Method for Determination of the Range of Failure Zone Around Macrocracks Surface in Rock Medium / Metoda badania zasięgu strefy zniszczenia wokół powierzchni makropęknięć w ośrodku skalnym

Abstract

In this work a method, developed by the author, of microscopic investigations of deformation structures occurring in rock medium is presented. This method is based on adoption of multi-stage complex procedure encompassing numerous diverse examinations and measurements. As a result of following this method, information about geometrical features of microfractures and microfissures distribution (coordinates, length, occurrence frequency and directions of propagation) is obtained, which in turn allow to determine the range and intensity of destruction zones around macroscopic fissures in investigated samples. Testing was performed on selected three samples of the Tumlin Sandstone (three microscopic sections), representing the following states of stress-strain: sample no. 1 (σ 3 = 200 MPa confining pressure and ε 1 = 5% longitudinal strain) sample no. 2 (σ 3 = 300 MPa confining pressure and ε 1 = 10% longitudinal strain) sample no. 3 (σ 3 = 300 MPa confining pressure and ε 1 = 15% longitudinal strain)On the basis of conducted research it has been stated that increasing confining pressure σ 3 = σ 2 results in the increase of number and range of microfissures occurrence. At confining pressure σ 3 = σ 2 200 MPa and longitudinal strain ε 1 = 5% a zone of intensive fracturing is noticeable, reaching about 6mm from the surface of macroscopic fracture. However, at higher confining pressure and higher longitudinal strains (σ 3 = σ 2 300 MPa and ε 1 = 10% as well as σ 3 = σ 2 300 MPa and ε 1 = 15%) microcracks and microfissures cover almost whole volume of the sample.Keywords: confining pressure, rock mass, slip surface, microcracks, stress, strain W artykule przedstawiono opracowaną przez autora metodę badań mikroskopowych struktur deformacji występujących w ośrodku skalnym. Metoda ta polega na zastosowaniu wieloetapowej złożonej procedury obejmującej wiele różnorodnych badań i pomiarów. W wyniku jej przeprowadzenia uzyskuje się informacje o geometrycznych cechach rozkładu mikrospękań i mikroszczelin (współrzędne, długość, częstość występowania i kierunki rozprzestrzenienia), które z kolei pozwalają na określenie zasięgu i intensywności strefy zniszczenia wokół pęknięć makroskopowych w badanych próbkach. Do badań zastosowano grubo ławicowy dolno triasowy piaskowiec pochodzący z północnej części obrzeżenia Gór

Environmental Impact of Exploration from Unconventional Gas Deposits in Poland

“…Such deposits have a natural system of fractures, though the matrix has a very low permeability 30 to 100 nD [13]. In coal-bed methane deposits the density of natural fractures is a significant parameter [21,22]. Natural gas production from such rock formations cannot be performed without additional operations, eg hydraulic fracturing.…”

“…In Table 1 we have average ranges of acoustic noxiousness of particular rig elements. Among the main sources of waste present in the precipitations are: chemicals used for making and regulating technological parameters of muds, biocides, oil products, corrosion inhibitors, chemicals used for drilling up and enhancement of hydrocarbon production, reservoir fluids in the form of brine and oil [21].…”