scholarly journals Kriging with Small Number of Data Supported by Jack-Knifing, Case Study in the Sava Depression (Northern Croatia)

2018 ◽  
Author(s):  
Tomislav Malvić ◽  
Josip Ivšinović ◽  
Josipa Velić ◽  
Rajna Rajić
Keyword(s):  
Ordinary Kriging ◽  
Cross Validation ◽  
Pannonian Basin ◽  
Hydrocarbon Reservoirs ◽  
Upper Miocene ◽  
System Data ◽  
Northern Croatia ◽  
Basin System

Presented is semivariogram and the Ordinary Kriging analyses of porosity data from the Sava Depression (Northern Croatia), as part of the Croatian part of the Pannonian Basin System. Data are taken from hydrocarbon reservoirs of the Lower Pontian (Upper Miocene) age, which belongs to the Kloštar-Ivanić Formation. Original datasets had been jack-knifed with purpose to “artificially” increased data and calculate the more reliable semivariograms. The results showed that such improvements can assist in the interpolation of more reliable maps. The both sets, made by original and jack-knifed data, need to be compared using geological recognition of non-allowed shapes (“bull-eyes”, “butterfly effects”) as well as cross-validation results. That comparison made possible to select the most appropriate porosity interpolation.

scholarly journals Kriging with a Small Number of Data Points Supported by Jack-Knifing, a Case Study in the Sava Depression (Northern Croatia)

Geosciences ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 36 ◽  
Author(s):  
Tomislav Malvić ◽  
Josip Ivšinović ◽  
Josipa Velić ◽  
Rajna Rajić
Keyword(s):  
Ordinary Kriging ◽  
Cross Validation ◽  
Pannonian Basin ◽  
Hydrocarbon Reservoirs ◽  
Sampled Data ◽  
Upper Miocene ◽  
Data Points ◽  
Northern Croatia ◽  
Basin System

The semivariogram and the ordinary kriging analyses of porosity data from the Sava Depression (Northern Croatia), are presented relative to the Croatian part of the Pannonian Basin system. The data are taken from hydrocarbon reservoirs of the Lower Pontian (Upper Miocene) age, which belong to the Kloštar Ivanić Formation. The original datasets had been jack-knifed with the purpose of re-sampling and calculating the more reliable semivariograms. The results showed that such improvements can assist in the interpolation of more reliable maps. Both sets, made by the original and re-sampled data, need to be compared using geological recognition of isoline’s shapes (such as “bull-eye” or “butterfly” effects) as well as cross-validation results. This comparison made it possible to select the most appropriate porosity interpolation.

scholarly journals SIMULATION OF CO2 INJECTION IN A DEPLETED GAS RESERVOIR: A CASE STUDY FOR UPPER MIOCENE SANDSTONE, NORTHERN CROATIA

2019 ◽  
Vol 34 (1) ◽  
pp. 139-149
Author(s):  
Amalia Lekić ◽  
Lucija Jukić ◽  
Maja Arnaut ◽  
Marija Macenić
Keyword(s):  
Co2 Injection ◽  
Gas Reservoir ◽  
Upper Miocene ◽  
Northern Croatia ◽  
Depleted Gas Reservoir

scholarly journals Application of the Modified Shepard’s Method (MSM): A Case Study with the Interpolation of Neogene Reservoir Variables in Northern Croatia

Stats ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 68-83 ◽  
Author(s):  
Tomislav Malvić ◽  
Josip Ivšinović ◽  
Josipa Velić ◽  
Jasenka Sremac ◽  
Uroš Barudžija
Keyword(s):  
Cross Validation ◽  
Statistical Properties ◽  
Inverse Distance Weighting ◽  
Geological Mapping ◽  
Interpolation Methods ◽  
Geometrical Features ◽  
Distance Weighting ◽  
Northern Croatia ◽  
Inverse Distance

Interpolation is a procedure that depends on the spatial and/or statistical properties of the analysed variable(s). It is a particularly challenging task for small datasets, such as in those with less than 20 points of data. This problem is common in subsurface geological mapping, i.e., in cases where the data is taken solely from wells. Successful solutions of such mapping problems depend on interpolation methods designed primarily for small datasets and the datasets themselves. Here, we compare two methods, Inverse Distance Weighting and the Modified Shepard’s Method, and apply them to three variables (porosity, permeability, and thickness) measured in the Neogene sandstone hydrocarbon reservoirs (northern Croatia). The results show that cross-validation itself will not provide appropriate map selection, but, in combination with geometrical features, it can help experts eliminate the solutions with low-probable structures/shapes. The Golden Software licensed program Surfer 15 was used for the interpolations in this study.

scholarly journals Recent Advances in Geomathematics in Croatia: Examples from Subsurface Geological Mapping and Biostatistics

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 188
Author(s):  
Tomislav Malvić ◽  
Marija Bošnjak ◽  
Josipa Velić ◽  
Jasenka Sremac ◽  
Josip Ivšinović ◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Wide Spectrum ◽  
Study Groups ◽  
Geological Mapping ◽  
Recent Advances ◽  
Numerical Indicator ◽  
Definition Of ◽  
Northern Croatia ◽  
Surface Geology

Geomathematics is extremely important in geosciences, particularly in the geology. The key for any geomathematical analysis is the definition of a typical model to be applied for further prognosis, either through deterministic or stochastic approaches. The selection of the appropriate procedure is presented in this paper. Two different geomathematical subfield datasets were used in subsurface geological mapping and palaeontology and different biostatistics applications, representing important geomathematical subfields in the Croatian geology. The different subsurface interpolation methods tested, validated and recommended for application were used to obtain the best possible outcome in reservoir modelling, in the cases with small datasets. Cross-validation may be chosen as the main selection criteria, applied to the Croatian part of the Pannonian Basin System (CPBS). Recent advances in biostatistics applied in palaeontology and case studies from Croatia are also presented, where biometric studies are of significant importance in fossil biota. Data, methods and problems in geosciences are vast subjects, and address a wide spectrum of fundamental science. Because geology includes subsurface and surface geology, and very different datasets regarding variable and number of data, we have chosen here two representative case study groups with original samples from Northern Croatia. Subsurface mapping has been presented on limited petrophysical datasets from the Northern Croatian, Miocene, hydrocarbon reservoirs. Biostatistics have been presented on very different samples, allowing us to achieve paleoenvironmental reconstructions of the size of relevant fossils, such as dinosaurs or other species and their paleoenvironments. All examples highlight examples of the valuable application of geomathematical tools in geology. The results, cautiously validated and correlated with other, non-numerical (indicator, categorical) geological knowledge, are of enormous assistance in creating better geological models.

scholarly journals Application of Modified Shepard's Method (MSM) case study with interpolation of Neogene reservoirs variables in the Northern Croatia

2019 ◽  
Author(s):  
Tomislav Malvić ◽  
Josip Ivšinović ◽  
Josipa Velić ◽  
Jasenka Sremac ◽  
Uroš Barudžija
Keyword(s):  
Cross Validation ◽  
Statistical Properties ◽  
Inverse Distance Weighting ◽  
Geological Mapping ◽  
Interpolation Methods ◽  
Geometrical Features ◽  
Distance Weighting ◽  
Northern Croatia ◽  
Inverse Distance

Interpolation is procedure that depends on spatial and/or statistical properties of analysed variable(s). It is special challenging task for data that included low number of samples, like dataset with less than 20 data. This problem is especially emphasized in the subsurface geological mapping, i.e. in the cases where data are taken solely from wells. Successful solutions of such mapping problems ask for knowledge about interpolation methods designed primarily for small datasets and dataset itself. Here are compared two methods, namely Inverse Distance Weighting and Modified Shepard’s Method, applied for three variables (porosity, permeability, thickness) measured in the Neogene sandstone hydrocarbon reservoirs (Northern Croatia). The results showed that pure cross-validation is not enough condition for appropriate map selection, but also geometrical features need to be considered, for datasets with less than 20 points.

scholarly journals Recent Advances in Geomathematics: Croatian Examples from Subsurface Geological Mapping and Biostatistics

2020 ◽  
Author(s):  
Tomislav Malvić ◽  
Marija Bošnjak ◽  
Josipa Velić ◽  
Jasenka Sremac ◽  
Josip Ivšinović ◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Wide Spectrum ◽  
Study Groups ◽  
Geological Mapping ◽  
Recent Advances ◽  
Numerical Indicator ◽  
Definition Of ◽  
Northern Croatia ◽  
Surface Geology

Geomathematics is extremely important in geosciences, particularly in the geology. The key for any geomathematical analysis is the definition of a typical model to be applied for further prognosis, either through deterministical or stochastical approaches. The selection of the appropriate procedure is presented in this paper. Two different geomathematical subfield datasets were used in subsurface geological mapping and palaeontology and different biostatistics applications, representing important geomathematical subfields in the Croatian geology. The different subsurface interpolation methods, tested, validated and recommended for application, were used to obtain the best possible outcome in reservoir modelling, in the cases with small datasets. Cross-validation may be selected as the main selection criteria, applied to the Croatian part of the Pannonian Basin System (abbr. CPBS). Recent advances in biostatistics applied in palaeontology and case studies from Croatia are also presented, where biometric studies are of significant importance in fossil biota. Data, methods and problems in geosciences is a vast subject, and address a wide spectrum of fundamental science. Because geology includes subsurface and surface geology, and very different datasets regarding variable and number of data, here are chosen two representative case study groups with original samples from Northern Croatia. Subsurface mapping has been presented on limited petrophysical datasets from the Northern Croatian, Miocene, hydrocarbon reservoirs. Biostatistics has been presented on very different samples, allowing to achieve paleoenvironmental reconstructions of size of relevant fossils, as dinosaurs or other species and their paleoenvironments. All examples highlight examples of the valuable application of geomathematical tools in geology. The results, cautiously validated and correlated with other, non-numerical (indicator, categorical) geological knowledge, are of enormous assistance in creating better geological models.

scholarly journals Mineral assemblage and provenance of the Pliocene Viviparus beds from the Area of Vukomeričke Gorice (Central Croatia)

2021 ◽  
Vol 74 (3) ◽  
pp. 253-271
Author(s):  
Tomislav Kurečić ◽  
◽  
Marijan Kovačić ◽  
Anita Grizelj ◽  
◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Chemical Analyses ◽  
Source Areas ◽  
Upper Miocene ◽  
Transport Distance ◽  
Magmatic Rocks ◽  
And Inversion ◽  
Uniform Composition ◽  
Basin System ◽  
Freshwater Environments

Viviparus beds are sediments deposited in lacustrine and fluvial freshwater environments (Lake Slavonia) during the Pliocene and the earliest Pleistocene. A detailed field study and mineralogical, petrographic and chemical analyses were carried out to determine their composition and origin in the area of Vukomeričke Gorice, Central Croatia. Viviparus beds are characterized by the vertical and lateral exchange of mineralogically and chemically mature pelites and sands. Pelitic sediments consist mainly of detrital quartz, calcite, dolomite and feldspar grains, with smectite as the most common clay mineral. Quartz and the most resistant lithic fragments dominate the sandy detritus. The composition of the sediments indicates their origin from the recycled orogen, while their textural immaturity suggests a short transport distance. Most of the material was re-deposited from the underlying Upper Miocene sediments, originally of Alpine provenance. A lesser proportion originated from Palaeogene sediments, Triassic carbonate rocks, basic or acidic magmatic rocks and metamorphites. The Medvednica and Žumberak Mts. were the most important source areas, while a smaller proportion of the material could have come from the Moslavačka gora Mt. and Banovina region. The uniform composition of the Viviparus beds over the entire vertical distribution of the sediments clearly indicates that the source areas did not change during their deposition. A significant change from the texturally and compositionally mature Upper Miocene clastic detritus of alpine origin, to the texturally immature material of the Viviparus beds of local origin is a consequence of compression and inversion of the previously extensional basin resulting in the uplifting and erosion of the mountains within the SW part of the Pannonian Basin System.

Sign in / Sign up

Export Citation Format

Share Document