Abstract
Much effort in hydraulic fracturing technology has focused on fracturing fluid development to maximize its proppant transportability, while keeping potential polymer damage to a minimum. This paper presents the results of a laboratory study that demonstrates and quantifies the effectiveness of a new method for enhancing and sustaining proppant pack conductivity.
The approach uses an aqueous-based surface modification agent (ASMA) as part of the pad fluid stage to treat the fracture faces before placement of proppant into the fractures. ASMA treatment forms a thin film that becomes tacky and hydrophobic on both the fracture face and formation particulates. This coating causes the proppant to adhere to the created fracture faces, which can help to mitigate proppant settling inside a hydraulic fracture, resulting in improved vertical distribution of proppant within the fracture. It was also determined that ASMA treatment helps reduce polymer damage and results in the binding of fines that are generated during the fracturing process.
This study used Berea sandstone and various shale core samples that were split along the core length to create artificial fracture faces. These fracture faces were then treated with an ASMA solution, followed by immersion in proppant fluid slurry, and were then reassembled for core flow testing under closure stress. A permeability comparison of the fractured cores, with and without ASMA treatment and proppant slurry exposure, demonstrated a dramatic increase in the fractures of the treated cores. The results show that ASMA treatments are applicable to most types of formations, including shales, sandstones, and coals. The experimental results are presented by examining the reliability of ASMA treatments on the fracture faces during formation of the fracture and the ASMA's effectiveness at forming a partial monolayer of proppant for enhancing well productivity.
