Study On The Conductivity Of Sandstone Artificial Fracture

Domestic gravel reservoirs generally have deep burials,severe heterogeneity and thick oil layers.These characteristics have caused a lot of trouble for fracturing.In this paper,we first conducted laboratory mechanical experiments on natural rock samples taken from the site.The results show that the hardness of gravel in gravel is much greater than that of matrix,and the hardness difference between gravel and gravel is also large;fine conglomerate is denser and more dense than coarse conglomerate Biased brittleness,with the increase of confining pressure,the plasticity characteristics of gravel conglomerate strengthen and the brittleness characteristic gradually weaken;through the rock sample observation after compression,it is found that the gravel conglomerate mainly breaks around gravel,breaks through and breaks down.Secondly,the large-scale true triaxial hydraulic fracturing experiment was conducted on the artificially prepared rock samples.It was concluded that the larger the gravel particle size,the more severe the overall bending of the crack,the more likely to be branch cracks,and the higher the pressure value of the pumping pressure curve,The greater the amplitude,the stronger the curve fluctuations;as the gravel content increases,the fracture geometry becomes more complicated,the surface is more uneven,more branch cracks appear,and the pumping pressure curve fluctuates more frequently and the fracture pressure value is higher.Finally,this paper mainly studies the fracture conductivity of sandstone and conglomerate from the two aspects of proppant and gravel.It is found that when the closing pressure is small,the higher the rock slab gravel content,the stronger the fracture conductivity.Afterwards,as the closing pressure increases,the gravel The higher the content,the faster the decrease of the conductivity,but the faster it is;the greater the proppant sand concentration at the beginning of the experiment,the stronger the fracture conductivity.When the sand concentration reaches a certain value,continue to increase the sand concentration,the fracture conductivity does not increase,even a downward trend.