scholarly journals Study on Dynamic Characteristics of Drill String Considering Rock-Breaking Process

2021 ◽  
Vol 9 ◽  
Author(s):  
Deyang Liang ◽  
Zhichuan Guan ◽  
Yuqiang Xu ◽  
Yongwang Liu
Keyword(s):  
Contact Force ◽  
Dynamic Characteristics ◽  
Rotation Speed ◽  
Low Frequency ◽  
Rock Breaking ◽  
Drill String ◽  
Drilling Process ◽  
Bottom Hole ◽  
Pdc Bit ◽  
High Rotation Speed

Using various tools to obtain downhole data to reach a precise pore pressure model is an important means to predict overpressure. Most downhole tools are connected to the lower end of drill string and move with it. It is necessary to understand the motion state and dynamic characteristics of drill string, which will affect the use of downhole tools. In this paper, a drilling process considering rock-breaking process in vertical wells is simulated using finite element method. In the simulation, gravity is applied to the whole drill string. The contact force between PDC bit and formation is the weight on bit (WOB). And a rotation speed is applied to the upper end of drill string. Analysis of the results shows that the vibration amplitude of bottom hole WOB (contact force between PDC bit and formation, which is the real WOB in drilling process) is bigger than the amplitude of wellhead WOB (acquired through conversion using Hook load, which is on behalf of the WOB obtained on drilling site). Both wellhead WOB and bottom hole WOB decline with a fluctuation in drilling process. In small initial WOB and low rotation speed conditions, the fluctuation of wellhead WOB focuses on low frequency, the fluctuation of bottom hole WOB focus on high frequency, and the phase of them are not identical. In large initial WOB and high rotation speed conditions, the fluctuation of wellhead WOB and bottom hole WOB both become more irregular. As for wellhead torque and bottom hole torque, the fluctuation of them mainly focuses on low frequency. And in high rotation speed conditions, wellhead torque may become negative. The research results are beneficial to the usage of downhole tools.

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.

The First Multilateral Well in Eastern Siberia on the Separated Oil Reservoirs

2021 ◽  
Author(s):  
Ruslan Fanisovich Gataullin ◽  
Stanislav Evgen’evich Ter-Saakov ◽  
Evgenij Vladimirovich Nikulin ◽  
Dmitriy Pavlovich Stifeev ◽  
Alexey Vyacheslavovich Filatov
Keyword(s):  
Low Frequency ◽  
Cost Effective ◽  
Drill String ◽  
Hole Drilling ◽  
Drill Bit ◽  
Eastern Siberia ◽  
Water Contact ◽  
Bottom Hole ◽  
Drilling Technology ◽  
Equipment Failures

Abstract This article describes engineering and technology solutions developed to successfully construct unconventional and unique horizontal well at the field of Eastern Siberia targeted to two isolated formations with an option to shut-off top Botuobinsky horizon after gas breakthrough and produce oil from underlying Ulakhansky bed further on. As oil-water contact in the lower part of Ulakhansky horizon makes fracturing the well inexpedient, multi hole drilling technology was implemented enabling drainage of the reserves that are far from the main borehole. The main objective of this well is to deplete Botuobinsky horizon subsequently shutting it off and continuing to recover petroleum reserves from Ulakhansky pay zone. Constructing such well is cost-effective, as it requires drilling only one intermediate casing interval instead of two. Accumulated experience of drilling and completing multi hole wells was used to ensure successful well construction; also, geological and stratigraphic data as well as possible complications while drilling Botuobunsky and Ulakhansky formations were analyzed in-depth. The following appliances were selected to meet the objective: –Bottom-hole equipment enabling drilling abrasive formations under conditions of high vibrations;–Special line of drill bits to ensure high ROP and successful sidetracking without additional tripping;–RSS with 152.4 mm drill bit. The goal set by the operating company was achieved through multi-faceted approach to performing the task, efficient cooperation of engineering technical services and continuous monitoring of output data while drilling. All that combined delivered the results listed below: –Sidetracks were carried out in an open horizontal hole without cement plugs and additional tripping for drill bit or BHA.–Minimized bottom-hole equipment failures under condition of increased high-frequency vibrations from bit while drilling hard formations due to implementation of modular PDM with data-transmitting channel.–Minimized bottom-hole equipment failures under condition of increased low-frequency vibrations from drill string with Hard Bending due to improved BHA design and optimized drilling parameters selection.–Liner was effectively run to Botuobinsky and Ulakhansky reservoirs with an option to shut-off the former after depletion and gas breakthrough. This well is the first one targeted at two isolated formations in East Siberia.

Wear Properties of Oil Palm Cellulose Fibre Reinforced Polymer Composites

2013 ◽  
Vol 845 ◽  
pp. 81-85
Author(s):  
D. Sujan ◽  
C.W. Nguong ◽  
S.N.B. Lee ◽  
Mesfin G. Zewge
Keyword(s):  
Drill Pipe ◽  
Low Frequency ◽  
Cellulose Fibre ◽  
Major Effect ◽  
Drill String ◽  
Drilling Process ◽  
Marine Riser ◽  
Wear Properties ◽  
Maximum Displacement ◽  
Drilling Tools

This paper attempts to explain the motion behaviour of the marine riser coupled to a drill string when the vortex induced vibration (VIV) is involved. Vibrations have been reported to have a major effect on the drilling performance, affecting the rate of penetration (ROP), causing severe damages to the drilling tools and also reduces the efficiency of the drilling process. There are two major components of drilling tools that are subjected to vibration, namely the marine riser and the drilling string. Analysis of vibration in the marine riser and drill string are two topical areas that have individually received considerable attention by researchers in the past. Though these two subjects are interrelated, borne by the fact that the marine riser encapsulates and protects the drill pipe, there have been few attempts to investigate them together as a unity. Due to the complexities of the models, simplified assumptions were made in order to undertake the investigation by using staggered approach. The results were compared with the experimental and simulation data from the open literature. It was found that the maximum displacement with negative damping occurs at low frequency and rotation speed.

scholarly journals The rock breaking capability analyses of sonic drilling

2021 ◽  
pp. 146134842110251
Author(s):  
Yonghang Qian ◽  
Yu Wang ◽  
Zhiqiao Wang ◽  
Bairu Xia ◽  
Liya Liu
Keyword(s):  
Longitudinal Vibration ◽  
Rock Breaking ◽  
Drill String ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Drilling Process ◽  
Percussive Drilling ◽  
Drilling Depth ◽  
Maximum Impact Force ◽  
Breaking Energy

Sonic drilling technology uses the longitudinal vibration of a drill string to realize fast and effective drilling. By setting the top and bottom boundary conditions of the drill string during drilling, a dynamic model of flexible sonic string percussive drilling is established in this article. At a certain drilling depth, with the excitation frequencies as the control parameters, the maximum impact force and rock breaking energy utilization rate are used to evaluate the rock breaking capability of the sonic drilling system under the linear bit–rock model. A surface diagram of the maximum breaking force reached within the working frequencies and at varying drilling depths is obtained. The curve graph of the rock breaking energy utilization rate varying with drilling depth under the first six orders of resonance is also calculated. Analysing the influence of changing drilling parameters on the rock breaking capability of sonic drilling systems can provide theoretical guidance for the actual drilling process.

scholarly journals Investigation of the Cross-Cutting Polycrystalline Diamond Compact Bit Drilling Efficiency

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Chun-Liang Zhang ◽  
Ying-Xin Yang ◽  
Hai-Tao Ren ◽  
Can Cai ◽  
Yong Liu ◽  
...  
Keyword(s):  
Cutting Force ◽  
Polycrystalline Diamond ◽  
Rock Breaking ◽  
The Novel ◽  
Cutting Efficiency ◽  
Bottom Hole ◽  
Pdc Bit ◽  
The Cross ◽  
Polycrystalline Diamond Compact ◽  
Cutting Modes

The parallel track scraping principle of conventional PDC bits largely limits the cutting efficiency and working life in deep formations. Cross-cutting polycrystalline diamond compact (PDC) bit may be an efficient drilling tool that increases the rock-breaking efficiency through both cross-cutting and alternate-cutting modes of the PDC cutter. The motion track equation of the cross-cutting PDC bit was derived by using the compound coordinate system, and the motion track was analyzed. Meanwhile, through the unit experiment and discrete element simulation, the cutting force, volume-specific load, and crack propagation were analyzed under different cutting modes. Through establishing a nonlinear dynamic model of the bit-rock system, the speed-up mechanism of the novel bit was analyzed based on rock damage, rock stress state, and motion characteristic of the bit during the rock-breaking process. Compared with unidirectional cutting, cross-cutting produces less cutting force, more brittle fracture, and a greater decrease of formation strength. The novel PDC bit can put more rock elements into a tensile stress condition than a conventional PDC bit, and the plastic energy dissipation ratio of the cross-cutting PDC bit is lower while the damage energy consumption ratio is higher than they are for conventional bits, which is beneficial to increasing the ratio of fracture failure and improving rock-breaking efficiency. Laboratory drilling tests show that the cross-cutting PDC bit can create mesh-like bottom-hole features. Drilling contrast experiments show that a mesh-like bottom-hole pattern can be obtained by using the cross-cutting PDC bit, of which the ROP is obviously higher than that of the conventional bit when drilling in sandstone or limestone formation. Meanwhile, the influence of deviation angle, weight on bit, and rock properties on cutting efficiency of the cross-cutting PDC bit are studied.

Optimal Design of Rotation Shaft Torque Testing System

2012 ◽  
Vol 476-478 ◽  
pp. 1987-1990
Author(s):  
Yuan Qiang Jin ◽  
Yu Li Zang
Keyword(s):  
Optimal Design ◽  
Cross Section ◽  
Dynamic Characteristics ◽  
Rotation Speed ◽  
Measuring System ◽  
Testing System ◽  
Optimized Design ◽  
Digital Plane ◽  
High Rotation Speed ◽  
Shaft Torque

Torque measuring in the extra-high rotation speed has not been resolved ideally yet, due to the restriction of the rough conditions. The dynamic characteristics of the developed digital plane grating angular-torquer measuring system are analyzed in this paper. The paper mainly calculates and designs the parameters of elastic shafts with different cross-section. Via the compare of dynamic characteristics and compactness of the elastic shafts with different cross-section, the optimized design is proposed at the end of the paper. The achievements of this paper can supply references to the study and design, maintaining and improvement of relative instruments.

Simulation of Drill Pipe Lateral Vibration due to Riser's Oscillation

2013 ◽  
Vol 845 ◽  
pp. 168-172
Author(s):  
Nabil Al Batati ◽  
Fakhruldin M. Hashim ◽  
William Pao
Keyword(s):  
Drill Pipe ◽  
Low Frequency ◽  
Major Effect ◽  
Drill String ◽  
Drilling Process ◽  
Marine Riser ◽  
Maximum Displacement ◽  
Drilling Performance ◽  
Drilling Tools ◽  
Negative Damping

This paper attempts to explain the motion behaviour of the marine riser coupled to a drill string when the vortex induced vibration (VIV) is involved. Vibrations have been reported to have a major effect on the drilling performance, affecting the rate of penetration (ROP), causing severe damages to the drilling tools and also reduces the efficiency of the drilling process. There are two major components of drilling tools that are subjected to vibration, namely the marine riser and the drilling string. Analysis of vibration in the marine riser and drill string are two topical areas that have individually received considerable attention by researchers in the past. Though these two subjects are interrelated, borne by the fact that the marine riser encapsulates and protects the drill pipe, there have been few attempts to investigate them together as a unity. Due to the complexities of the models, simplified assumptions were made in order to undertake the investigation by using staggered approach. The results were compared with the experimental and simulation data from the open literature. It was found that the maximum displacement with negative damping occurs at low frequency and rotation speed.

scholarly journals Non-Linear Dynamic Analysis of Drill String System with Fluid-Structure Interaction

2021 ◽  
Vol 11 (19) ◽  
pp. 9047
Author(s):  
Rongpeng Wang ◽  
Xiaoqin Liu ◽  
Guiqiu Song ◽  
Shihua Zhou
Keyword(s):  
Dynamic Characteristics ◽  
Chaotic Motion ◽  
Period Doubling ◽  
Drill String ◽  
Jump Discontinuity ◽  
Drilling Process ◽  
Prevention Measures ◽  
Fluid Structure ◽  
Non Linear ◽  
Effect Of Support

In this research, the non-linear dynamics of the drill string system model, considering the influence of fluid—structure coupling and the effect of support stiffness, are investigated. Using Galerkin’s method, the equation of motion is discretized into a second-order differential equation. On the basis of an improved mathematical model, numerical simulation is carried out using the Runge—Kutta integration method. The effects of parameters, such as forcing frequency, perturbation amplitude, mass ratio and flow velocity, on the dynamic characteristics of the drill string system are studied under different support stiffness coefficients, in which bifurcation diagrams, waveforms, phase diagrams and Poincaré maps of the system are provided. The results indicate that there are various dynamic model behaviors for different parameter excitations, such as periodic, quasi-periodic, chaotic motion and jump discontinuity. The system changes from chaotic motion to periodic motion through inverse period-doubling bifurcation, and the support stiffness has a significant influence on the dynamic response of the drill string system. Through in-depth study of this problem, the dynamic characteristics of the drill string can be better understood theoretically, so as to provide a necessary theoretical reference for prevention measures and a reduction in the number of drilling accidents, while facilitating the optimization of the drilling process, and provide basis for understanding the rich and complex nonlinear dynamic characteristics of the deep-hole drill string system. The study can provide further understanding of the vibration characteristics of the drill string system.

Application of the piecewise constant method in nonlinear dynamics of drill string

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Yi Zhou ◽  
Lin Yang ◽  
Changyue Fan ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Drill String ◽  
Vibration Velocity ◽  
Kutta Method ◽  
Time Step ◽  
Piecewise Constant ◽  
Runge Kutta Method ◽  
Runge Kutta

Abstract Aiming at the current development of drilling technology and the deepening of oil and gas exploration, we focus on better studying the nonlinear dynamic characteristics of the drill string under complex working conditions and knowing the real movement of the drill string during drilling. This paper firstly combines the actual situation of the well to establish the dynamic model of the horizontal drill string, and analyzes the dynamic characteristics, giving the expression of the force of each part of the model. Secondly, it introduces the piecewise constant method (simply known as PT method), and gives the solution equation. Then according to the basic parameters, the axial vibration displacement and vibration velocity at the test points are solved by the PT method and the Runge–Kutta method, respectively, and the phase diagram, the Poincare map, and the spectrogram are obtained. The results obtained by the two methods are compared and analyzed. Finally, the relevant experimental tests are carried out. It shows that the results of the dynamic model of the horizontal drill string are basically consistent with the results obtained by the actual test, which verifies the validity of the dynamic model and the correctness of the calculated results. When solving the drill string nonlinear dynamics, the results of the PT method is closer to the theoretical solution than that of the Runge–Kutta method with the same order and time step. And the PT method is better than the Runge–Kutta method with the same order in smoothness and continuity in solving the drill string nonlinear dynamics.

scholarly journals Prediction of shallow bit position based on vibration signal monitoring of bit broken rock

2021 ◽  
Vol 17 (1) ◽  
pp. 155014772199170
Author(s):  
Jinping Yu ◽  
Deyong Zou
Keyword(s):  
Acoustic Emission ◽  
Time Domain ◽  
Vibration Signal ◽  
Rock Breaking ◽  
Drill String ◽  
Mean Square ◽  
Drilling Force ◽  
Emission Signal ◽  
Force Signal ◽  
The Mean

The speed of drilling has a great relationship with the rock breaking efficiency of the bit. Based on the above background, the purpose of this article is to predict the position of shallow bit based on the vibration signal monitoring of bit broken rock. In this article, first, the mechanical research of drill string is carried out; the basic changes of the main mechanical parameters such as the axial force, torque, and bending moment of drill string are clarified; and the dynamic equilibrium equation theory of drill string system is analyzed. According to the similarity criterion, the corresponding relationship between drilling process parameters and laboratory test conditions is determined. Then, the position monitoring test system of the vibration bit is established. The acoustic emission signal and the drilling force signal of the different positions of the bit in the process of vibration rock breaking are collected synchronously by the acoustic emission sensor and the piezoelectric force sensor. Then, the denoised acoustic emission signal and drilling force signal are analyzed and processed. The mean value, variance, and mean square value of the signal are calculated in the time domain. The power spectrum of the signal is analyzed in the frequency domain. The signal is decomposed by wavelet in the time and frequency domains, and the wavelet energy coefficients of each frequency band are extracted. Through the wavelet energy coefficient calculated by the model, combined with the mean, variance, and mean square error of time-domain signal, the position of shallow buried bit can be analyzed and predicted. Finally, by fitting the results of indoor experiment and simulation experiment, it can be seen that the stress–strain curve of rock failure is basically the same, and the error is about 3.5%, which verifies the accuracy of the model.

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