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.

Model Development of Torsional Drillstring and Investigating Parametrically the Stick-Slips Influencing Factors

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Parimal Arjun Patil ◽  
Catalin Teodoriu
Keyword(s):  
Nonlinear Differential Equations ◽  
Torsional Oscillation ◽  
Stick Slip ◽  
Friction Forces ◽  
Rock Interaction ◽  
Torsional Oscillations ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Drilling Parameters ◽  
Bottom Hole Assembly

Drillstring vibration is one of the limiting factors maximizing drilling performance. Torsional vibrations/oscillations while drilling is one of the sever types of drillstring vibration which deteriorates the overall drilling performance, causing damaged bit, failure of bottom-hole assembly, overtorqued tool joints, torsional fatigue of drillstring, etc. It has been identified that the wellbore-drillstring interaction and well face-drill bit interaction are the sources of excitation of torsional oscillations. Predrilling analysis and real time analysis of drillstring dynamics is becoming a necessity for drilling oil/gas or geothermal wells in order to optimize surface drilling parameters and to reduce vibration related problems. It is very challenging to derive the drillstring model considering all modes of vibrations together due to the complexity of the phenomenon. This paper presents the mathematical model of a torsional drillstring based on nonlinear differential equations which are formulated considering drillpipes and bottom-hole assembly separately. The bit–rock interaction is represented by a nonlinear friction forces. Parametric study has been carried out analyzing the influence of drilling parameters such as surface rotations per minute (RPM) and weight-on-bit (WOB) on torsional oscillations. Influences of properties of drillstring like stiffness and inertia, which are most of the times either unknown or insufficiently studied during modeling, on torsional oscillation/stick-slip is also studied. The influences of different rock strength on rate of penetration (ROP) considering the drilling parameters have also been studied. The results show the same trend as observed in fields.

The Effect of Stick Slip Vibration on the Backward Whirl of Bottom Hole Assembly in Drillstring

2016 ◽  
Author(s):  
Dapeng Zhao ◽  
Sigve Hovda ◽  
Sigbjørn Sangesland
Keyword(s):  
Torsional Vibration ◽  
Borehole Wall ◽  
Stick Slip ◽  
Rock Interaction ◽  
Bottom Hole ◽  
Nonlinear Contact ◽  
Backward Whirl ◽  
Bottom Hole Assembly ◽  
Rotary Speed ◽  
Drill Collar

The whirl phenomena in the bottom hole assembly (BHA) is believed to be formed by the imbalance of the rotational drill collar. Backward whirl is caused by the nonlinear contact between the BHA and the borehole, and can be extremely damaging to the down hole tools and borehole. In the previous studies, a two-degrees-of-freedom lumped parameter model is developed for representing the drill collar in lateral motions (whirl). Due to the bit-rock interaction, the stick slip torsional vibration is very common. In the current work, therefore, the torsional vibration causing fluctuation of rotary speed is taken into account. The simulation results indicate that the drill collar whirls forward at lower constant rotary speed. With increasing rotary speed, the backward whirl is activated by the contact between the drill collar and the borehole wall. The nonlinear contact forces obey the Hertzian contact law, which led to lateral bounce of the drill collar and impact borehole wall chaotically. The modified Karnopp friction model is adopted to simulate the stick slip rotary vibration of the BHA. The different characters of lateral vibrations are identified by a power spectrum density diagram with and without consideration of the stick slip vibration.

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.

Mechanisms and Mitigation of 3D Coupled Vibrations in Drilling with PDC Bits

2021 ◽  
Author(s):  
Shilin Chen ◽  
Chris Propes ◽  
Curtis Lanning ◽  
Brad Dunbar
Keyword(s):  
Torsional Oscillation ◽  
Excitation Frequency ◽  
Low Frequency ◽  
Coupled Vibration ◽  
Stick Slip ◽  
Rock Interaction ◽  
Bottom Hole ◽  
New Type ◽  
Design Characteristics ◽  
Axial Resonance

Abstract In this paper we present a new type of vibration related to PDC bits in drilling and its mitigation: a vibration coupled in axial, lateral and torsional directions at a high common frequency (3D coupled vibration). The coupled frequency is as high as 400Hz. 3D coupled vibration is a new dysfunction in drilling operation. This type of vibration occurred more often than stick-slip vibration. Evidences reveal that the coupled frequency is an excitation frequency coming from the bottom hole pattern formed in bit/rock interaction. This excitation frequency and its higher order harmonics may excite axial resonance and/or torsional resonance of a BHA. The nature of 3D coupled vibration is more harmful than low frequency stick-slip vibration and high frequency torsional oscillation (HFTO). The correlation between the occurrence of 3D coupled vibration and bit design characteristics is studied. Being different from prior publications, we found the excitation frequency is dependent on bit design and the occurrence of 3D coupled vibration is correlated with bit design characteristics. New design guidlines have been proposed to reduce or to mitigate 3D coupled vibration.

Stick-slip investigation of dual drilling and reaming bottom hole assembly

2021 ◽  
pp. 095440622110184
Author(s):  
Mohammed F Al Dushaishi ◽  
Mortadha T Alsaba ◽  
Ahmed K Abbas ◽  
Tariq Tashtoush
Keyword(s):  
Field Studies ◽  
Drill Bit ◽  
Coupled Vibration ◽  
Stick Slip ◽  
Premature Failure ◽  
Bottom Hole ◽  
Vibration Model ◽  
Dual Action ◽  
Bottom Hole Assembly ◽  
Element Approach

Drillstring vibration is known to cause failures of drilling equipment, including the drill bit. In particular, stick-slip vibration has been known for causing premature failure of the drill bit, hence resulting in reducing the rate of penetration. With dual reaming while drilling, cutting forces are acting on the drillstring due to the simultaneous contact of the reamer and the drill bit. Field studies have shown dramatic changes in the dynamics of the bottom hole assembly due to the dual cutting actions. This paper investigates the dynamics of bottom hole assembly for dual reaming and drilling operation, with emphasis on stick-slip vibrations due to the reamer and the bit contact with the formation. A coupled vibration model representing the drillstring was created to simulate the stick-slip vibrations caused by the bit and reamer interactions using the finite element approach. The numerical analysis showed an elevated stick-slip vibration due to the dual-action of the reamer and the bit. Sensitivity analysis indicated that the cutter aggressiveness for the bit and the reamer are the most significant parameters affecting stick-slip behavior.

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.

Investigation on Effect of Downhole Vibration Force on Drilling Performance With a Dynamic BHA Model

2015 ◽  
Author(s):  
Lei Wang ◽  
Jianming Yang ◽  
Stephen Butt ◽  
Hongyuan Qiu
Keyword(s):  
Finite Element Method ◽  
Angular Frequency ◽  
Mean Value ◽  
Rock Interaction ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Mean ◽  
Simulation Results ◽  
Force Excitation

A dynamic bottom hole assembly (BHA) model is built with finite element method (FEM) in this paper. This model is used for evaluation the influence of externally added vibration to the BHA system. With this dynamic model along with a general bit-rock interaction formula, the BHA’s motion in axial and torsional directions are examined. Parametric study is carried out by varying the parameters of the applied vibration force, including the mean value, amplitude, angular frequency, and the location of this force excitation. The simulation results indicate that externally applied vibration force is indeed able to improve drilling performance. In particular, the mean value and amplitude of the applied force have a almost linear relation with ROP and WOB. The stresses distributions along BHA are investigated as well.

scholarly journals Stochastic modeling for hysteretic bit–rock interaction of a drill string under torsional vibrations

2019 ◽  
Vol 25 (10) ◽  
pp. 1663-1672 ◽  
Author(s):  
Fabio F. Real ◽  
Anas Batou ◽  
Thiago G. Ritto ◽  
Christophe Desceliers
Keyword(s):  
Stochastic Model ◽  
Drill String ◽  
Hysteretic Behavior ◽  
Drilling Process ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
Rock Interaction ◽  
Proposed Model ◽  
The Stability ◽  
Torque On Bit

This paper aims at constructing a stochastic model for the hysteretic behavior of the nonlinear bit–rock interaction of a drill string under torsional vibrations. The proposed model takes into account the fluctuations of the stick–slip oscillations observed during the drilling process. These fluctuations are modeled by introducing a stochastic process associated with the variations of the torque on bit, which is a function of the bit speed. The parameters of the stochastic model are calibrated with field data. The response of the proposed stochastic model, considering the random bit–rock interaction, is analyzed, and statistics related to the stability of the drill string are estimated.

scholarly journals Dynamic Analysis of Bottom Hole Assembly With External Vibrating Force Excitation

2013 ◽  
Author(s):  
Lei Wang ◽  
Stephen Butt ◽  
Jianming Yang
Keyword(s):  
Cfd Simulation ◽  
Model Simulation ◽  
Fluid Pressure ◽  
Rock Interaction ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Force Excitation ◽  
Valve Part

Based on the Downhole Oscillating Device (DOD) newly developed for purpose of improving drilling efficiency, Computational Fluid Dynamics (CFD) simulation is conducted. The axial vibration force created by the DOD is thoroughly investigated. The simulation is focused on the valve part which generates the fluid pressure pulsations. Fluid flow rate and/or back pressure is applied to the model as boundary conditions. The DOD’s application will also induce the inertia phenomenon of the fluid column above the tool. This phenomenon is also studied based on parametric analysis. Within the simulation results, a dynamic model is developed to further investigate the effect of the oscillating force generated by the DOD on drilling efficiency. Nonlinearities in the bit-rock interaction are taken into account in the model. Simulation results show that application of the DOD in drilling may improve the ROP at least by 5%.

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