Answer both 1 (i) and (ii) 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. 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?

Answer both 1 (i) and (ii) 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. 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?

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...

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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?
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
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.
Question 2 * A well with a diameter of 0.6 m is constructed in a confined aquifer. 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 rated 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 of 30 m. From these data: o Find the depth of the water in the test well Calculate the permeability of the aquífer.
PROBLEM NO. 3 SOIL PERMEABILITY A pump test was conducted on a test well drilled into a confined aquifer, with the results showr ** elow. If water was pumped at a steady flow of 205 gal/min, deter... the coefficient of permeability (k in ft/sec) of the permeable soil in the aquifer. 150 ft 75 ft IMPERMEABLE LAYER 20 ft: 12 ft TEST WELL IMPERMEABLE LAYER AQUIFER 16 ft OBSERVATION WELLS Lectures 5
A pumping test was carried out in confined aquifer thickness 2 m and the following measurement was recorded. Rate of pumping was 10 m^3/s; drawdown in pumping well was 2.0 m while on the observation well located at 15 m and 20 m from the centre of the pumping well were 1.6 m and 1.4 m, respectively. Determine the hydraulic conductivity of soil.
Problem (4) The following results have been reported for field pumping test from a well, where the top permeable layer is unconfined and underlain by an impermeable layer, for a steady state condition: m3 q = 0.68 min h, = 5.6m at r, = 60m h, = 5m at r, = 30m Calculate the hydraulic conductivity (cm/s) of the permeable layer.
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Q1) B) using the Bingham plastic model determine the pressure losses in the annulus for the following well: (4 Marks) Data Length of drill pipe= 9000 ft Drill pipe = OD/ID = 5 in /4.276 in Hole diameter = 8.5 in |Page Plastic viscosity = 25 cp Yield point = 20 Ibf/100ft2 Flow rate = 300 gpm Mud density = 10 ppg %3D
The following data relate to a pump-out test: Diameter of well = 24 cm; Thickness of confined aquifer = 27 m; Radius of circle of influence = 333 m; Draw down during the test = 4.5 m; Discharge = 0.9 m^3/s.What is the permeability of the aquifer in mm/s? Choices: a. 2.15 x 10^-2 b. 4.5 x 10^-1 c. 93 X 10^-1 d. 1.6 X 10^-1
A well was constructed to pump water from a confined aquifer. Two observation wells were constructed at distances of 350 m and 800m respectively. At a steady pumping rate of 0.39 m^3/min, the drawdown in the observation wells were respectively equal to 1.6 m and 7.8 m. Diameter of the test well is 0.95 m and thickness of confined aquifer is 16 m. a. Determine the hydraulic conductivity of the soil in m/min. (IN EXPONENTIAL FORM AND IN 2 DECIMAL PLACES) b. Determine the drawdown at the test well in m. (IN 2 DECIMAL PLACES) c. What is the value of the transmissivity of the confined aquifer in m^2/day? (IN 2 DECIMAL PLACES)
Question 2: * A soil sample 10 cm in diameter is placed In a tube 1 m long. A constant supply of water is allowed to flow into one end of the soil at A and the outflow at B is collected by a beaker. The average amount of water collected is 1 cubic centimeter every 10 seconds. The tube is inclined and has a head difference of 1.2 m. Determine the following o Hydraulic Gradient o Seepage velocity if porosity is 0.375 o Hydraulic conductivity Flow Rate Discharge Velocity