Mechanical characteristics evaluation of the Fu2 member shale reservoir in the Subei Basin
In order to understand the mechanical characteristics,compressibility and frac-ture extension law of shale reservoir in Fu2 member of Subei Basin,mineral composition analysis,triaxial mechanical experiment,and in-situ stress magnitude and direction experi-ment were carried out with the core of HY1 well as the research object,which provided technical support for block compressibility evaluation and fracturing process optimization.The results show that calcite(23.9%),quartz(22.7%)and clay minerals(21.3%)dominate the Fu2 member of Gaoyou Sag.The average brittleness index is 58.6,the average brittleness of page 1～2 layer is 69.7,the average brittleness index of page 3 layer is 57.9,and the aver-age brittleness index of page 4～5 layer is 48.4.The core average Poisson's ratio and average Young's modulus of Fu2 member in Gaoyou Depression are 0.183 and 15 469.6 MPa.The stress-strain curve shows that the core of the Fu2 member mainly exhibits elastic characteris-tics.The maximum vertical stress(81.00～83.00 MPa)and minimum horizontal principal stress(60.00～64.00 MPa)are in the middle,and the maximum horizontal principal stress(73.00～76.00 MPa)is in the direction of N43.76E.The mineral in Fu2 member is relatively brittle,the brittleness index is high,and the average stress difference coefficient is 0.2,which can form a certain branch joint,which is beneficial to the formation of complex cracks.
mineral compositiontriaxial stressmechanical parameterscrustal stress
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