Mathematical Modeling of PDC Bit Drilling Process Based on a Single-Cutter Mechanics

1993 ◽  
Vol 115 (4) ◽  
pp. 247-256 ◽  
Author(s):  
A. K. Wojtanowicz ◽  
E. Kuru
Keyword(s):  
Polycrystalline Diamond ◽  
Rock Properties ◽  
Drilling Process ◽  
Drilling Parameters ◽  
Pdc Bit ◽  
Analytical Development ◽  
Assumed Similarity ◽  
Balance Of Forces ◽  
Bit Life ◽  
Polycrystalline Diamond Compact

An analytical development of a new mechanistic drilling model for polycrystalline diamond compact (PDC) bits is presented. The derivation accounts for static balance of forces acting on a single PDC cutter and is based on assumed similarity between bit and cutter. The model is fully explicit with physical meanings given to all constants and functions. Three equations constitute the mathematical model: torque, drilling rate, and bit life. The equations comprise cutter’s geometry, rock properties drilling parameters, and four empirical constants. The constants are used to match the model to a PDC drilling process. Also presented are qualitative and predictive verifications of the model. Qualitative verification shows that the model’s response to drilling process variables is similar to the behavior of full-size PDC bits. However, accuracy of the model’s predictions of PDC bit performance is limited primarily by imprecision of bit-dull evaluation. The verification study is based upon the reported laboratory drilling and field drilling tests as well as field data collected by the authors.

scholarly journals Change of the Properties of Steel Material of the Roller Cone Bit Due to the Influence of the Drilling Operational Parameters and Rock Properties

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5949
Author(s):  
Jurij Šporin ◽  
Tilen Balaško ◽  
Primož Mrvar ◽  
Blaž Janc ◽  
Željko Vukelić
Keyword(s):  
Structural Changes ◽  
Simultaneous Thermal Analysis ◽  
Rock Properties ◽  
Drilling Process ◽  
Drill Bit ◽  
Operational Parameters ◽  
Rock Materials ◽  
Steel Material ◽  
Drilling Parameters ◽  
Bit Life

The breakdown of the drill bit or rapid decrease of the rate of penetration during the drilling process results in a delay in the progress of drilling. Scientists and engineers are increasingly focusing on research to extend the bit life and improve the drilling rate. In our work, “in situ” drilling parameters were monitored during the drilling process with the roller cone drill bit IADC 136, diameter 155.57 mm (6 1/8"). After drilling, the bit was thoroughly examined to determine the damage and wear that occurred during drilling. The following modern and standardized investigative methods were used: an analysis of rock materials and an analysis of micro and macrostructure materials of the roller cone bit. Analyses were carried out using optical and electron microscopy, a simultaneous thermal analysis of materials of drill bit, analysis of the chemical composition of materials of drill bit, and a determination of the geomechanical parameters of rock materials. The resulting wear, local bursts, and cracks were quantitatively and qualitatively defined and linked to the drilling regime and the rock material. The results of our investigation of the material of the roller cone bit can serve as a good base for the development of new steel alloys, which can resist higher temperatures and enable effective drilling, without structural changes of steel material.

First Application of Hybrid Bit Technology to Optimize Drilling Through S Shape Directional Section with High Chert Content in UAE Land Operations

2021 ◽  
Author(s):  
Ygnacio Jesus Nunez ◽  
Munir Bashir ◽  
Fernando Ruiz ◽  
Rakesh Kumar ◽  
Mohamed Sameer ◽  
...  
Keyword(s):  
Good Condition ◽  
Polycrystalline Diamond ◽  
Steering System ◽  
Directional Drilling ◽  
Main Challenge ◽  
Drilling Parameters ◽  
Pdc Bit ◽  
Heterogeneous Formation ◽  
Polycrystalline Diamond Compact ◽  
Cutting Mechanisms

Abstract This paper highlights the solution, execution, and evaluation of the first 12.25″ application of hybrid bit on rotary steerable system in S-Shape directional application to drill interbedded formations with up to 25 % chert content in UAE land operations. The main challenge that the solution overcame is to drill through the hard chert layers while avoiding trips due to PDC bit damage nor drilling hour's limitation of TCI bit while improving the overall ROP and achieving the directional requirement. The solution package has demonstrated a superior ROP over rollercone bits, as well as improved PDC cutter durability and lower reactive torque leading to better steerability and stability which will be detailed in this paper. A significant contributor to such success was utilizing a new hybrid bit technology which incorporates the dual cutting mechanisms of both polycrystalline Diamond Compact (PDC) and rollercone bits. This allows a more efficient drilling by bringing the durability of the crushing action of rollercone to drill through hard interbedded lithology and the effectiveness of the shearing action of PDC cutters to improve ROP without sacrificing the toughness of the cutting structure edge. The proposed solution in combined with continues proportional rotary steering system managed to drill 4,670 ft through heterogeneous formation with chert nodules, with an average ROP of 38.29 ft\hr improving ROP by 15% and eliminating extra trips of utilizing roller cone bits to be able to drill though the chert nodules and avoid the PDC bit damage. Leading reduction in cost per foot by 35 %. Additionally, the hybrid bit exceed the expectation achieving 878 thousand of revolutions, with effective bearing and with the drilling cutting structure in a very good condition. Furthermore, the directional objectives were met with high quality directional drilling avoiding wellbore tortuosity. Such success was established through application analysis, specific formations drilling roadmaps and optimized drilling parameters in order to improve the overall run efficiency. The combination of roller cone and PDC elements in a hybrid bit designed to deliver better efficiency and torque stability significantly increased performance drilling the section in one single run, proven that heterogeneous formations can be drill.

Hybrid Physics-Field Data Approach Improves Prediction of ROP / Drilling Performance of Sharp and Worn PDC Bits

2021 ◽  
Author(s):  
Guodong David Zhan ◽  
Arturo Magana-Mora ◽  
Eric Moellendick ◽  
John Bomidi ◽  
Xu Huang ◽  
...  
Keyword(s):  
Prediction Models ◽  
Collaborative Study ◽  
Hybrid Approach ◽  
Polycrystalline Diamond ◽  
Rock Properties ◽  
Quantitative Prediction ◽  
Model Learning ◽  
Drilling Performance ◽  
Pdc Bit ◽  
Polycrystalline Diamond Compact

Abstract This study presents a hybrid approach that combines data-driven and physics models for worn and sharp drilling simulation of polycrystalline diamond compact (PDC) bit designs and field learning from limited downhole drilling data, worn state measurements, formation properties, and operating environment. The physics models include a drilling response model for cutting forces, worn or rubbing elements in the bit design. Decades of pressurized drilling and cutting experiments validated these models and constrained the physical behaviour while some coefficients are open for field model learning. This hybrid approach of drilling physics with data learning extends the laboratory results to application in the field. The field learning process included selecting runs in a well for which rock properties model was built. Downhole drilling measurements, known sharp bit design, and measured wear geometry were used for verification. The models derived from this collaborative study resulted in improved worn bit drilling response understanding, and quantitative prediction models, which are foundational frameworks for drilling and economics optimization.

Study of the Influence of Controlled Axial Oscillations of pVARD on Generating Downhole Dynamic WOB and Improving Coring and Drilling Performance in Shale

2019 ◽  
Author(s):  
Abdelsalam N. Abugharara ◽  
John Molgaard ◽  
Charles A. Hurich ◽  
Stephen D. Butt
Keyword(s):  
Sampling Rate ◽  
Polycrystalline Diamond ◽  
Rotary Drilling ◽  
Labview Software ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Wide Range ◽  
Pdc Bit ◽  
Weight On Bit ◽  
Polycrystalline Diamond Compact

Abstract This work concentrates on the investigation of enhancing drilling performance through increasing drilling rate of penetration (ROP) by using a passive vibration assisted rotary drilling (pVARD) tool. It also involves analysis of how ROP was significantly increased when drilling using pVARD compared to drilling using conventional system “rigid” using coring and drilling in shale rocks. The apparatus used was a fully instrument laboratory scale rig and the bits were dual-cutter polycrystalline diamond compact (PDC) bit for drilling and diamond impregnated coring bit for coring. The flow rate was constant of (7 litter / min) using clean water at atmospheric pressure. In addition, for accuracy data recording, a data acquisition system (DAQ-Sys) using a LabVIEW software was utilized to record data at 1000HZ sampling rate. The output drilling parameters involved in the analysis included operational rpm, torque (TRQ), and ROP. All the output-drilling parameters were analyzed with relation to downhole dynamic weight on bit (DDWOB). The result of this work explained how pVARD can increase the DDWOB and improve ROP. The result also demonstrated generating a balanced and concentric increase in DDWOB and minimizing the wide-range fluctuation of DDWOB generated in rigid drilling, particularly at high DDWOB.

Saving 2.2 Days from Drilling in Hard and Abrasive Sandstone Formation with Innovative 360 Rolling Diamond Element Bit Technology

2021 ◽  
Author(s):  
Lan Ngo Vi ◽  
Wanwarang Khobchit ◽  
Teerawat Teerachotmongkol ◽  
Zayyan Mohammad ◽  
Ali Abbasgholipour ◽  
...  
Keyword(s):  
Polycrystalline Diamond ◽  
Entire Interval ◽  
Main Challenge ◽  
Cutter Life ◽  
Drilling Parameters ◽  
Pdc Bit ◽  
Drilling Cost ◽  
Sandstone Formation ◽  
Vibration Simulation ◽  
Bit Life

Abstract This project drilled in Sin Phu Horm field. The main challenge in this field is the formation. The 8.5-in section is designed to drill through the hard and abrasive sandstone formation (known as Nam Phong formation) with unconfined compressive strength (UCS) between 6,000 and 24,000 psi and peak up to 55,000 psi. Multiple bit runs and heavy set of Polycrystalline Diamond Compact (PDC) bits were observed in the offset wells with slow rate of penetration (ROP) and short intervals, which resulted in a high drilling cost. In the offset runs, the average interval was observed between 200 and 300 meters and average on-bottom ROP ranged from 2 to 8 m/hr. Worn cutters were the main dull characteristic in the offset PDC bits and the bits were pulled out of hole due to slow ROP. Due to the challenging formation, the goal was to increase the interval per bit run and ROP which resulted to reduce the number of bit trips and drilling cost. Looking at the dull grading of the offset PDC bits, it was obvious that the slow ROP was caused by the cutters worn by the abrasive and hard Nam Phong formation. The fixed-cutter PDC bits were run in the offset wells and worn cutters were observed in the shoulder area. The worn portion of the cutter occurred only in the exposed side, while the portion in the cutter pocket remained intact. Utilizing the portion in the cutter pocket helps to prolong cutter life, increase the ROP, and bit life longevity. Thus, it can help to reduce undesired bit trips. Based on the worn cutter observation, the new design of the 8.5-in PDC bit equipped with innovative 360 rolling cutter (RC) bit was proposed. A comprehensive vibration simulation drilling parameters roadmap were provided to minimize shock and vibration. Two bits were run with rotary steerable BHA to drill Nam Phong formation in the field. The first bit drilled 431 meters at an average ROP of 6.8 m/hr and the second bit drilled 391 meters at an average ROP of 5.5 m/hr. Two runs using the 360 RC bits drilled 822 meters in total of 1,236 meters entire interval of Nam Phong formation, which was equivalent to 66%, achieving the operator's goal while saving 2.2 days solely from two runs of RC bit. This success increased the operator's confidence to run 360 RC bits in the subsequent wells to reduce the number of bit trips and increase the ROP. This paper will discuss the application and evolution of 360 RC bit, along with the result achieved by the bit fitted equipped with this cutter in Thailand onshore.

The Use of a Sensor Modules System for Measuring Drilling Parameters in a Bit, Significantly Reduces the Construction Time of Wells in Eastern Siberia

2021 ◽  
Author(s):  
Andrey Alexandrovich Rebrikov ◽  
Anton Anatolyevich Koschenkov ◽  
Anastasiya Gennadievna Rakina ◽  
Igor Dmitrievich Kortunov ◽  
Nikita Vladimirovich Koshelev ◽  
...  
Keyword(s):  
Oil And Gas ◽  
New Technologies ◽  
Field Tests ◽  
Depth Of Cut ◽  
Drilling Process ◽  
Eastern Siberia ◽  
Construction Time ◽  
Stage Of Development ◽  
Drilling Parameters ◽  
Pdc Bit

Abstract Currently, production and exploration drilling has entered a stage of development where one of the highest priority goals is to reduce the time for well construction with new technologies and innovations. One of the key components in this aspect is the utilizing of the latest achievements in the design and manufacture of rock cutting tools – drill bits. This article presents some new ideas on methods for identifying different types of vibrations when drilling with PDC bits using a system of sensors installed directly into the bit itself. In the oil and gas fields of Eastern Siberia, one of the main reasons for ineffective drilling with PDC bits are vibrations, which lead to premature wear of the cutting structure of the bit and the achievement of low ROPs in the dolomite and dolerite intervals. For efficient drilling of wells of various trajectories with a bottom hole assembly (BHA), including a downhole motor (PDM) and a PDC bit, special attention is paid to control of the bit by limiting the depth of cut, as well as the level of vibrations that occur during drilling process. Often, the existing complex of surface and BHA equipment fails to identify vibrations that occur directly on the bit, as well as to establish the true cause of their occurrence. Therefore, as an innovative solution to this problem, a system of sensors installed directly into the bit itself is proposed. The use of such a system makes it possible to determine the drilling parameters, differentiated depending on the lithological properties of rocks, leading to an increase in vibration impact. Together with the Operators, tests have been successfully carried out, which have proven the effectiveness of the application of this technology. The data obtained during the field tests made it possible to determine the type and source of vibration very accurately during drilling. In turn, this made it possible to precisely adjust the drilling parameters according to the drilled rocks, to draw up a detailed road map of effective drilling in a specific interval. Correction of drilling parameters based on the analysis of data obtained from sensors installed in the bit made it possible to reduce the resulting wear of the PDC bit cutting structure and, if necessary, make changes to the bit design to improve the technical and economic indicators. Thus, the use of a system of sensors for measuring the drilling parameters in a bit ensured the dynamic stability of the entire BHA at the bottomhole when drilling in rocks of different hardness, significantly reduced the wear of the drilling tools and qualitatively improved the drilling performance.

Issues in Polycrystalline Diamond Compact Cutter–Rock Interaction From a Metal Machining Point of View—Part II: Bit Performance and Rock Cutting Mechanics

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Demeng Che ◽  
Peidong Han ◽  
Ping Guo ◽  
Kornel Ehmann
Keyword(s):  
Metal Cutting ◽  
Polycrystalline Diamond ◽  
Rock Cutting ◽  
Point Of View ◽  
Rock Interaction ◽  
Metal Machining ◽  
Pdc Bit ◽  
Rock Cutting Mechanics ◽  
Cutting Processes ◽  
Polycrystalline Diamond Compact

In Part I of this paper, the issues related to temperature, stress and force were reviewed and parallels were drawn between both metal machining and rock cutting. Part II discusses the issues more directly related to polycrystalline diamond compact (PDC) bit performance and rock mechanics. However, relevant issues in various metal cutting processes will continue to be presented to clarify the gaps and similarities between these two classes of processes.

scholarly journals Simulation and Experimental Study of the Rock Breaking Mechanism of Personalized Polycrystalline Diamond Compact Bits

2020 ◽  
Vol 13 (5) ◽  
pp. 122-131
Author(s):  
Yu Jinping ◽  
◽  
Zou Deyong ◽  
Sun Yuanxiu ◽  
Zhang Yin
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Tensile Stress ◽  
Crack Propagation ◽  
Tangential Force ◽  
Polycrystalline Diamond ◽  
Rock Breaking ◽  
Pdc Bit ◽  
Breaking Mechanism ◽  
Polycrystalline Diamond Compact

Rock breaking is a complex physical process that can be influenced by various factors, such as geometrical shape and cutting angle of rock breaking tools. Experimental study of the rock breaking mechanism of personalized bits is restricted due to long cycle and high cost. This study simulated the rock breaking mechanism of polycrystalline diamond compact (PDC) bit by combining finite element method and experiment. The simulation was performed to shorten the period and reduce the cost of studying the rock breaking mechanism of PDC bits. A rock breaking finite element model for sting cutters of personalized PDC bit was established to simulate the rock breaking process. The crack propagation pattern, dynamic stress of rock breaking, and rock breaking mechanism of sting cutters of personalized PDC bit were analyzed. The correctness of the simulation results was verified through experiments. Results demonstrate that the rock breaking load increases with the crack propagation in the fracture initiation and propagation stages, with the maximum tangential force of 1062.5 N and maximum axial force of 1850.0 N. The load changes in a small range when the crack penetrates the rock, with the tangential force of 125.0–500.0 N and axial force of 375.0–875.0 N. The rock breaking mechanism of the sting cutters of bit is consistent with maximum tensile stress theory. The rock begins to break when the tensile stress of rock is 36.9 MPa. The sting cutters of personalized PDC bit have better wear resistance than the sting cutters of conventional bit. The average wear rates of personalized PDC and conventional bits are 1.74E-4 and 2.1E-4 mm/m, respectively. This study serves as reference for shortening the study period of rock breaking mechanism, efficiently designing personalized PDC bit structure, reducing bit wear, and enhancing rock breaking efficiency.

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.

Drill Bit Failure Forensics using 2D Bit Images Captured at the Rig Site

2021 ◽  
Author(s):  
Pradeepkumar Ashok ◽  
Jian Chu ◽  
Ysabel Witt-Doerring ◽  
Zeyu Yan ◽  
Dongmei Chen ◽  
...  
Keyword(s):  
Image Processing ◽  
Polycrystalline Diamond ◽  
Sensor Data ◽  
Vibration Data ◽  
Damage And Failure ◽  
Root Cause ◽  
Pdc Bit ◽  
Cause Of Failure ◽  
The Individual ◽  
Bit Life

Abstract Identifying the root cause of damage of a pulled bit as soon as possible will aid preparation for future bit runs. Today, such bit damage analyses are often anecdotal, subjective and error-prone. The objective of this project was to develop a software algorithm to automatically analyze 2D bit images taken at the rig site, and to quickly identify the root cause of bit damage and failure. A labelled dataset was first created whereby the damage seen in bit photos was associated with the appropriate root cause of failure. Particular attention was given to the radial position of the cutters that were damaged. Using the 2D bit images (which can be obtained at the rig site), a convolutional neural network along with other image processing techniques were used to identify the individual cutters, their position on the bit, the degree of wear on each cutter. A classifier was then built to directly identify root cause of failure from these images. This work utilized a large dataset of wells which included multiple bit images, surface sensor data, downhole vibration data, and offset well rock strength information. This dataset helped relate the type of dysfunction as seen in the downhole and surface sensor data to the damage seen on the bit. This dataset however only covered some types of dysfunctions and some types of bit damage. It was therefore augmented with bit images for which the type of failure was determined through analysis by a subject- matter expert. A classifier was subsequently developed which properly identified the root causes of failure when the bit photo quality met certain minimum standards. One key observation was that bit images are not always captured appropriately, and this reduces the accuracy of the method. The automated forensics approach to Polycrystalline Diamond Compact (PDC) bit damage root cause analysis described in this paper can be performed using 2D bit photos that can be easily captured on a phone or camera at the rig site. By identifying the potential root causes of PDC damage through image processing, drilling parameters and bit selection can be optimized to prolong future bit life. The algorithm also enables uniformity in bit analysis across a company's operations, as well as the standardization of the process.

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