Lateral vibration analysis of pre-bent pendulum bottom hole assembly used in air drilling

2018 ◽  
Vol 24 (22) ◽  
pp. 5213-5224
Author(s):  
He Zhang ◽  
Qinfeng Di ◽  
Wenchang Wang ◽  
Feng Chen ◽  
Wei Chen
Keyword(s):  
Finite Element ◽  
Dynamic Performance ◽  
Drilling Process ◽  
Lateral Vibration ◽  
Tangent Point ◽  
Critical Speeds ◽  
Weighted Residuals ◽  
Bottom Hole ◽  
Air Drilling ◽  
Bottom Hole Assembly

In the air drilling process, the pre-bent pendulum bottom hole assembly (PBP-BHA) has excellent performance in controlling the well deviation and improving the wellbore quality, but the mechanism that is closely related to the dynamics of the PBP-BHA has not been ascertained. In this paper, an effective technique combining the weighted residuals method with the finite element method is presented to study the PBP-BHA lateral vibration. First, a three-dimensional nonlinear static model of pre-bent BHA is established under small deformation condition and solved by the weighted residuals method and optimization method, so as to define the tangent point according to the deformation characteristics of the PBP-BHA. This tangent point determines the end of the effective PBP-BHA length that starts from the drill bit. Subsequently, the finite element model of PBP-BHA is established to solve the lateral natural frequencies and mode shapes of the PBP-BHA. After considering the borehole wall constraint, the modal superposition technique is used to obtain the steady dynamic responses of the PBP-BHA. Meanwhile, the dynamic performance of the PBP-BHA used in the actual air drilling process is calculated to obtain its critical speeds and working status chart. The critical speeds of the PBP-BHA are 80 r/min and 190 r/min, which are far away from the surface rotary speed in the actual drilling site. Through comparing with the dynamic characteristics of regular BHA with the same structural parameters, it is discovered that the bend angle in the PBP-BHA plays a crucial role in improving the dynamic performance of the PBP-BHA. Moreover, the technique presented in this study can be used to make a reasonable design of BHA configuration and optimize drilling parameters.

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

Analysis Behavior of a Rig Shafting Vibration Set Changes Bearing Parameters

2013 ◽  
Vol 437 ◽  
pp. 98-101 ◽  
Author(s):  
Van Thanh Ngo ◽  
Dan Mei Xie
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Degree Of Freedom ◽  
Mode Shapes ◽  
Lateral Vibration ◽  
Eigenvalues And Eigenvectors ◽  
Fem Model ◽  
Critical Speeds ◽  
Bearing Stiffness

Frequently, in the design of machines, some of parameters that directly affect the rotordynamics of the machines are not accurately known. In particular, bearing stiffness support is one such parameter. Taking a rig shafting as an example, this paper studies the lateral vibration of the rig shafting with multi-degree-of-freedom by using finite element method (FEM). The FEM model is created and the eigenvalues and eigenvectors are calculated and analyzed to find natural frequencies, critical speeds, mode shapes. Then critical speeds and mode shapes are analyzed by set bearing stiffness changes. The model permitted to identify the critical speeds and bearings that have an important influence on the vibration behavior.

Dynamic Stability of Lateral Vibration of Bottom Hole Assemblies

2008 ◽  
Vol 385-387 ◽  
pp. 809-812 ◽  
Author(s):  
Guang Hui Zhao ◽  
Zheng Liang
Keyword(s):  
Parametric Resonance ◽  
Separation Of Variables ◽  
Mathieu Equation ◽  
Parameter Method ◽  
Lateral Vibration ◽  
Oil Drilling ◽  
Bottom Hole ◽  
Parametric Resonances ◽  
Air Drilling ◽  
Weight On Bit

Bottom hole assemblies (BHA) of oil drilling engineering were simplified as simply supported beam, and parametric resonances of BHA in mud drilling and air drilling were studied. Lateral vibration of BHA, which was induced by bit/formation interaction, was described and reduced into Mathieu equation by means of separation of variables and Galerkin method. Modified strained parameter method was adopted in stability analysis. The parametric resonance zones expressed by weight on bit (WOB) are presented here. It is found that drilling method, speed of rotation (SOR), material properties, and length of compression drillstring all can influence parametric resonance zones. So unstable responses can be avoided by adjusting these parameters.

Finite Element for Simulating BHA-Casing-Rock Interactions

2015 ◽  
Vol 723 ◽  
pp. 246-251
Author(s):  
Yousif E.A. Bagadi ◽  
De Li Gao ◽  
Abdelwahab M. Fadol
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Numerical Solutions ◽  
Oil Industry ◽  
Element Model ◽  
Additional Increase ◽  
Gas Well ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
Drilling Cost

The Bottom Hole Assembly (BHA) design is consider a very important subject in the planning of any oil and gas well, and any mistake in BHA design will lead to additional increase in drilling cost, due to corrections needed in well trajectory.This study was intended to predict the trajectory path, by analyzing the tendency of the BHA to build, hold, or drop the angle of inclination. The other task of this work was to measure the effect of formation strength on wellbore trajectory. In this work finite element model (FEM) results are evaluated and verified using lab data supported with results obtained from some published analytical and numerical solutions and also verified with worldwide utilized software in Oil Industry (Landmark). The FE results significantly match with tubular mechanic lab data. The BHA model permits prediction of wellbore curvature based on both BHA mechanical behavior and geological influences.

Dynamic Modelling of Horizontal Shafts With Annular Surface Contact and Friction: Application to Oilwell Drilling

2014 ◽  
Author(s):  
Md. Mejbahul Sarker ◽  
D. Geoff Rideout ◽  
Stephen D. Butt
Keyword(s):  
Three Dimensional ◽  
Dynamic Modelling ◽  
Lateral Vibration ◽  
Horizontal Section ◽  
Stick Slip ◽  
Rock Interaction ◽  
Bottom Hole ◽  
Proposed Model ◽  
Bottom Hole Assembly ◽  
Friction Dynamics

Lateral whirl vibrations in long sections of horizontal oilwell drillstrings, which are essentially enclosed shafts lying on the low side of the wellbore, are potentially destructive to the bit, pipes and downhole tools. Forward or backward whirl can lead to impact with the borehole, and stick slip and bit bounce can cause tool joint failure, twist-off, and bit damage. A complete deviated drillstring has been modelled by having decoupled axial and torsional segments for the vertical and curved portions, and nonlinear three-dimensional multibody segments with lateral vibration in the final horizontal section ending at the bit. The model can predict how axial and torsional bit-rock reactions are propagated to the surface, and the role that lateral vibration near the bit plays 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.

scholarly journals Prediction of Performance of Rotary Bottom Hole Assembly For Directional Well

2013 ◽  
Vol 4 (3) ◽  
pp. 1-15
Author(s):  
Dr.Mohammed S. AL-Jawad ◽  
Dr.A.A.AL- Dabaj ◽  
Hassan Abdul Hadi Abdul Hussien
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Contact Forces ◽  
Three Dimensions ◽  
Normal Contact ◽  
Axial Forces ◽  
Bottom Hole ◽  
Principal Axes ◽  
Bottom Hole Assembly

A finite element model was constructed to predict inclination tendency for multistabilizer rotary BHA in three dimensions, static condition. The bottom hole assembly was idealized with beam element capable of resisting axial forces, bending moments about the two principal axes, and twisting moments about its centroidal axis. Bit and stabilizer were treated as contact point and restricted from movement in all directions. Each element is loaded with gravity and normal contact forces.           Model validation showed closer agreement between the model and Jiazhi's method (analytic) for slick, single, and two stabilizers BHA, compared to Akgun results. Predictions with finite element model showed that for building assembly, the weight on bit had small effect on bit side force especially in high angle wells. Also inclination tendency (building, dropping) would depend on position of the stabilizer, diameter of drillcollar behind the bit, and number of stabilizers.

Mathematical Models for 3D Analysis of Rotary Steering BHA Under Small Deflection

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Li Zifeng ◽  
Li Jingyuan
Keyword(s):  
Mathematical Models ◽  
Mechanical Analysis ◽  
3D Analysis ◽  
Tangent Point ◽  
Lateral Forces ◽  
Bottom Hole ◽  
Small Deflection ◽  
Bottom Hole Assembly ◽  
New Type ◽  
Diameter Change

A new type of rotary steering stabilizer used in a common rotary bottom hole assembly (BHA) to control well path was developed. In order for design and use of this kind of BHA, mathematical models were proposed for 3D mechanical analysis of rotary steering BHA with small deflection. The mathematical models include (1) differential equations; (2) boundary conditions of drill bit, stabilizer, diameter change, tangent point, and bore hole wall; (3) methods for calculating lateral forces and deflection angles of the bit; and (4) models for determining navigation ability and navigation parameters. As an example, a given rotary steering BHA was studied.

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