Study on the conductivity of proppant in shale reservoir

Abstract

At present, in the process of developing shale reservoirs by hydraulic fracturing, proppants play a critical role in the overall fracturing effect. Therefore, accurately evaluating the conductivity of different proppants determines the development effect of shale reservoirs. In this paper, proppant screening is first carried out, and the conductivity of four different proppants under laying concentration and closing pressure is studied, including 10-20 mesh quartz sand proppants with non-standard particle size, and the influence of different factors on the embedding degree is analyzed. It is concluded that the bearing capacity of ceramsite proppant is usually 2-3 times stronger than that of quartz sand. The larger the particle size of quartz sand proppant is and the higher the concentration of sand is, the stronger the conductivity is. When the closed pressure of large-size quartz sand is less than 30 MPa, the laying concentration of 14 kg/m2 can obtain higher conductivity, and when it is greater than 30 MPa, 12 kg/m2 is more suitable for field application. The ceramsite proppant has been on the rise with the increase of closing pressure and sand concentration. The embedding depth gradually increases with the increase of closing pressure and the decrease of sand concentration. The embedding depth of shale is greater than that of sandstone, and the flow conductivity of proppant is usually lower than that of sandstone. According to the experimental results, large-size quartz sand has strong conductivity, but it is not easy to migrate and has poor bearing capacity. Therefore, large-size quartz sand proppant can be used in the low-pressure part near the well, supplemented by small-size quartz sand (40-70 mesh) to obtain better fracturing results. This study provides some technical guidance for shale reservoir development and shale fracturing dessert identification.