Water Industry: borehole video surveys and other geophysical techniques
BOREHOLE CONDITION ASSESSMENT
The condition of a borehole is paramount to its ongoing performance. With a new borehole, when drilling and other work has been completed, checks ensure that design and specification have been met and allow benchmark readings for monitoring future hydro-geological and borehole condition changes. Checks to existing boreholes should be made part of an ongoing maintenance programme, thus highlighting any potential problems before they develop into major problems or disruptions in supply.
Prior to the decision to rehabilitate a borehole, various methods can provide vital information so that the most suitable and economical decisions can be made.
Our assessment service utilises a combination of down-hole video cameras and various geophysical techniques to provide a cost-effective solution to borehole evaluation.
• Locates and identifies causes of obstructions.
• Determines the condition of casings.
• Identification of corrosion and bio-fouling.
• Evaluation of cement grouts.
• Location of voiding behind linings.
• Measurement of water quality.
• Locates running sand.
New Borehole drilling
• Verifies correct type, size and position of casings and screens.
• Checks the integrity of casings, grout seals and borehole stability.
• Provides benchmark data for monitoring changes.
WIDE DIAMETER WELL SURVEYS
European Geophysical Services offer a specialist wide diameter well and shaft CCTV survey service including the use of a Remote Operated Vehicle (ROV).
Our vast experience in this area has allowed us to carry out successful surveys in wells over 10m in diameter and over 300m deep. Both CCTV camera and ROV can provide orientation data on features and tunnel directions.
The ROV provides the facility for detailed surveys of the well or shaft walls with the ability to survey up to 250m along water filled adit systems and tunnels. This greatly reduces the health and safety implications of using specialist divers by allowing an initial survey of the hazards before divers enter the water, or negating the need for diver entry at all.The ROV can be used with a sonar attachment which provides measurements of well or shaft diameters and tunnel widths. (Tunnel heights are measured with the ROV depth readings.)