scholarly journals A Dynamic Model for Continuous Lowering Analysis of Deep-Sea Equipment, Based on the Lumped-Mass Method

2020 ◽  
Vol 10 (9) ◽  
pp. 3177
Author(s):  
Pan Gao ◽  
Keliang Yan ◽  
Mingchen Ni ◽  
Xuehua Fu ◽  
Zhihui Liu
Keyword(s):  
Dynamic Model ◽  
Oil And Gas ◽  
System Response ◽  
Dynamic Force ◽  
Structural Damping ◽  
Lumped Mass ◽  
Nonlinear Loads ◽  
Oil And Gas Development ◽  
Lumped Mass Method ◽  
Heave Motion

The installation of subsea equipment is a critical step in offshore oil and gas development. A dynamic model to evaluate the lowering process is proposed. The cable–payload system is discretized as a series of spring dampers with the lumped-mass method. For the first time, not only the lowering velocity but also the rope’s structural damping and the nonlinear loads, such as drag force and snap load, are considered. The lowering velocity of the cable is considered through a variable-domain technique. Snap loads are considered by setting the internal forces in the elements to be zero when the cable slacks. A series of simulations reveals that the lowering velocity has great effects on the dynamic force in the cable. However, the structural damping of the cable has little effect on the system response. The snap load may occur in the cable when subjected to rapid downward heave motion, and decreases with the lowered depth increasing. The cable stiffness affects the system’s resonance depth, but has little effect on the peak dynamic force. The present work should be a valuable reference for future subsea equipment installation analysis.

scholarly journals A New Mathematical Modeling Method for Four-Stage Helicopter Main Gearbox and Dynamic Response Optimization

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yuan Chen ◽  
Rupeng Zhu ◽  
Guanghu Jin ◽  
Yeping Xiong ◽  
Jie Gao ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Sensitivity Analysis ◽  
Dynamic Response ◽  
Dynamic Model ◽  
Structural Parameters ◽  
Modeling Method ◽  
System Response ◽  
Analysis Method ◽  
Lumped Mass ◽  
Sensitivity Analysis Method

A new mathematical modeling method, namely, the finite element method and the lumped mass method (LMM-FEM) mixed modeling, is applied to establish the overall multinode dynamic model of a four-stage helicopter main gearbox. The design of structural parameters of the shaft is the critical link in the four-stage gearbox; it affects the response of multiple input and output branches; however, only the meshing pairs were frequently shown in the dynamic model in previous research. Therefore, each shaft is also treated as a single node and the shaft parameters are coupled into the dynamic equations in this method, which is more accurate for the transmission chain. The differential equations of the system are solved by the Fourier series method, and the dynamic response of each meshing element is calculated. The sensitivity analysis method and parameter optimization method are applied to obtain the key shaft parameters corresponding to each meshing element. The results show that the magnitude of dynamic response in converging meshing pair and tail output pair is higher than that of other meshing pairs, and the wall thickness has great sensitivity to a rotor shaft. In addition, the sensitivity analysis method can be used to select the corresponding shaft node efficiently and choose parameters appropriately for reducing the system response.

Dynamic Modeling of Bottomhole Assembly

2014 ◽  
Author(s):  
Madhu Vadali ◽  
Zhijie Sun ◽  
Yuzhen Xue ◽  
Jason Dykstra
Keyword(s):  
Dynamic Model ◽  
Oil And Gas ◽  
System Development ◽  
Beam Theory ◽  
Flexible Beam ◽  
Fluid Mud ◽  
Directional Drilling ◽  
Lumped Mass ◽  
Stick Slip ◽  
Drilling System

This paper presents a comprehensive 4D dynamic model of a bottomhole assembly (BHA) used for directional drilling of oil and gas wells. Although directional drilling has been in practice for some time, it still poses several challenges, particularly related to building an autonomous drilling system. The difficulty with drilling automation derives from the complexity of the process that includes interaction with the borehole and fluid (mud) flow and complex downhole vibrations, such as bit-bounce (axial), whirl (lateral), and stick/slip (torsional). Moreover, the measurements from a limited number of downhole sensors are usually contaminated with high noise levels, and can only be transmitted at low rates with long transmission delays using mud pulsing, or at a high cost using wired pipe. Therefore, it is preferable that the directional drilling system work autonomously with limited communication to the surface. To facilitate this, a compressive physics-based model of the BHA behavior was created to be used in control system development. In this work, the 4D dynamic model of the BHA accounts for the dynamics in rotation, axial motion, and bending along two lateral directions. The model uses a lumped mass-spring system and the system parameters (mass and stiffness) are derived from the shear beam theory of a flexible beam under certain boundary conditions. Simulation results of the model were successful in qualitatively replicating the three types of downhole vibrations, namely bit-bounce, whirl, and stick/slip, and are discussed in this paper. The model is shown to qualitatively replicate downhole conditions and can be implemented in real-time, thereby making it suitable for autonomous directional drilling control.

Study on Dynamic Model and Characteristic of Internal Parallel Moving Gears Transmission

2010 ◽  
Vol 139-141 ◽  
pp. 2672-2676
Author(s):  
Fang Wen ◽  
Gan Wei Cai ◽  
Yuan Ni ◽  
Hai Xia Zhang
Keyword(s):  
Dynamic Model ◽  
Theoretical Basis ◽  
Moving Load ◽  
Lumped Mass ◽  
Modeling Process ◽  
Lumped Mass Method ◽  
Tooth Number ◽  
New Type ◽  
Planetary Transmission ◽  
Multi Phase

Internal parallel moving gears transmission is a new type of planetary transmission with small tooth number difference. The dynamic model of the system is established by using lumped mass method. In the modeling process, the factors including the elasticity of all eccentric shafts, the elasticity of planetary bearing, the elasticity of supporting bearing on output shaft and the elasticity of meshing gears are considered, and the coordinate relation of the system is derived. The practical example and computer simulation was carried out and the dynamic characteristic is obtained. The results show that the gear transmission becomes steadier when simultaneously inputting the power from the three symmetrical shaft and utilizing multi-phase parallel mechanism, and the load of supporting bearing can be greatly reduced. This paper offers theoretical basis on correctly designing internal parallel moving gears transmission, reducing moving load and extending the service life.

Consideration of Geopolitical Challenges within the Analysis of Geoenvironmental Risks for Oil and Gas Development of the Russian Arctic

2019 ◽  
Vol 16 (6) ◽  
pp. 50-59
Author(s):  
O. P. Trubitsina ◽  
V. N. Bashkin
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Optimal Operation ◽  
The Arctic ◽  
Stage Model ◽  
Oil And Gas Development ◽  
Gas Industry ◽  
The Impact ◽  
Further Development ◽  
Geopolitical Risks

The article is devoted to the consideration of geopolitical challenges for the analysis of geoenvironmental risks (GERs) in the hydrocarbon development of the Arctic territory. Geopolitical risks (GPRs), like GERs, can be transformed into opposite external environment factors of oil and gas industry facilities in the form of additional opportunities or threats, which the authors identify in detail for each type of risk. This is necessary for further development of methodological base of expert methods for GER management in the context of the implementational proposed two-stage model of the GER analysis taking to account GPR for the improvement of effectiveness making decisions to ensure optimal operation of the facility oil and gas industry and minimize the impact on the environment in the geopolitical conditions of the Arctic.The authors declare no conflict of interest

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