Sustaining Fracture Conductivity

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe industry has developed standard methods to effectively evaluate the propping agents used in hydraulic fracturing operations. The understanding gained from the consistant application of the methods has greatly helped to optimize productivity.of hydraulicly fractured wells.This paper presents two mechanisms that may significantly increase the understanding of how to optimize fracture conductivity to sustain productivity. The standard methods use well "aged" (passive) proppant and simulated formation materials; whereas, in practice, formation faces are highly activated as an immediate result of mechanical fracturing, as is a significant portion of the pumped proppant.The chemistry that occurs at freshly exposed mineral surfaces is different than that of the aged surfaces used in the laboratory. For example, condensation of polymers on freshly generated surfaces may result in polymer chains becoming anchored to the surface. This anchoring prevents some polymer from being removed by normal gel-breaking mechanisms and forms points of attraction for the collection of broken polymer and fines debris, leading to significant permeability damage and reduced fluid recovery.After a treatment when pressure is relieved and well clean-up begins, temperature and stress gradients are high; significant crushing of proppant and formation material may occur as a packed fracture moves toward an equilibrium condition. The presence of hHigh-ionic-strength fracturing fluids, particularly at high pH, may promote a rapid mineral diagenesis-type reaction that leads to proppant compaction, embedment, and crystalline overgrowth permeability damage.This paper provides laboratory and field data supporting the conclusion that the application of a thin, highly dielectric, polymer film to coat proppant can result in a long-term reduction in mineral dissolution rate, compaction, embedment, and polymer anchoring sites. Field data shows this effect has a dramatic improvement in fracturing fluid recovery and well productivity.

Application of polymers for coating of proppant in hydraulic fracturing of subterraneous formations: A comprehensive review

“…Improvement of fracture conductivity may be due to the formation of coated proppant pack with high porosity. Almond et al (1995) and Weaver et al (2005) indicated that polymer coated proppant is the best way to increase fracture conductivity. Nguyen et al (2000) introduced a new approach for improving fracture conductivity.…”

“…2). The promising role of polymer coated proppant in reduction of proppant scales are discussed by Weaver et al (2008); Weaver (2005); Underdown and Das (1985); Browne and Wilson (2003) and Weaver et al (2006).…”

Ultra-lightweight composite proppants prepared via suspension polymerization

“…Composite particles, due to its deformable nature of polymer formed very small amount of fines. 5,28 The amount of fines formed never exceeded 8 wt%. It indicates that the composite particles have good crush resistance, which means the particles could withstand high pressure.…”

Storing and Securing Carbon Dioxide in Depleted Shale Formations

“…keep the fractures open during fracture fluid flowback and hydrocarbon production stages since the shale formation is always very deep (~1-3 km or deeper ) and the hydrostatic pressure could be more than 200 atm. 45 Figure 2.5 illustrates a typical shale production scheme. As the production proceeds and the hydrocarbons are depleted, secondary or tertiary fracking is normally needed to create new fractures, aiming to boost production.…”