Problems of Ultra-Deepwater Drilling

Shaughnessy, J.M.; Armagost, W.K.; Herrmann, Robert P.; Cleaver, M. A.

doi:10.2118/52782-ms

Cited by 15 publications

(10 citation statements)

References 8 publications

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“…Shale formations are fine-grained sedimentary rocks composed of mainly clay, silts, and sometimes, sand particles. Shale formations range from clay-rich, weak formations to shaly siltstone, highly cemented formations [16]. They have extremely low permeability and high proportion of clay minerals.…”

Section: Shale Instabilitymentioning

confidence: 99%

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Wellbore Stability Problems in Deepwater Gas Wells

Aregbe¹

2017

WJET

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The analysis of wellbore stability in deepwater gas wells is vital for effective drilling operations, especially in deepwater remote areas and for modern drilling technologies. Wellbore stability problems usually occur when drilling through hydrocarbon formations such as shale, unconsolidated sandstone, fractured carbonate formations and HPHT formations with narrow safety mud window. These problems can significantly affect drilling time, costs and the whole drilling operations. In deepwater gas wells, there is also the possible of gas hydrate problems because of the low temperature and high pressure conditions of the environment as well as the coexistence of gas and water inside the wellbore. These hydrates can block the mud line, surface choke line and even the BOP stack if no hydrate preventive measures are considered. In addition, the dissociation of these hydrates in the wellbore may gasify the drilling fluid and reduce drilling mud density, hydrostatic pressure, change mud rheology and cause wellbore instabilities. Traditional wellbore stability analysis considered the formation to be isotropic and assumed that the rock mechanical properties are independent of in-situ stress direction. This assumption is invalid for formations with layers or natural fractures because the presence of these geological features will influence rock anisotropic properties, wellbore stress concentration and failure behavior. This is a complicated phenomenon because the stress distribution around a wellbore is affected by factors such as rock properties, far-field principal stresses, wellbore trajectory, formation pore pressure, reservoir and drilling fluids properties and time. This research work reviews the major causes of wellbore stability problems in deepwater gas wells and outlines different preventive measures for effective drilling operation, because real-time monitoring of drilling process can provide necessary information for solving any wellbore stability problems in a short time.

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Section: Shale Instabilitymentioning

confidence: 99%

“…In order to analyze the stability of deepwater gas wells, it is important to define the initial in-situ conditions of the formation. The first step in this analysis is to determine the formation pore pressure, rock compressive strength and stresses acting on the formation at the wellbore wall [16] [17]…”

Section: Mechanical Instabilitymentioning

confidence: 99%

Wellbore Stability Problems in Deepwater Gas Wells

Aregbe¹

2017

WJET

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“…There are two kinds of hydraulic connectors, wellhead connector and LMRP connector, which are activated hydraulically and connect the BOP stack to the wellhead or the LMRP to the BOP stack. Great damages to the riser, stack, or wellhead will likely result if the connector does not release and the rig moves off location [27].…”

Section: System Descriptionmentioning

confidence: 99%

Application of Petri nets to performance evaluation of subsea blowout preventer system

Liu¹,

Liu²,

Cai³

et al. 2015

ISA Transactions

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“…The number of turns can be expressed as a function of the valve dimensions as follows: (1) where is filling factor of the coil, which is the ratio of profitable copper section to overall actuator section, and are the inner and outer diameters of the coil, respectively, is the length of the coil, and is the diameter of the copper wire (see Fig. 2).…”

Section: A Thermal Modelmentioning

confidence: 99%

“…Two redundant multiplex control pods, normally located on the lower marine riser package on the seafloor, are of crucial importance to the performance and reliability of BOP systems. The control pods contain 224 submersible solenoid valves immersed in low-temperature and high-pressure seawater [1]. To check the subsea BOP system, a complete system test is performed every 8 minutes.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Submersible Solenoid Valves for Subsea Blowout Preventers

Cai

Tian

et al. 2011

IEEE Trans. Magn.

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An analytical optimization approach of the submersible solenoid valve constrained in a specific small volume is presented. In order to maximum the electromagnetic force, thermal model and electromagnetic model are constructed, and five radial dimensions are optimized when the main limiting quantity is the maximum allowed temperature. A numerical optimization calculation is performed in order to verify the proposed analytical approach. The optimal solution of the numerical calculation is compared with the solution of the analytical approach, which shows a good agreement between the two methods. A thermal analysis of the optimal submersible solenoid valve based on AYSYS is also performed to verify the thermal model. A comparative study between the experimental and simulated static characteristics of the optimal submersible solenoid valve is also performed. The results show that the proposed analytical approach is correct.

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Problems of Ultra-Deepwater Drilling

Cited by 15 publications

References 8 publications

Wellbore Stability Problems in Deepwater Gas Wells

Wellbore Stability Problems in Deepwater Gas Wells

Application of Petri nets to performance evaluation of subsea blowout preventer system

Optimization of Submersible Solenoid Valves for Subsea Blowout Preventers

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