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The selection of optimal operational parameters for drilling oil and gas wells is a complex dynamic problem that depends on multiple parameters. Numerous physical and mechanical processes such as rock cutting, friction, hydraulics, and different modes of vibrations, occur during drilling, which should be accounted for in numerical models. It is wid...
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... axial load is applied to the right end of the rod via hand-driven screw. Table 1 displays the rod and pipe parameters. In accordance with theory and experimental data, a rod lying on the lower side of a horizontal pipe will buckle if the axial load reaches the value called the critical buckling load. ...Citations
... The author in the paper in [60] presented a rigid-flexible multibody system approach to model drill string dynamics. The research modelled the drill string as a series of uniform flexible beams interconnected by linear viscous-elastic force elements. ...
The complex dynamics of drill strings under various vibration modes during drilling operations present significant challenges to the oil and gas industry due to the high costs associated with oil well drilling. This analytical study aims to provide a comprehensive overview of the most important and widely used mathematical modeling tools and techniques for describing the behaviors of drill strings under various conditions. The study highlights significant scientific contributions and research papers that have utilized or addressed these methods, including finite element, lumped mass, partial differential, wave equation, and Cosserat theory. This emphasis is meant to be partial but reflects the frequent use of these methods in drill string modeling. It also sheds light on the evolution and classification of different mathematical models used, divided into two main categories: static models and dynamics models, and how they have been involved with advancements in drilling technologies. Finally, this review underscores the potential for significant cost savings in the oil and gas industry by incorporating artificial intelligence and modern technologies into well drilling and drilling operations control, which is closely tied to improving the productivity and efficiency of oil and gas fields.
... Лысиков Н.Н. 1 , Погорелов Д.Ю. 2 1 -ООО "Вычислительная механика", Брянск, Россия 2 -Брянский государственный технический университет, Брянск, Россия lysikov@umlab.ru ...
... Стандартные инженерные подходы предполагают оценку состояния скважины и внутрискважинного оборудования без учета временного фактора: гидравлический анализ скважины, анализ сил сопротивления продольному движению и вращению бурильной колонны в целом, статический и вибрационный анализ нижней компоновки колонны, оценка направления проходки и т.д. [2]. Новые подходы, обусловленные развитием численных методов и производительности вычислительной техники, позволяют также исследовать движение колонны в скважине во временной области в масштабах сравнимых с масштабом реального времени. ...
Approaches and methods for applying mathematical models implemented in software package "Universal Mechanism" for assessing the behavior of the drill string including modern systems for supporting the construction of wells for oil and gas production are considered.
... These excitations generate various types of vibration in the system, which constitute in the overall the main factor of loss in the effectiveness of the bit penetration during drilling, and the premature fault of certain mechanical components (Franca, 2004). On the other hand, there is a consensus that the main source of friction is the BHA in its interaction with the hole (Pogorelov et al., 2012). ...
In order to better understand the dynamic behavior of a drillstring subjected to various electrical and mechanical excitations, torsional effects will be investigated separately. An optimized concentrated parameters model was proposed based on a test bench made up by a double torsional pendulum, coupled to a DC motor by means of a planetary gearbox. The double pendulum is made up of metallic rotors driven by a very slender steel shaft, one at the extremity of the shaft and the other in an intermediate position. The shaft is fixed to the output of the gearbox connected to the DC motor. The rotors, on the other hand, are supported on roller bearings by a rigid frame, in a way to separate possible flexural vibrations from the torsional vibrations that shall be investigated. In the proposed model for the coupled electro-mechanical system, the torsional system is composed by the slender shaft, both inertias, one modeling the outer rotor and the other the inner one, and the engine rotor fixed to the shaft by means of the gearbox. It was represented by an optimized concentrated parameters mathematical model with a predetermined number of degrees of freedom. The modes of vibration were a priori calculated analytically from a similar continuous model based on the torsional wave equation of the shaft. For validation purposes, some dynamic responses of the system were superimposed, obtained both, by numerical simulation of the proposed mode as well as by experimental tests. The complexity of this model is easily increased and the techniques explored in this paper to define optimal parameters for the model can be valuable for engineering applications.
... A benchmark of buckling pipe in wellbore was computed with the proposed BIB-contact method. An experiment [37] and some numeric simulations with different methods [38,39] have been conducted for this benchmark, and our numeric results were compared with these results. Another similar example can be found in the work of Liu [8,9,40] and [10], Screwing speed ω = π/4 rad/s even though the considered pipe in these studies was much longer and stiffer. ...
... The numeric results of an axial load versus an axial movement were compared with those of the references in Fig. 15. The result with the inexact-Newton-iteration-based method agreed with the experiment data, and was nearly the same as the result with the modal multibody method in the first half of the helical buckling process [39]. Although the result of the inexact-Newton iteration will converge with that of the Newton iteration in every time step with an infinite number of iterations, numeric differences exist between them due to the truncation error of iteration. ...
... The system parameters and dynamic equations for this system, but not the drillstring and drillstring contact, were detailed in [32]; the diameters, element length and material parameters of the drillstring and riser are shown with the contact settings in Table 9. The inside diameter and outside of the riser in Table 9 are average values, Axial load vs. axial movement Experiment [Wu, 1993] FEM [Tikhonov, 2006] Modal Multibody [Pogorelov, 2012] Newton because the riser was assembled with joints that had different diameters in different depths of seawater, as described in the basic model devised in [32]. ...
Beam-in-beam large sliding contact exists in simulations of drillstring-riser systems, offshore pipe-in-pipe systems, medical catheter-guidewire-stent systems, among others. Large sliding between the pipes may lead to discontinuity of contact force and non-sparsity of system Jacobian in numeric simulations, which then may result in non-physical disturbances and low efficiency. To overcome this phenomenon, a consistent-contact-force algorithm and a highly efficient implicit-integration scheme are proposed in this paper. Geometric treatments are applied in gap and overlap areas to obtain continuous contact force, in addition to contact-history-based fast detection. The contact force Jacobian is ignored as the flexible multibody system is solved with an inexact Newton iteration and an empirical formula is used to estimate the convergence conditions. Four numeric examples are computed to verify the presented method, including a buckling benchmark and a riser-recoil industrial application. The numeric results show that the proposed method is accurate and highly efficient.
... Considering forces and degrees of freedom, the equation of motion in a vector-dimension (Pogorelov et Al., 1998 and2012), is established as: ...
A West Texas operator historically used four to seven PDC bits to TD their Ward County, Wolfcamp B laterals. Formations there are lithologically more challenging when compared to the same interval in adjacent Reeves County. Drilling performance in Reeves County Wolfcamp A laterals averages approximately 1,091 Feet/Day while those in Ward County seldom make 600 Feet/Day. Often daily progress is less than that. The objective was to improve Ward County lateral drilling performance.
In the study presented here, we examined the BHAs, bits and motors in consecutive Wolfcamp B laterals on the same pad which used 7 and 5 bits to reach TD respectively. Several of these PDC bits were Damaged Beyond Repair (DBR) as illustrated later. We demonstrate the process of utilizing Time Domain Analyses (TDA) as an accurate method to identify and analyze the nonlinear, dynamic behavior of drilling systems. These enhanced models allow the engineer to explore a full range of alternative BHA responses based upon current drilling conditions. They account for most of the specific details of downhole equipment such as the bit, the rotary steerable systems (RSS) or steerable mud motor, the MWD and their interaction with the hole. The software used allows virtual sensors to be placed anywhere along the drill string to evaluate the dynamics for additional insights.
... Trajectory along which the drillstring will move in the process of loading it is influenced by different factors, namely: internal stresses in individual drill pipes and the resulting oscillations [7]. For example, in [8][9][10], the results of numerical simulation of the drilling process are presented, taking into account the effect on the motion path of the oscillations of the drill. ...
... It is of interest in connection with the drilling technique and drilling simulation, cf. [9][10][11][12][13][14][15][16][17]. ...
The behavior of an oil drill string is considered on example of a rotating flexible shaft in a rigid tube. The tube (a model of the borehole) is assumed to be an arbitrary space curve, and the shaft is considered as a nonlinear elastic Cosserat rod. The nonlinear dynamic equations for the shaft are derived and solved by means of computer mathematics. The boundary value problem for the quasi-static rotation is reduced to the ordinary differential equation (ODE). The shooting method is applied for solving the obtained nonlinear ODE. The quasi-static rotation is shown to exhibit jumps for some sets of parameters. The dynamic problem is solved by the differential-difference method. The rotation behavior, the resultant forces, and moments in the rod as well as the contact reaction of the inner surface of the tube are determined. The differences between the static and dynamic solutions are demonstrated.
... The existing works on drilling system dynamics modeling are mainly for the offline drilling analysis or pre-job planning and thus not restricted by computational load. Since the drillstring is typically very long, most of the conventional modeling approaches need large number of meshes along the drill-string which result in high-dimensional models, including models using finite element (FEM) [2], finite rigid body method [3] etc. This becomes a major barrier for control design, as a model of too high order can result in a high order controller that is not feasible for real-time implementation. ...
This paper proposes a novel computationally efficient dynamics modeling approach for down-hole well drilling system. The existing drilling modeling methods are either computationally intensive such as those using finite element method (FEM) or weak in fidelity for complex geometry such as those using transfer matrix method (TMM). To take advantage of the benefits of FEM and TMM and avoid their drawbacks, this paper presents a new hybrid method integrating both of the aforementioned modeling approaches, enabled by the unique structural geometry of the drilling system. The new method is then applied to the down-hole well drilling system modeling, incorporating the dynamics of top drive, drill-string, bottom-hole-assembly (BHA), and bit-rock interaction. The hybrid integration approaches for both the axial and torsional dimensions are explicitly derived, and we also give directions on how to resolve those for flexural dimension. To this end, numerical simulation results are presented to demonstrate the effectiveness of the proposed hybrid modeling approach.
... The analytical model was able to analyze the bending vibrations of the BHA lying on the low side of the horizontal borehole. Another analytical model for simulating the snaking and whirling mode of drillstring is presented by Pogorelov et al. (2012). The rigid-flexible multi-body system approach was used in the modeling. ...
Failure of horizontal oilwell drilling equipment, in particular the bottom-hole-assembly, is very costly. Vibration causes tool joint failure, twist-off, and bit-damage, and has motivated extensive research on understanding and predicting the dynamic shock-loading response of the bottom-hole-assembly. This paper presents a model to analyze the dynamics of a horizontal oilwell bottom-hole-assembly. A nonlinear three-dimensional multibody shaft model has been verified and extended to include stick-slip whirl phenomena due to the contact between the rotating bottom-hole-assembly and wellbore. The model has been verified with a dynamic finite element analysis through comparisons of the response of an enclosed shaft under axially compressive load rotating inside the wellbore. Finally, a complete deviated drillstring has been simulated by combining the bottom-hole assembly model with a model of the drill pipe and collars. The pipe and collars are modeled using a lumped-segment approach that predicts axial and torsional motions. The model can predict how axial and torsional bit-rock reactions are propagated to the surface, and the role that lateral vibrations near the bit play in exciting those vibrations and stressing components in the bottom-hole-assembly. The proposed model includes the mutual dependence of these vibrations, which arises due to bit-rock interaction and friction dynamics between the drillstring and wellbore wall. A force excitation source, which simulates an axially-vibrating downhole tool, has been implemented in the horizontal section of the virtual drillstring. Simulations show a better weight transfer to the bit due to the tool, with a low frequency and high amplitude force excitation giving best performance but potentially increasing the severity of lateral shock. The model, implemented using the bond graph formalism, is a useful tool for design and sensitivity analysis due to its physically meaningful parameters and low simulation times on a personal computer.
... The existing works on drilling system dynamics modeling are mainly for the offline drilling analysis or pre-job planning and thus not restricted by computational load. Since the drill string is typically very long, most of the conventional modeling approaches need large number of meshes along the drill string which result in high-dimensional models, including models using finite element (FEM) [2], finite rigid body method [3] and etc. This becomes a major barrier for control design, as a model of too high order can result in a high order controller that is not feasible for real-time implementation. ...
This paper proposes a novel computationally efficient dynamics modeling approach for downhole well drilling system. The existing drilling modeling methods are either computationally intensive such as those using finite element method (FEM), or weak in fidelity for complex geometry such as those using transfer matrix method (TMM). To take advantage of the benefits of FEM and TMM and avoid their drawbacks, this paper presents a new hybrid method integrating both of the aforementioned modeling approaches, enabled by the unique structural geometry of the drilling system. Numerical simulation results are presented to demonstrate the effectiveness of the proposed hybrid modeling approach.
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