Study On The Fracturing Fluids Proppant Carrying Property And Rheo-kinetics Of Crosslinking Process

In this paper, the relationship between single-particle settling rate of proppant and viscoelasticity of five kinds of linear gel fracturing fluids, including hydroxypropyl guar (HPG), modified cellulose(FAG-500), high-temperature resistance polymer (XST239), seawater polymer(XSP) and rapid soluble xanthan gum(XCD), was studied. The static crosslinking processes and intrinsic rheokinetics equations, the crosslinking processes and rheokinetics in shearing fields for HPG, FAG-500 and XST239 fracturing fluids were studied respectively. Main conclusions were made as followed:1) Linear gel fracturing fluids are all shear thinning fluids. Nonlinear co-rotational Jeffreys model can be used to describe the flow curves. Power law model is suitable for the relationship between single-particle settling rate of proppant and viscoelasticity of the five linear gel fracturing fluids. The micro structures of linear gel fracturing fluids were also observed.2) The effects of temperature, concentration of crosslinking agent and thickening agent on the Elasticity Indexes (EI) curve in static crosslinking processes of HPG, FAG-500 and XST239 fluids are made clear. The intrinsic crosslinking rheokinetics models are proven to well describe the static crosslinking process. The intrinsic crosslinking rheokinetics models of HPG, FAG-500 and XST239 under experienmental conditions are obtained. The crosslinking process of FAG-500 can be divided to two stages, which can be described by the intrinsic crosslinking rheokinetics model.3) The effects of temperature, concentration of crosslinking agent and thickening agent on the viscosity curve during the crosslinking process in shearing field for HPG, FAG-500 and XST239 are also obtained. Shearing rheokinetics models are established under experienmental conditions for these fracturing fluids.4) The crosslinking processes and flow regime of sand-carrying fluids with different kinds of fracturing fluids, proppants, and sand proportion are observed on the Visualizing Simulation System of Proppant Transportation (VSSPT). The viscosity curve is described by the shearing rheokinetics. The physical meaning of model parameters are clear and reasonable. The studies provide the rheological basis for the application of fracturing fluid.