Comparative Study of Gravel Suspension Properties of Hydroxyethyl Cellulose and Xanthan Gravel Pack Fluids

Transportation of proppant from surface to the desired location downhole during gravel packing operations in the petroleum industry is challenging. Various fluid systems have been used to do this. Depending on the type of polymer used as viscosifier, the fluid systems have different properties. Part of the criteria used to qualify gravel carrier fluids in hydraulic fracturing and gravel pack operations is their ability to suspend and transport solids. Almost all fluids can transport solids if the velocity is high enough. However, at low velocity or in a static state, the tendency of the solids to settle out is high for many fluids. Therefore, it is essential to formulate fluid system that is capable of proppant suspension and transport, especially at the low velocity areas of the wellbore during job execution. The fluid property and gel structure play a very important role in this regard. In this paper, the sand suspension properties of Hydroxyethyl cellulose (HEC) and xanthan polymer fluids were investigated at various temperatures for different polymer loadings. The study showed that settling rate is affected by thermal stability of the polymer fluid system and by the rate of degradation of the polymer by chemical breakers. HEC exhibited higher apparent viscosity than xanthan for the same polymer concentration, but xanthan showed superior sand suspension capability than HEC at the same condition. The result obtained can help in engineering designs to determine optimum pump rate without fear of proppant settling out of the suspension.