Microseismic data denoising using a 3C group sparsity constrained time-frequency transform
Bibliographic record
Abstract
ABSTRACT Noise contamination is an important problem in microseismic data processing, due to the low magnitude of the seismic events induced during fluid injection. In this study, a noncoherent noise attenuation technique based on a constrained time-frequency transform is presented. When applied to 1C data, the transform corresponds to a sparse representation of the microseismic signal in terms of a dictionary of complex Ricker wavelets. The use of complex wavelets possesses the advantage that signals with arbitrary phase can be represented with enhanced sparsity. A synthetic example illustrates the superior performance of the sparse constraint for denoising objectives when compared to the standard least-squares regularization. As the arrival time and frequency content of any wavefront are equivalent in the three components of a single receiver, the extension of the sparse transform to 3C data is accomplished when the three components are considered to share the same sparsity pattern in the time-frequency plane. Application of the 3C sparse transform to synthetic and real microseismic data sets demonstrate the advantages of this technique when the denoised results are compared against the original and low-pass filtered version of the noisy data. Furthermore, a comparison of hodograms between original, low-pass, and denoised traces shows that the denoising process preserves the phase and relative amplitude information present in the input data. The benefits of the 3C transform are highlighted particularly in cases where the wave arrivals are measured in the three components of a receiver but are only visible in two components due to the prevailing signal-to-noise ratio.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".