Geophysics Seismic Survey Service -
Data Processing, Recording, Test

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Overview

A seismic survey is a method used to explore and map the subsurface of the Earth. The primary purpose of a seismic survey is to locate and assess the size and shape of potential hydrocarbon (oil and gas) reservoirs, but it can also be used to explore for other types of subsurface resources, such as mineral deposits, and to study the geology of the Earth’s crust.

Seismic surveys use a combination of geophysics and geology to create images of the subsurface. The primary tool used in a seismic survey is a seismic source, which generates a controlled impulse of energy, typically in the form of a loud noise or a vibration. This energy travels through the Earth and is reflected back to the surface by different subsurface layers, such as rock formations or underground reservoirs. The reflections are detected by a series of sensors, called geophones or hydrophones, which are placed on the surface or in boreholes.

The data collected by the geophones or hydrophones is processed and analyzed to create a subsurface image, which can be used to identify potential drilling locations, to determine the size and shape of subsurface reservoirs, and to study the geology of the Earth’s crust. Seismic survey can be done with both land and marine (also called Ocean Bottom Seismic) way. The survey method used land typically involves setting up a grid of geophones on the surface and then shooting seismic energy into the ground using trucks or other vehicles equipped with a vibrator or an air gun. Marine seismic survey involves using a vessel to tow a hydrophone array behind it and using explosive or air guns as a seismic source. Overall, seismic surveys are a powerful tool for exploring and mapping the subsurface of the Earth, but they can also have environmental impacts, such as noise pollution and disruption of marine life, so careful planning and regulations are necessary.
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Types Of Seismic Survey Exploration

Seismic exploration refers to the different dimensions of data that are collected and the resulting subsurface images that are created during a seismic survey. There are three types of seismic surveys we provide, they are;

1D Seismic Exploration

Also known as vertical seismic profiling (VSP), involves collecting data along a single vertical line, typically by using a borehole or a geophone placed at a single location. This type of survey provides a detailed image of the subsurface at a specific location and is used to study the geology and fluid content of a particular subsurface formation.

2D Seismic Exploration

Involves collecting data along a single line, or a series of closely spaced lines, across an area of interest. The data collected is used to create a cross-sectional image of the subsurface, showing the different layers of rock and other subsurface features that the seismic energy encountered as it passed through the Earth. This type of survey is used to understand the geology and structural geology of an area, such as fault and fold patterns, and also used in hydrocarbon exploration and production.

3D Seismic Exploration

Is the most advanced and data-intensive type of seismic survey, it involves collecting data over a much larger area, typically a grid of many closely spaced lines. The data is then used to create a three-dimensional image of the subsurface, providing a much more detailed and accurate view of the subsurface geology and the location of subsurface features such as hydrocarbon reservoirs. This type of survey is used for detailed reservoir characterization, such as to detect subtle changes in rock properties or fluid content that may indicate the presence of hydrocarbons or other subsurface resources.

1D, 2D, and 3D seismic exploration, in terms of the increasing dimensionality of data and images, have increasing cost and complexity, but also have increasing resolution, detail, and accuracy. The choice of which survey to use depends on the specific exploration or research goals and the geology of the area being studied.

 

Different Types Of Seismic Methods

There are several different types of seismic surveys, each with their own unique characteristics and applications.
Some of the main types of seismic surveys include:

Refraction Seismic Surveys

This type of seismic survey is used to measure the refraction, or bending, of seismic energy as it travels through the Earth. It is used to determine the velocity of subsurface materials and to create a less detailed subsurface image compared to reflection seismic.

Reflection Seismic Surveys

This is the most common type of seismic survey and is used to create images of the subsurface by measuring the reflection of seismic energy from subsurface rock formations and other subsurface features. It is divided into two main categories: 2D and 3D

Surface - Wave Seismic Surveys

Also known as surface-wave analysis or surface-wave testing, is a type of passive seismic survey that is used to study the shallow subsurface. The main principle is to measure the ground motion caused by surface waves, which are a type of seismic wave that travels along the surface of the Earth. These waves can be generated naturally by earthquakes, wind, or ocean waves, or they can be artificially generated by mechanical or vibroseis sources

Each of these different types of seismic surveys has its own strengths and weaknesses, and the choice of which survey to use depends on the specific exploration or research goals and the geology of the area being studied.

 

What Is The Application And
Benefits Of The Seismic Survey Method?

Seismic survey methods are used for a wide range of applications and have many benefits.
Some of the main applications and benefits of seismic surveys include:

The primary application of seismic surveys is to locate and assess the size and shape of potential hydrocarbon (oil and gas) reservoirs. Seismic data can be used to identify subsurface structures that are likely to contain hydrocarbons, to estimate the size and shape of the reservoirs, and to identify the most promising drilling locations.

 

Seismic surveys can also be used to explore for other types of subsurface resources, such as mineral deposits. The data can be used to identify subsurface structures that are likely to contain valuable minerals and to estimate the size and shape of the deposits.

 

Seismic surveys can be used to study the geology of the Earth’s crust and to map subsurface soil and rock layers. This information can be used to predict site effects such as soil liquefaction and lateral spreading and to study the properties of the shallow subsurface such as ground water, soil and rock properties.

 

Seismic surveys can also be used to map subsurface hazards such as sinkholes, buried mines, and other potential hazards.

 

Seismic survey is a non-destructive method of exploring the subsurface. It does not require drilling, excavation or other invasive procedures, which can cause damage to the environment and to surface structures.

 

Seismic survey can be a cost-effective way to explore the subsurface. It can be used to target drilling locations more accurately, which can help to reduce the number of dry wells and the overall cost of exploration.

 

Seismic survey can provide high-resolution images of the subsurface, which can be used to make more accurate exploration and production decisions.

 

Seismic survey can be completed in a relatively short time-frame, which allows for quick results to be obtained and for exploration to progress quickly.

 

Seismic survey can be conducted on land and offshore in both shallow and deep water environments.

 

In summary, Seismic survey methods are versatile, non-destructive, cost-effective, high-resolution and time-efficient tools that can be used to explore the subsurface of the earth for hydrocarbons and other resources, and to study the geology of the Earth’s crust.

How Many Types Of Seismic Instruments Are There?

There are several different types of seismic instruments that are used in a seismic survey, each with their own unique characteristics and applications.
Some of the main types of seismic instruments we use are;

Active Seismic Instruments

Use an energy source, such as a vibrator or an air gun, to introduce energy into the subsurface. This energy travels through the Earth and is reflected back to the surface by subsurface layers, such as rock formations or underground reservoirs. The reflections are detected by sensors, such as geophones or hydrophones, which are placed on the surface or in boreholes. Active seismic instruments are typically used in reflection seismic surveys, which are the most common type of seismic survey and are used to create images of the subsurface by measuring the reflection of seismic energy.

Passive Seismic Instruments

On the other hand, rely on natural sources of energy, such as earthquakes or ocean waves, to introduce energy into the subsurface. These instruments detect the ground motion caused by the seismic waves as they travel through the Earth. Passive seismic instruments are typically used in microtremor surveys, surface-wave seismic surveys, and passive seismic tomography. These types of survey can be used to study the shallow subsurface geology, near-surface soil properties and site effects such as soil liquefaction and lateral spreading.

Active seismic surveys are generally more expensive and time-consuming to acquire compared to passive seismic surveys. The main advantage of passive seismic surveys is that they can be conducted continuously, providing long-term monitoring of subsurface properties, and also are less invasive and less likely to have an environmental impact.

Active seismic surveys, however, provide more detailed images of the subsurface, which can be used to make more accurate exploration and production decisions. The choice of which method to use depends on the specific exploration or research goals and the geology of the area being studied.

 

What Are The 4 Types Of Seismic Waves?

P-waves (Primary Waves)

P-waves are the fastest type of seismic wave and are the first to arrive at a seismic station. They travel through the Earth by pushing and pulling the ground in the same direction as the wave is moving. P-waves can travel through solids, liquids, and gases and are the most common type of seismic wave used in exploration seismology.

S-Waves (Secondary Waves)

S-waves are slower than P-waves and arrive at a seismic station after P-waves. They travel through the Earth by shaking the ground up and down and at right angles to the direction of the wave. S-waves can only travel through solid materials and are used to study the deeper structure of the Earth.

Rayleigh Waves

Rayleigh waves are surface waves that travel along the surface of the Earth. They are caused by the combination of P and S waves and move the ground in an elliptical motion, which causes the ground to rise and fall, and move from side to side. Rayleigh waves are responsible for most of the ground motion that is felt during an earthquake.

Love Waves

Love waves are also surface waves but unlike Rayleigh waves, which move the ground in an elliptical motion, Love waves move the ground horizontally. They can be more destructive than Rayleigh waves because they can cause strong shaking and ground displacement in the direction perpendicular to the direction of the wave propagation.

Each of these seismic waves has its own characteristics, such as speed, direction of motion, and type of material they can travel through. Seismic waves travel through different layers of the Earth with different velocities and are reflected, refracted and scattered by the different rock layers. The study of seismic waves is crucial in understanding the Earth’s structure, composition and the tectonics.

FAQs

Seismic surveys are an important tool for subsurface exploration and are commonly used in the search for oil, gas, and other minerals. Seismic surveys are necessary for exploration because they provide detailed images of the subsurface structure and can help identify the location and characteristics of subsurface rock formations that may contain these resources. Some of the reasons why seismic surveys are necessary for exploration include: High Resolution: Seismic surveys can provide high-resolution images of the subsurface, which can be used to make more accurate decisions about the location of resources and the design of drilling and production operations. Depth Penetration: Seismic surveys can penetrate to depths of several kilometers, making them useful for exploring the deeper subsurface where many resources are found. Identify Structure: Seismic surveys can help identify the structure and composition of subsurface rock formations, including rock layers, faults and folds, which are often associated with oil, gas and mineral deposits. Time-efficient : Seismic surveys are relatively fast and efficient means of exploring large areas of the subsurface in a short period of time, comparing to the drilling and excavation which are more expensive and time-consuming methods. Non-destructive: Seismic surveys are a non-destructive method of exploration, which means that they do not involve drilling or excavation, and do not cause significant damage to the environment or surface structures. Cost-effective : Seismic surveys are relatively cost-effective compared to drilling and excavation, making them a useful tool for exploration in areas where resources are difficult or expensive to access. In summary, seismic surveys are an essential tool for subsurface exploration because they provide detailed images of the subsurface structure, can be used to identify the location and characteristics of subsurface rock formations that may contain resources, and can be done in a relatively short period of time and at a lower cost than other exploration methods, such as drilling and excavation.
The primary difference between 2D and 3D seismic surveys is the amount of data that is collected and the resulting subsurface image that is created. 2D seismic surveys typically involve acquiring data along a single line, or a series of closely spaced lines, across an area of interest. The data collected is then used to create a cross-sectional image of the subsurface, showing the different layers of rock and other subsurface features that the seismic energy encountered as it passed through the Earth. 2D seismic surveys are generally less expensive and quicker to acquire compared to 3D, but they provide less detailed subsurface information. On the other hand, 3D seismic surveys involve acquiring data over a much larger area, typically a grid of many closely spaced lines. The data is then used to create a three-dimensional image of the subsurface, providing a much more detailed and accurate view of the subsurface geology and the location of subsurface features such as hydrocarbon reservoirs. 3D seismic surveys are generally more expensive and time-consuming to acquire compared to 2D, but they provide much more detailed subsurface information that can be used to make more accurate exploration and production decisions. Another difference is that 2D seismic data is mainly used for understanding geology and structural geology of a particular area, such as fault and fold patterns, whereas 3D seismic data is usually used for more detailed reservoir characterization, such as to detect subtle changes in rock properties or fluid content that may indicate the presence of hydrocarbons or other subsurface resources. In summary 2D seismic survey provide a cross-sectional image of the subsurface which is mainly used for structural mapping and understanding geology. 3D seismic survey provide a three-dimensional image of the subsurface which is mainly used for more detailed reservoir characterization and exploration of subsurface resources.
Seismic surveys are used in a wide range of industries, some of the main industries that use seismic surveys include: Oil and Gas: Seismic surveys are an important tool in the oil and gas industry, they are used to identify and map subsurface rock formations that may contain hydrocarbons. Seismic data is used to determine the location, size and character of potential oil and gas reservoirs, and to design drilling and production operations. Mining: Seismic surveys are used in the mining industry to locate and map subsurface mineral deposits such as gold, silver, copper, and other valuable minerals. They are also used to map subsurface geology in order to design open-pit and underground mining operations. Civil Engineering and construction: Seismic surveys are used to study the subsurface structure and soil properties for foundation design, slope stability, landslide hazard mapping, and mapping of soil liquefaction and lateral spreading hazards. Environmental studies: Seismic surveys can be used to study the shallow subsurface and detect potential subsurface hazards such as contaminated areas, buried waste, and other potential environmental problems. Geothermal Energy: Seismic surveys are used to explore geothermal resources by mapping subsurface structure and identifying areas where hot water or steam is likely to be present. Hydrogeology: Seismic surveys can be used to study near-surface aquifer properties, such as the depth, thickness, and continuity of aquifers, which are useful for groundwater management and sustainable water supply planning. Water resources: Seismic surveys can be used to study shallow subsurface structure and identify areas of potential groundwater, surface water, and groundwater recharge. Archeology and cultural heritage: Seismic surveys can be used to locate and study shallow buried archaeological features, such as buried ruins, artifacts, and other cultural resources. These are some of the main industries that use seismic surveys, but Seismic surveys are also used in many other industries and applications, such as natural hazards research and infrastructure planning.
Seismic surveys can provide very detailed images of the subsurface, but the accuracy of these images depends on several factors, including: Quality of Data: The accuracy of the seismic data is affected by the quality of the data acquisition and processing techniques. Factors such as the number of sensors used, the spacing between sensors, and the amount of noise in the data can all affect the accuracy of the seismic data. Surface topography: Surface topography, vegetation, and other surface features can cause errors in the seismic data, particularly when interpreting shallow depths. Complex geology: Seismic data can be more difficult to interpret in areas with complex geology, such as areas with a lot of faults, folds, or other structural features. Inversion methods: The final interpretation of seismic data is the result of various inversion methods that are applied to seismic data and the choice of the method can affect the accuracy of the final interpretation. Resolution: The resolution of the seismic data is limited by the wavelength of the seismic energy and the density of the sensor array. Generally, the resolution decreases with depth, and the resolution is higher in shallow depths than in deeper ones. With that said, seismic surveys are still considered one of the most accurate and reliable methods for subsurface imaging, and advances in technology and processing techniques have made them even more accurate over time. Additionally, it is important to note that interpretation of seismic data requires good understanding and experience with seismic data processing and interpretation. By combining different types of geophysical methods, more accurate and detailed information can be obtained.