Weight-On-Bit Variations Analyses in the Drillstring of Rotary Drilling Systems Under Stick-Slip Vibrations

Abstract In the current oil and gas drilling industry, the modernization of rig fleets has been shifting toward high mobility, artificial intelligence, and computerized systems. Part of this shift includes a move toward automation. This paper summarizes the successful application of a fully automated workflow to drill a stand, from slips out to slips back in, in a complex drilling environment in onshore gas. Repeatable processes with adherence to plans and operating practices are a key requirement in the implementation of drilling procedures and vital for optimizing operations in a systematic way. A drilling automation solution has been deployed in two rigs enabling the automation of both pre-connection and post-connection activities as well as rotary drilling of an interval equivalent to a typical drillpipe stand (approximately 90 ft) while optimizing the rate of penetration (ROP) and managing drilling dysfunctionalities, such as stick-slip and drillstring vibrations in a consistent manner. So far, a total of nine wells have been drilled using this solution. The automation system is configured with the outputs of the drilling program, including the drilling parameters roadmap, bottomhole assembly tools, and subsurface constraints. Before drilling every stand, the driller is presented with the planned configuration and can adjust settings whenever necessary. Once a goal is specified, the system directs the rig control system to command the surface equipment (draw works, auto-driller, top drive, and pumps). Everything is undertaken in the context of a workflow that reflects standard operating procedures. This solution runs with minimal intervention from the driller and each workflow contextual information is continuously displayed to the driller thereby giving him the best capacity to monitor and supervise the operational sequence. If drilling conditions change, the system will respond by automatically changing the sequence of activities to execute mitigation procedures and achieve the desired goal. At all times, the driller has the option to override the automation system and assume control by a simple touch on the rig controls. Prior to deployment, key performance indicators (KPI), including automated rig state-based measures, were selected. These KPIs are then monitored while drilling each well with the automation system to compare performance with a pre-deployment baseline. The solution was used to drill almost 60,000 ft of hole section with the system in control, and the results showed a 20% improvement in ROP with increased adherence to pre-connection and post-connection operations. Additionally, many lessons were learned from the use and observation of the automation workflow that was used to drive continuous improvement in efficiency and performance over the course of the project. This deployment was the first in the region and the system is part of a comprehensive digital well construction solution that is continuously enriched with new capabilities. This adaptive automated drilling solution delivered a step change in performance, safety, and consistency in the drilling operations.

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Analysis of Torsional Stick-Slip Situations from Recorded Downhole Rotational Speed Measurements

SPE Drilling & Completion ◽

10.2118/199678-pa ◽

2021 ◽

pp. 1-15

Author(s):

Eric Cayeux ◽

Adrian Ambrus ◽

Lars Øy ◽

Arvid Helleland ◽

Svein Brundtland ◽

...

Keyword(s):

Rotational Speed ◽

Rotational Velocity ◽

The Other ◽

Drilling Process ◽

Stick Slip ◽

Torsional Oscillations ◽

Direct Observations ◽

New Information ◽

Weight On Bit ◽

Downhole Measurements

Summary The use of recorded downhole rotational speed measurements with a bandwidth up to 9 Hz gives new insights into the conditions under which stick-slip torsional oscillations occur. Observations made while drilling two reservoir sections have shown that, out of all the stick-slip situations identified, 72% of them for one well and 64% for the other well occurred in off-bottom conditions. In these off-bottom conditions, stick-slip was systematically observed while starting the topdrive (TD) until a sufficiently high TD rotational velocity was requested. For these two sections, off-bottomstick-slip was either related to using TD speeds below 120 rev/min or to reaming down during reciprocation procedures. In on-bottom conditions, stick-slip events occurred predominantly when the TD speed was less than 120 rev/min (53 and 32% of the on-bottom cases) but also in association with downlinking to the rotary steerable system (RSS) (23 and 46% of the on-bottom cases), and this, even though the TD speed was larger than 120 rev/min. These on-bottomstick-slip situations did not necessarily occur at a very high weight on bit (WOB) because 98% of them for one well and 46% for the other well took place when the WOB was lower than 10 ton. Downhole measurements have shown that when the drillstring is subject to strong stick-slip conditions, the downhole rotational speed changes from stationary to more than 300 rev/min in just a fraction of a second. Direct observations of downhole rotational speed at high frequency help in discovering conditions that were not suspected to lead to large torsional oscillations. This new information can be used to improve drilling operational procedures and models of the drilling process, therefore enabling increased drilling efficiency.

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

Volume 11: Petroleum Technology ◽

10.1115/omae2020-19286 ◽

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.

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Experimental Investigation of the Stick-Slip Phenomena of the Drill Pipe

Volume 1: Offshore Technology; Offshore Geotechnics ◽

10.1115/omae2015-41877 ◽

2015 ◽

Author(s):

Tokihiro Katsui ◽

Yoshitomo Mogi ◽

Tomoya Inoue ◽

Chang-Kyu Rheem ◽

Miki Y. Matsuo

Keyword(s):

Drill Pipe ◽

Small Time ◽

Numerical Results ◽

Experimental Results ◽

Frictional Torque ◽

Drill Bit ◽

Stick Slip ◽

Model Experiments ◽

Pipe Model ◽

Weight On Bit

The stick-slip is one of the critical problems for the scientific drilling, because it causes a crushing of the sampled layer. The present study investigates the characteristics of stick-slip phenomena of the drill pipe with the model experiments and numerical methods. The model experiments are carried out using a 1m length drill pipe model made with the Teflon. The angular velocity at the top and the bottom of the pipe are measured with the gyro sensor on some conditions of rotating speed at the pipe top and the weight on bit (load at the pipe bottom). The numerical simulations are also carried out to reproduce the stick-slip phenomena of the model experiments. The stick-slip is a kind of torsional vibration which is governed by the convection equation. By considering the boundary condition at the top and bottom of the pipe, we can obtain a neutral delayed differential equation (NDDE). The solutions of the NDDE is depend on not the initial value but the initial history of the solution, because NDDE contains a delayed function term. Therefore, it should be solved carefully to avoid the numerical error. The NDDE is solved with the 4th order Runge-Kutta scheme with very small time increment until the truncation error could be neglected. And also, we have found out that the effect of the initial history on the solution become to be very small after a certain period of time. The experimental results are compared with the numerical results under the same rotating condition. The experimental results of the stick-slip suggest that the period of the slip is mainly depend on the rotation speed at the pipe top and the magnitude of the slip is mainly depend on the weight on bit. Those characteristics of the stick-slip such as the period or the magnitude of slip are also obtained with the numerical calculations. However, in order to obtain an acceptable numerical results of NDDE, we have to adjust the frictional torque acting on the drill bit. Though, the frictional torque model was determined by reference to the measured torque at the top of the drill pipe model in the present study, it is desired to be improved. Therefore, the physical model of the frictional torque on the drill bit should be evaluated much carefully for the precise estimation of the stick slip in the future.

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Laboratory investigation of drillstring vibrations

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1550 ◽

2009 ◽

Vol 223 (10) ◽

pp. 2249-2262 ◽

Cited By ~ 32

Author(s):

Y A Khulief ◽

F A Al-Sulaiman

Keyword(s):

Dynamic Models ◽

Drilling Fluid ◽

Experimental Investigations ◽

Published Data ◽

Test Rig ◽

Stick Slip ◽

Vibrational Response ◽

Weight On Bit ◽

Magnetic Tension ◽

Variable Speed Motor

Experimental investigations of drillstring dynamics are essential to complement the theoretical studies and to alleviate the complexity of such dynamic models. This article presents an experimental investigation using a specially designed drilling test rig. The test rig can simulate the drillstring vibrational response because of various excitation mechanisms, including stick-slip, well—borehole contact, and drilling fluid interaction. The test rig is driven by a variable speed motor that allows for testing different drilling speeds, while a magnetic tension brake is used to simulated stick-slip. In addition, a shaker is employed to excite the drillstring axially in order to simulate the weight-on-bit. The drillstring is instrumented for vibration measurements. The experimental measurements in conjunction with the finite-element mathematical model of the drillstring are used to characterize and tune some modelling parameters. Comparisons with published data demonstrate the reliability of the developed scheme for prediction of drillstring vibrations.

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Experimentally-Tuned Mathematical Model for Drillstring Vibrations

Volume 5: 6th International Conference on Multibody Systems, Nonlinear Dynamics, and Control, Parts A, B, and C ◽

10.1115/detc2007-35057 ◽

2007 ◽

Author(s):

Y. A. Khulief ◽

F. A. Al-Sulaiman

Keyword(s):

Dynamic Models ◽

Drilling Fluid ◽

Experimental Studies ◽

Published Data ◽

Test Rig ◽

Stick Slip ◽

Multibody Model ◽

Drilling Performance ◽

Weight On Bit ◽

Functional Operation

Field experience manifests that drillstring vibration is one of the major causes for a deteriorated drilling performance. It is crucial to understand the complex vibrational mechanisms experienced by a drilling system in order to better control its functional operation and improve its performance. Experimental studies of drillstring dynamics are essential to complement the theoretical studies, and to alleviate the complexity of such dynamic models. This paper presents an experimental investigation using a specially designed drilling test rig. The test rig can simulate the drillstring vibrational response due to various excitation mechanisms, which include stick-slip, well-borehole contact, and drilling fluid interaction. The test rig is driven by a variable speed motor which allows for testing different drilling speeds, while a magnetic tension brake is used to simulated stick-slip. In addition, a shaker is employed to excite the drillstring axially in order to simulate the weight-on-bit (WOB). The drillstring is instrumented for vibration measurements. The experimentally identified parameters are used to refine the finite element multibody model of the drillstring, which was derived earlier by the investigators [1]. Comparisons with published data demonstrate the reliability of the developed scheme for prediction of drillstring vibrations.

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Drilling Vibration Modes and Penetration Rate Modeling using Artificial Neural Network and Multiple Linear Regression Analysis in Khoman Formation at the Egyptian Western Desert

10.21203/rs.3.rs-337955/v1 ◽

2021 ◽

Author(s):

Sherif A. Ezz ◽

Mohamed S. Farahat ◽

Said Kamel ◽

Ahmed Z. Nouh

Keyword(s):

Neural Network ◽

Regression Analysis ◽

Penetration Rate ◽

Drill String ◽

Western Desert ◽

Circulation Rate ◽

Vibration Level ◽

Stick Slip ◽

Weight On Bit ◽

Rotary Speed

Abstract Drill string vibrations are one of the most serious problems encountered while drilling as the bit and drill string interaction with formations under certain drilling conditions usually induces complex shocks and vibrations into the drill string components resulting in premature failure of the equipment and reduced drilling penetration rate. In severe cases where shocks and vibrations accumulated into drill string till exceeded its maximum yield or torsional strength, fatigue will occur and thereby increase the field development costs associated with replacing damaged components, fishing jobs, lost-in-hole situations, and sidetracks. Thus, real-time monitoring for downhole generated vibrations and accordingly adjusting drilling parameters including weight on bit, rotary speed, and circulation rate play a vital role in reducing the severity of these undesirable conditions. Vibration optimization must be done incorporation with the penetration rate, as a minimum economical penetration rate is required by the operator. In this study, three penetration rate and vibration level models were developed for axial, lateral, and stick-slip drilling modes using both MATLAB™ Software neural network and multiple regression analysis. It is found that the three models' results for vibration level and penetration rate; as compared with those recorded drilling data; showed an excellent match within an acceptable error of average correlation coefficient (R) over 0.95. The prediction of penetration rate and vibration level is thoroughly investigated in different axial, lateral, and stick-slip vibration drilling modes to be able to best select the optimum safe drilling zone. It is found that the axial vibration could be dampened by gradually increasing the weight on bit and increasing rotary speed while both the lateral and torsional vibrations are enhanced by increasing the rotary speed and decreasing the weight on bit.

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