New Epoxy Chemistry to Generate Highly Conductive Channels Within the Fracture Geometry Pillar Fracture

Abstract

A conventional proppant pack may lose up to 99% of its conductivity due to gel damage, fines migration, multiphase flow, and non-Darcy flow. Therefore, the concept of pillar fracturing was developed to generate highly conductive paths for hydrocarbon to flow. The success of the pillar fracturing treatment depends on delivering the proppant as pillar stages with a good suspension. This suspension keeps the proppant within the stage, prevents the proppant from diffusing out of the stage, and improves the mechanical strength of the pillar during closure. Resin based chemistries were proposed in the literature for proppant pack consolidation. However, most of these resins are incompatible with the aqueous fracturing fluids. This warrants for special precautions to be undertaken during pumping of the treatment to avoid formation damage. This paper discusses a new chemistry that has been developed to substitute the porous proppant pack in the fracture with an isolated structure of propped pillars containing a network of open channels. Also, this paper further discusses the experimental procedures to test compatibility of the newly developed chemistry with crosslinked fracturing fluids, optimization to use the minimum concentrations, and making hard plugs of proppants pillars under pressure and temperature (up to 350°F). Furthermore, proppant suspension tests with and without pulsing were conducted at temperatures up to 300°F to evaluate the ability of creating the conductive channels. Finally, the mechanical strength of the created pillars was evaluated using triaxle load frames to confirm that the created pillar will resist the closure stress and keep the fracture open. Experimental results showed that embedded fluid after gelation can transport the proppant during the injection and closure time without settling, thus avoiding any issues with proppant screen outs. The compatibility test showed that different concentrations of the embedded gel fluid (from 20-50 vol %) was compatible with crosslinked fracturing fluid and fracturing fluid additives. Moreover, this new chemistry was able to suspend the proppants. Additionally, the consolidated proppant pack showed excellent mechanical strength enhancement with the developed fluid system where the proppant pillar can hold the fracture open at high closure stress. Also, it was interesting to notice that oxidizer breakers enhanced the mechanical strength of the developed proppant pillar. The created pillar was conductive and hydrocarbon flowed through it. The data obtained from this study showcases the development of a new fluid chemistry that can replace conventionally used techniques to transport proppant inside the fracture.