Fracture conductivity in many hydraulic-fracturing treatments can be inadequate. It is greatly affected by the concentration of the packed proppant in the fracture. Higher concentrations yield higher conductivity by virtue of a wider fracture. However, there are practical limitations to the amount of proppant that can be placed into any particular reservoir, and therefore production is often conductivity limited.
An alternate approach to achieve high conductivity is to create a fracture by placing well-distributed, low-density particles characterized by a proppant concentration less than 0.1 lbm/ft2. Low particle concentrations result in fractures that have high porosity and are fundamentally different from fractures with packed beds of conventional proppants.
In this paper, the theoretical basis for the conductivity of these fractures is presented. A 3-D model has been developed to simulate high-porosity fractures created with these particles. Test data used to refine the model can be used to predict the conductivity of the fracture based on the porosity level, the closure stress, and the material properties.
Production data from two application areas in North America are shown to highlight the benefits of using this type of fracturing proppant.
A screening life cycle analysis (LCA) is included to evaluate and highlight the beneficial attributes of using a low-density proppant to achieve fractures with high conductivity. The LCA considers the impact of logistics and fracture design on the environment.