High Strength, Ultralightweight Proppant Lends New Dimensions to Hydraulic Fracturing Applications

Abstract

Since the earliest fracturing treatments more than 50 years ago, many different materials have been used including sand, glass beads, walnut hulls, and metal shot. Today's commonly used proppants include various sands, resin-coated sands, intermediatestrength ceramics, and sintered bauxite-each employed for its ability to cost-effectively withstand the respective reservoir closure stress environment. As the relative strength of the various materials increases, so too have the respective particle densities, ranging from 2.65 g/cm 3 for sands to 3.4 g/cm 3 for the sintered bauxite. Unfortunately, increasing particle density leads directly to an increasing degree of difficulty with proppant transport and a reduced propped-fracture volume for equal amounts of the respective proppant, thereby reducing fracture conductivity. Intuitively, one expects that a lesser-density proppant would be easier to transport, allowing for reduced demands on the fracturing fluids, and if it had sufficient strength, would provide increased width, and hence, enhanced fracture conductivity.Previous efforts undertaken to employ lower-density materials as proppant have generally resulted in failure because of insufficient strength to maintain fracture conductivity at even the lowest of closure stresses (1,000 psi). Recent research on material properties has at last led to the development of an ultralightweight (ULW) material with particle strength more than sufficient for most hydraulic fracturing applications. The current ULW proppants have apparent specific gravities of 1.25 and 1.75 g/cm 3 . Laboratory tests will demonstrate exceptional fracture conductivity at stresses to 8,000 psi. This paper presents data illustrating the performance of the new ULW proppant over a broad range of conditions and a discussion of relative performance in field applications.

Investigation of ultra-light weight proppant application in shale fracturing

“…However, most ULWPs cannot provide as much conductivity as conventional proppants due to their weaker strengths. Generally speaking, the strength of a proppant decreases with decreasing density [16]. Another disadvantage of ULWP is the more complex manufacturing process and hence higher proppant cost.…”

“…Rickards et al [16] introduced two ultralight-weight proppants. One is a porous ceramic particle coated with resin with a specific gravity of 1.75 (called ULW-3 in this paper), while another is a grounded walnut hull coated with resin with a specific gravity of 1.25 (called ULW-2).…”

Waterless fracturing technologies for unconventional reservoirs-opportunities for liquid nitrogen

“…Although self-propping by rubblizing fracture surfaces is considered as a contribution for fracture opening at shallow depths, this possibility is minimized for deep formations having tight cementation. However, with the recent development of ultralight weight proppants (Rickards et al 2006;Gu et al 2015), hundreds of gas fracturing jobs pumping 100% nitrogen were successfully performed in shallow shale and siltstone gas plays in Canada during 2006(Canyon, 2016.…”

Investigation of the Basic Properties of Ceramic Proppants in Raw State Obtained by the Method of Mechanical Granulation

“…As a result, the greatest hopes are in ceramic proppants whose properties can be shaped and adapted to present needs [14]. Ceramic proppants [15,16] with appropriate parameters: size, durability, roundness and sphericity, resistant to the conditions prevailing in the deposit may increase the stimulation of the shaft as much as 30%.…”