“When the well is dry, we learn the worth of water.” – Anonymous

Hydrofracturing

Considering the cost factor involved in drilling bore wells, rejuvenation of failed wells through some technique is thought off. The innovative technology of ‘’Hydrofracturing’’ is a new approach to revitalize the bore well to improve the yield by applying water pressure in the bore wells The hydrofracturing technique was first used in oil wells to increase oil and gas production.

Hydro fracturing is a well development process that involves injecting water under high pressure into a hard rock formation in the well. This is intended to increase the size and extent of existing bed rock fractures pumping water into the fractures at high pressure as high as 3000 psi and flow rate at about of 85 gpm. Hydraulic pressure is applied to an isolated zone of bore well to initiate and propagate fractures. The water injected at high pressure break up fissures and joints, cleans away all impurities there by the permeability of rock formation is increased.

The basic reason for the failure of bore well in hard rock terrain is the poor hydrological characteristics of fracture system. Normal procedures for hydro fracturing operation includes Pre logging for better identification of aquifer zones, Pre pump test, Hydro fracturing and Post pump test for determination of the well yielding capacity compared before and after hydro fracturing.

Normally up to three zones in each well are done. Operation must be commenced from bottom most fracture zones. Hydro fracturing will be fruitful and effective only if the process is done in the fractured zones below the water table. The ratio of yield of the bore well after hydro fracturing to the yield before fracturing is defined as the Improvement Ratio. [IR].

Well Monitoring

Camera Inspections

The camera housing is made of ACRYLIC PIPE FOR MORE CLARITY OF CAMERA and is precisely sealed to prevents condensation and water intrusion. The LED lights are specially designed long-life and it makes the camera images so clear that you can find it satisfactory. The resolution is 410,000 pixels. You can watch the down hole images which are sent to the surface unit by the camera in real time and the video data are recorded to disk in a standard video file on the notebook.

Seasonal/Continuous Water level monitoring:

Water table undergoes a seasonal fluctuation following a natural cycle. Water table rises during rainy season due to recharge received from rainfall and falls back during summer season due to lack of recharge and continuing extraction of groundwater. In geohydrology, the highest water level is referred to as the post-monsoon water level and the lowest level in summer as pre-monsoon water level. Quantum of water being received by an aquifer from annual recharge can be computed from the annual ground water fluctuation in conjunction with estimated groundwater extraction in that area.

The prime cause of over-exploitation is the rising demand for groundwater. An aquifer is said to be over-exploited when the annual groundwater extraction is higher than the annual recharge. For sustainable utilization of groundwater, only that much water should be extracted which is replenished every year by rainfall through groundwater recharge. To achieve this, we must either reduce our groundwater extraction (demand side management) or increase recharge to the extent possible by adapting artificial recharge measures (supply side management). Else, the groundwater table will continue to fall leading to an unprecedented situation.

Drawdown / Recuperation tests:

Step draw down tests are tests at different pumping rates designed to determine well efficiency. In a step-drawdown test, the discharge rate in the pumping well is increased from an initially low constant rate through a sequence of pumping intervals (steps) of progressively higher constant rates. Each step is typically of equal duration, lasting from approximately 30 minutes to 2 hours. Each step should be of sufficient duration to allow dissipation of wellbore storage effects.

The recovery test is not strictly a pumping test, because it involves monitoring the recovery of the water level after the pump has been switched off. Recovery tests are valuable for several reasons:

  • They provide a useful check on the aquifer characteristics derived from pumping tests, for very little extra effort – just extending the monitoring period after the pump has been switched off.
  • The start of the test is relatively ‘clean.’ In practice, the start of a constant-rate test, for example, rarely achieves a clean jump from no pumping to the chosen pumping rate. Switching a pump off is usually much easier than starting a pump, and the jump from a constant pumping rate to no pumping can be achieved fairly cleanly.
  • Similarly, recovery smoothes out small changes in the pumping rate that occurred during the pumping phase, and there is no problem with well losses from turbulent flow. This results in more reliable estimates of aquifer properties when the recovery data are analysed.
  • The water levels in the borehole are easier to measure accurately in the absence of turbulence caused by the pumping (especially in the early stages of the test, when water levels are changing quickly). Some people find that it is easier to take readings quickly with a dipper when the water level is rising than when it is falling.
  • Recovery tests represent a good option for testing operational boreholes that have already been pumping at a constant rate for extended periods. In these cases, the recovery test can be performed when the pumps are first switched off, followed by a constant discharge test when the pumps are switched back on again.