WATER WELL BOREHOLE CAMERA
ApplicationsBorehole camera is a complete miniature inspection system. Downhole conditions are too complex to predict and estimate with accuracy. To pinpoint the problem such as damaged casing or screens, obstruction, break, corrosion, punctures, encrustations, location of lost pumps or tools and also viewing sources of contamination by assessing the presence of color, turbidity, algae etc. along the screen lengths. In a nut shell borehole camera would give a clear picture for ‘fishing’ technique to be implemented for rejuvenate the sick production tubewell. Why water well Geo-Scanning SystemIn production tubewell or in any tubewell filled with clear water, prime use of borehole camera includes the investigation of casing/ slotted pipes conditions such as holes, location of fractures, boreholes environment etc. A periodic monitoring of large number of production wells generally conducted in water supply department, managed either by Municipal Corporation or governments, will increase the life of the well. Damaged casings or ScreensThe frequent sickness of the tube wells in the alluvial area (sand, gravels and boulder etc) are mainly due to damaged casings or screens. The major problems do occur at the welding joints, screen open area and reducer which results in sand pumping, lowering of yield and contamination. Sometimes the casing is punctured due to lowering of the pumps, high encrustation and dropping of tools. The modern water well scanning system is essentially applied to assess the extent of damage. Encrustation A large number of tubewell in alluvial area are prone to reduction in discharge due to deposition of inorganic salts mainly soluble CaCo3 present in ground water on tube wells screen. When the well is under pumping, the hydrostatic pressure in the water bearing formation decreases. This reduction in pressure increases the pH and enhances the ground water equilibrium to shift towards the precipitation of calcium carbonate in well water resulting in incrustation. This results in clogging of screen openings and aquifer around (water bearing zone) the screen. Thus reducing the opening area, which ultimately leads to reduction in well efficiency and its yield over years of operation.Borehole camera is applied on such pumping wells to locate the incrustation in the well screens to vervitalize. Obstructions in wellObstruction, in general, caused in the tubewells operating in alluvial areas by rupturing of screens due to pressure variations compaction of overburden and even sometimes by roots wedging. This type of obstructions cause some malfunctions in the operations of well. The borehole camera helps in indentifying such defects so that proper planning or rehabilitation of the well can be done. Well Screen InspectionThe corrosion, punctures, the integrity of the tubewell and similar problems associated with tubewell screens and gravel pack are common problems in the production wells. In particular the borehole camera is applied to investigate the problem present in the tubewell.
Intergrity of wellEarly detection of potential problems saves money, time and even the well. Borehole camera helps in viewing the integrity of the well, which gives the picture of the health of well.
Geological inspection (Hard Rock Area) Bore hole camera used to view the rock lithology of the borehole wells indentify the contact zone, type of formation, nature of formation seepages and water falling in the well.
Viewing Sources of ContaminationDue to release of effluent by industries, generally the groundwater in the vicinity is likely to be contaminated. Borehole camera logging can be conducted to identify the source entry points within the well by assessing the presence of colour, turbidity, algae etc. along the screen lengths. The qualitative interpretation of such log demarcates the disposition of contaminated aquifer system. The remedial measures can be done by sealing of entry source points within the well.
Rehabilitation of old wellsAt Sites where the original constructional details of a tubewell are unknown borehole Camera system is used to locate casing, diameter changes and even entry passage of water.
Locating lost pumps or toolsAccidents like dropping of the pumps, column pipes, and tools do occur in the course of maintaining the production water well. The Borehole Camera would give a clear picture for proper “fishing” technique to be organized for recovery of equipment.