require the Contractor to construct new wells nearby. All materials pulled
into the well by the development process shall be removed prior to
performing the pumping test.
3.4.1.1
Jetting
Jetting should be performed using either a single or double ring jet. If a
double ring jet is used the rings should be 600 mm 2 feet apart. The
jetting tool shall be constructed of high-strength material and
conservatively designed and proportioned so that it will withstand high
pressures. The jetting tool shall have [two [7][8][10] mm [3/16]
[1/4][3/8] inch diameter hydraulically balanced nozzles spaced 180 degrees]
[four [7][8][10] mm [3/16][1/4][3/8] inch diameter holes spaced 90 degrees]
apart and which shall exert the jetting force horizontally through the
screen slots. The rings shall be constructed such that the tips of the
jets shall be within 13 mm 1/2 inch from the inner surface of the well
screen. The pump used in conjunction with the jetting tool shall be
capable of providing [pressures up to [1700] [_____] kPa [250][_____] psi.]
[a minimum jetting fluid exit velocity of 45 meters per second 150 feet per
second.] Prior to commencing jetting, and following each jetting cycle,
all sand and/or other materials shall be removed from inside the screen.
The jetting process shall start at the bottom of the screen and consist of
rotating the jetting tool [slowly] [1 cycle per 30 seconds] [[_____] cycles
per [_____] seconds] while rotating the pipe [180][90] degrees for two
minutes at each location then raising the pipe [150][_____] mm [6][_____]
inches. All wells, more than 100 mm 4 inches in diameter, shall be pumped
during the jetting cycle to remove incoming sand and other material. Such
pumping shall be at a rate not less than 115 percent of the rate at which
fluid is introduced through the jetting tool. This will allow a flow of
material into the well as it is being developed. Water used for
development shall be free of sand. The contracting officer may require
other means of developing the well such as intermittent pumping method,
variation of the intermittent pumping method, or surge block if it appears
that the development of the well is not producing the desired results.
3.4.1.2
Intermittent Pumping
Intermittent pumping shall be performed by pumping the well at a capacity
sufficient to produce a rapid drawdown of approximately [_____] m feet
stopping the pump (backflow through pump will not be permitted) to permit
the water surface to rise to its former elevation, and repeating this
procedure. Cycle time for this procedure will vary as directed but will
not be more than 3 cycles per minute. A pump discharge in excess of
[_____] L/s gpm will be required. A deep well turbine pump, or electric
submersible pump with check valve, shall be used with any attachment
necessary to accomplish rapid starting and stopping for intermittent
pumping. The intake shall be set at least 3 m 10 feet below the maximum
expected drawdown in the well. Prior to commencing intermittent pumping,
and periodically during development by this method, all sand and/or other
materials shall be removed from inside the screen. The amount of drawdown
may be decreased if, in the opinion of the Contracting Officer, the
efficiency of the well might otherwise be impaired.
3.4.1.3
Surging
**************************************************************************
NOTE: The method of surging specified in the above
paragraph may be modified to specify a procedure
considered most suitable for the particular project.
SECTION 02525A
Page 21
Previous Page
