The Well / Aquifer Model (Initial Test Results) - 9
3.2.5 Data Logging Cycle
Figure 8 is a flow chart showing a typical
data logging cycle during a model test run. Logging start time and frequency of
measurements are coded in prior to start-up of the model run. The computer
continuously reads the real time clock to see if it is time to take a reading.
Each time a predetermined "log data" time matches the real time of day,
the logging cycle is initiated, as shown in Figure 8. Thus,
all the basic hydraulic characteristics of the test are immediately available on a
"real time" basis or stored for future analysis and evaluation.
Figure 8
4.1 General Description of Test Methodology
A general testing procedure was standardized for the first series
of 25 tests on the Santa Barbara and Silverado formations, using six different well
screen types. This procedure consisted of the following:
- After installing the particular well screen to be tested, the model was allowed
to reach steady state flow conditions. This stabilization, principally deaeration,
usually took two to three days, during which time the newly installed well screen
and gravel pack were developed to maximum capacity after reaching equilibrium
conditions.
- A physical monitoring procedure was then initiated which consisted of taking the
necessary series of pressure, flow, and sand content measurements. All piezometers
were read using the automatic instrumentation procedures. The 44 piezometers
selectively placed within the aquifer and gravel pack obtained the measurements
necessary to determine the piezometer head distribution throughout the model. Two
piezometers on either side of the venturi meter obtained flow data on well
discharge. One piezometer located in the well itself reflected the actual pumping
level. The Scanivalve instrument provided automatic data logging capabilities for
pressure measurements. Sand content in the well discharge was measured using a
HIAC particle counter. Equivalent parts per million of sand content were
calculated.
All data logging operations were under supervision of a microcomputer with real
time control capability.
Six different well screens were chosen for initial testing in the
model. Screen choice was made with consideration to design as well as percentage of
open area. A wide range was thought necessary to test the hydraulic flow
characteristics as specified in the initial objectives of the well/ aquifer model.
The following table gives a summary of the six screens used in the initial model
tests.
SCREENS USED IN THE INITIAL TESTING
