scholarly journals EXPERIENCE IN APPLYING EXPERT ANALYSIS AND RANK CORRELATION DURING GEOLOGICAL AND FORECASTING WORK ON HYDROCARBONS

2021 ◽  
Vol 26 (1(38)) ◽  
pp. 233-248
Author(s):  
О. V. Chepizhko ◽  
V. V. Yanko ◽  
V. M. Kadurin ◽  
І. М. Naumko ◽  
S. М. Shatalin

Problem Statement and Purpose. The diverse and extensive geological materials and geophysical data used in forecasting and prospecting operations for oil and gas exploration within the Black Sea’s northwestern shelf are usually interpreted in a complex manner. This complexity, however, is often spontaneous and fragmentary, with no new theoretical concepts taken into account. For example, the theory of global fluidogenesis represents an alternative hypothesis to the organogenic-sedimentary formation of hydrocarbon deposits but is commonly not considered. The authors of this article believe that the complexity should be replaced by a method of directed rank interpretation of geological information, in which ranking distinguishes the maximum information on one of the sections of geological work with regard to its completeness and consistency. The purpose of this study is to apply expert analysis and rank correlation of obtained information to geological and forecasting research on hydrocarbons. To achieve this goal, two basic principles, rank and direction, are considered. The data include seismic, tectonic-geodynamic, lithological, geochemical, mineralogical, and meiobenthic characteristics of the sea bottom scaled according to their sensitivity to the independent variable, i. e., hydrocarbons. Study area, material, and methods. The Pradneprovskaya area has been chosen for analysis. It is a promising location for oil and gas exploration in the shallow part of the inner northwestern shelf of the Black Sea. Geologically, this is the area of junction for the South Ukrainian monocline with the system of blocks included in the Predobrudzha-Crimean riftogenic trough. The area was studied by geophysical, geochemical (hydrocarbon gases, liquid hydrocarbons), mineralogical (X‑ray diffraction of clay minerals, thermobarogeochemistry of inclusions in minerals), and paleontological (foraminifera, nematodes, ostracods) methods, along with the drilling of a deep (2352 m) parametric well (Pradneprovskaya‑2). Results. It is shown that expert analysis of the diverse information within the framework of selected tasks, which are poorly formalized into a single system, provides the basis for an effective method of comparing information databases formed on different principles. This analysis is founded on the principle of directed (vector) ranking, where each rank narrows the search area and becomes more sensitive to the hydrocarbon deposit. The article gives an example of how this method can be used for a specific objective in its entirety, namely: (a) selection of information ranks (parameters), (b) selection of experts, (c) calculation of the rank matrix, (d) determination of hierarchical dependencies of ranks, (e) verification of the matrix, and (e) calculation of the concordance coefficient. The obtained results indicate that the proposed method of expert analysis with rank correlation under modern conditions using diverse geological materials that are not formalized into a single database, provides high reliability in the comprehensive interpretation of data. The method will help optimize geological and forecasting research on hydrocarbons within the Black Sea shelf.

2020 ◽  
Vol 42 (4) ◽  
pp. 33-49
Author(s):  
O.V. CHEPIZHKO ◽  
V.V. YANKO ◽  
V.M. KADURIN ◽  
I.M. NAUMKO ◽  
S.M. SHATALIN

For the first time the importance of mineralogical and lithological-petrographical ranks in the line of geological information ranks is substantiated for implementation of long-term forecasts, standard and non-standard approaches to research of physical and geochemical parameters as a basis of creation of complex system of forecast criteria and prospecting indicators of hydrocarbons within the sedimentary cover of Black sea based on the theory of global fluid-flows derivation. These criteria have different sensitivity to the object (hydrocarbon deposits) and are therefore ranked. The ranking determined the following parameters: 1) seismic data within the object, obtained by the method of deep seismic sounding, RWM SDP; 2) parameters of tectono-geodynamic structures; 3) the main characteristics of sedimentary cover and bedrock; 4) geochemical characteristics; 5) parameters of mineral complexes and fluid inclusions in mineral neoformations; 6) the value of the distribution of meiobenthos. Based on modern views of oil and gas geology, structural-tectonic and lithological-facies criteria are among the main ones. The study of the mineralogical component of sediments is made with using mineralogical, thermobarogeochemical and X-ray spectral methods. Fixation of anomalies of fluid flow at the bottom of the Black Sea as to the distribution of abiotic parameters in order to assess the prospects of oil and gas is determined by structural and tectonic features and high permeability of fluid flow; parameters of mineral complexes (minerals, facies) and genetic connections; heterogeneity of geochemical characteristics of bottom sediments; the presence of hydrocarbon inclusions in authigenic minerals of bottom sediments.


2013 ◽  
Vol 10 (6) ◽  
pp. 3943-3962 ◽  
Author(s):  
A. Capet ◽  
J.-M. Beckers ◽  
M. Grégoire

Abstract. The Black Sea northwestern shelf (NWS) is a shallow eutrophic area in which the seasonal stratification of the water column isolates the bottom waters from the atmosphere. This prevents ventilation from counterbalancing the large consumption of oxygen due to respiration in the bottom waters and in the sediments, and sets the stage for the development of seasonal hypoxia. A three-dimensional (3-D) coupled physical–biogeochemical model is used to investigate the dynamics of bottom hypoxia in the Black Sea NWS, first at seasonal and then at interannual scales (1981–2009), and to differentiate its driving factors (climatic versus eutrophication). Model skills are evaluated by a quantitative comparison of the model results to 14 123 in situ oxygen measurements available in the NOAA World Ocean and the Black Sea Commission databases, using different error metrics. This validation exercise shows that the model is able to represent the seasonal and interannual variability of the oxygen concentration and of the occurrence of hypoxia, as well as the spatial distribution of oxygen-depleted waters. During the period 1981–2009, each year exhibits seasonal bottom hypoxia at the end of summer. This phenomenon essentially covers the northern part of the NWS – which receives large inputs of nutrients from the Danube, Dniester and Dnieper rivers – and extends, during the years of severe hypoxia, towards the Romanian bay of Constanta. An index H which merges the aspects of the spatial and temporal extension of the hypoxic event is proposed to quantify, for each year, the intensity of hypoxia as an environmental stressor. In order to explain the interannual variability of H and to disentangle its drivers, we analyze the long time series of model results by means of a stepwise multiple linear regression. This statistical model gives a general relationship that links the intensity of hypoxia to eutrophication and climate-related variables. A total of 82% of the interannual variability of H is explained by the combination of four predictors: the annual riverine nitrate load (N), the sea surface temperature in the month preceding stratification (Ts), the amount of semi-labile organic matter accumulated in the sediments (C) and the sea surface temperature during late summer (Tf). Partial regression indicates that the climatic impact on hypoxia is almost as important as that of eutrophication. Accumulation of organic matter in the sediments introduces an important inertia in the recovery process after eutrophication, with a typical timescale of 9.3 yr. Seasonal fluctuations and the heterogeneous spatial distribution complicate the monitoring of bottom hypoxia, leading to contradictory conclusions when the interpretation is done from different sets of data. In particular, it appears that the recovery reported in the literature after 1995 was overestimated due to the use of observations concentrated in areas and months not typically affected by hypoxia. This stresses the urgent need for a dedicated monitoring effort in the Black Sea NWS focused on the areas and months concerned by recurrent hypoxic events.


2002 ◽  
Vol 46 (8) ◽  
pp. 59-66 ◽  
Author(s):  
E. Okuş ◽  
A. Aslan-Yilmaz ◽  
A. Yüksek ◽  
S. Taş ◽  
V. Tüfekçi

As part of a five years monitoring project “Water Quality Monitoring of the Strait of Istanbul”, February-December 1999 nutrient dynamics of the Black Sea-the Sea of Marmara transect are studied to evaluate the effect of discharges given by deep disposals. Through a one-year study, upper layer nutrient concentrations were generally under the effect of northwestern-shelf Black Sea originated waters. This effect was strictly observed in July, when the upper layer flow was the thickest. On the other hand, partly in November but especially in December the northwestern-shelf Black Sea originated water flow was a minimum resulting in similar concentrations in both layers. Nutrient fluctuations also affected the chlorophyll a and POC concentrations as parameters of productivity. The nutrient concentrations decreased with the effect of spring bloom and highest chlorophyll a values were detected in November at Strait stations that did not match to the Sea of Marmara values. This fact represents the time-scale difference between the Black Sea and the Sea of Marmara. On the contrary, high nutrient concentrations in the lower layer (especially inorganic phosphate), and therefore low N:P ratios reflect the effect of deep discharge. Vertical mixing caused by meteorological conditions of the shallow station (M3) under the effect of surface discharges resulted in homogenous distribution of nutrients. Nutrient concentrations of the stations affected by deep discharge showed that the two-layer stratification of the system did not permit the discharge mix to the upper layer.


2017 ◽  
Vol 265 ◽  
pp. 580-586 ◽  
Author(s):  
L.N. Fesenko ◽  
I.V. Pchelnikov ◽  
R.V. Fedotov

A selection of anode coatings has been studied to get sodium hypochlorite in low concentrationduring the electrolysis of 3% solution of sodium salt and the Black Sea water. The corrosive resistance of anodes has been determined, with different batches of ruthenium and iridium oxides, as well as their characteristics: chlorine outlet while passing throughthe current, voltage on the cell, the dynamics of concentration growth of available chlorine in solution.


Author(s):  
A.K. Akhmadiev ◽  
◽  
V.N. Ekzaryan

The paper notes that the hydrocarbon potential of the Black Sea-Caspian region is not exhausted, and therefore the development of its resources is intensifying. The exploitation of oil and gas fields is closely associated with negative consequences for theenvironment. Therefore, the geo-environmental features of the area must be studied and taken into consideration. In relation to the Black Sea-Caspian region the authors have identified and described such features as: the diversity of geopolitical, regional-geological, geographical conditions; the factor of stability of the geological environment; oil pollution of the marine environment and the organization of monitoring of oil pollution.


2021 ◽  
Author(s):  
Valentina Yanko ◽  
Anna Kravchuk ◽  
Irina Kulakova ◽  
Tatiana Kondariuk

<p>This <span>presentation</span> represents a case study that reviews research into the relationship between meiobenthos distribution and concentrations of hydrocarbon gases (HG), primarily methane, in the sediments of the northwestern part of the Black Sea, including gases released by mud volcanoes and gas seeps. Evidence forming the basis of this research comes from meiobenthos here represented by 29 species of benthic foraminifers, 7 species of ostracods, and 44 species of nematodes. The potential use of these meiobenthic organisms as indicators of gaseous hydrocarbons reservoirs existing under the seabed is evaluated according to two linked axes, namely the dual analysis of abiotic factors (physical and chemical parameters of the water column, gasmetrical, geochemical, lithological, and mineralogical properties of the sediments) and biotic characteristics (quantitative and taxonomic composition of foraminifers, nematodes, and ostracods). Studies of this kind have been directed toward developing interdisciplinary methods to improve the search for HG accumulations, especially methane, under the seabed. Development of such methods might have substantial socio-economic importance for the economy of Ukraine as well as that of other Black Sea countries, and such methods might also contribute to the sustainable development of Black Sea ecosystems.</p>


Author(s):  
I.V. Nedosekova ◽  
I.V. Karpenko ◽  
G.S. Starchenko ◽  
I.V. Karpenko ◽  
G.S. Starchenko

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