Experimental study on the flow conductivity of quartz sand-ceramsite proppant

In order to optimize the proppant for the reservoirs with closure stress of 25-35 MPa, the FCES-100 fracture conductivity evaluation system was used to measure the percent reduction and flow conductivity of ceramsite and quartz sand that are used on site in the Changqing Oilfield, the flow conductivity of quartz sand-ceramsite mixed proppant by varying their volume ratio, and the flow conductivity of quartz sand-stern chase ceramsite proppant by varying their ratio, according to the recommended practices under SY/T 6302-2009. It is shown that, at different closure stresses, the flow conductivity of quartz sand-stern chase ceramsite proppant is higher than that of quartz sand-ceramsite uniform mixture when the volume ratio of quartz sand to ceramsite is 1:1, 2:1 and 3:1. The higher the closure stress is, the larger their difference is. In the same conditions, the stern chase type is preferred. When the volume ratio of quartz sand to ceramsite is 1:1, the mixed type is close to the stern chase type in terms of flow conductivity. As for the reservoirs with closure stress of 35 MPa, either mixed type (1:1) or stern chase type suitable, but considering the cost, it is recommended to select the stern chase type (2:1). It is suggested to adopt stern chase type (3:1) for the reservoirs with closure stress of 25 MPa and stern chase type (4:1) for the reservoirs with closure stress of 20 MPa. When the closure stress is 25-35 MPa, the proppant can provide sufficient flow conductivity if the ceramsite accounts for 50%, which can be taken as the upper limit of ceramsite. The experimental data provides the important basis for the optimization of proppant in reservoirs with in-situ closure stress of 25-35 MPa.