JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV Year PETROLEUM RESERVOIR STIMULATION Previous Question Paper (January/February - 2023 - R18)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What is the importance of in-situ stress in hydraulic fracturing design?
Answer
In-situ stress is critical in hydraulic fracturing design because it determines the fracture propagation path and fracture geometry. The fracture will always initiate and propagate perpendicular to the direction of the minimum principal in-situ stress, as this requires the least amount of energy to overcome the rock's confining pressure. Understanding the stress profile across different geological layers allows engineers to predict fracture containment, prevent unwanted growth into water-bearing zones, and optimize the placement of perforations to ensure effective reservoir stimulation.
Define Perforation Skin Effect.
Answer
Perforation skin effect is an additional pressure drop that occurs near the wellbore due to the restricted flow geometry created by perforations. When a well is completed with perforations rather than an open-hole completion, the fluid must converge from the reservoir into the small, discrete channels of the perforations, creating a localized flow constriction.
This effect is quantified as a component of the total skin factor, denoted as Sp. It depends on several factors, including the perforation density, the penetration depth of the charges, the diameter of the perforation tunnels, and the phase angle of the perforation pattern. If the perforations are poorly designed or damaged during the completion process, this geometric restriction significantly increases the total skin, thereby reducing the productivity index of the well.
Mention the significance of dimensionless fracture concentration.
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What are the limitations of water based fluids?
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What is the use of dynamic downhole testing?
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Explain briefly the pressure-dependent leak off.
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What is stress intensity factor?
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What are the benefits of high proppant concentrations?
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What are the principles of acid fracturing?
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State the potential problems during diversion treatment.
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Part B
Describe the inflow performance relationship (IPR) for pseudo steady state for an oil well in detail.
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State the rock mechanical property measurements in stimulation and its applications.
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Illustrate briefly the leak off issues in designing a fracture treatment is accurate knowledge of how rapidly fluid will leak out of the fracture into the reservoir.
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Explain the typical ASR curve and differential strain curve analysis briefly.
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Mention the fracture propagation models. Describe the linear elastic fracture mechanics briefly.
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Describe briefly the cell-based pseudo-three-dimensional models of fracture.
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Illustrate the Perkins-Kern-Nordgren Model in detail.
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Describe how fracture fluid and damage the formation in detail.
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Describe the formation pressure capacity for PKN-type fracture briefly.
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State the pseudo radial concepts and Give the important characteristic points in fracture diagnostic techniques.
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Illustrate the proponent transport prediction from fluid rheological data in detail.
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Mention the guidelines of methods used to control the precipitates caused by acidizing is proper acid staging, lower acid concentrations.
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Illustrate the effect of reservoir properties in fracture design and evaluation.
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Explain the treatment fluid selection in sandstone acidizing briefly.
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Explain the linear fracture-mechanics model to predict fracture-height growth
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Derive a material balance equation during pumping and closure for stimulation treatment.
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What are the various additives and treating techniques for acid fluid-loss control?
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Describe the process of the treatment response diagnosis.
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Explain the factors controlling the effectiveness of acid fracturing treatments.
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Differentiate between acid fracturing and fracturing with propping agent and nonreactive fluids.
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