Browsing by Subject "fractures"

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Access status: Open Access ,
Pomiary XRMI w utworach cechsztynu
(Wydawnictwa AGH, 2013) Romaniuk, Wiesława
Pomiar XRMI bazuje na kontraście mikroopornościowym skał. Sonda jest nazywana przyrządem »o rozszerzonym zakresie«, ponieważ daje bardzo dobrej jakości obraz ściany otworu, nawet w formacjach o wysokiej oporności (>2000 $\Omega$ $\cdot$ m) i przy stosowaniu zasolonych płuczek o relatywnie niskich opornościach (<0,1 $\Omega$ $\cdot$ m). Dzięki dużej rozdzielczości pionowej pomiarów sonda ta daje możliwość interpretacji powierzchni warstwowania wraz z informacją o tym, w którym kierunku i pod jakim kątem są one nachylone oraz zidentyfikowania fałdów, uskoków i mikrouskoków, spękań, niezgodności kątowych. Na obrazach mikroopornościowych zaznaczają się również struktury powstałe w wyniku odwiercenia otworu: szczeliny indukowane, struktury wykruszeniowe typu breakouts, ślady świdra. Pomiary sondą XRMI mają wiele zastosowań w interpretacji strukturalnej i sedymentologicznej, mogą dostarczać również informacji o właściwościach mechanicznych górotworu, przydatnych zarówno w procesach wiercenia otworu, jak i podczas zabiegów szczelinowania.
Access status: Open Access ,
The fluid flow modeling procedure including a critically stressed fracture analysis of coalbed methane reservoir: a case study of Upper Silesian Coal Basin, Poland
(Wydawnictwa AGH, 2023) Kępiński, Michał; Ryder, Paweł; Dudek, Jacek; Podsobiński, Daniel
The geomechanical modeling turned out to be an essential component of the hydrocarbon exploration assisting reduction of risk of drilling issues and optimization of hydraulic fracturing treatment. This study provides a workflow of critically stressed fracture (CSF) analysis dedicated for coal layers. The main focus of the paper is applying the 1D mechanical models and following modelling of hydraulic fracturing treatment to describe the fracture behavior under the impact of the stresses at the wellbore scale. Another objective of presented study is demonstration of benefits of 1D and 3D CSF analysis to understand fracture contribution to gained volume of hydrocarbon after fracturing of coal seam. Interpretation of fracture orientation and their behavior is vital to effective development of coal bed methane (CBM) resources as the CSF can be responsible for considerable part of CBM production. Natural fractures and faults contribute to fluid flow through rock. It is often noted that natural fractures may not be critically stressed at ambient stress state. However, during stimulation the optimally oriented natural fracture sets have an inclination to become critically stressed. Hence, understanding of the recent stress state and fracture orientations is significant for well planning and fracturing design. The outcome of this study are comprehensive 1D mechanical Earth models (MEMs) for analyzed wells and explanation of behavior of identified CSF under variable stress state as well as understanding of the connectivity of natural fractures within zone subjected to fracturing treatment.
Access status: Restricted ,
Zastosowanie sejsmiki do określenia anizotropii w celu charakterystyki szczelin i spękań
(Data obrony: 2014-07-24) Młyńczak, Mateusz
Wydział Geologii, Geofizyki i Ochrony Środowiska
In contrast to the isotropic medium, vertical and horizontal wave velocity differs - which is related to the anisotropy medium. Polar anisotropy „VTI” causes the so-called „Hockey sticks”on the far offsets, because the wave velocity increases by going along the layer. Based on Plock - Sierpc - Płońsk 2D data Thomsen parameters were calculated for nonhyperbolic moveout corrections to align the so-called „Hockey sticks”. The result is a quality improvement of seismic section through better stacking far offsets. On the other hand azimuthal anisotropy called „HTI” is associated with the occurrence of cracks and fractures. Area with the best fold, the range of azimuths and offsets was divided into bins using Werynia – Widełka 3D seismic data. In each bin the CMP collections was sorted by azimuths. When seismic reflexes take shape of sinusoid which is related to the anisotropy, we are peaking maxims corresponding to fast direction. Results are presented in the form of maps on which every single line is associated with fast direction and tell us about the azimuth of fractures and cracks.