Problems An aquifer of 20m average thickness is overlain by an impermeable layer of 30m thickness. A test well of 0.5m diameter and two observation wells at a distance of 10m and 60m from the test well are drilled through the aquifer. After pumping at a rate of 0.1 m³/s for a long time, the following draw downs are stabilized in these wells. First observation well, 4m, second observation well, 3m. Show the arrangement in a diagram. Determine the coefficient of Permeability and the drawdown in the test well.

Problems An aquifer of 20m average thickness is overlain by an impermeable layer of 30m thickness. A test well of 0.5m diameter and two observation wells at a distance of 10m and 60m from the test well are drilled through the aquifer. After pumping at a rate of 0.1 m³/s for a long time, the following draw downs are stabilized in these wells. First observation well, 4m, second observation well, 3m. Show the arrangement in a diagram. Determine the coefficient of Permeability and the drawdown in the test well.

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN:9781305970939

Author:Braja M. Das, Khaled Sobhan

Publisher:Braja M. Das, Khaled Sobhan

Chapter7: Permeability

Section: Chapter Questions

Problem 7.22P: Refer to Figure 7.24. The following data were collected during the field permeability measurement of...

See similar textbooks

Similar questions

A 30 cm well penetrates 45 m below the static water table. After a long period of pumping at a rate of 1200 lpm, the drawdown in the wells 20 m and 45 m from the pumped well is found to be 3.8 and 2.4 m respectively. Determine the transmissivity (-K*aquifer thickness) of the aquifer. What is the drawdown in the pumped well? [Hint: Use water table depth as aquifer thickness in the case of unconfined aquifer]
Question 3 a. An oil well in the Nameless Field is producing at a stabilized rate of 600 STB/day at a stabilized bottom-hole flowing pressure of 1800 psi. Analysis of the pressure buildup test data indicates that the pay zone is characterized by a permeability of 120 md and a uniform thickness of 25 ft. The well drains an area of approximately 40 acres. The following additional data is available: w = 0.25 ft, A = 40 acres Bo = 1. 25 bbl/STB, Ho = 2. 5 cp Calculate the pressure profile (distribution) and list the pressure drop across 1 ft intervals from rw to 1.25 ft, 4 to 5 ft, 19 to 20 ft, 99 to 100 ft, and 744 to 745 ft.
A saturated aquifer sample core of diameter 2.54 cm and length of 6 cm weighs 63 grams. After drying the sample weighs 53 grams. The core sample was placed into an permeameter and exposed to a unit hydraulic gradient. The measured flowrate was 25.4 milliliters/second. The water levels in three wells in the same aquifer were measured in meters above MSL. The levels were: Well MW-1: 83.1 m; Well MW-2: 84.6 m; Well MW-3: 83.9 m. Well MW-2 is located 1km due north of Well MW-1, and Well MW-3 is located 700 meters Northeast of Well MW-1. Determine: 1. Estimate the porosity of the aquifer. 2. Estimate the hydraulic conductivity of the aquifer. 3. Sketch the relative positions of the three wells. Use MW-1 as the origin of the local (your sketch) coordinate system, and North is to the top of your sketch. 4. Determine the magniture and direction of the hydraulic gradient in the aquifer monitored by the three wells. Indicate the hydraulic gradient on your sketch (direction and magnitude) 5.…
Refer to Figure 7.24. The following data were collected during the field permeability measurement of a confined aquifer using a pumping test. Determine the hydraulic conductivity of the permeable layer. Use Eq. (7.49). Thickness of the aquifer, H = 4.5 m Piezometric level and radial distance of the first observation well: h1 = 2.9 m; r1 = 17.8 m Piezometric level and radial distance of the second observation well: h2 = 1.8 m; r2 = 8.1 m Rate of discharge from pumping, q = 0.5 m3/min
A field pumping test was conducted from an aquifer of sandy soil of 4 m thickness confined between two impervious strata. When equilibrium was established, 105 liters of water was pumped out per hour. The water elevation in an observation well 3.50 m away from the test well was 2.1 m and another 6.0 m away was 2.7 m from the roof level of the impervious stratum of the aquifer. Find the value of k of the soil in m/sec.
A 0.3 m well has a 25 m long screen that covers the entire depth of an aquifer. The aquifer medium has an effective grain size of 1.5 mm. The well is pumped at a rate of 0.2 m³/s. Assess the validity of Darcy's law near the well. Assume, porosity = 0.25 (Dynamic viscosity of water at 20°C is 1.005*10-3 Ns/m2)
2. A confined aquifer is recharged by a continuous supply of water from the certain source. The average thickness of the aquifer was determined to be 25 m and the average width is 4 km. The hydraulic conductivity of the aquifer was obtained at 40 m/day and its void ratio is 0.3333. The piezometer heads in two wells 1.325 km apart are 65 meters and 60 meters from a common reference datum. Determine the rate of flow in cubic meters per day. Determine: •compute the rate of flow through the aquifer in m3/day •compute the seepage velocity in m/day •compute the time of travel from the head of the aquifer to a point 8 km downstream in days
2. A well with a diam. of 0.6 m. is constructed in a confined aquifer as shown. The sand aquifer has a uniform thickness of 15 m. overlain by an impermeable layer with a depth of 35 m. A pumping test was conducted to determine the coefficient of permeability of the aquifer. The initial piezometric surface was 15 m. below the ground surface datum of the test well and observation wells. After water was pumped at a rate of 13 liters/sec. for several days, water levels in the wells stabilized with the following drawdowns, 6.4 m. in the test well, 3.7 m. in the observation well 10 m. from the test well and 2.4 m. in the second observation well at a distance 30 m. From these data, o Find the depth of water in the test well. • Calculate the permeability of the aquifer. O Compute the transmissibility of the impermeable layer. 71-30 Ground surface 20 15m Water Leve intern 72=10 Static water level observation wall -impermeable confined aquifer hi hr
Please explain part 1 (ii) of the question given. 1) i) A 6 inch diameter well that fully penetrates a 40ft thick open aquifer is pumped at a rate of 100 gpm. The drawdown in the well is 22ft when a steady water level is established. The drawdown in a well 152ft distant is 12ft. Estimate the coefficient of permeabiliity of the soil deposit. Answer of permeability is K= 9.88 x10-4 ft/sec. ii) Discuss the validity of the answer obtained in 1( i ) and suggest how would you improve the test data obtained to produce a better value of k. Why?
3.1 Construct IPR of a vertical well in an oil reservoir. Consider (1) transient flow at 1 month, (2) steady-state flow, and (3) pseudo-steady-state flow. The following data are given: Porosity, o = 0.25 Effective horizontal permeability, k = 10 md Pay zone thickness, h = 50 ft Reservoir pressure, pe or p = 5,000 psia Bubble point pressure, p, = 100 psia Fluid formation volume factor, B, = 1.2 Fluid viscosity, M. = 1.5 cp Total compressibility, c, = 0.0000125 psi- Drainage area, A = 640 acres (re = 2,980 ft) Wellbore radius, rw Skin factor, S = 5 0.328 ft
Qs. The difference between the free water levels in two wells 48 m part in an aquifer is 0.6m. It took an interval of 8 hours between detecting the traces of a tracer material at the two wells in succession. The porosity of the aquifer is 25%. The coefficient of permeability of the aquifer is_______ cm/sec.please dont solve wrong
A 300 mm diameter test well penetrates 24 m below the static water table. After 24 hours of pumping at 70 liters per second, the water level in an observation well at a distance of 96 m from the test well is lowered by 0.60 m and the other observation well at a distance of 34 m from the test well, the drawdown is 1.2 m. 1. Compute the coefficient if permeability of the unconfined aquifer in m/day. 2. Compute the transmissibility of the unconfined aquifer in m2/day.