Study on Relationship between Sedimentation Rate of Single Proppant Particle and Viscoelasticity of Linear Colloid Fracturing Fluid

The effect of viscoelasticity of thickening agent solution on the sedimentation rate of proppant particles was studied through static sedimentation test of a single proppant particle in the solution of thickening agent used in linear colloid fracturing fluids.Effort was made to explain the study results using characterization of the internal structure of the linear colloid fracturing fluid.It is understood that the sedimentation rate of a single proppant particle decreases with increase in viscoelastic modulus.Some linear colloids, such as hydroxypropyl guar gum(HPG) and FAG-500, a cellulose, appear to be more viscous, while XST239, a high temperature polymer, has viscosity that is equivalent to its elasticity.The sand suspension capacity of these three thickening agents is a mixture of the function of the viscosity and the elasticity of these agents, and thus has the maximum fitting correlation coefficient with the complex modulus G^*.The fitting results are:lgu=-1.6928 lgG^*+0.2468, lgu=-0.9214 lgG^*-0.1824, lgu=-1.6928 lgG^*+0.2468, lgu=-0.8307 lgG^*-0.2132.Low concentration XCD solution is more of an elastic solution, and the sedimentation rate of proppant particles is determined by the elastic modulus of the solution:lgu=-2.0426 lgG'-0.1286.Characterization by FE-SEM shows that XCD solution has honeycomb structures inside it, and XST239 solution has dense lamellar structures in it, while in HPG and FAG-500 solutions, there are loose lamellar structures.