Acquiring 3D seismic data for coal mining exploration in China

15th Feb, 2023
Project snapshot

Project snapshot

Client name: Shanxi Coalfield Geophysical Survey Company

Survey location: Luliang, Shanxi Province, China

Survey terrain: Loess, mountains, farmland, and villages

Survey size: 7km2

Application acquired for: Coal mining


Project goals

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  • Detect and characterise other structures relevant to mine planning, such as folds with amplitudes exceeding 10 m
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  • Map the main coal seam subcrop with a depth uncertainty of less than 30m
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  • Investigate whether faults in the main coal seam with throws exceeding 5 m can be interpreted accurately
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  • Understand the thickness and velocity variation of the shallow low-velocity zone in the overburden
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  • Identify the occurrence and thickness variation of minable coal seams in the exploration area
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  • Precisely delimit the extent of coal free zones in the exploration area
How we helped

What we supplied

The STRYDE Nimble system was used for this project. Two Nest Cases were supplied, enabling 180 Nodes to be charged and harvested simultaneously. A total of 6,000 STRYDE Nodes™ were used on the project.

Field equipment for efficient stakeless Node deployment and retrieval was also supplied: the STRYDE Navigator Tablet and App for field positioning; Initialisation Devices for starting and stopping data acquisition; and ergonomic Backpacks for easy transportation of Nodes and peripherals by foot.

What we supplied

Survey snapshot

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Survey type

3D

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Number of nodes deployed during the survey

6,000 STRYDE Nodes™

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Seismic crew size

24 crew members

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Source used

Vibroseis and dynamite

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Line and receiver point spacing

40 m receiver line spacing, 10 m receiver point spacing; 60 m source line spacing, 10 m source point spacing Production operating times: 24 hour vibroseis operations. Dynamite source points were only acquired during daytime

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Production operating times

24 hour vibroseis operations. Dynamite source points were only acquired during daytime

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Number of nodes deployed per day

870 nodes were deployed each day by 8 teams, consisting of 3 people per team

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Total duration of the acquisition

16 days


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Node charge and harvesting crew size

Only 2 people were required to perform all charging and data harvesting operations for the 6,000 STRYDE Nodes™ used in the survey

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Vehicles required to roll spread per day

4 pickup trucks

“We chose STRYDE due to the data quality that was able to be acquired from a lightweight, simple, and low-cost wireless system. Compared with other nodal systems, the STRYDE system is much lower priced and its impact on operational efficiency is higher, and this is even more magnified when compared to wired geophone systems! We look forward to using STRYDE again soon.”

Zeng Qing Cheng, Project Director and Chief Geophysicist at Shanxi Coal
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Survey planning

Challenges experienced during survey planning

Terrain

The survey area is covered by Quaternary loess deposits, causing large lateral variations in surface and near-surface properties. Recorded signal quality and amplitude/frequency character in conventional surveys can vary significantly between adjacent traces due to differences in source and receiver coupling, amplification effects and the presence of low-velocity layers. Acquisition of high-resolution seismic data is required to adequately sample such effects and generate high quality interpretable images of the subsurface.

Known goaf

There is goaf in part of the survey area, which was expected to negatively impact the quality of reflection data in that area. It was therefore critical to densify the survey in and around the goaf to improve the spatial sampling of the wavefield and output image quality.

Land access and permitting

The survey design was constrained by exclusion zones in and around local villages and needed to satisfy local government permitting requirements.

Weather windows

The project was conducted in mountainous terrain. Acquisition had to be completed before seasonal snow falls commenced, as seismic operations could not be conducted safely with snow and ice in the survey area. Hazards such as landslides and mud flows can occur during thaws and present a serious risk to personnel and equipment, so no seismic production is possible during such periods either.

Seismic acquisition

Benefits and how STRYDE helped overcome these challenges 

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Reduced project timeline

The node’s compact weight and size, combined with stakeless operations using STRYDE’s state-of-the-art Navigator Tablet and App, enabled extremely efficient node deployment and retrieval operations and allowed the overall project timeline to be accelerated, even in challenging terrain.

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Reduced operational costs  and equipment

The STRYDE system has transformed the price point of land seismic equipment relative to the cost of conventional seismic instruments. Furthermore, the ability to deploy the miniature nodes quickly meant planning, preparation, and logistical overheads were greatly reduced, unlocking further cost savings and efficiency gains.  

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Portability in a challenging environment

Being able to carry hundreds of nodes by foot, and thousands in small pickup trucks meant logistical requirements for the project were significantly reduced, reducing exposure to HSE risk and enabling the team to deploy and retrieve Nodes quickly and safely in mountainous areas.

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Exceptional data quality

Dense point-sensor acquisition with STRYDE’s piezoelectric accelerometer sensor resulted in high quality, high fold data, with rich high-frequency content.

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Rapid access to seismic equipment

Providing access to STRYDE’s seismic sensors within 1 week of project approval ensured the team was able to align the project with the mine’s operational plan and exceeded expectations about the survey timeline.

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Speedy onboarding and start-up  

The simplicity of the STRYDE system means that it is extremely easy to use and is even accessible to people with no previous seismic experience. The team required only a couple of hours of training to onboard them to the system prior to deployment operations commencing. This allowed the team to start up efficiently and effectively, with minimal operator deployment and retrieval errors.  

Survey outputs

Data deliverables

Data deliverables

Raw seismic data required to process into 3D images for data interpretation and reporting.
Seismic trace count

Seismic trace count

About 336,000,000.00 traces of data was acquired