The application of liquid resin in hydraulic fracturing helps to increase hydrocarbon production by improving conductivity, controlling proppant flowback, inhibiting fines migration, and reducing sand production. This study compares natural sand and proppant in terms of the grain-to-grain relationship (texture) of coated and uncoated samples and describes how microfractures, micropores, and grains are filled and encapsulated by liquid resin.

During proppant placement, the concentration of the resin can delay the curing time, which induces consolidation of the proppant pack in the fractures. By extending the curing period, there is more time for the proppant to develop grain-to-grain contact in the fracture as well as for capillary action to pull the liquid-resin coating to the contact points of the proppant grains, thereby providing a highly cohesive consolidated proppant pack. The resin concentration used falls within the oilfield industry’s applicable practices. Several evaluation techniques were used to understand the crystallinity and morphology of coated and uncoated sand/proppant. These techniques included thin section petrography, scanning electron microscopy (SEM), and geomechanical tests.

Photomicrographs analysis and SEM images have shown the presence of a very large amount of monocrystalline quartz in the uncoated sand samples, which also displayed reduced mechanical strength as a result of microimperfections in the uncoated sand. A comparative study showed that after resin coating the angular and microfractured sand, mechanical properties of the angular and microfractured sand improve as a result of enhanced interlocking effects of this type of sand.

This paper provides a qualitative description of the variation in coated and non-coated sand/proppant in terms of grain-to-grain contact. Moreover, the study also hypothesizes how resin-coated sand can help to fill in micropores and microfractures.

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