Novel Trends in Fracturing Proppant Flowback Control

Abstract

Abstract The success of a fracturing treatment and long-term productivity highly depend on the residual proppant pack conductivity over time. One of the challenges operators face is the conductivity loss due to proppant flowback or sand production during production operations. As proppant particles come out of the fracture along with the production, the fracture conductivity diminishes with time as the fracture width decreases. This choking effect causes well production decline while the high-velocity low-concentration proppant particles wreak havoc on both downhole and surface equipment. As a result, proppant flowback costs millions of dollars through loss of production and expensive equipment damage. Wells experiencing these problems require remediation ranging from routine wellbore cleanouts to expensive artificial lift equipment repairs. Hydraulic fracturing became the mandatory stimulation technique to economically produce hydrocarbons in mature fields. However, proppant flowback following the fracturing treatment has been a major concern because of its detrimental effect on production equipment, leading to plugging or erosion of surface and downhole completions. The net impact of proppant flowback can be reduced production, damaged equipment, and downtime. This has prompted a detailed integrated study including both laboratory testing and development of the necessary numerical simulation models to fully understand the post-fracturing proppant flowback mechanism. Resin-coated proppant (RCP) was originally developed for post-fracturing treatment proppant flowback control. However, RCP requires a specific temperature trigger to get activated, which puts some restriction on the RCP application range. In addition, RCP requires prolonged shut-in time, which may cause issues with well cleanout, and RCP is relatively expensive. Another innovative solution that can be used for flowback control in certain conditions is a new flowback technology with nondegradable fiber proppant, designed specifically for low-temperature applications. This technology provides extraordinary proppant-pack integrity by interlocking proppant grains in a flexible 3D network. The grains do not require temperature activation and so perform equally well at any temperature below 200°F, both in oil and gas reservoirs. The fibers can be applied with any proppant (sand or ceramic), and they keep the proppant consolidated even at stress cycling conditions. Unlike RCP or other chemical treatment method, the nondegradable fibers rely on mechanical interference of the particles and not on chemical bonding. The key advantages of this technology are that consolidation is not dependent on activation temperature or time, and the proppant does not interfere with fracturing fluids or additives such as breakers that are known to be adversely affected by the presence of resin material. This paper presents the results of extensive laboratory evaluation and numerical simulation models of fiber performance, as well as global field case histories of successful application of the fiber as a solution for proppant flowback control in low-temperature environments. In all wells, remedial work has significantly dropped due to the excellent proppant flowback control. Meanwhile, the proppant flowback issues have been completely stopped, which led to remarkable success.