Dynamic mechanical behavior analysis of deep water drilling riser under hard hang-off evacuation conditions

Bi-nonlinear vibration model of tubing string in oil & gas well and its experimental verification

Friction-wear failure mechanism of tubing strings used in high-pressure, high-temperature and high-yield gas wells

Dynamical mechanics behavior and safety analysis of deep water riser considering the normal drilling condition and hang-off condition

The landing string is an important component of deepwater riserless drilling systems Determination of the dynamic characteristics of the landing string plays an essential role in its design for ensuring its safe operation In this paper, a dynamic model is developed to investigate the dynamic response characteristics of a landing string, where a landing string in a marine environment is modeled as a flexible slender tube undergoing coupled transverse and axial motions The heaving motion of the drilling platform is taken as the upper boundary condition and the motion of the drilling bit caused by the interaction between the rock and the bit as the lower boundary condition A semiempirical Morison equation is used to simulate the effect of the load imposed by the marine environment The dynamic model, which is nonlinearly coupled and multibody, is discretized by a finite element method and solved by the Newmark technique Using the proposed model, the dynamic responses of the displacement, axial force, and moment in the landing string are investigated in detail to find out the influences of driving depth of surface catheter, platform motion, bit movement, and marine environment on the dynamical characteristics of the landing string

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Nonlinear Dynamic Characteristic Analysis of a Landing String in Deepwater Riserless Drilling

Dynamic behavior of a deepwater hard suspension riser under emergency evacuation conditions

The intensive exploration to improve the accuracy of the calculation model of velocity slip and theoretical head has always been a major issue in pump research. Discontinuous blade of disc pump is different from the continuous blade of traditional pump. Disc pump realizes energy transfer by the effect of boundary layer. In order to fill in the theoretical blank of current research on the velocity slip and theoretical head of blade disc pump, the velocity slip is calculated by the systematic analysis under solid–liquid flow. In this study, the current misconception of velocity slip was corrected. Based on the different normal velocity components between particle and liquid on the blade surface, a new method is proposed to further verify the difference of solid–liquid flow velocity in impeller passage. Through the proposed method of calculating average circumferential velocity, the calculation model of the velocity slip coefficient and theoretical head of disc pump with linear and curved blade are given and verified. The accuracy of calculation model is increased by 39.4%. This model has good application value in theoretical head calculation, which lays a foundation for further research on energy conversion, energy efficiency prediction and reverse optimization design of disc pump with different blade shapes.

Analytical Methods and Verification of Impeller Outlet Velocity Slip of Solid–Liquid Disc Pump with Multi-Type Blades

The use of large-charged perforating bullets after well perforation produces large impact loads, which can easily lead to early unsealing of packers, damage to testing instruments, stress failure of tubing strings, buckling deformation, and other adverse incidents. This study focuses on the safety of large-charged perforating bullets used in downhole tools. In addition, a dynamic model of downhole perforation tools with multi-shock absorber was designed, and ANSYS software was used to validate its accuracy. Perforation impact loading field experiments were developed, and the loading pressure was measured over time to obtain an even more accurate equation to calculate loading. Analysis of the effects of different numbers of shock absorbers on the dynamic characteristics of downhole tools was conducted, finding that increasing the number of shock absorbers from one to two significantly decreased the dynamic response amplitude of the downhole tools (displacement, axial force, and packer force). However, when the number was increased to three, the change in response amplitude was not significant. Based on the maximum acceleration of each section of the tubing string, the testing instrument is best installed at its upper end. As the number of shock absorbers is increased, the number of regions of the tubing string that undergo buckling deformation decreases. Increasing the number of shock absorbers helps prevent buckling deformation in the tubing string, and increases its service life.

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Guorong Wang

Papers

Dynamic behavior of a deepwater hard suspension riser under emergency evacuation conditions

Nonlinear Dynamic Characteristic Analysis of a Landing String in Deepwater Riserless Drilling

Analytical Methods and Verification of Impeller Outlet Velocity Slip of Solid–Liquid Disc Pump with Multi-Type Blades

Investigation into the dynamic characteristics of downhole perforation tools with multiple shock absorbers