This paper discusses the assessment methodology of geologic probabilities of success of drillable prospects determined by petroleum exploration geologists. The commonly accepted industry standard assessment methods suggest the probability evaluation of key components of oil and gas accumulation: source rock, reservoir, seal rock and trap, and migration and timing. On the assumption that the risked events resulting in the assembly of the key components are geologically and eventalgebraically independent, the geological probability is computed as the product of the probabilities of each. Without challenging the overall correctness of the approach, this study argues that the presumed independency does not always apply. For these cases, probability evaluation of the actually and truly independent geologic and hydrodynamic processes is advised.
Understanding and simulating the interaction of groundwater and surface water is essential to hydrologists. Water supply and water quality aspects are a few examples of common water-resource issues where understanding the interconnections of groundwater and surface water is fundamental to develop an effective water-resource management and policy. In our study a detailed investigation of a riverbank aquifer was performed to be able to simulate and predict the behavior of the flow system. The continuous hydraulic head measurements in the area of interest showed strong influence on the hydraulic head field caused by intensively changing river head at a distance from the river up to 3,500 m. Based on the results steady state and transient flow calculations were compared, and a great effort has been made to ensure that the model more precisely describe the time and space variable flow field. Beside fulfilling the standard calibration requirements, a multi-step calibration process was performed.
In June 2003 Hungary accepted the European Standard for Aggregates for Railway Ballast (MSZ EN 13450: 2003). The European norm, compared with the Hungarian Standard, also includes a new examination method called the micro-Deval method for railway ballast aggregates, which was previously not used in Hungary. This paper presents the test results of aggregates for railway ballast-producing quarries, according to newly accepted Standard. The test materials consist of andesite, basalt, dolomite and limestone. The results cover a significant range. The study was aimed at finding a relation between the testing methods, in order to reduce the testing procedure; however, no clear relationship was found.
Authors:István Vető, Katalin Báldi, Stjepan Ćorić, Magdolna Hetényi, Attila Demény, and István Futó
understand the relationship between depositional environment and source rock quality.
In this study, our results are obtained by a combined application of standard geochemical and micropaleontological methods on the marine Middle Miocene (Badenian age
Authors:Nawal Bouya, Hmidou El Ouardi, Hassania El Habibou, Véronique Ansan, and Eric Mercier
The aim of this work is to interpret the geologic structures of the Agourai area (Paleozoic and Mesozoic structures) from processed magnetic maps. The detected magnetic anomalies from different standard methods used in aeromagnetism (Residual map, RTP map, horizontal gradient map) were compared to geologic structures and permit enhancing the mapping quality of some areas, and thus defining many geologic features. Existing geologic maps and geologic field studies allow interpreting some detected anomalies. It was thus possible to define the limits between the Paleozoic basement and the Mesozoic cover, to determine magnetic anomalies according to NE-SW trends compatible with the regional geologic structures and finally to detect a NE to SW-oriented fault system in the Mesozoic cover of the Agourai Plateau. Despite the reliability of this approach, some folded basaltic sills occurring in this region were not well detected, probably because of their reduced thickness.
The uncertainty in the semivariogram has hardly been investigated in previous geostatistical studies. This paper presents an efficient methodology of uncertainty assessment based on the bootstrap. By applying this computer-intensive statistical method one can easily simulate the distribution of the empirical semivariogram estimate for each lag. The lag-wise standard errors and confidence intervals of a given level can then be easily calculated from the bootstrap replicates. These estimations are valid in any situation when classical statistics fail. The bootstrap also provides a mathematical-statistical tool to decide whether the semivariogram reaches its maximum at a given lag or not. It leads directly to a simple determination of the range of influence. Effects beyond the range, such as the hole effect, can be explored with the same approach. The empirical semivariogram, supplied by measures of uncertainty, adequately describes the true spatial behavior of the studied variable. This universal method renders the customary theoretical semivariogram models obsolete.