Mechanical properties of tight sandstone in Yan'an Panlong area under true triaxial conditions
In order to analyze the strength and deformation of the tight sandstone in Yan'an Panlong area under different loading states,a true triaxial experiment was carried out using YSZS-2000 electro-hydrau-lic servo rock true triaxial testing machine.In the experiment,the relationship between compressive strength and confining pressure under conventional triaxial stress and the effect of σ3 and σ2 on the strength and de-formation of tight sandstone under true triaxial stress were studied.The results show that under true triaxial stress both σ3 and σ2 protect the strength of tight sandstone,which enhances the bearing capacity of rock.The elastic modulus and peak strength of the rock sample increase with the increase of σ3 and σ2,while the peak strain gradually decreases.From the shape of σ1-ε1 curve,it can be seen that the curve rises and falls sharply before and after the peak value,indicating that the tight sandstone in the study area has obvious brittle characteristics.Therefore,the study area is prone to forming fractures during the fracturing process,which is beneficial for unconventional oil and gas and provides a good reference for oil and gas production of tight sandstone.
true triaxial testunconventional oil and gastight sandstonestrengthdeformation
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