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Search Results for The problem of nonstationarity
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The problem of nonstationarity
Paper presented at the 1990 SEG Annual Meeting, September 23–27, 1990
Paper Number: SEG-1990-1683
... nonstationarity in the direct arrival or primary part OI thedowngoing wavefield.Absorptionandtime-varyingphaseshift (possibly the result of normal dispersion) are discussed as possible explanations of the observed nonstationarity. These observation: are made in the upper 0.9 seconds two-way travel time il...
Paper presented at the SPE Annual Technical Conference and Exhibition, October 6–9, 1996
Paper Number: SPE-36569-MS
... the simplified simulation with the true well-test permeability. The problem of nonstationarity between the well-test regions is addressed. The results obtained here show that there is a reduction of reservoir uncertainty when well-test information is added. Introduction Most conventional...
Paper presented at the 2010 SEG Annual Meeting, October 17–22, 2010
Paper Number: SEG-2010-3662
... created by Raymond Abma (personal communication) shows a simple curved event (Figure 2a), in- cluding both nonstationarity and aliasing. In general, exist- ing methods are able to solve only one of the two problems. Figure 2b shows the interpolated result using Claerbout s sta- tionary t-x PEF. Note that...
SPE Journal 9 (04): 429–436.
Paper Number: SPE-84594-PA
Published: 01 December 2004
... Paris center of geostatistics. By analyzing the limitations and the potential of the truncated Gaussian method, Galli et al . 5 found a way to apply this method to a 3D problem with vertical nonstationarity in the proportions of lithofacies. They showed that this method preserved the consistency of the...
Paper presented at the 2015 SEG Annual Meeting, October 18–23, 2015
Paper Number: SEG-2015-5916027
...-whiting factor is so commonly used that people usually fail to investigate its hazards, which probably smear useful reflectivity information and degrade the ultimate deconvolution result. In this paper, we treat the process as an inversion problem and employ the strategy of shaping regularization to...
International Journal of Offshore and Polar Engineering 26 (02): 88–99.
Paper Number: ISOPE-16-26-2-088
Published: 01 June 2016
... wave short-crestedness, shielding effects from the HLV, radiation damping from the MP, and the nonstationarity of the process. The influence of each factor on the allowable sea states and operability is assessed. A large number of time-domain simulations are performed, considering random waves, to...
SPE Journal 16 (02): 318–330.
Paper Number: SPE-118916-PA
Published: 11 November 2010
... different facies are given in Table 2 . The performance of our proposed approach for simultaneously updating the facies distribution and the petrophysical properties was evaluated using two different test problems designed with different features of nonstationarity. TABLE 2 MEAN AND STANDARD...
SPE Journal 18 (06): 1033–1042.
Paper Number: SPE-163147-PA
Published: 06 May 2013
... . This paper recalls and further demonstrates that facies proportions can be modeled by local beta distributions. However, the highly variable shapes of the conditional probability-density functions (PDFs) for the random variables in the field lead to complex nonstationarity and nonlinearity issues. A...
Paper presented at the 2016 SEG International Exposition and Annual Meeting, October 16–21, 2016
Paper Number: SEG-2016-13873107
..., optimum prediction parameters are difficult to determine — in fact in some cases no stationary value of the search parameter can optimally predict all multiples without introducing damaging artifacts. A re-formulation and implementation in the time-domain permits time-nonstationarity to be enforced in...
Paper presented at the 2014 SEG Annual Meeting, October 26–31, 2014
Paper Number: SEG-2014-0329
... is proposed, in which the nonstationarity is due to the Q attenuation and dispersion effects. The deabsorption preprocessing is then needless, as the NAVA inversion performs AVA inversion and deabsorption simultaneously. Namely, the NAVA inversion integrates the two-step procedure of inverse Q...
SPE Journal 6 (02): 137–143.
Paper Number: SPE-71309-PA
Published: 01 June 2001
... seismic amplitude map. A rejection scheme is used, which requires fast, repetitive simulation of gridblock columns and generation of convolutional responses. The nonstationarity of the model means that this cannot be achieved using the conventional large kriging system. We use a different, but comparably...
SPE Reservoir Evaluation & Engineering 5 (01): 68–78.
Paper Number: SPE-76905-PA
Published: 01 February 2002
..., such as Markov Chain Monte Carlo (MCMC) methods, and model extensions to account for nonstationarity, discontinuity, and varying spatial properties at various scales of resolution are easily accessible in the MRF framework. Our proposed method is computationally efficient and well suited to reconstruct...
Paper presented at the 2011 SEG Annual Meeting, September 18–23, 2011
Paper Number: SEG-2011-3601
... regularization. In the second step, we solve the other least-square system tailored specifically to signal and noise separation. Using synthetic and real data examples, we successfully apply this method to the problem of nonstationary signal and two different noise separation. coefficient upstream oil...
SPE Reservoir Evaluation & Engineering 10 (01): 77–85.
Paper Number: SPE-93159-PA
Published: 01 February 2007
... within stacked lava domes while accounting for pressure data by means of history matching to address nonstationarity in the real field. Building a suitable training image is commonly a difficult aspect of multipoint methods and poses particular problems for volcanic reservoirs. It was accomplished here...
SPE Reservoir Evaluation & Engineering 7 (06): 416–426.
Paper Number: SPE-81544-PA
Published: 01 December 2004
... (MCMC) meth- ods, and (b) model extensions to account for nonstationarities, discontinuity, and varying spatial properties at various scales of resolution are accessible in the MRFs. We construct fine-scale porosity distribution from well and seismic data, explicitly accounting for the varying scale and...
Paper presented at the The 29th International Ocean and Polar Engineering Conference, June 16–21, 2019
Paper Number: ISOPE-I-19-289
... noise. Earlier works are based on the finite impulse response (FIR) filter and least mean square (LMS) algorithm. By employing steepest-descent search directions, LMS algorithms are computationally simple, numerically robust and widely applied. To solve the classical problem of online frequency...
Paper presented at the 2003 SEG Annual Meeting, October 26–31, 2003
Paper Number: SEG-2003-1945
... predictability is estimated with multidimensional prediction-error filters. These filters are time-variant in order to handle the nonstationarity of the seismic data. Attenuation of surface-related multiples is illustrated with field data from the Gulf of Mexico with 2-D and 3-D filters. The 3-D filters allow...
Paper presented at the SEG International Exposition and Annual Meeting, September 15–20, 2019
Paper Number: SEG-2019-3199116
...). The nonstationarity means frequency components of seismic signals are varied with time. A time-frequency (TF) analysis tool can transform the time-domain nonstationary signals into a TF space with an additional frequency dimension to characterize local spectral variations (Partyka et al., 1999). Often...
Paper presented at the 2017 SEG International Exposition and Annual Meeting, September 24–29, 2017
Paper Number: SEG-2017-17415496
... to , and (2) we also fail to correctly and . We may choose to solve both problems or . The quality of image-gathers associated with prestack migration may or may not warrant the simultaneous solution. In areas with irregular topography, complex near-surface, and complex subsurface, it may not. What...
SPE Journal 23 (04): 1359–1371.
Paper Number: SPE-189975-PA
Published: 12 February 2018
... the original MPS algorithm, helped in the investigation of further applications of MPS to practical problems. Since that breakthrough, several other MPS algorithms have been proposed (for a comprehensive review, see Tahmasebi and Sahimi 2016a , b ). For example, Arpat and Caers ( 2007 ) introduced a...
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