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f Improved Borehole Stability in Shales through Optimized Drilling Fluid Salt Concentration
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 3rd EAGE Shale Workshop - Shale Physics and Shale Chemistry, Jan 2012, cp-275-00014
- ISBN: 978-94-6282-062-3
Abstract
Severe borehole instability problems may be encountered when drilling through shales, potentially representing a substantial cost to the operator. Such rock mechanical instabilities may have both physical and chemical origin. They are however generally influenced by time dependent mechanisms related to various diffusion processes, implying that even though a borehole is initially stable, it may turn unstable some days after drilling. In practice, the challenge is then to keep the borehole sufficiently stable until casing is set.