Calculation Of Filtration And Flowback Rate Of Fracturing Fluid In Fuyang Oil Layer

Hydraulic fracturing is an important technology of stimulation. In the process of fracturing, it is inevitable for the fracturing fluid to leak into the formation, so the effective flowback of fracturing fluid after fracturing operation is an important step in hydraulic fracturing. Fuyang oil layer falls into low porosity and low permeability oil layer, which has a poor reservoir property. In this paper, the filtration and flowback rate of fracturing fluid of Fuyang oil layer and the volume of fracturing fluid that can not be flowed back are determined, the influence factors of filtration and flowback rate are analysized in order to offer a theoretic basis for improving the flowback rate of fracturing fluid and provide the guidance of fracturing and flowback operations.In this paper, according to the theory of fluid flow in porous media,a 2D calculation model of fracturing fluid filtrate loss in the stage of fracturing operation is established on comprehensive consideration of the formation condition and the fluid property. According to the theory of volumetric balance, the fracturing fluid model and the blowing flowback model of shut-in stage are established. The numerical solution of the fracturing fluid and the blowing flowback model are given. The filtration, the blowing flowback volume and the blowing flowback rate of the actual well of Fuyang oil layer are calculated by VB programming. The influence factor of the filtration and blowing flowback rate and the filtration rates of the reservoirs which have different permeability are analyzed. By using the method of ion density component analyse and calculating the pumping and drainage data, the rate of the fracturing fluid which is draining out in the pumping stage can be solved. That is pumping flowback rate. According to the capillary force theory, the pressure gradient which is from fracturing fluid flowing in hollow billets with different sizes can be calculated. Combining intrusive mercury curve from wells in Fuyang oil layer, the effect of the capillary force on the flowback of fracturing fluid is analyzed.