Stress measurements in deep boreholes using the Borre (SSPB) probe

✍ Scribed by J. Sjöberg; H. Klasson

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 474 KB
• Volume: 40
• Category: Article
• ISSN: 1365-1609
• DOI: 10.1016/s1365-1609(03)00115-1

✦ Synopsis

The Borre probe is a unique tool for overcoring stress measurements. It allows three-dimensional stress determination in deep (500 m or more), water-filled boreholes. The probe has been used extensively worldwide for the last 25 years, and has proven to be a reliable tool for measurements in both shallow and deep boreholes. In this paper, the present version of the Borre probe and the measurement procedure is described in detail. The case record of the probe is presented, along with comparisons with results from other stress measurement methods, providing a qualitative verification of the method. Some of the potential error sources are discussed. This includes choice and application of adhesive, gauge misorientation and microcracking. Testing and the implementation of quality control procedures help to minimize the effect of these errors. Examples of typical measurement precision are presented and discussed. A new version of the probe that allows more efficient measurements through wireline pilot hole drilling, as well as improved strain data recording during overcoring is also described.