JNTU
JNTU B.Tech III DRILLING TECHNOLOGY Previous Question Paper (May - 2019 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Define collapse pressure and write the formula for determining safety factor in collapse.
Answer
Collapse pressure is the external pressure acting on the casing wall that causes it to fail by buckling or crushing. The safety factor in collapse is defined as:
Write the functions of the following in drilling operations:
i) Swivel
ii) Kelly
iii) Rotary table
Answer
- Swivel: Supports the weight of the drill string, allows rotation, and provides a pressure-tight seal for circulating drilling fluid.
- Kelly: A heavy steel pipe with a square or hexagonal cross-section that transmits rotational torque from the rotary table to the drill string.
- Rotary table: Provides the rotational power to the Kelly and drill string to rotate the drill bit.
Define normal pore pressure, abnormal pore pressure and subnormal pore pressure.
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Calculate the hydrostatic pressure for the following wells:
(i) mud weight = 9 ppg, hole depth = 10100 ft measured depth, 9900 ft true vertical depth
(ii) mud gradient = 0.468 psi / ft, hole depth = 10100 ft measured depth, 9900 ft true vertical depth.
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Define kick tolerance and write the factors effecting kick tolerance.
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Write the steps for calculating kick tolerance. How fracture gradient influences kick tolerance?
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Write the functions of casings.
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Write the purpose of following cement additives with example:
i) Accelerators
ii) Retarders
iii) Extenders
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Define the following in terms of directional drilling:
i) True vertical depth
ii) Kick off point
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Write the functions of following fishing tools and equipment:
i) Overshots
ii) Bumper subs
iii) Impression blocks
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Part B
Describe different rheological models used to explain drilling fluid properties. Also write the equations relating shear rate and shear stress with figure for each model.
Determine the quantity of barite required to change the density of mud from 1.5 kg/l (12.53 ppg) to 2 kg/l (16.7 ppg). Calculate the increase in pit volume due to the addition of such a quantity of barite for an initial mud volume of 10m3 (63 bbl).
Answer
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Explain different functions and types of drilling fluids.
Given the following well data: θ600 = 36, θ300 = 24, hole size, Dh = 12 in (311mm), drill pipe, Dp= 5 in (127 mm), flow rate, Q = 600 gpm (2272 l/min), hole depth = 7100 ft (2164 m), drill collars = 8 in OD, 620 ft long, mud weight = 75 pcf. Determine thickness or effective viscosity, using the Bingham plastic model.
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Explain the parameters obtained from LWD / MWD tools for detection of abnormal pore pressure while drilling.
A sonic log was run in a well at 8000 ft. The normal transit time (Δtn) for this depth is 110ms and from logs (Δt0) is 130 ms. Calculate the pore pressure at 8000 ft if the overburden pressure is 7,500 psi. Normal pore pressure gradient is 0.465psi/ft.
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Explain determination of pore pressure from sonic log and resistivity log.
Describe different parameters / properties / information’s obtained from mud logging.
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Write down the reasons for performing a formation integrity test.
Draw fracture integrity test setup and explain how the test is carried out.
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What are different stresses acting at any point below earth’s surface? Explain in terms of angle between them and their direction with a neat sketch.
Draw formation integrity test graph. Mark the position of different pressures on the graph and explain them.
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What is a liner? Discuss the advantages and disadvantages of using a liner. Draw and explain different types of liners.
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Describe different classes of cements used in oilfield operations, mentioning the depth range of their use.
Calculate the collapse pressure for the following casing string assuming lost circulation at the casing shoe: Current mud = 15 ppg, Casing was run in = 11 ppg, Casing Setting Depth = 10,000 ft.
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Explain the functioning of whip stock and jetting technique in directional drilling.
Determine the azimuth with respect to true north of the following wells:
Well 1: Observed azimuth N45° E, Declination 3° west
Well 2: Observed azimuth N45° E, Declination 3° east
Well 3: Observed azimuth S80° W, Declination 5° west
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What is azimuth? Explain with a diagram of a quadrant system.
Draw and explain different types of well profiles for directional drilling.
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