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Showing 1 to 20 of 118 for “"wellbore"”.
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Wellbore instability mechanisms in clays
This dissertation investigates the stability of wellbores drilled in Ko-consolidated clays using non-linear finite element method (FEM) and effective stress soil models to characterize the behavior of clay and unconsolidated shale formations. Two constitutive models are used: Modified Cam Clay …
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Wellbore stability in water-sensitive shales
<p>Wellbore instability is a widespread problem, especially when drilling in deep, low strength shale formations at high temperature and pressure. The instability can be caused by the high compressive effective stress or tensile stress due to the stress concentration and pore pressure increase …
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Wellbore Strengthening by Means of Nanoparticle-Based Drilling Fluids
Wellbore strengthening is the mechanism of increasing the fracture pressure of the rock at depth. Application of wellbore strengthening in the drilling industry enable safe drilling by preventing mud losses, drilling in narrow mud windows, accessing reserves in depleted reservoirs, and also has the …
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Investigation of wellbore stability in a North Sea field development
… and natural gas fields. As part of well design, wellbore stability and pore pressure analysis are main factors in determining the safe operating window for selecting mud density. The motivation for this research was to conduct wellbore stability based on exploration wells as basis for planning …
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Integrated multiphase flow modeling in wellbore for downhole pressure predictions
… pressure (P_wf) and pressure profile in the wellbore are of undeniable significance. One would ask why not deploy downhole pressure gauges to obtain P_wf readings. Unfortunately, it is not economical or practical to do so. The harsh in-situ conditions are not optimal for such gauges, …
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Wellbore Microannulus Characterization and Seal Repair: Computational and Lab Scale Modeling
… Carbon Capture and Storage (CCS). Pre-existing wellbores penetrate the reservoirs where supercritical CO2 is to be injected. These wellbores can potentially be a pathway for contamination if CO2 leaks through wellbore flaws to an overlying aquifer or the atmosphere. Characterizing wellbore …
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Exploring wellbore and reservoir temperature profiles in fluid circulation and production operations
<p>"The wellbore heat flow occurs during different well operations resulting from any temperature differences between the wellbore fluid and the adjacent formation. Understanding the direction and mechanism of heat flow whether it is conduction or convection help to represent this heat exchange …
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Extending the reach of drilling: better wellbore trajectory and torque & drag models
… in recent years, as the average length of the wellbore horizontal section continue to be extended. Drilling these complex wells, whether it is to reach reserves far from existing facilities or to expose reservoir sections for production and reservoir management advantages, requires accurate …
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Real-time monitoring of cement sheath integrity under high-angle HPHT wellbore conditions.
… to prevent leakages well beyond the life of the wellbore. The results of a recent engineering study of 15,500 wellbores in the Gulf of Mexico show that, as a wellbore turns fifteen years of age, it develops a fifty percent chance of being adversely affected by sustained casing pressure. Even …
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A Calculation Model for Steam Property Variation Along Wellbore Trajectory in SAGD Process
… decreases during the steam flow inside vertical wellbore because the steam loses its heat through wellbore system to formation due to temperature gradient. And in horizontal wellbore, steam even flow into formation through slotted liner which takes away energy directly. For a SAGD project, the …
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The Hampering Active Wellbore Kit (HAWK) for rapidly controlling a free flowing oil well
… safety tool, referred to as the Hampering Active Wellbore Kit (HAWK), is a machine that gradually introduces a continuous medium (e.g. wire) from a spool through the choke/kill lines of a failed BOP to gradually stem the flow through the BOP. The machine can couple to a standard choke/kill line on …
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Development and evaluation of a coaxial cable sensing system for CO₂ sequestration wellbore integrity monitoring
… sensing system for monitoring and evaluation of wellbore stability during CO<sub>2</sub> injection.</p> <p>The real-time distributed sensing system is composed of Fabry-Perot interferometer based coaxial cable temperature and strain sensors. A high pressure high temperature (HPHT) sensor testing …
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An experimental investigation into the stress-dependent mechanical behavior of cohesive soil with application to wellbore instability
… soils with reference to the applications of wellbore instabilities through an extensive program of laboratory element and model borehole tests. The laboratory tests use Resedimented Boston Blue Clay (RBBC) as an analog test material. Undrained triaxial shear tests have been performed on …
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Development of an optimised integrated underbalanced drilling strategy for cuttings transport in gas-liquid flow through wellbore annuli.
… two-phase flow patterns which affect the wellbore hydraulics and cuttings transport efficiency during UBD operations. Thus, this study developed a rigorous integrated strategy for maximising the efficiency of UBD for the transport of cuttings in gas-liquid two-phase flow through wellbore …
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Chemo-poro-elastic fracture mechanics of wellbore cement liners : the role of eigenstress and pore pressure on the risk of fracture
Between 2001 and 2010, United States natural gas wells have been drilled at a mean annual rate of 24,500. Moreover, an investigation in the Marcellus region revealed a 3.4% incidence rate of well-barrier leakages that were caused primarily by casing and cementing problems. Considering the …
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Emergence of Delamination Fractures around Casing and Its Stability
The cement sheath failures and nearby wellbore failures may lead to upward flow of drilling fluid or formation fluid, which may have significantly adverse consequences like loss of reserve and environmental hazards. In order to maintain wellbore integrity in the long term, it is expedient to …
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Cuttings transport and hydraulics optimisation for underbalanced drilling (UBD) operations in concentric and eccentric, directional and extended reach wells.
… drilling facilitates the effective control of wellbore pressures - amongst several other important advantages - when compared to conventional drilling technology. However, this involves the flow of multiphase fluids, which introduces additional complexities due to highly transient flow …
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Modeling of Pipe Friction and Smear Effect in Drilling Operations
… on two such issues: 1) to model the influence of wellbore friction on downhole temperatures of the drilling fluid, 2) to understand the smear effect mechanism observed in a casing while drilling operation through mathematical studies. An analytical model has been proposed to estimate the increase …
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Simulating and diagnosing three-dimensional multistage hydraulic fracturing with the generalized finite element method
… of fluid along with the isolated segments of the wellbore into the formation. In order to reduce operational costs, hydraulic fractures are usually created in stages (or clusters) where multiple fractures are propagated at the same time. It is estimated, however, that the majority of the …
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