Seismic solutions utilizing existing in-mine infrastructure for mineral exploration: A case study from Maseve platinum mine, South Africa

2022 ◽  
Vol 41 (1) ◽  
pp. 54-61
Author(s):  
Moyagabo K. Rapetsoa ◽  
Musa S. D. Manzi ◽  
Mpofana Sihoyiya ◽  
Michael Westgate ◽  
Phumlani Kubeka ◽  
...  
Keyword(s):  
South Africa ◽  
Seismic Data ◽  
Mineral Exploration ◽  
Ground Surface ◽  
Seismic Survey ◽  
Noisy Environment ◽  
Borehole Data ◽  
Passive Seismic ◽  
Below Ground

We demonstrate the application of seismic methods using in-mine infrastructure such as exploration tunnels to image platinum deposits and geologic structures using different acquisition configurations. In 2020, seismic experiments were conducted underground at the Maseve platinum mine in the Bushveld Complex of South Africa. These seismic experiments were part of the Advanced Orebody Knowledge project titled “Developing technologies that will be used to obtain information ahead of the mine face.” In these experiments, we recorded active and passive seismic data using surface nodal arrays and an in-mine seismic land streamer. We focus on analyzing only the in-mine active seismic portion of the survey. The tunnel seismic survey consisted of seven 2D profiles in exploration tunnels, located approximately 550 m below ground surface and a few meters above known platinum deposits. A careful data-processing approach was adopted to enhance high-quality reflections and suppress infrastructure-generated noise. Despite challenges presented by the in-mine noisy environment, we successfully imaged the platinum deposits with the aid of borehole data and geologic models. The results open opportunities to adapt surface-based geophysical instruments to address challenging in-mine environments for mineral exploration.

Passive Seismic Marchenko Imaging

2020 ◽  
Author(s):  
Zhongyuan Jin
Keyword(s):  
Free Surface ◽  
Seismic Data ◽  
Low Cost ◽  
Body Waves ◽  
Seismic Survey ◽  
Significant Difference ◽  
Passive Seismic ◽  
Seismic Acquisition ◽  
Imaging Property ◽  
Internal Multiples

<p>In recent years, seismic interferometry (SI) has been widely used in passive seismic data, it allows to retrieve new seismic responses among physical receivers by cross-correlation or multidimensional deconvolution (MDD). Retrieval of reflected body waves from passive seismic data has been proved to be feasible. Marchenko method, as a new technique, retrieves Green’s functions directly inside the medium without any physical receiver there. Marchenko method retrieves precise Green’s functions and the up-going and down-going Green’s functions can be used in target-oriented Marchenko imaging, and internal multiples related artifacts in Marchenko image can be suppressed. </p><p>Conventional Marchenko imaging uses active seismic data, in this abstract, we propose the method of passive seismic Marchenko imaging (PSMI) which retrieves Green’s functions from ambient noise signal. PSMI employs MDD method to obtain the reflection response without free-surface interaction as an input for Marchenko algorithm, such that free-surface multiples in the retrieved shot gathers can be eliminated, besides, internal multiples don’t contribute to final Marchenko image, which means both free-surface multiples and internal multiples have been taken into account. Although the retrieved shot gathers are contaminated by noises, the up-going and down-going Green’s functions can be still retrieved. Results of numerical tests validate PSMI’s feasibility and robustness. PSMI provides a new way to image the subsurface structure, it combines the low-cost property of passive seismic acquisition and target-oriented imaging property of Marchenko imaging, as well as the advantage that there are no artifacts caused by internal multiples and free-surface multiples.</p><p>Overall, the significant difference between PSMI and conventional Marchenko imaging is that passive seismic data is used into Marchenko scheme, which extends the Marchenko imaging to passive seismic field. Passive seismic Marchenko imaging avoids the effects of free-surface multiples and internal multiples in the retrieved shot gathers. PSMI combines the low-cost property of passive seismic acquisition and target-oriented imaging property of Marchenko imaging which is promising in future field seismic survey.</p><p>This work is supported by the Fundamental Research Funds for the Central Universities (JKY201901-03). </p>

Long Beach 3D Seismic Survey: Data Mining Continuous Passive Seismic Data

2013 ◽  
Author(s):  
D. Hollis ◽  
C. Cox ◽  
R. Clayton ◽  
F. Lin ◽  
D. Li ◽  
...  
Keyword(s):  
Data Mining ◽  
Survey Data ◽  
Seismic Data ◽  
Seismic Survey ◽  
3D Seismic ◽  
Long Beach ◽  
Passive Seismic

Quantifying subresolution saturation scales from time‐lapse seismic data: A reservoir monitoring case study

Geophysics ◽  
2003 ◽  
Vol 68 (3) ◽  
pp. 803-814 ◽  
Author(s):  
Madhumita Sengupta ◽  
Gary Mavko ◽  
Tapan Mukerji
Keyword(s):  
Seismic Response ◽  
Seismic Data ◽  
Flow Simulation ◽  
Time Lapse ◽  
Seismic Survey ◽  
Spatial Frequencies ◽  
Reservoir Monitoring ◽  
Offset Time ◽  
Flow Simulator

The goal of this paper is to interpret and analyze time‐lapse seismic data quantitatively to better understand subsurface fluid saturations and saturation scales. We present a case study of a time‐lapse seismic survey. Water and gas were injected into an oil‐producing reservoir, and repeat seismic surveys were collected to monitor the subsurface fluids over a period of 14 years. In this study, we show that the subresolution spatial distribution of fluids, not captured by traditional flow simulators can impact the seismic response. Although there is a good qualitative match between the fluid changes predicted by the flow simulator and the fluid changes interpreted from the seismic data, the simulator predicts smooth saturation profiles that do not quantitatively match the time‐lapse seismic changes. We find that downscaling smooth saturation outputs from the flow simulator to a more realistic patchy distribution is required to provide a good quantitative match with the near‐ and far‐offset time‐lapse data, even though the fine details in the saturation distribution are below seismic resolution. We downscaled the smooth saturations from the simulator by incorporating high spatial frequencies from well logs and constraining the saturations to the total mass balance predicted by the flow simulator. The computed seismic response of the downscaled saturation distributions matched the real time‐lapse seismic data much better than the saturation distributions taken directly from the simulator. This study demonstrates the feasibility of using seismic and well‐log data to constrain subblock saturation scales, unobtainable from flow simulation alone. This important result has the potential to significantly impact and enhance the applicability of seismic data in reservoir monitoring.

Reprocessing of legacy seismic data for gold exploration: case study from Witwatersrand goldfields, South Africa

2021 ◽  
Author(s):  
N. Mutshafa ◽  
M. Manzi ◽  
M. Westgate ◽  
I. James ◽  
R. Durrheim ◽  
...  
Keyword(s):  
South Africa ◽  
Seismic Data ◽  
Gold Exploration

Integrated shale-gas reservoir characterization: A case study incorporating multicomponent seismic data

2018 ◽  
Vol 6 (2) ◽  
pp. SE23-SE37
Author(s):  
Laurie M. Weston Bellman
Keyword(s):  
Seismic Data ◽  
Reservoir Characterization ◽  
Data Interpretation ◽  
Seismic Profile ◽  
Gas Production ◽  
Seismic Survey ◽  
Reservoir Properties ◽  
Converted Wave ◽  
Multistage Hydraulic Fracturing

The objective of this case study is to predict geologic properties of a shale reservoir interval to guide production and completion planning for successful development of the reservoir. The conditioning, analysis, and blending of the converted-wave (PS) seismic data into a quantitative interpretation (QI) workflow are described in detail, illustrating the successful integration of geologic information and multiple seismic attributes. A multicomponent 3D seismic survey, several wells with dipole sonic logs, and a multicomponent (3C) 3D vertical seismic profile are available for the study. For comparisons of the incremental value of PS data, the QI workflow is completed entirely using only PP data and then modified and redone to incorporate information from the PS data. Predictions of the geologic properties for both workflows are assessed for accuracy against the existing well log and core evidence. Determining reservoir properties of the shale units of interest is important to the successful placement of horizontal wells for efficient multistage hydraulic fracturing and maximum gas production. Although conventional interpretation of conventional seismic data can only provide reservoir geometry, the quantitative analysis of prestack multicomponent data in this study reveals detailed distinctions between reservoir units and relative measures of porosity and brittleness bulk properties within each unit. Using all of the elastic properties derived from the seismic data analysis allowed for the classification of lithological units, which were, in turn, subclassified based on unit-specific reservoir properties. The upper reservoir units (Muskwa and Otter Park) were shown to have more variability in brittleness than the lower reservoir unit (Evie). Validation at a reliable well control confirmed these distinctive units and properties to be very high resolution and accurate, particularly when the PS data were incorporated into the workflow. The results of this method of analysis provided significantly more useful information for appraisal and development decisions than conventional seismic data interpretation alone.

Investigation and Remediation of Groundwater Contamination at a Pesticide Facility — a Case Study

1995 ◽  
Vol 30 (3) ◽  
pp. 469-492 ◽  
Author(s):  
R.S. Carter ◽  
W.H. Stiebel ◽  
P.J. Nalasco ◽  
D.L. Pardieck
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Ground Surface ◽  
Pump And Treat ◽  
Volatile Organic ◽  
Hydraulic Gradients ◽  
Below Ground ◽  
Process Wastewater ◽  
Bedrock Aquifer

Abstract Soil and groundwater beneath a 22-year old agrichemical formulating and warehousing facility in Cambridge, Ontario, have been impacted with pesticides in addition to volatile organic and nitrosoamine compounds associated with their formulation. Thirty-three compounds, including 15 pesticides released to the soil from an underground process wastewater system, concrete-lined pits, storage areas and infrequent spills, are present in the water table at a depth of 10 m in overburden sediments. Groundwater flow in the overburden is complex and dissolved compound migration is influenced by spatially variable vertical hydraulic gradients induced from the underlying dolostone aquifer which is pumped by municipal supply wells located at distances ranging from 600 m to 1500 m from the site. One pesticide, metolachlor(2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-melhylethyl) acetamide), has been measured consistently above Ontario drinking water objectives in the overburden and at a depth of 30 to 39 m below ground surface in the bedrock aquifer adjacent to the site. A groundwater pump and treat system is operating and is controlling further off-site migration of dissolved compounds in the overburden, and treating the captured groundwater with granular activated carbon.

Cooperative inversion of gravity and seismic data with different spatial coverage

2020 ◽  
Author(s):  
mahtab Rashidifard ◽  
Jérémie Giraud ◽  
Vitaliy Ogarko ◽  
Mark Lindsay ◽  
Mark Jessell
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Degree Of Freedom ◽  
Seismic Survey ◽  
Small Scale ◽  
Gravity Inversion ◽  
Spatial Coverage ◽  
Cooperative Inversion

<p>Combining two or more geophysical datasets with different resolutions and characteristics is now a common practice to recover one or more physical properties. Building 3D geological models for mineral exploration targeting is often an expensive task even for inversion of a single dataset, because of extremely complicated structures with small scale targets. In this context, seismic methods, among all other traditional techniques in mineral exploration, are receiving increasing attention due to their higher resolution in depth. With more limited spatial coverage and higher resolution, they are usually used to refine the interpretation of potential field data.</p><p>As each seismic survey is designed for a particular intention with specific targets and may not be available in all regions of interests, we develop an iterative cooperative inversion algorithm for inverting gravity and seismic travel-time data. This enables the utilization of localized high-resolution seismic data in a larger full 3D volume which is covered by gravity data. Geological information in the form of probabilistic geological modelling is used to extend information away from the high-resolution data and constrain the inversion result. We use these data as the prior model and to derive constraints incorporated into the objective function of gravity inversion. This allows us to obtain information about the probability of the presence of lithologies associated with the formation of mineral systems. To ensure structural consistency between density and velocity we develop a geologically constrained structure-based coupling technique following the same principle as the cross-gradient technique but with a higher degree of freedom in spatial directions. We apply local structure-based constraints conditioned by a geological probability distribution, which is considering direction and magnitude and provide a higher degree of freedom for model variations. An investigation of the proposed methodology and a proof-of-concept using realistic synthetic data are presented. Our results reveal that the methodology has the potential to constrain the gravity inversion results using the limited seismic data.</p>

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