A Modular Mechanism for Downhole Weight-on-Bit and Torque Reaction in Small Diameter Boreholes

2021 ◽  
pp. 1-15
Author(s):  
Anirban Mazumdar ◽  
Stephen Buerger ◽  
Adam Foris ◽  
Jiann-cherng Su
Keyword(s):  
Axial Force ◽  
Small Diameter ◽  
Field Testing ◽  
Drill String ◽  
Force Transmission ◽  
Drilling Performance ◽  
Weight On Bit ◽  
In Series ◽  
Mechanical Devices ◽  
Scalable Design

Abstract Drilling systems that use downhole rotation must react torque either through the drill-string or near the motor to achieve effective drilling performance. Problems with drill-string loading such as buckling, friction, and twist become more severe as hole diameter decreases. Therefore, for small holes, reacting torque downhole without interfering with the application of weight-on-bit, is preferred. In this paper we present a novel mechanism that enables effective and controllable downhole weight on bit transmission and torque reaction. This scalable design achieves its unique performance through four key features: 1) mechanical advantage based on geometry, 2) direction dependent behavior using rolling and sliding contact, 3) modular scalability by combining modules in series, and 4) torque reaction and weight on bit that are proportional to applied axial force. As a result, simple mechanical devices can be used to react large torques while allowing controlled force to be transmitted to the drill bit. We outline our design, provide theoretical predictions of performance, and validate the results using full-scale testing. The experimental results include laboratory studies as well as limited field testing using a percussive hammer. These results demonstrate effective torque reaction, axial force transmission, favorable scaling with multiple modules, and predictable performance that is proportional to applied force.

A Dynamic Model for Rotary Rock Drilling

1982 ◽  
Vol 104 (2) ◽  
pp. 108-120 ◽  
Author(s):  
I. E. Eronini ◽  
W. H. Somerton ◽  
D. M. Auslander
Keyword(s):  
Drill Pipe ◽  
Tooth Wear ◽  
Drill String ◽  
Rock Drilling ◽  
Large Power ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Weight On Bit ◽  
Rotary Speed ◽  
Mud Pressure

A rock drilling model is developed as a set of ordinary differential equations describing discrete segments of the drilling rig, including the bit and the rock. The end segment consists of a description of the bit as a “nonideal” transformer and a characterization of the rock behavior. The effects on rock drilling of bottom hole cleaning, drill string-borehole interaction, and tooth wear are represented in the model. Simulated drilling under various conditions, using this model, gave results which are similar to those found in field and laboratory drilling performance data. In particular, the model predicts the expected relationships between drilling rate and the quantities, weight on bit, differential mud pressure, and rotary speed. The results also suggest that the damping of the longitudinal vibrations of the drill string could be predominantly hydrodynamic as opposed to viscous. Pulsations in the mud flow are found to introduce “percussive” effects in the bit forces which seem to improve the penetration rate. However, it is known from field observations that drill pipe movements, if strong enough, may induce mud pressure surges which can cause borehole and circulation problems. Bit forces and torques are shown to be substantially coupled and the influence of certain rock parameters on variables which are measurable either at the bit or on the surface support the expectation that these signals can furnish useful data on the formation being drilled. Other results, though preliminary, show that the effects of the lateral deflections of the drill string may be large for the axial bit forces and significant for the torsional vibrations. For the latter, the unsteady nature of the rotation above the bit increases and the resistance to rotation due to rubbing contact between the drill string and the wellbore accounts for very large power losses between the surface and the bit.

Drilling System Optimization Leads to Expedited Wells Delivery

2021 ◽  
Author(s):  
Efe Mulumba Ovwigho ◽  
Saleh Al Marri ◽  
Abdulaziz Al Hajri
Keyword(s):  
Drill Pipe ◽  
System Optimization ◽  
Drill String ◽  
Stick Slip ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Single String ◽  
Innovative Solution ◽  
Open Hole ◽  
Weight On Bit

Abstract On a Deep Gas Project in the Middle East, it is required to drill 3500 ft of 8-3/8" deviated section and land the well across highly interbedded and abrasive sandstone formations with compressive strength of 15 - 35 kpsi. While drilling this section, the drill string was constantly stalling and as such could not optimize drilling parameters. Due to the resulting low ROP, it was necessary to optimize the Drill string in order to enhance performance. Performed dynamic BHA modelling which showed current drill string was not optimized for drilling long curved sections. Simulation showed high buckling levels across the 4" drill pipe and not all the weight applied on surface was transmitted to the bit. The drilling torque, flowrate and standpipe pressures were limited by the 4" drill pipe. This impacted the ROP and overall drilling performance. Proposed to replace the 4" drill pipe with 5-1/2" drill pipe. Ran the simulations and the model predicted improved drill string stability, better transmission of weights to the bit and increased ROP. One well was assigned for the implementation. Ran the optimized BHA solution, able to apply the maximum surface weight on bit recommended by the bit manufacturer, while drilling did not observe string stalling or erratic torque. There was also low levels of shocks and vibrations and stick-slip. Doubled the on-bottom ROP while drilling this section with the same bit. Unlike wells drilled with the previous BHA, on this run, observed high BHA stability while drilling, hole was in great shape while POOH to the shoe after drilling the section, there were no tight spots recorded while tripping and this resulted in the elimination of the planned wiper trip. Decision taken to perform open hole logging operation on cable and subsequently run 7-in liner without performing a reaming trip. This BHA has been adopted on the Project and subsequent wells drilled with this single string showed similar performance. This solution has led to average savings of approximately 120 hours per well drilled subsequently on this field. This consist of 80 hours due to improved ROP, 10 hrs due to the elimination of wiper trip and a further 30 hrs from optimized logging operation on cable. In addition, wells are now delivered earlier due to this innovative solution. This paper will show how simple changes in drill string design can lead to huge savings in this current climate where there is a constant push for reduction in well times, well costs and improved well delivery. It will explain the step-by-step process that was followed prior to implementing this innovative solution.

Partial Admission, Axial Impulse Type Turbine Design and Partial Admission Radial Turbine Test for SCO2 Cycle

2017 ◽  
Author(s):  
Hyungki Shin ◽  
Junhyun Cho ◽  
Young-Jin Baik ◽  
Jongjae Cho ◽  
Chulwoo Roh ◽  
...  
Keyword(s):  
Axial Force ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Small Diameter ◽  
Volume Flow ◽  
Working Fluid ◽  
Rotating Speed ◽  
Turbo Generator ◽  
Partial Admission ◽  
Reduce Development Time

Power generation cycle — typically Brayton cycle — to use CO2 at supercritical state as working fluid have been researched many years because this cycle increase thermal efficiency of cycle and decrease turbomachinery size. But small turbomachinery make it difficult to develop proto type Supercritical Carbon dioxide (S-CO2) cycle equipment of lab scale size. KIER (Korea Institute of Energy Research) have been researched S-CO2 cycle since 2013. This paper is about 60kWe scale and sub-kWe class turbo generator development for applying to this S-CO2 cycle at the lab scale. A design concept of this turbo-generator is to use commercially available components so as to reduce development time and increase reliability. Major problem of SCO2 turbine is small volume flow rate and huge axial force. High density S-CO2 was referred as advantage of S-CO2 cycle because it make small turbomachinery possible. But this advantage was not valid in lab-scale cycles under 100kW because small amount volume flow rate means high rotating speed and too small diameter of turbine to manufacture it. Also, high inlet and outlet pressure make huge axial force. To solve these problem, KIER have attempt various turbines. In this paper, these attempts and results are presented and discussed.

scholarly journals RESEARCH OF AXIAL FORCE AND THE TORQUE ACTION ON A DRILL STRING AT ROTARY AND COMBINED DRILLING METHODS

2018 ◽  
pp. 7-15 ◽  
Author(s):  
Ya. S. Hrydzhuk
Keyword(s):  
Energy Saving ◽  
Mechanical System ◽  
Axial Force ◽  
Axial Load ◽  
Drill String ◽  
Numerical Calculations ◽  
Industrial Data ◽  
Analytical Functions ◽  
Distributed Parameters ◽  
Well Depth

The estimation approach of the work performed by the main force factors acting on the drill string, rotary and combined drilling methods, was proposed. The problem of obtaining analytical functions of force factors action for a mechanical system with distributed parameters was formulated. To solve the problem, the axial load and torque functions of the drill string analysis was performed, depending on the alternating parameter - the well depth. By integrating these functions, analytical dependencies were established for determining the axial load and torque acting on the drill string in sections of directional and S-shaped wells. Relying on industrial data, numerical calculations of the size of work on sections of such wells were carried out. The obtained research results can be further used to find energy-saving modes of the drill string.

Drilling in the Digital Age: Machine Learning Assisted Bit Selection and Optimization

2021 ◽  
Author(s):  
Peter Batruny ◽  
Hafiz Zubir ◽  
Pete Slagel ◽  
Hanif Yahya ◽  
Zahid Zakaria ◽  
...  
Keyword(s):  
Machine Learning ◽  
Monte Carlo Analysis ◽  
Specific Model ◽  
Planning Decisions ◽  
Drilling Performance ◽  
Weight On Bit ◽  
Data Points ◽  
Ideal Tool ◽  
Rotary Speed ◽  
Artificial Neural Network Ann

Abstract Conventionally, a bit is selected from offset well bit run summaries. This method of selection is not always accurate since each bit is run under different conditions which might not be reflected in an offset study analysis. The large quantities of data generated from real time measurements in offset wells makes machine learning the ideal tool for analysis and comparison. Artificial Neural Network (ANN) is a relatively simple machine learning tool that combines inputs and calculation layers to compute a specified output layer. The ANN is fed over thousands of data points from 17-1/2 in hole sections across multiple wells. A specific model is then trained for every bit with weight on bit (WOB), rotary speed (RPM), bit hydraulics, and lithological properties as inputs and rate of penetration (ROP) as output. The model is finalized when a satisfactory statistical set of KPI's are achieved. Using a combination of Monte-Carlo analysis and sensitivity analysis, different bits are compared by varying parameters for the same bit and varying the bit under the same parameters. A bit and its optimized parameters are proposed, resulting in an average instantaneous ROP improvement of 32%. Performance benchmarked with individual drilling parameters shows improved ROP response to WOB, RPM, and bit hydraulics in the optimized run. This project solidifies machine learning as a powerful tool for bit selection and parameter optimization to improve drilling performance. Machine learning will become a significant part of well planning, design, and operations in the future. This study demonstrates how ANN's can be used to learn from previous operations and influence planning decisions to improve bit performance.

scholarly journals Influence of Weight-on-Bit on Percussive Drilling Performance

2020 ◽  
Author(s):  
Xianfeng Song ◽  
Ole Morten Aamo ◽  
Pascal-Alexandre Kane ◽  
Emmanuel Detournay
Keyword(s):  
Percussive Drilling ◽  
Drilling Performance ◽  
Weight On Bit

Drilling Cutting Analysis to Assist Drilling Performance Evaluation in Hard Rock Hole Widening Operation

2020 ◽  
Author(s):  
Daiyan Ahmed ◽  
Yingjian Xiao ◽  
Jeronimo de Moura ◽  
Stephen D. Butt
Keyword(s):  
Performance Enhancement ◽  
Ore Deposits ◽  
Drilling Process ◽  
Rotary Drilling ◽  
Pilot Hole ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Weight On Bit ◽  
Drilling Operations

Abstract Optimum production from vein-type deposits requires the Narrow Vein Mining (NVM) process where excavation is accomplished by drilling larger diameter holes. To drill into the veins to successfully extract the ore deposits, a conventional rotary drilling rig is mounted on the ground. These operations are generally conducted by drilling a pilot hole in a narrow vein followed by a hole widening operation. Initially, a pilot hole is drilled for exploration purposes, to guide the larger diameter hole and to control the trajectory, and the next step in the excavation is progressed by hole widening operation. Drilling cutting properties, such as particle size distribution, volume, and shape may expose a significant drilling problem or may provide justification for performance enhancement decisions. In this study, a laboratory hole widening drilling process performance was evaluated by drilling cutting analysis. Drill-off Tests (DOT) were conducted in the Drilling Technology Laboratory (DTL) by dint of a Small Drilling Simulator (SDS) to generate the drilling parameters and to collect the cuttings. Different drilling operations were assessed based on Rate of Penetration (ROP), Weight on Bit (WOB), Rotation per Minute (RPM), Mechanical Specific Energy (MSE) and Drilling Efficiency (DE). A conducive schedule for achieving the objectives was developed, in addition to cuttings for further interpretation. A comprehensive study for the hole widening operation was conducted by involving intensive drilling cutting analysis, drilling parameters, and drilling performance leading to recommendations for full-scale drilling operations.

Real-Time Software to Estimate Friction Coefficient and Downhole Weight on Bit During Drilling of Horizontal Wells

2014 ◽  
Author(s):  
Mazeda Tahmeen ◽  
Geir Hareland ◽  
Bernt S. Aadnoy
Keyword(s):  
Friction Coefficient ◽  
Real Time ◽  
Information Transfer ◽  
Horizontal Wells ◽  
Drill String ◽  
Surface Measurement ◽  
Drilling Process ◽  
Drilling Data ◽  
Weight On Bit ◽  
Drag Analysis

The increasing complexity and higher drilling cost of horizontal wells demand extensive research on software development for the analysis of drilling data in real-time. In extended reach drilling, the downhole weight on bit (WOB) differs from the surface seen WOB (obtained from on an off bottom hookload difference reading) due to the friction caused by drill string movement and rotation in the wellbore. The torque and drag analysis module of a user-friendly real-time software, Intelligent Drilling Advisory system (IDAs) can estimate friction coefficient and the effective downhole WOB while drilling. IDAs uses a 3-dimensional wellbore friction model for the analysis. Based on this model the forces applied on a drill string element are buoyed weight, axial tension, friction force and normal force perpendicular to the contact surface of the wellbore. The industry standard protocol, WITSML (Wellsite Information Transfer Standard Markup Language) is used to conduct transfer of drilling data between IDAs and the onsite or remote WITSML drilling data server. IDAs retrieves real-time drilling data such as surface hookload, pump pressure, rotary RPM and surface WOB from the data servers. The survey data measurement for azimuth and inclination versus depth along with the retrieved drilling data, are used to do the analysis in different drilling modes, such as lowering or tripping in and drilling. For extensive analysis the software can investigate the sensitivity of friction coefficient and downhole WOB on user-defined drill string element lengths. The torque and drag analysis module, as well as the real-time software, IDAs has been successfully tested and verified with field data from horizontal wells drilled in Western Canada. In the lowering mode of drilling process, the software estimates the overall friction coefficient when the drill bit is off bottom. The downhole WOB estimated by the software is less than the surface measurement that the drillers used during drilling. The study revealed verification of the software by comparing the estimated downhole WOB with the downhole WOB recorded using a downhole measuring tool.

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