be a computer-implemented method. See later. Figure 3 The description includes a computer device 300 that can be used to perform the method. The method can be used... Figure 1 The settings shown (or any variations described herein) are used to perform this, and with Figure 1 The same reference numerals represent the same characteristics. For the purposes of this method, it is assumed that only one of noise source 106 and the other noise source 132 exists, although in some implementations both may exist.

[0103] In step 202, the seismic sensor 128 is inserted into the target area 118 below the surface 112. This can be accomplished by pushing the seismic sensor 128 into the target area via the drive mechanism 116, or the seismic sensor can be inserted into an existing well or borehole. The seismic sensor 128 is inserted to the depth at which seismic testing (e.g., SCPT or VSP) is desired.

[0104] In step 204, a noise signal is generated. The noise signal can be designed to include the frequency content required to generate P-waves and / or S-waves for measurement by the seismic sensor 128 within the target area 118. Controlling the frequency content of the generated noise 114 allows for customization of the output noise to generate the desired seismic waves in the target area 118. For example, frequencies in the 30-200 Hz range may contribute to the generation of S-waves, and frequencies in the 30-1000 Hz range may contribute to the generation of P-waves.

[0105] In some examples, the noise signal may have the same, similar, or shared characteristics with ambient noise. As will be apparent to those skilled in the art, the noise signal can be generated in any number of ways to resemble ambient noise. In some implementations, the noise signal mimics / matches ambient noise by recording ambient noise for the noise sources 106, 132 to replicate the output. For example, the generated noise signal may be based on the ambient noise distribution of the target area 118, which is determined separately based on measurements from the seismic sensor 128 when the noise sources 106, 132 are not operating. In some implementations, the noise signal is based on the color of the noise, such as white noise. Thus, if this functionality is required, the generated noise 114 can be integrated with the ambient noise for reception by the receiver.

[0106] When the noise signal used for output is the same as or similar to the ambient noise, the impact and interference caused by the generated noise 114 will be reduced, or in some cases, will not be noticed by the local environment, wildlife, and community. By replacing the pulse source (such as an air gun) with such noise sources 106, 132, the acoustic energy is extended over a longer duration, which reduces the peak pressure in the surrounding environment of the water body 110 or the land-based implementation, greatly reducing the environmental impact. The generated signal can also be designed to improve the signal-to-noise ratio of the measured seismic wave arrival by transmitting a longer signal. This is beneficial when operational noise (from vehicles, aircraft, propulsion systems, etc.) is high, as high operational noise can negatively impact data quality.

[0107] In some implementations, the noise signal is generated as a chirp, a frequency sweep (linear, nonlinear, optimized), or using a pseudo-random binary sequence. In some implementations, the signal is spread over a wide frequency band, such as at least one of 2-120Hz, 5-100Hz, 30-200Hz, and 30-1000Hz. Spread spectrum techniques can be used to achieve this. In some implementations, the pseudo-random binary sequence is at least one of a maximum-length sequence, a Gold sequence, or a Kasami sequence. As will be apparent to those skilled in the art, any type of sequence (pseudo-random binary or otherwise) or other methods can be used to generate noise signals with similar noise properties. Advantageously, the pseudo-random binary sequence is deterministic and can be generated efficiently using simple low-level hardware implementations. For example, a combination of linear feedback shift registers can be used to generate a maximum-length sequence, and two maximum-length sequences can be used to generate a Gold sequence (i.e., a Gold code).

[0108] In some implementations, the noise signals / noise output by noise sources 106 and 132 are generated to comply with environmental, health, and safety standards, laws, regulations, or rules. The methods and systems described herein can be applied to, for example, marine applications. Marine seismic or marine geophysical surveys often use air guns, which can lead to destructive effects such as injury to species in the surrounding environment, hearing loss, and behavioral changes. By using noise signals similar to ambient noise, the impact and disturbance to marine life can be minimized.

[0109] In some implementations, the noise signal is processed so that noise sources 106 and 132 output noise at an intensity that matches, is equal to, or substantially equal to the average intensity of the ambient noise received at, for example, the seismic sensor 128. In some implementations, the amplitude of the noise signal is reduced or increased to match the ambient noise intensity. In some implementations, noise sources 106 and 132 are controlled (as a supplement or alternative to noise signal processing) to output noise at an intensity / volume that matches the ambient noise intensity based on the noise signal by correspondingly increasing or decreasing the output intensity / volume of noise sources 106 and 132. By matching the noise output by noise sources 106 and 132 to the average intensity of the ambient noise, the impact and disturbance of noise on the local environment, wildlife, and communities can be controlled and minimized.

[0110] In some implementations, the noise signals output by noise sources 106 and 132 are limited to a threshold output level. The threshold output level can be the average intensity of ambient noise in all directions of the ambient noise distribution. However, the threshold output level can also be any suitable threshold, such as the highest recorded ambient noise level, based on environmental, health, or safety standards, laws, regulations, or rules.

[0111] In some implementations, the threshold output level may include one or more threshold output sub-levels based on one or more frequency values ​​and / or frequency ranges. In some implementations, the threshold output level is based on the species living on or near the surface of the target area. For example, a noise signal may be modified or designed to meet a maximum permissible noise level at a specific frequency and / or one or more frequency ranges, e.g., with respect to the species. In some implementations, there are one or more threshold output levels for each of one or more corresponding species living on or near the surface of the target area. In a further implementation, the threshold output level is based on the species having the lowest threshold output level.

[0112] In some implementations, the generated noise signal can be processed in various ways to enhance, tune, or otherwise manipulate it to target a specific frequency range or a specific frequency of interest. In some implementations, the specific frequency range is 2-120 Hz or optionally 5-100 Hz to ensure that the noise signal includes the frequency content required to generate Scholte waves, P-waves, and / or S-waves for geotechnical imaging at surface 112 and / or within target region 118. Frequencies in the 30-200 Hz range can be used because they contribute to S-wave generation, and frequencies in the 30-1000 Hz range can be used because they contribute to P-wave generation. In some implementations, spread spectrum techniques are used, for example, to spread the signal across one or more of the aforementioned frequency bands. In some implementations, a cost function can be used to process the noise signal, rewarding increased intensity (enhancement) at certain frequencies or frequency ranges at the expense of other frequencies or frequency ranges. In some implementations, different seeds are used to generate the noise signal using a random number generator, which makes it possible to generate noise signals (and the resulting noise output) that are uncorrelated with each other. In some implementations, noise signals are filtered to attenuate or boost frequencies outside a specific frequency range, for example, by using digital filters, high-pass filters, low-pass filters, etc. In some implementations, filtering can be achieved using, for example, the cost function described above. In some implementations, optimization functions are used, which increase the intensity at certain frequencies or frequency ranges without affecting the intensity at other frequencies. By processing generated noise signals in this way, the impact and disturbance on the local environment, wildlife, and communities can be reduced.

[0113] In some implementations, a second noise source 106, 132 or one or more noise sources included in the disclosed methods and systems may be present, for example, configured as an array coupled to a single ROV 104, or, in the case of multiple ROVs 104, each coupled to a corresponding noise source 106, 132, to increase the generation of P-waves and / or S-waves within the target area 118. It is also possible to minimize the impact and disturbance to the local environment, wildlife, and community by, for example, using multiple noise sources 106, 132 to output noise at a lower intensity than with a single noise source, while maintaining or even reducing data acquisition time.

[0114] In some implementations, the noise signals output at each of the multiple noise sources 106, 132 are generated to be different from each other and / or uncorrelated. In some implementations, random number generators with different seeds (e.g., for each noise signal) can be used to generate noise signals that are uncorrelated. In some implementations, the noise signals can be uncorrelated by outputting noise signals via different types / familiarities of devices for the multiple noise sources 106. In some implementations, the noise signals can be generated to be uncorrelated by processing the noise signals via modulation, filtering, and / or phase shifting. In some implementations, the phase of the noise signals is shifted by each of the multiple noise sources 106, 132 outputting noise signals at different times / time ranges relative to each other. In some implementations, a set of uncorrelated noise signals is generated using a pseudo-random binary sequence (e.g., using a golden sequence), wherein each of the multiple noise sources 106, 132 outputs a noise signal different from this set of uncorrelated noise signals. It will be apparent to those skilled in the art that there are multiple methods to generate uncorrelated noise signals, and any of the examples above can be combined to generate uncorrelated noise signals.

[0115] Next, in step 206, noise sources 106 and 132 output noise based on the generated noise signal to generate pressure waves in the water body 110, which are incident on surface 112 or directly on the surface of the noise source 132 set on the seabed frame 134 (for land applications, pressure waves incident on surface 112 can be generated in the air). This, in turn, generates seismic waves in the target area 118. As discussed, combining noise sources 106 and 132 to output noise can improve the quality (e.g., accuracy and precision) of determining the land properties of the target area without the environmental impact of pulse sources (such as air guns).

[0116] In some implementations, noise sources 106 and 132 output noise at different locations on the surface at increasing distances from the seismic sensor 128, for example, to perform variable offset VSP. While measuring seismic waves 120, noise sources 106 and 132 can be gradually moved away from the seismic sensor 128.

[0117] Since the noise signal is expected to be emitted for a long period of time, it can be cycled or otherwise extended to meet the expected operating time required for the noise output. In some implementations, the cycling or extension of the noise signal can be performed at the noise source 106, 132 via a processor on the noise source 106, 132 or via computing device 300. In some implementations, the noise signal can also be processed at the processor on the noise source or via computing device 300 to control the intensity, duration, and frequency distribution of the noise output by noise sources 106, 132. In some implementations, the noise signal is generated locally by noise sources 106, 132. In some implementations, the noise signal is generated by computing device 300 and transmitted to noise sources 106, 132 (via wired or wireless communication), for example, from at least one of ROV 104, first vehicle 102, second vehicle 108, or a remote operations center. In some implementations, computing device 300 controls various aspects of the operation of noise sources 106 and 132, such as intensity, frequency distribution, duration (including the start and stop of operation of noise sources 106 and 132), and / or noise distribution (i.e., what noise sources 106 and 132 are outputting). In some implementations, noise sources 106 and 132 can be automatically or manually timed or configured to operate only within a specific time range of the day (e.g., during the day). In some implementations, in the presence of one or more noise sources 106 and 132, including multiple noise sources 106 and 132, noise sources 106 and 132 can be controlled to operate sequentially, simultaneously, not at all, or in any combination. Similarly, in other implementations, where one or more generated noise signals are present, noise sources 106 and 132 can be similarly operated to output one or more generated noise signals in any combination from the one or more noise sources.

[0118] In some implementations, where noise sources 106 and 132 comprise an array of noise sources 106 and 132, the array of noise sources 106 and 132 can be configured to form a noise beam incident on the surface 112 of the bed of the water body 110 to maximize the generation of P-waves and / or S-waves within the target region 118. In some implementations, the noise beam is incident on the surface 112 of the bed of the water body 110 at an angle in the range of 10 to 40 degrees, optionally at an angle of 30 degrees. This further optimizes the generation of P-waves and / or S-waves.

[0119] Next, in step 208, the response signal of the generated seismic wave, measured by the seismic sensor 128, is received.

[0120] In some implementations, the seismic sensor 128 includes a first seismic sensor element 122 vertically offset from the second seismic sensor element 124. This vertical offset allows for the simultaneous measurement of seismic waves 120 generated by noise sources 106 and 132 at two depths. The seismic wave velocity within the depth range is then determined by calculating the propagation time difference between the first seismic sensor element 122 and the second seismic sensor element 124. In some implementations, the seismic sensor 128 includes a seismic sensor array capable of simultaneously measuring the seismic waves 120 generated by noise sources 106 and 132 on the array.

[0121] In some implementations, the seismic sensor 128 comprises a single sensor element. The seismic sensor 128 can be moved while noise sources 106 and 132 continuously output generated noise, enabling the continuous generation of seismic waves by noise sources 106 and 132. Therefore, seismic waves can be measured sequentially at two depths, and the known properties of the continuous output and the generated noise from noise sources 106 and 132 allow for comparison of the results to calculate the propagation time difference between the two locations of the seismic sensor 128. This would be impossible if pulse sources were used because the seismic waves generated by pulse sources are very short in duration, and there is a lack of control over the properties of the seismic waves generated by sequentially triggering pulse sources. For example, sequentially triggering an air gun could result in different seismic wave characteristic distributions within the target area, making comparisons even more difficult.

[0122] Next, in step 210, one or more land properties of the target area are determined based on the received response signal (and, optionally, output to the user via a user equipment). This may involve conventional SCPT and / or VSP processing steps.

[0123] In some implementations, step 210 may include cross-correlating the generated noise 114 with a signal indicative of the response of the generated seismic wave 120 measured by the seismic sensor 128. By performing this cross-correlation, the seismic data is effectively compressed, thus allowing for a clearer representation of subsurface structures and geological features. This process is also known as matched filtering, where filters are designed to maximize the signal-to-noise ratio of a particular desired signal.

[0124] In some implementations, step 210 may further include determining the propagation time difference of the generated seismic waves measured by seismic sensor 128 and using these to calculate the seismic wave velocity. The arrival time of the seismic wave 120 is picked up manually or using a thresholding or automatic picking algorithm. The arrival time refers to the time it takes for the direct seismic wave 120 to propagate from the noise source 106 to the seismic sensor 128. The time delay between the arrival time of the direct seismic wave 120 and the arrival time of the top and bottom sensors is relatively small. This difference in arrival time represents the propagation time and is used to calculate the seismic wave velocity of the direct seismic wave 120.

[0125] In some implementations, step 210 may further include inverting the arrival time, for example, using Snell's law (1D medium assumption) that takes into account the seismic wave propagation path or using propagation time tomography to obtain a 2D or 3D seismic wave velocity model around the target area 118. The inversion process can use procedural equations to numerically calculate the propagation time of the seismic wave front as it propagates through the medium at varying speeds. By iteratively updating the initial seismic wave velocity model, optimization techniques can be used to minimize the difference between the recorded arrival time and the predicted arrival time.

[0126] Although Figure 2 The steps (and the other steps mentioned above) are described in sequence, but it will be apparent to those skilled in the art that these steps can be reordered, performed concurrently with other steps, or performed multiple times.

[0127] Figure 3 A block diagram illustrating one implementation of a computing device 300 is shown, in which a set of instructions can be executed to cause the computing device to perform any or more of the methods discussed herein. In alternative implementations, the computing device may be connected (e.g., networked) to other machines in a local area network (LAN), intranet, extranet, or the Internet. The computing device may operate within the capabilities of a server or client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computing device may be a personal computer (PC), tablet computer, set-top box (STB), personal digital assistant (PDA), cellular phone, web device, server, network router, switch, or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) specifying the action to be taken by the machine. Furthermore, although only a single computing device is shown, the term "computing device" should also be considered as any collection of multiple machines (e.g., computers) that individually or jointly execute a set (or more) of instructions to perform any or more of the methods discussed herein.

[0128] Example computing device 300 includes a processor 302, main memory 304 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM), such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), static memory 306 (e.g., flash memory, static random access memory (SRAM), etc.), and auxiliary memory (e.g., data storage device 318), which communicate with each other via bus 330.

[0129] Processor 302 represents one or more general-purpose processors, such as microprocessors, central processing units, etc. More specifically, processor 302 may be a Complex Instruction Set Computing (CISC) microprocessor, a Reduced Instruction Set Computer (RISC) microprocessor, a Very Long Instruction Word (VLIW) microprocessor, a processor implementing other instruction sets, or a processor implementing combinations of instruction sets. Processor 302 may also be one or more special-purpose processors, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), network processors, etc. Processor 302 is configured to execute processing logic (instruction 322) to perform the operations and steps discussed herein.

[0130] The computing device 300 may also include a network interface device 308. The computing device 300 may also include a video display unit 310 (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device 312 (e.g., a keyboard or a touch screen), a cursor control device 314 (e.g., a mouse or a touch screen), and an audio device 316 (e.g., a speaker).

[0131] It is obvious that Figure 3 Some functions of the computer device 300 shown may be missing. For example, one or more computing devices 300 may not require a display device 310 (or any associated adapter). This is, for example, the case for a particular server-side computer device 300 that is only used for its processing power and does not need to display information to a user. Similarly, a user input device 312 may not be required. In its simplest form, the computer device 300 includes a processor 302 and a memory 304.

[0132] Data storage device 318 may include one or more machine-readable storage media (or more specifically, one or more non-transitory computer-readable storage media) 328 on which one or more sets of instructions 322 are stored, embodying any one or more methods or functions described herein. During the execution of instructions 322 by computer system 300, instructions 322 may also reside wholly or at least partially in main memory 304 and / or processor 302, which also constitute computer-readable storage media.

[0133] The various methods described above can be implemented by a computer program. A computer program may include computer code arranged to instruct a computer to perform one or more of the methods described above. The computer program and / or code for performing these methods may be provided to a device such as a computer on one or more computer-readable media, or more generally on a computer program product. The computer-readable media may be transient or non-transient. One or more computer-readable media may be, for example, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, or a propagation medium for data transmission, such as for downloading code via the Internet. Alternatively, one or more computer-readable media may take the form of one or more physical computer-readable media, such as semiconductor or solid-state memory, magnetic tape, removable computer disk, random access memory (RAM), read-only memory (ROM), rigid disk, and optical disk, such as CD-ROM, CD-R / W, or DVD.

[0134] In one implementation, the modules, components and other features described herein can be implemented as discrete components or integrated into the functionality of hardware components such as ASICs, FPGAs, DSPs or similar devices.

[0135] A "hardware component" is a tangible (e.g., non-transient) physical component (e.g., a group or one or more processors) capable of performing certain operations and which can be configured or arranged in some physical manner. A hardware component may include dedicated circuitry or logic permanently configured to perform certain operations. A hardware component may be or include dedicated processors, such as field-programmable gate arrays (FPGAs) or ASICs. A hardware component may also include programmable logic or circuitry that is temporarily configured by software to perform certain operations.

[0136] Therefore, the phrase “hardware component” should be understood to include tangible entities that can be physically constructed, permanently configured (e.g., hardwired) or temporarily configured (e.g., programmed) to operate or perform certain operations described herein.

[0137] Furthermore, modules and components can be implemented as firmware or functional circuitry within a hardware device. Additionally, modules and components can be implemented in any combination of hardware devices and software components, or solely in software (e.g., code stored or otherwise embodied in a machine-readable or transportable medium).

[0138] Unless otherwise expressly stated, it will be apparent from the following discussion that throughout the description, the use of terms such as “provide,” “calculate,” “update,” “generate,” “output,” “receive,” “process,” “execute,” “determine,” “select,” “compare,” and “identify” refers to the actions and processes of a computer system or similar electronic computing device that manipulate and convert data represented as physical (electronic) quantities in computer system registers and memories into other data similarly represented as physical quantities in computer system memory or registers or other such information storage, transmission, or display devices.

[0139] It should be understood that the above description is intended to be illustrative and not limiting. Many other implementations will become apparent to those skilled in the art upon reading and understanding the above description. While this disclosure has been described with reference to specific example implementations, it should be recognized that this disclosure is not limited to the described implementations, but can be modified and varied within the spirit and scope of the appended claims. Therefore, the specification and drawings should be considered illustrative rather than restrictive. Consequently, the scope of this disclosure should be determined by reference to the appended claims and the full scope of their equivalents.

[0140] While at least one exemplary embodiment has been given in the foregoing detailed description, it should be understood that numerous variations exist, some of which have only been mentioned above. It should also be understood that one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiments. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope of disclosure set forth in the appended claims and their legal equivalents.

Claims

1. A method for determining one or more land properties of a target area below a surface, the method comprising: Insert the seismic sensor into the target area below the surface; Generate noise signals; The noise source outputs noise at the surface or outputs noise incident on the surface based on the generated noise signal to generate seismic waves in the target area; Receive a response signal, the response signal indicating the generated seismic wave measured by the seismic sensor; and One or more land properties of the target area are determined based on the received response signals.

2. The method according to claim 1, wherein, The noise signal is generated using a pseudo-random binary sequence.

3. The method according to claim 2, wherein, The pseudo-random binary sequence is at least one of a maximum-length sequence, a Gold sequence, or a Kasami sequence.

4. The method according to any one of the preceding claims, wherein, The noise signal was generated using a random number generator.

5. The method according to any one of the preceding claims, wherein, The noise signal is output as a strength based on the average intensity of the ambient noise measured at the seismic sensor, a strength matching the average intensity of the ambient noise measured at the seismic sensor, or a strength equal to the average intensity of the ambient noise measured at the seismic sensor.

6. The method according to any one of the preceding claims, wherein, The noise signal is generated to contain frequency content within a specific frequency range of 30-200Hz.

7. The method according to any one of claims 1 to 5, wherein, The noise signal is generated to contain frequency content within a specific frequency range of 30-1000Hz.

8. The method according to any one of the preceding claims, wherein, The seismic sensor includes at least two vertically offset seismic sensor elements.

9. The method according to any one of the preceding claims, wherein, The noise source is a vibration noise source, such as a loudspeaker.

10. The method according to any one of the preceding claims, wherein, The noise source is connected to at least one of the following: The structure on the surface; and The vehicle on the surface, such as a truck or tracked vehicle.

11. The method according to any one of the preceding claims, wherein, The surface is the surface of a bed of water.

12. The method according to claim 11, wherein, The noise source is connected to one of the following: The structure of the bed in the water body; and Vehicles on or in the water, such as ships, USVs, or ROVs.

13. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of the preceding claims.

14. A system comprising: One or more processors; One or more processors having computer-readable instructions stored thereon, the computer-readable instructions being configured to cause the one or more processors to perform operations including the steps of any one of claims 1 to 12.

15. A computer-readable medium comprising instructions that, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 12.

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