The productivity of a well following fracturing is directly proportional to both the fracture-flow-capacity: formation-flow-capacity contrast ( flow capacity of the fracture divided by the flow capacity of the formation) and the extent of the fractured area.
The fracture’s fluid carrying capacity is controlled by the fracture width, the proppant distribution, and the proppant concentration. The post-fracture width is controlled by the size of the prop that was placed during fracturing operations, the characteristics of the formation, the proppant strength, and the well depth. To insure proper concentration and distribution, the propping agent may be diluted with another material that is similar in particle size, shape, and density, and that is soluble in well fluids. The diluent occupies space in the fracture and prevents the proppant from being deposited in a full monolayer. After fracturing, the spacer material is dissolved, leaving the proppant in a sparse distribution with wide channels throughout the fracture so that hydrocarbons can flow into well.