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Collaborating Authors
Jaiswal, Priyank
Abstract In earth science, integrating noninvasive continuous data streams with discrete invasive measurements remains an open challenge. We address such a problem — that of predicting whole-core mineralogy using discrete measurements with the help of machine learning. Our targets are sparsely sampled mineralogy from X-ray diffraction, and features are continually sampled elemental oxides from X-ray fluorescence. Both data sets are acquired on a core cut from a Mississippian-age mixed siliciclastic-carbonate formation in the U.S. midcontinent. The novelty lies in predicting multiple classes of output targets from input features in a small multidimensional data setting. Our workflow has three salient aspects. First, it shows how single-output models are more effective in relating selective target-feature subsets than using a multi-output model for simultaneously relating the entire target-feature set. Specifically, we adopt a competitive ensemble strategy comprising three classes of regression algorithms — elastic net (linear regression), XGBoost (tree-based), and feedforward neural networks (nonlinear regression). Second, it shows that feature selection and engineering, when done using statistical relationships within the data set and domain knowledge, can significantly improve target predictability. Third, it incorporates k-fold cross-validation and grid-search-based parameter tuning to predict targets within 4%–6% accuracy using 40% training data. Results open doors to generating a wealth of information in energy, environmental, and climate sciences where remotely sensed data are inexpensive and abundant but physical sampling may be limited due to analytic, logistic, or economic issues.
- Geology > Mineral > Silicate (1.00)
- Geology > Geological Subdiscipline > Geomechanics (0.93)
- Geology > Geological Subdiscipline > Mineralogy (0.92)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.46)
- North America > United States > West Virginia > Appalachian Basin > Marcellus Shale Formation (0.99)
- North America > United States > Virginia > Appalachian Basin > Marcellus Shale Formation (0.99)
- North America > United States > Texas > Meramec Formation > Meramec Formation > Mississippi Chat > Mississippi Lime > St. Louis Formation (0.99)
- (33 more...)
ABSTRACT Denoising becomes a nontrivial task when the noise and signal overlap in multiple domains, such as time, frequency, and velocity. Fortunately, signal and noise waveforms, in general, tend to remain morphologically different and such differences can be used to separate body-wave signals from other waveforms such as ground roll and cultural noise. The key in denoising using a near-source wavelet is to find a wavelet that is a close approximation of the true source signature and remains uncontaminated by the Green’s function in any significant manner. An inverse filter designed using such a wavelet selectively compresses the body waves that can be extracted using median and low-pass filters. The overall phenomenon is explained with a synthetic example. The idea is also tested on a land data set generated using a large weight-drop source in which the wavelet recorded approximately 3 m from the source location fulfills the criteria set in our method. The results suggest that the incremental effort of recording an extra trace close to the source location during acquisition may provide previously unavailable denoising opportunities during processing, although the trace itself may be redundant for imaging.
- Information Technology > Data Science (0.94)
- Information Technology > Artificial Intelligence (0.71)
We show how clay diagenesis influences the mechanistic behavior of a rock different under saturated and dry conditions. We found that saturated and dry elastic velocities of samples from the Meramec formation, Oklahoma, could be related to their known porosity and composition through a common rock physics model only if clay and quartz were considered structural in dry and partly disseminated in saturated conditions. In-situ smectite-to-illite transformation can explain the observations in that it creates products at pore linings that remain loosely connected with the matrix behaving like a suspension in saturated condition but coalesce with the matrix as the system dehydrates during the desiccation process. The novelty of this study is using rock physics to understand a process rather than the end product.
- Geology > Mineral > Silicate > Phyllosilicate (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying (0.69)
- North America > United States > Texas > Anadarko Basin (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Cana Woodford Shale Formation (0.99)
- North America > United States > Kansas > Anadarko Basin (0.99)
- (2 more...)
Gas hydrate quantification in Walker Ridge block 313, Gulf of Mexico, from full-waveform inversion of ocean-bottom seismic data
Wang, Jiliang (Chinese Academy of Sciences) | Jaiswal, Priyank (Oklahoma State University) | Haines, Seth S. (U.S. Geological Survey) | Yang, Yihong (Oklahoma State University) | Hart, Patrick E. (U.S. Geological Survey) | Wu, Shingo (Chinese Academy of Sciences)
ABSTRACT The Gulf of Mexico (GOM) Joint Industry Project Leg 2 logging-while-drilling data in Walker Ridge lease block 313 (WR313) in the GOM detected gas hydrate in coarse- and fine-grained sediments at sites WR313-G and WR313-H. The coarse-grained units are thin () and highly saturated, whereas the fine-grained unit is thick (approximately 200 m) with low saturation and fracture-filling gas hydrate. Unlike its coarse-grained counterpart, the seismic character of the fine-grained unit does not clearly indicate the presence of gas hydrate, which would likely have remained undiscovered in the absence of drilling. In this paper, through frequency-domain acoustic full-waveform inversion (FWI) of ocean-bottom seismometer data along a 2D multichannel seismic transect near sites WR313-G and WR313-H, we detect and quantify gas hydrate in the fine-grained unit. Key results are as follows: First, the base of the gas hydrate stability zone, which is not obvious in the reflection profile, can be discerned in the FWI results. Second, the gas hydrate in the fine-grained unit is mainly confined to the area between two sets of opposite-dipping normal faults implying that the fault architecture may be partially responsible for this gas hydrate accumulation and distribution.
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.46)
- Geology > Structural Geology > Tectonics > Compressional Tectonics (0.46)
- Geology > Structural Geology > Fault > Dip-Slip Fault (0.34)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Asia > India > Andhra Pradesh > Bay of Bengal > Krishna-Godavari Basin (0.99)
- Asia > China > South China Sea > Zhujiangkou Basin (0.99)
Introduction to special section: Interpretable seismic velocity
Chen, Jianxiong (Anadarko Petroleum Corporation) | Liaw, Alfred (SEG China) | Zhu, Xianhuai (Forland Geophysical Services (FGS)) | Wang, Xin (Chevron Energy Technology Company) | Li, Tao (Aramco Asia Beijing Research Center) | Jaiswal, Priyank (Oklahoma State University) | Cheng, Xin (Schlumberger) | Wu, Yafei (Anadarko Petroleum Corporation)
An efficient fully spectral method for constant-Q seismic-wave propagation
Shukla, Khemraj (Oklahoma State University USA) | Carcione, José M. (INOGS Italy) | Pestana, Reynam C. (Universidade Federal da Bahia, Brazil) | Santos, Juan (UBA Argentina and Purdue University USA) | Jaiswal, Priyank (Oklahoma State University USA)
ABSTRACT We present a new modeling approach for wave propagation in anelastic media, based on a fractional spatial differential operator. The problem is solved with the Fourier pseudo-spectral method in the spatial domain and the REM (rapid expansion method) in the time domain, which, unlike the finite-difference scheme, does not require an intermediate storage of the solution and is more accurate. To show the accuracy of the scheme, an analytical solution in a homogeneous anelastic medium is computed and compared with the numerical solution. We present an example of propagation at a reservoir scale and show the efficiency of the algorithm against the conventional finite-difference scheme. The new method, being spectral in time and space simultaneously, offers a highly accurate and efficient solution for wave propagation in attenuating media. Presentation Date: Wednesday, October 17, 2018 Start Time: 8:30:00 AM Location: 205A (Anaheim Convention Center) Presentation Type: Oral
ABSTRACT When elastic property contrasts across a reflector is low, its primary amplitude-versus-offset (AVO) response can be approximated by a straight line within 30° incidence angle whose intercept and gradient can be used in turn to constrain P- and S- wave velocities of the over- and underlying media. This paper postulates that by approximating the converted-wave AVO response by a straight line within 30° incidence angle, both primary and mode-converted intercepts and gradients can be used to additionally constrain the density of the over- and underlying media. The paper further shows that the six possible combinations of primary and mode-converted intercepts and gradients are associated with characteristic variations in elastic properties contrasts across the reflector and, through rock physics modeling, provides mechanistic insights into the causation of those variations. Ongoing work applies this concept to field data. Presentation Date: Wednesday, October 17, 2018 Presentation Date: Wednesday, October 17, 2018 Start Time: 9:20:00 AM Location: Poster Station 11 Presentation Type: Poster
- North America > United States > Texas (0.28)
- North America > United States > Oklahoma (0.28)
- Geology > Geological Subdiscipline > Geomechanics (0.90)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.46)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (22 more...)
ABSTRACT Seismic recorded gathers are imprinted with multiples energy. Multiples are attenuated using different established methods in the industry. A careful estimate of multiples and their subsequent subtraction is common practice in preserving primaries and aid in interpretation of seismic data. Most established methods use two characteristics of multiples, delayed arrival time with respect to primaries, and periodicity. An attempt is made to use coherency as the foundation for attenuating multiples. Karhunen Loeve Transform is used on dataset, using multiple velocity. Principal components attributing to multiples are selected and composed back to seismic traces. These multiples are then subtracted from the original gather. The results are compared with conventional radon method. The method offers advantage over radon, because no transformation has taken place, which often results in inaccurate curvature values for gathers in the dataset, and leaves artifacts on real gathers. The method can be applied in windows, with varying principal component filtering criteria, thus providing opportunity to pick the proportion of principal components associate with multiples with different coherency. This approach can further optimize practice of separating primaries from multiples at different offsets, as varying percentage of principal components for each window can be selected. Since original multiples have been selected from the dataset for subsequent subtraction, without any additional process, the method does not entail designing filters or subsequent adaptive subtraction. It has successfully attenuated both surface and interbed multiples. Presentation Date: Monday, October 15, 2018 Start Time: 1:50:00 PM Location: 211A (Anaheim Convention Center) Presentation Type: Oral
Gas hydrate quantification using full-waveform inversion of sparse ocean-bottom seismic data: A case study from Green Canyon Block 955, Gulf of Mexico
Wang, Jiliang (Institute of Deep-sea Science and Engineering) | Jaiswal, Priyank (Oklahoma State University) | Haines, Seth S. (U.S. Geological Survey) | Hart, Patrick E. (U.S. Geological Survey) | Wu, Shiguo (Institute of Deep-sea Science and Engineering)
ABSTRACT We present a case study of gas hydrate quantification using dense short-offset multichannel seismic (MCS) and sparse long-offset ocean-bottom-seismometer (OBS) data in lease block Green Canyon 955 (GC955), Gulf of Mexico (GOM), where the presence of gas hydrate was interpreted using logging while drilling (LWD) data acquired by the GOM Gas Hydrate Joint Industry Project Leg II expedition. We use frequency-domain full-waveform inversion (FWI) of seven OBS gathers to invert for a P-wave velocity model of an approximately 7 km long MCS profile connecting two LWD sites, GC955-H and GC955-Q. We build the starting model for FWI using traveltime inversion (TI) of the MCS and OBS data. In addition, we use the TI model for depth migrating the MCS stack. At the LWD sites, we constrain the hydrate saturation () using sonic and resistivity logs. Unfortunately, as is typical of seismic quantification problems, the FWI model resolution is not sufficient to extrapolate the LWD-based . Therefore, we apply Backus averaging to the sonic log, at 60 m wavelength, bringing it within approximately 8% of the FWI model and make the assumption that averaging the sonic log is same as redistributing the gas hydrate within the Backus wavelength. In this manner, instead of , the FWI model is able to estimate the total gas hydrate volume. In the end, we use the FWI model and the migrated stack to constrain the locations and bulk volumes of free gas and gas hydrate. Our results demonstrate that with careful processing, reasonable estimates on locations and bulk volumes of submarine gas hydrate accumulations can be achieved even with sparse seismic data that are not adequate for amplitude-based assessments.
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Structural Geology > Tectonics (0.67)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Asia > India > Andhra Pradesh > Bay of Bengal > Krishna-Godavari Basin (0.99)
- Asia > China > South China Sea > Zhujiangkou Basin (0.99)
- Well Drilling > Drilling Measurement, Data Acquisition and Automation > Logging while drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Non-Traditional Resources > Gas hydrates (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)