Tynyna S.V., Babenko V.G. Investigation of the fluids influence on change of sandstones collectors mechanical properties during saturation and degassing

Details
Parent Category: Geo-Technical Mechanics, 2019
Category: Geo-Technical Mechanics, 2019, № 148

Geoteh. meh. 2019, 148, 162-169

https://doi.org/10.1051/e3sconf/201910900103

INVESTIGATION OF THE FLUIDS INFLUENCE ON CHANGE OF SANDSTONES COLLECTORS MECHANICAL PROPERTIES DURING SATURATION AND DEGASSING

1TynynaS.V., 2 Babenko V.G.

1Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine,  2Ukrainian State University of Chemical Technology

UDC 622.831:539.3                                        

Language: English

Abstract. The article discusses the effect of fluids on the properties of rocks. It is known that surface active environments, including gas, can significantly change the mechanical characteristics of solids. To establish the dependence of the effect of methane on the strength characteristics of rocks, the results of full-scale and laboratory studies are considered. The experiments were carried out on samples of outburst sandstone formation m3, taken at a depth of  915 m. Analysis of research results allowed to establish the effect of changes in gas saturation of rocks on their mechanical properties before and after degassing and partial discharge of experimental areas after they have been worked by wall face along m3 formation. It has been established that the reason for the increase in drill ability and strength of sandstones was their degassing, and not a change in the stress state of the environment. This led to a change in the deformation properties of rocks in gas-saturated and degassed states.

Shown, that the mechanical characteristics of outburst and outburst-safe sandstones differ noticeably among themselves. But these differences are clearly seen in the gas-saturated state of the rocks and are largely smoothed out when they are degassed. Sandstone strength in outburst zones is on average f = 8, in outburst-safe f = 11, i.e. it differs 1.4 times.

The results of experimental studies have shown that methane, like other fluids, reduces the strength of outburst sandstones.

This in particular can be explained why, when tested on degassed samples taken in outburst and outburst-safe zones, the differences in strength properties are not traced or expressed weakly, which leads to contradictory interpretations in assessing the causes of local zonality of emissions.

Shown, that the fact that the change in the mechanical characteristics of outburst sandstones during their gas saturation and degassing occurs within the same limits indicates that mass transfer processes and the degree of gas saturation of the rocks affect the change in properties and are not accompanied by irreversible changes in the structure of the environment.

It is established that decrease in strength and increase in deformation properties of rocks in a gas-saturated state testify that for their destruction smaller tension and energy value are required. This is one of the forms of influence of gas on outburst, which must be considered when studying the nature and mechanism of gas-dynamic phenomena and quantifying their parameters.

Keywords: sandstone, stress state of the medium, gas saturation of rocks, mechanical properties, fluid, change in strength.

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About the authors

Tynyna Sergiy Volodymyrovych, Candidate of Technical Sciences (Ph.D), Senior Researcher at the Department of Elastomeric Component Mechanics in Mining Machines, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine (IGTM NAS of Ukraine), Dnipro, Ukraine This email address is being protected from spambots. You need JavaScript enabled to view it. .

Babenko VasylGrygorovych, Senior Lecturer, Ukrainian State University of Chemical Technology, Dnipro, Ukraine This email address is being protected from spambots. You need JavaScript enabled to view it.