Water pressure test by wireline packer assembly to determine the in-situ permeability of rocks in deep geohydraulic test boreholes: practice method, equipment, and a case study

The data derived from geomechanical and hydrogeological investigations conducted in deep bore-holes and in-situ tests play a critical role in ensuring underground engineering projects' successful design and implementation. Water pressure tests, frequently applied in hydrogeological, geotechnical, and mining projects, are integral for evaluating hydraulic properties such as the permeability of rocks. These properties, mainly influenced by discontinuities and the absorption characteristics of the rock mass, help assess rock tightness, grout efficiency, and geomechanical behaviour under various conditions like hydrofracturing and hydro-jacking. Water pressure tests offer crucial insights into the in-situ permeability of rock. The Wireline Packer System provides a more efficient approach by allowing permeability tests to be conducted while the drill string remains in place, minimizing delays in operational time. Over the last 20 years, inflatable packer technology compatible with the wireline core drill string has evolved to meet the needs of deep geotechnical engineering applications. Therefore, deeper and more reliable water pressure tests can be easily incorporated into hydro-geological and geotechnical investigations. This study examined the properties of the specially manufactured inflatable tubing, composite cable, and other equipment, as well as the problems and solutions encountered during the application of these tests. The field water pressure tests were performed in 8 boreholes at 357-782 meter depths for the geotechnical investigation of a tunnel site. Suggestions are also made for techniques and equipment properties that should be applied in future successful water pressure tests in deep boreholes. The fact that the water takes values of the boreholes agree with those suggested in literature indicates that the tests were conducted successfully and the Lugeon values to be calculated are reliable.

Journal

BALTICA

Year

2025

Volume

38

Issue

1

Pages

55-64

ISSN

0067-3064

eISSN

1648-858X

DOI

10.5200/baltica.2025.1.5

WoS UID

WOS:001519104200005