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 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%.

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.

Bottom Hole Assembly Design Enhancement Successfully Eliminate Hole Problems and Reduce Significant Drilling Time : South S Field Case Study

2020 ◽  
Author(s):  
Y. D. Mulia
Keyword(s):  
Contact Area ◽  
Cost Savings ◽  
Assembly Design ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Unconsolidated Sand ◽  
Bottom Hole Assembly ◽  
Drilling Parameter ◽  
Drilling Time

For S-15 and S-14 wells at South S Field, drilling of the 12-1/4” hole section became the longest tangent hole section interval of both wells. There were several challenges identified where hole problems can occur. The hole problems often occur in the unconsolidated sand layers and porous limestone formation sections of the hole during tripping in/out operations. Most of the hole problems are closely related to the design of the Bottom Hole Assembly (BHA). In many instances, hole problems resulted in significant additional drilling time. As an effort to resolve this issue, a new BHA setup was then designed to enhance the BHA drilling performance and eventually eliminate hole problems while drilling. The basic idea of the enhanced BHA is to provide more annulus clearance and limber BHA. The purpose is to reduce the Equivalent Circulating Density (ECD,) less contact area with formation, and reduce packoff risk while drilling through an unconsolidated section of the rocks. Engineering simulations were conducted to ensure that the enhanced BHA were able to deliver a good drilling performance. As a results, improved drilling performance can be seen on S-14 well which applied the enhanced BHA design. The enhanced BHA was able to drill the 12-1/4” tangent hole section to total depth (TD) with certain drilling parameter. Hole problems were no longer an issue during tripping out/in operation. This improvement led to significant rig time and cost savings of intermediate hole section drilling compared to S-15 well. The new enhanced BHA design has become one of the company’s benchmarks for drilling directional wells in South S Field.

Optimizing Bottom Hole Assembly Design Criteria to Improve Mechanical Performance in Slim Hole Drilling Environment

2021 ◽  
Author(s):  
Stephen Fleming ◽  
Roberto Ucero ◽  
Yuliya Poltavchenko
Keyword(s):  
Mechanical Performance ◽  
State Of The Art ◽  
Hole Drilling ◽  
Force Analysis ◽  
Software Suite ◽  
Assembly Design ◽  
Positive Displacement ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Bottom Hole Assembly

Abstract After analyzing the historical data of neighboring wells adjacent to the drilling site, 11 bit trips were required due to the low mechanical performance of the bottom hole assembly elements. This observation is based on maximum circulation hours and low helical bucking values that make it uneconomic to drill the sections with a positive displacement motor drive system. A redesign the bottom hole assembly was proposed to achieve an improved mechanical performance which allowed the section to be drilled with a single assembly. With a focus on increasing the mechanical limitations of the downhole elements, the use of 4 ¾" equipment is considered instead of the 3 ½" standard equipment used in this hole size. One of the biggest challenges was modifying the 4 ¾" positive displacement motor (PDM) to fit into the 5 ½" hole given that the mud motor has a maximum unmodified diameter of 5 ½". Using the force analysis module of a State-of-the-art BHA modelling software suite, multiple iterations were performed to simulate and validate an alternative PDM design and accompanying directional assembly. This new design featured modifications to an existing 4 ¾" PDM deploying a long gauge bit in combination with a fit for purpose measurement while drilling system. After numerous runs using this assembly design, it was found that there was no additional or unexpected wear of the modified Mud Motor components or associated elements of the downhole equipment. These observations act to validate the pre-job engineering force analysis. With the improved mechanical specifications of the 4 ¾" Bottom Hole Assembly (BHA) components, circulating hours were increased from 100 hours to 250+ hours in a stepwise process. This enabled drilling of the entire 5 ½" section with a single BHA, comparing favorably to the legacy approach with an average of eleven bit runs. The modified 4 ¾" PDM coupled with long gauge bit technology enabled a reduction in the oriented to rotate drilling ratio and an associated increase in the overall rate of penetration (ROP). It can be concluded that the substitution of 4 ¾" drilling equipment for 3 ½" in the 5 ½" hole section, increased the drilling efficiency between 30-50% according to field data obtained in Ukraine. The modified 4 ¾" PDM combined with long gauge bit technology has the potential to improve 5 ½" hole drilling performance in other locations. Following a structured planning process using State-of-the-art BHA modelling software suite enabling the evaluation of the significant forces that act in the drilling assembly and so significantly reducing the risks associated with exceeding the original design limits of the assembly. By improving the mechanical performance of the drilling assembly in a 5 ½" hole, new territory for drilling engineers and design engineers is now available to increase the drilling performance in slim wellbores.

scholarly journals A Combined RMS-MEAN Value Approach for an Inverter Open-Circuit Fault Detection

2019 ◽  
Vol 63 (3) ◽  
pp. 169-177
Author(s):  
Mohamed Amine Khelif ◽  
Azeddine Bendiabdellah ◽  
Bilal Djamal Eddine Cherif
Keyword(s):  
Fault Detection ◽  
Induction Machines ◽  
Mean Value ◽  
Open Circuit ◽  
Major Research ◽  
Three Phase ◽  
Paper Work ◽  
The Mean ◽  
Simulation Results ◽  
Structural Failures

Currently, with the power electronics evolution, a major research axis is oriented towards the diagnosis of converters supplying induction machines. Indeed, a converter such as the inverter is susceptible to have structural failures such as faulty leg and/or open-circuit IGBT faults. In this paper, the detection of the faulty leg and the localization of the open-circuit switch of an inverter are investigated. The fault detection technique used in this work is based essentially upon the monitoring of the root mean square (RMS) value and the calculation of the mean value of the three-phase currents. In the first part of the paper work, the faulty leg is detected by monitoring the RMS value of the three-phase currents and comparing them to the nominal value of the phase current. The second part, the open-circuit IGBT fault is localized simply by knowing the polarity of the calculated mean value current of the faulty phase. The work is first accomplished using simulation work and then the obtained simulation results are validated by experimental work conducted in our LDEE laboratory to illustrate the effectiveness, simplicity and rapidity of the proposed technique.

Hybrid Drill Bit Technology on Performance Motor Bottom Hole Assembly Yields Breakthrough Drilling Performance in Kuwait

2019 ◽  
Author(s):  
Waleed Al-Baghli ◽  
Mohammad Al-Salamin ◽  
Sulaiman Sulaiman ◽  
Atef Abdelhamid ◽  
Ali Alnemer ◽  
...  
Keyword(s):  
Drill Bit ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Bottom Hole Assembly

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.

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.

Post Well Vibration Analysis in the North Sea: A Tool to Understand Drilling Performance

2015 ◽  
Author(s):  
M. F. Al Dushaishi ◽  
R. Nygaard ◽  
E. Hoel ◽  
S. Hellvik ◽  
M. Andersen
Keyword(s):  
North Sea ◽  
Vibration Damping ◽  
Rate Of Penetration ◽  
Drill Stem ◽  
The North ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The North Sea ◽  
The Impact

Severe drill stem vibrations could leads to excessive damage to the bottom hole assembly causing an increase in nonproductive time. Different drill stem vibrations models are used to predict and avoid resonance regions by optimizing the selection of bottom hole assembly components and operating parameters such as weight on bit, and surface RPM. In addition to avoid the resonance regions, specialized tools have been developed to reduce vibrations. However a complete understanding on how to mitigate vibration and its effect on drilling performance is still lacking. This study investigates the cause of drill stem vibrations, its effect on drilling performance, and the effect of including vibration reductions tools in the bottom hole assembly design in several recent drilled wells in the North Sea. Vibration damping tools used in this study were able to reduce both lateral and torsional drill stem vibration compared to a well with no vibration damping tool. Torsional drill stem vibrations tend to increase through rich sand zones causing an increase in lateral vibrations. The impact drill stem vibrations have on drilling performance was identified through rate of penetration. As lateral vibration intensity increases, instantaneous rate of penetration decreases.

scholarly journals Modeling and Experimental Study on Motion States of Laboratory-Scale Bottom Hole Assembly in Horizontal Wells

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 925
Author(s):  
Wei Li ◽  
Genlu Huang ◽  
Hongjian Ni ◽  
Fan Yu ◽  
Wu Jiang
Keyword(s):  
Numerical Simulation ◽  
Similarity Criterion ◽  
Horizontal Wells ◽  
Circular Motion ◽  
Rotary Drilling ◽  
Circular Arc ◽  
Bottom Hole ◽  
Drilling Engineering ◽  
Bottom Hole Assembly ◽  
Simulation Results

Motion states of bottom hole assembly (BHA) have a great effect on the trajectory control and drilling efficiency while rotary drilling. In order to study the motion states of BHA in horizontal wells, a BHA dynamic model with the finite element method was established. Meanwhile, an indoor experimental setup based on similarity criterion was designed and built to verify the numerical simulation results. Finally, the effects of measuring positions, rotate speeds, weight on bit (WOB), and friction coefficients on the motion states were analyzed in numerical simulation and experiment. The results show that the experimental results can match well with the numerical simulation results. The motion states of BHA in horizontal wells can be divided into three kinds, including circular arc swing, "8" shape swing, and dot-like circular motion. The circular arc swing mainly appears at middle section of BHA and occurs through the collective result of gravity and tangential friction. The dot-like circular motion mainly appears at near-bit or near-stabilizer area because drill bit and stabilizer can steady the BHA at the center part of the wellbore. The "8" shape swing mainly appears at the crossed area and occurs through collective disturbance of the other two motions. Moreover, rotate speed and friction coefficient have promotions on the lateral vibration while WOB have a much smaller effect. Through analyses, related suggestions are given for the drilling engineering. The related conclusions and suggestions in this paper can help to further understand the lateral dynamic characteristics of BHA in horizontal wells and select suitable parameters for drilling engineering.

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