首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Characterization of a hydraulically induced crystalline‐rock fracture
Authors:Thomas J Burbey  Ryan A Brandon
Institution:1. Department of Geosciences, Virginia Tech, Blacksburg, VA, USA;2. ARM Group Inc., Hershey, PA, USA
Abstract:Hydraulic fracturing has become an important technique for enhancing the permeability of hydrocarbon source rocks and increasing aquifer transmissivity in many hard rock environments where natural fractures are limited, yet little is known about the nature or behaviour of these hydraulically induced fractures as conduits to flow and transport. We propose that these fractures tend to be smooth based on observed hydraulic and transport behaviour. In this investigation a multi‐faceted approach was used to quantify the properties and characteristics of an isolated hydraulically induced fracture in crystalline rocks. Packers were used to isolate the fracture that is penetrated by two separate observation wells located approximately 33 m apart. A series of aquifer tests and an induced gradient tracer test were performed to better understand the nature of this fracture. Aquifer test results indicate that full recovery is slow because of the overall low permeability of the crystalline rocks. Drawdown tests indicate that the fracture has a transmissivity of 1–2 m2/day and a specific storage on the order of 2–9 × 10?7/m. Analysis of a potassium–bromide tracer test break through curve shows classic Fickian behaviour with minimal tailing analogous to parallel plate flow. Virtually all of the tracer was recovered, and the breakthrough curve dilution indicates that the swept area is only about 11% of a radial flow field and the estimated aperture is ≤0.5 mm, which implies a narrow linear flow region. These outcomes suggest that transport within these hydraulically induced ‘smooth’ fractures in crystalline rocks is rapid with minimal mixing, small local velocity fluctuations and no apparent diffusion into the host rock or secondary fractures. Copyright © 2016 John Wiley & Sons, Ltd.
Keywords:fractured rocks  aquifer testing  tracer tests  hydraulic fracturing  Blue Ridge
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号