Ricardo A. Olea, Ph.D. (Former Employee)
Science and Products
Filter Total Items: 84
Kriging: Understanding allays intimidation Kriging: Understanding allays intimidation
In 1938 Daniel Gerhardus "Danie" Krige obtained an undergraduate degree in mining engineering and started a brilliant career centered on analyzing the gold and uranium mines in the Witwatersrand conglomerates of South Africa. He became interested in the disharmony between the poor reliability of reserve estimation reports and the magnitude of the economic decisions that were based on...
Authors
Ricardo A. Olea
XVAN: A computer program for the analysis of spatial estimation errors XVAN: A computer program for the analysis of spatial estimation errors
[No abstract available]
Authors
Ricardo A. Olea
Semivariogram modeling by weighted least squares Semivariogram modeling by weighted least squares
Permissible semivariogram models are fundamental for geostatistical estimation and simulation of attributes having a continuous spatiotemporal variation. The usual practice is to fit those models manually to experimental semivariograms. Fitting by weighted least squares produces comparable results to fitting manually in less time, systematically, and provides an Akaike information...
Authors
X. Jian, Ricardo A. Olea, Y.-S. Yu
Estimation of regionalized compositions: A comparison of three methods Estimation of regionalized compositions: A comparison of three methods
A regionalized composition is a random vector function whose components are positive and sum to a constant at every point of the sampling region. Consequently, the components of a regionalized composition are necessarily spatially correlated. This spatial dependence-induced by the constant sum constraint-is a spurious spatial correlation and may lead to misinterpretations of statistical...
Authors
V. Pawlowsky, Ricardo A. Olea, J.C. Davis
Expert systems for automated correlation and interpretation of wireline logs Expert systems for automated correlation and interpretation of wireline logs
CORRELATOR is an interactive computer program for lithostratigraphic correlation of wireline logs able to store correlations in a data base with a consistency, accuracy, speed, and resolution that are difficult to obtain manually. The automatic determination of correlations is based on the maximization of a weighted correlation coefficient using two wireline logs per well. CORRELATOR has...
Authors
Ricardo A. Olea
Volumetric calculations in an oil field: The basis method Volumetric calculations in an oil field: The basis method
The basis method for estimating oil reserves in place is compared to a traditional procedure that uses ordinary kriging. In the basis method, auxiliary variables that sum to the net thickness of pay are estimated by cokriging. In theory, the procedure should be more powerful because it makes full use of the cross-correlation between variables and forces the original variables to honor...
Authors
Ricardo A. Olea, V. Pawlowsky, J.C. Davis
Boundary assessment under uncertainty: A case study Boundary assessment under uncertainty: A case study
Estimating certain attributes within a geological body whose exact boundary is not known presents problems because of the lack of information. Estimation may result in values that are inadmissible from a geological point of view, especially with attributes which necessarily must be zero outside the boundary, such as the thickness of the oil column outside a reservoir. A simple but...
Authors
V. Pawlowsky, Ricardo A. Olea, J.C. Davis
Sampling design for spatially distributed hydrogeologic and environmental processes Sampling design for spatially distributed hydrogeologic and environmental processes
A methodology for the design of sampling networks over space is proposed. The methodology is based on spatial random field representations of nonhomogeneous natural processes, and on optimal spatial estimation techniques. One of the most important results of random field theory for physical sciences is its rationalization of correlations in spatial variability of natural processes. This
Authors
G. Christakos, Ricardo A. Olea
Quantitative assessment of mineral resources with an application to petroleum geology Quantitative assessment of mineral resources with an application to petroleum geology
The probability of occurrence of natural resources, such as petroleum deposits, can be assessed by a combination of multivariate statistical and geostatistical techniques. The area of study is partitioned into regions that are as homogeneous as possible internally while simultaneously as distinct as possible. Fisher's discriminant criterion is used to select geological variables that...
Authors
Jan Harff, J.C. Davis, Ricardo A. Olea
A multiple-objective optimal exploration strategy A multiple-objective optimal exploration strategy
Exploration for natural resources is accomplished through partial sampling of extensive domains. Such imperfect knowledge is subject to sampling error. Complex systems of equations resulting from modelling based on the theory of correlated random fields are reduced to simple analytical expressions providing global indices of estimation variance. The indices are utilized by multiple...
Authors
G. Christakos, Ricardo A. Olea
Lognormal kriging for the assessment of reliability in groundwater quality control observation networks Lognormal kriging for the assessment of reliability in groundwater quality control observation networks
Groundwater quality observation networks are examples of discontinuous sampling on variables presenting spatial continuity and highly skewed frequency distributions. Anywhere in the aquifer, lognormal kriging provides estimates of the variable being sampled and a standard error of the estimate. The average and the maximum standard error within the network can be used to dynamically...
Authors
L. Candela, Ricardo A. Olea, E. Custodio
Sampling design optimization for spatial functions Sampling design optimization for spatial functions
A new procedure is presented for minimizing the sampling requirements necessary to estimate a mappable spatial function at a specified level of accuracy. The technique is based on universal kriging, an estimation method within the theory of regionalized variables. Neither actual implementation of the sampling nor universal kriging estimations are necessary to make an optimal design. The...
Authors
Ricardo A. Olea
Non-USGS Publications**
Buatois, L.A., Mángano, M.G, Olea, R.A., Wilson, M.A., 2016. Decoupled evolution of soft and hard substrate communities during Cambrian Explosion and Great Ordovician Biodiversification Event. Proceedings of the National Academy of Sciences, vol. 113, no. 25, p. 6945−6948 and 28 pp. of Supporting Information.
Schuenemeyer, J. H., Olea, R.A., 2014. Distributional assumptions and parametric uncertainties in the aggregation of geologic resources. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 49−52.
Pardo-Igúzquiza, E., Olea, R. A., Dowd, P.A, 2014. Semivariogram model inference using the median bootstrap statistics. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 79−82.
Karacan, C. Ö., Olea, R.A., 2014. Coalbed methane production analysis and filter simulation for quantifying gas drainage from coal seams. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 549−552.
Olea, R.A., Luppens, J.A., Tewalt, S.J., 2014. Moving away from distance classifications as measures of resource uncertainty. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 585−588.
Olea, R.A., Houseknecht, D.W., Garrity, C. P. and Cook, T.A., 2011, Assessment of shale-gas resources using correlated variables and application to the Woodford play, Arkoma basin, southeast Oklahoma: Special issue on New Quantitative Applications of Geomathematics in Earth Sciences of the Geological Survey of Spain Bulletin, Boletín Geológico y Minero, vol. 122, no.4, p. 483–496.
Martín-Fernández, J. A., Palarea-Alabaladejo, J., and Olea, R.A., 2011, Dealing with zeros. In V. Pawlowsky-Glahn and A. Buccianti (eds.), Compositional Data Analysis—Theory and Applications: Wiley & Sons, Ltd, Chichester, UK, p. 43–58.
Martín-Fernández, J. A., Palarea-Alabaladejo, J., and Olea, R.A., 2011, Dealing with zeros. In V. Pawlowsky-Glahn and A. Buccianti (eds.), Compositional Data Analysis—Theory and Applications: Wiley & Sons, Ltd, Chichester, UK, p. 43–58.
Bunnell, J. E., Garcia, L. V., Furst, J. M., Lerch, H., Olea, R. A., Suitt, S. E., and Kolker, A., 2010, Navajo coal combustion and respiratory health near Shiprock, New Mexico. Journal of Environmental and Public Health, vol. 2010, article ID 260525, DOI:10.1155/2010/260525, 14 p.
Olea, R. A., 2009, Crossvalidation of cumulative probabilities for parameter selection in geostatistical estimation and simulation: Proceedings of the 2009 Conference of the International Association for Mathematical Geosciences, http://iamg09.stanford.edu
Martín-Fernández, J. A., Olea, R. A., and Palarea-Albaladejo, J., 2009, Multivariate approach using bootstrapping for the inference of distributional parameters of samples containing compositional values below detection limit. Abstract in Proceedings of the 31st Spanish Congress of Statistics and Operations Research, Murcia, Spain, p. 54, CD-ROM. (ISBN: 978-84-691-8159-1)
Kolker, A , Engle, M. A., Hower, J. C., O’Keefe, J. M. K., Heffern, E. L., Radke, L. F., Prakash, A., ter Schure, A., Román-Colón, Y., and Olea, R., 2009, Measuring CO2 emissions from coal fires in the U.S.: Proceedings, Annual International Coal Conference, Pittsburgh, PA, September, 2009, 7 p.
Olea, R. A., 2008, Basic Statistical Concepts and Methods for Earth Scientists: U.S. Geological Survey, Open-File Report 2008-1017, http://pubs.usgs.gov/of/2008/1017/, 191 p.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 84
Kriging: Understanding allays intimidation Kriging: Understanding allays intimidation
In 1938 Daniel Gerhardus "Danie" Krige obtained an undergraduate degree in mining engineering and started a brilliant career centered on analyzing the gold and uranium mines in the Witwatersrand conglomerates of South Africa. He became interested in the disharmony between the poor reliability of reserve estimation reports and the magnitude of the economic decisions that were based on...
Authors
Ricardo A. Olea
XVAN: A computer program for the analysis of spatial estimation errors XVAN: A computer program for the analysis of spatial estimation errors
[No abstract available]
Authors
Ricardo A. Olea
Semivariogram modeling by weighted least squares Semivariogram modeling by weighted least squares
Permissible semivariogram models are fundamental for geostatistical estimation and simulation of attributes having a continuous spatiotemporal variation. The usual practice is to fit those models manually to experimental semivariograms. Fitting by weighted least squares produces comparable results to fitting manually in less time, systematically, and provides an Akaike information...
Authors
X. Jian, Ricardo A. Olea, Y.-S. Yu
Estimation of regionalized compositions: A comparison of three methods Estimation of regionalized compositions: A comparison of three methods
A regionalized composition is a random vector function whose components are positive and sum to a constant at every point of the sampling region. Consequently, the components of a regionalized composition are necessarily spatially correlated. This spatial dependence-induced by the constant sum constraint-is a spurious spatial correlation and may lead to misinterpretations of statistical...
Authors
V. Pawlowsky, Ricardo A. Olea, J.C. Davis
Expert systems for automated correlation and interpretation of wireline logs Expert systems for automated correlation and interpretation of wireline logs
CORRELATOR is an interactive computer program for lithostratigraphic correlation of wireline logs able to store correlations in a data base with a consistency, accuracy, speed, and resolution that are difficult to obtain manually. The automatic determination of correlations is based on the maximization of a weighted correlation coefficient using two wireline logs per well. CORRELATOR has...
Authors
Ricardo A. Olea
Volumetric calculations in an oil field: The basis method Volumetric calculations in an oil field: The basis method
The basis method for estimating oil reserves in place is compared to a traditional procedure that uses ordinary kriging. In the basis method, auxiliary variables that sum to the net thickness of pay are estimated by cokriging. In theory, the procedure should be more powerful because it makes full use of the cross-correlation between variables and forces the original variables to honor...
Authors
Ricardo A. Olea, V. Pawlowsky, J.C. Davis
Boundary assessment under uncertainty: A case study Boundary assessment under uncertainty: A case study
Estimating certain attributes within a geological body whose exact boundary is not known presents problems because of the lack of information. Estimation may result in values that are inadmissible from a geological point of view, especially with attributes which necessarily must be zero outside the boundary, such as the thickness of the oil column outside a reservoir. A simple but...
Authors
V. Pawlowsky, Ricardo A. Olea, J.C. Davis
Sampling design for spatially distributed hydrogeologic and environmental processes Sampling design for spatially distributed hydrogeologic and environmental processes
A methodology for the design of sampling networks over space is proposed. The methodology is based on spatial random field representations of nonhomogeneous natural processes, and on optimal spatial estimation techniques. One of the most important results of random field theory for physical sciences is its rationalization of correlations in spatial variability of natural processes. This
Authors
G. Christakos, Ricardo A. Olea
Quantitative assessment of mineral resources with an application to petroleum geology Quantitative assessment of mineral resources with an application to petroleum geology
The probability of occurrence of natural resources, such as petroleum deposits, can be assessed by a combination of multivariate statistical and geostatistical techniques. The area of study is partitioned into regions that are as homogeneous as possible internally while simultaneously as distinct as possible. Fisher's discriminant criterion is used to select geological variables that...
Authors
Jan Harff, J.C. Davis, Ricardo A. Olea
A multiple-objective optimal exploration strategy A multiple-objective optimal exploration strategy
Exploration for natural resources is accomplished through partial sampling of extensive domains. Such imperfect knowledge is subject to sampling error. Complex systems of equations resulting from modelling based on the theory of correlated random fields are reduced to simple analytical expressions providing global indices of estimation variance. The indices are utilized by multiple...
Authors
G. Christakos, Ricardo A. Olea
Lognormal kriging for the assessment of reliability in groundwater quality control observation networks Lognormal kriging for the assessment of reliability in groundwater quality control observation networks
Groundwater quality observation networks are examples of discontinuous sampling on variables presenting spatial continuity and highly skewed frequency distributions. Anywhere in the aquifer, lognormal kriging provides estimates of the variable being sampled and a standard error of the estimate. The average and the maximum standard error within the network can be used to dynamically...
Authors
L. Candela, Ricardo A. Olea, E. Custodio
Sampling design optimization for spatial functions Sampling design optimization for spatial functions
A new procedure is presented for minimizing the sampling requirements necessary to estimate a mappable spatial function at a specified level of accuracy. The technique is based on universal kriging, an estimation method within the theory of regionalized variables. Neither actual implementation of the sampling nor universal kriging estimations are necessary to make an optimal design. The...
Authors
Ricardo A. Olea
Non-USGS Publications**
Buatois, L.A., Mángano, M.G, Olea, R.A., Wilson, M.A., 2016. Decoupled evolution of soft and hard substrate communities during Cambrian Explosion and Great Ordovician Biodiversification Event. Proceedings of the National Academy of Sciences, vol. 113, no. 25, p. 6945−6948 and 28 pp. of Supporting Information.
Schuenemeyer, J. H., Olea, R.A., 2014. Distributional assumptions and parametric uncertainties in the aggregation of geologic resources. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 49−52.
Pardo-Igúzquiza, E., Olea, R. A., Dowd, P.A, 2014. Semivariogram model inference using the median bootstrap statistics. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 79−82.
Karacan, C. Ö., Olea, R.A., 2014. Coalbed methane production analysis and filter simulation for quantifying gas drainage from coal seams. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 549−552.
Olea, R.A., Luppens, J.A., Tewalt, S.J., 2014. Moving away from distance classifications as measures of resource uncertainty. In Mathematics of Planet Earth, Proceedings of the 15th Annual Conference of the International Association for Mathematical Geosciences, Pardo-Igúzquiza, E., Guardiola-Albert, C., Heredia, J., Moreno-Merino, L., Durán, J.J., Vargas-Guzmán, J.J., editors, p. 585−588.
Olea, R.A., Houseknecht, D.W., Garrity, C. P. and Cook, T.A., 2011, Assessment of shale-gas resources using correlated variables and application to the Woodford play, Arkoma basin, southeast Oklahoma: Special issue on New Quantitative Applications of Geomathematics in Earth Sciences of the Geological Survey of Spain Bulletin, Boletín Geológico y Minero, vol. 122, no.4, p. 483–496.
Martín-Fernández, J. A., Palarea-Alabaladejo, J., and Olea, R.A., 2011, Dealing with zeros. In V. Pawlowsky-Glahn and A. Buccianti (eds.), Compositional Data Analysis—Theory and Applications: Wiley & Sons, Ltd, Chichester, UK, p. 43–58.
Martín-Fernández, J. A., Palarea-Alabaladejo, J., and Olea, R.A., 2011, Dealing with zeros. In V. Pawlowsky-Glahn and A. Buccianti (eds.), Compositional Data Analysis—Theory and Applications: Wiley & Sons, Ltd, Chichester, UK, p. 43–58.
Bunnell, J. E., Garcia, L. V., Furst, J. M., Lerch, H., Olea, R. A., Suitt, S. E., and Kolker, A., 2010, Navajo coal combustion and respiratory health near Shiprock, New Mexico. Journal of Environmental and Public Health, vol. 2010, article ID 260525, DOI:10.1155/2010/260525, 14 p.
Olea, R. A., 2009, Crossvalidation of cumulative probabilities for parameter selection in geostatistical estimation and simulation: Proceedings of the 2009 Conference of the International Association for Mathematical Geosciences, http://iamg09.stanford.edu
Martín-Fernández, J. A., Olea, R. A., and Palarea-Albaladejo, J., 2009, Multivariate approach using bootstrapping for the inference of distributional parameters of samples containing compositional values below detection limit. Abstract in Proceedings of the 31st Spanish Congress of Statistics and Operations Research, Murcia, Spain, p. 54, CD-ROM. (ISBN: 978-84-691-8159-1)
Kolker, A , Engle, M. A., Hower, J. C., O’Keefe, J. M. K., Heffern, E. L., Radke, L. F., Prakash, A., ter Schure, A., Román-Colón, Y., and Olea, R., 2009, Measuring CO2 emissions from coal fires in the U.S.: Proceedings, Annual International Coal Conference, Pittsburgh, PA, September, 2009, 7 p.
Olea, R. A., 2008, Basic Statistical Concepts and Methods for Earth Scientists: U.S. Geological Survey, Open-File Report 2008-1017, http://pubs.usgs.gov/of/2008/1017/, 191 p.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government