152
Wei
et al
.,
Water table response to a pumping test in the hinterland core area of the Taklimakan Desert, China
Tecnología y Ciencias del Agua
, vol. VIII, núm. 2, marzo-abril de 2017, pp. 151-158
•
ISSN 2007-2422
studying, hydrogeologists devoted themselves
to theoretical and practical work on pumping
tests, it was found the influence of barometric
pressure on water level cannot be ignored, that
pressure efficiency is expressed by a simple
linear equation at first (Jacob, 1940). After long
time duration of studying, for the pumping test
process, it was found that the groundwater level
(especially the deep well water level) response
is not linear, but rather a complex nonlinear
response, which makes it inappropriate to use a
linear regression method for the pressure correc-
tion (Quilty & Roeloffs, 1991; Seo, 2001). Among
lots of researchers, Rasmussen and Crawford
(1997) used a regression deconvolution method
to determine pressure correction and achieved
good results.
The hinterland of the Taklimakan Desert,
which belongs to a sedimentary area in the
southern section of the Tarim Basin, is an ancient
alluvial flood plain that formed from many riv-
ers in the northern slope of the Kunlun Moun-
tains. Precipitation and condensed water sup-
ply no recharge to groundwater basically (Yu,
1992), which is mainly affected by the Kunlun
Mountain piedmont plain groundwater lateral
runoff recharge. There are rich oils and natural
gas resources, but the climate is extremely dry,
and the precipitation is below 50 mm with an
annual evaporation of 3 000 mm, no surface
water exists generally (Xu, Li, Zhou, & Zhou,
2001). Therefore, the water used for production
and living comes entirely from the exploitation
of groundwater, unconfined water, particularly,
which is formed by river infiltration and lateral
groundwater infiltration belonging to pore wa-
ter stored in Quaternary deposits, whose main
hydrochemical types are Na-Mg-Cl-SO
4
and
Na-Cl-SO
4
(Wei, Fan, Xu, Jin, & Zhou, 2016), and
salinity is 3-10 g/l. The depth of groundwater
between longitudinal dune usually is 1-5 m, and
over 20 m at top of ones. It was found that when
the groundwater depth is less than 1.5 m, the
groundwater is affected by strong evaporation
(Fan
et al
., 2010), coincide with the terrain trend,
the water table is relatively flat, with a flow
velocity measured between 21 m/year and 205
m/year (Lei, Li, Jin, & Xu, 2008).
In this paper, a single-well pumping test
established at the core area of pumping in the
hinterland of the Taklimakan Desert was used
to calculate the hydrogeological parameters,
in order to provide a reference of the future
groundwater research, especially the construc-
tion of hydrological modeling.
Methods and experiments
We observed the water level of the whole year
and conducted single-well pumping test from
2009 Jul. 27th to Aug. 12th day in the core area of
water supplying in the oil field with observation
time interval was every 30 min. The pumping
well is located in the hinterland of the Taklimak-
an Desert (38º 58’ 20.77”, 83
º
39’ 39.60”) (figure
1), with the observation well (38° 58’ 21.78”, 83°
39’ 37.35”) logging in the northwest at a distance
of
r
= 58.6 m (figure 2). The elevation of pump-
ing well is 1 104.9 m. The thickness and effective
thickness of unconfined aquifer are 66.00 and
40 m, respectively in the study area where the
depth of groundwater is 6m, the formation is
single fine sand of Quaternary. The casing pipe
of the partial penetrating observation well is
hard PVC material and depth was measured by
Solinst Levelogger Model 3001. In the experi-
ment, discharge rate was set as 32 m
3
/h and it
was regarded as having achieved stable state
when the fluctuation of the drawdown was not
more than 1% (Wang
et al
., 2013). The regression
deconvolution was performed in order to adjust
the groundwater level using BETCO from Sand-
ia Labs (USA). The hydrogeological parameters
were calculated by Aquifer Test 2011.1 designed
by Waterloo Hydrogeologic Inc. (incorporated
into Schlumberger Water Services since 2005)
to provide a reference for the construction of
hydrological modeling.
Barometric pressure correction
In measuring groundwater level, many natural
forces have important theoretical and practical
significance to the borehole water level (Guo
& Jiao, 2008). In particular, when the impact of
