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Hydraulic fracturing
Mazáček, Michal ; Mls, Jiří (advisor) ; Fischer, Tomáš (referee)
This bachelor thesis deals with the process of hydraulic fracturing. Hydraulic fracturing (also called fracking or fracjob) is a method used for the stimulation of the oil or gas reservoirs. The point of the method is to inject the liquid under high pressure into the formation. The injection cause widening of existing fractures or making new ones. The goal of this thesis was to describe basic knowledge that are necessary to successful treatment. There were basics of rock mechanics described such as linear elasticity, plasticity etc. The main chapter describes the parameters of the fracture such as fracture wide, fracture height, fluid flow and fluid loss. Furthermore, the kinds of liquids were discussed in one chapter. In the end, the fracturation which had been done in Texas(USA) were shown and the spreading of the fractures were discussed.
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Historical seismicity and geophysical survey of tectonics in the Cheb area
Hrdličková, Markéta ; Fischer, Tomáš (advisor) ; Horálek, Josef (referee)
This work deals with the documentation of the space-time distribution of seismic activity in the years 1897-1908 in the western Bohemia, using original sources. The region of Vogtland / northwest Bohemia is known as one of the most interesting European regions with the occurrence of earthquake swarms. Seismic catalogs are available for this area only for the last few decades when the seismic stations were in operation. For the earlier period only macroseismic observations are available. The aim of this work is to compile the catalog of earthquakes for the years 1897-1908 with the use of the macroseismic data. This requires estimating the origin time of earthquakes using the distribution of the macroseismic observations in time. First, the original historical materials Mittheilungen der Erdbeben-Commission der kaiserlichen Akademie der Wissenschaften in Wien were compared with geophysical catalog of Vít Kárník Erdbebenkatalog der Tschechoslowakei bis zum 1956, which is a summary of selected data from the original materials. Macroseismic observations from the catalog were digitized in the form spreadsheet tables. It turned out that in most cases the data in the Kárník's catalog represent observations of earthqukes and in isolated cases these are the seismic events themselves. Cluster analysis was...
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Modelling of the low-velocity layer in seismic prospection
Procházka, Jan ; Fischer, Tomáš (advisor) ; Skopec, Jiří (referee)
The subject of the thesis is to compare layered model and tomographic model. These models are used for description of low velocity layer in seismic survey. The goal of the work was to find out the conditions whether to prefer tomographic model instead of layered model. Program Geostar was used for modelling of low velocity layer. This program is a part of software package produced by CGG Veritas company. Geostar is available at department of Applied Geophysics for study purposes. Four synthetic models were created for comparison of tomographic and layered models. Models of low velocity layer were computed for layered an tomographic model in Geostar environment. Original models were compared to created models. Accuracy was estimated on root mean square error and static correction which was exactly known. In all cases, layered model showed better results then tomographic model. 1
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Seismic monitoring of fluid contacts from horizontal wells
Janská, Eva ; Vilhelm, Jan (advisor) ; Fischer, Tomáš (referee)
When producing oil from a thin layer with a gas cap, gas is generally unwanted since the reservoir looses pressure. The pressure loss might cause the fluid vertical migration and therefore a misplacement of the horizontal production well. This is the main reason why the oil production is held back when a gas breakthrough occurs. The well is chocked, or run on lower production rates, until the oil column is recovered, but it is not known how long this will take. If the gas-oil contact could be monitored over time, then the gas breakthrough could be better prevented by reducing production from a particular well branch or even by blinding a specific part of the branch. The aim of this research is to test if monitoring of the gas-oil contact by a seismic acquisition inside the horizontal well is feasible. This could be done much cheaper, more often and with better repeatability than classical 4D seismic. The feasibility was investigated on 2D Troll subsurface models, using finitedifference acoustic modelling. Receivers are planned in the horizontal part of the production well and suggesting the best source position was one of objectives. The influence of variations in geological settings was also investigated. The most accurate information about the gas-oil contact shape and its distance from the well is...
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How to constitute the company
Fischer, Tomáš ; Dvořáček, Jiří (advisor) ; Honzl, Václav (referee)
The goal of my work is to create a guide of constituting of Limited Liability Company. The merit is to prepare the list of acts that are needed to be performed and every needed information. The work is divided into theoretical and practical part. The theoretical part is more descriptive, the practical one chronologically presents all steps necessary for constituing the Limited Liability Company.
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