Rethinking Proppant: From Liquid to Solid

Abstract

Propping open fractures to maximize production requires placing enough stout particles of sand or ceramic in a fracture to hold it open for years. The downside of bigger and stronger particles is that they are denser than the fluid used to deliver them, so some will settle in transit. It is also difficult to move proppant past the corners in networks of fractures. The end result is only a limited area gets well propped. There has been a long line of methods offered to deliver more proppant deeper—lighter particles, viscous fluids, and coatings that limit settling. The SPE Hydraulic Fracturing Technology Conference has become a showcase for new ideas. The most striking innovation presented at the March conference in The Woodlands, Texas, was from Oil Chem Technologies, which reported patenting a chemical combination designed to flow into a reservoir as a liquid, which then turns into strong, spherical balls able to hold open a fracture. Saudi Aramco has invested in this innovation and is working with the Houston-area company to measure its properties, with a goal of field testing it later this year, said Paul Berger, vice president and technical director for Oil Chem. “The goal of this technology development is to convert injected fracturing fluid into a highly permeable proppant pack in-situ,” according to the paper he presented at the conference (SPE 173328). “Since the fracturing fluid itself forms the proppant, it can penetrate the fracture length, height, and complex network, maximizing the effective fracture area.” The fracturing conference also presented: Research at Shell to find a strong ceramic shape less likely to settle out of fluid has led to a W-shaped proppant design. Its complex outline causes drag, making it less likely to settle. University of Texas research into whether mild acid can be used to create lasting pathways in microfractures too small to prop open. The goals are similar to those for acidizing carbonate formations— etching production pathways by dissolving calcite. Fairmont Santrol’s large exhibit featuring its Propel SSP Proppant Transport coating. It was competing on the show floor with Trican’s MVP Frac, a coating which can make proppant buoyant by adsorbing gases such as nitrogen. All were selling new ideas at a time when operators were reacting to the oil price crash by sharply reducing the number of wells completed, and relying more on the oldest type of proppant, which is sand. Fairmount Santrol’s polymer coating is able to reduce settling allowing more proppant to reach fractures. The company has taken an invention that it debuted 2 years ago at the conference, and modified it so it can be practically delivered through its extensive proppant supply network. On a huge screen, the proppant supplier featured four promising field tests. The company is seeking early adopters to make a case for its polymer coating, which it says can improve production and reduce the cost of pumping jobs. “People are looking for technology,” to improve results, said Brian Goldstein, product director for Propel SSP technology at Fairmount Santrol. “The change in the market changes the way you think.”