Injection or Withdrawal Test?

 

See Also:

Static Water Level

Data Logger File Format  

Time, Adjusted Time, Drawdown, and Head


An Injection Slug Test or Slug-In test occurs when a slug of water or some other material is inserted into the well causing the water level in the well to rise initially, then slower lower throughout the test.


A Withdrawal Slug Test or Slug-Out test occurs when a slug of water is removed from the well causing the water level to lower initially and then rise throughout the test.

Super Slug handles both injection and withdrawal slug tests. It should be noted that injection test results may be of questionable accuracy when the static water level is lower than the top of the screen or gravel pack.

It does not matter if the drawdown values are the depth to the water from the top of the well, or the height of the water column. It also does not matter if the drawdown value is increasing or decreasing throughout the test.


Following the injection or withdrawal of the slug, the following will be true:


For Injection Tests -- If the depth to water is being measured, the "drawdown" values will increase. If the height of the water column in the well is being measured, the "drawdown" values will decrease.


For Withdrawal Tests -- The opposite is true. If the depth to water is being measured, the "drawdown" values will decrease. If the height of the water column in the well is being measured, the "drawdown" values will increase.

In Super Slug documentation, the word "drawdown" is used to refer to the actual water level measurements made during the test.