Day 1 Tue, March 07, 2023最新文献

{"title":"Testing and Characterization of High-Frequency Torsional Oscillations in a Research Lab to Develop New HFTO Suppressing Solutions","authors":"Everhard Eli, Kueck Armin, Huang Xu, Lam Sui-Long, Heinisch Dennis, Reckmann Hanno, Bomidi John","doi":"10.2118/212527-ms","DOIUrl":"https://doi.org/10.2118/212527-ms","url":null,"abstract":"\u0000 Vibration from High Frequency Torsional Oscillation (HFTO) damages drilling tools and electronics. Destructive HFTO can occur in harsh drilling environments which reduces drilling performance and reliability and leads to non-productive time and associated costs. Because it is faster, cheaper, more precise, and more controllable compared to field testing, a laboratory test environment is optimal for developing HFTO countermeasures. However, until now, a full-scale test rig that reliably generates controllable HFTO did not exist. This paper will describe for the first time a laboratory drilling rig that generates HFTO and, therefore, can be used to develop and qualify anti-HFTO procedures and tools.\u0000 To study the HFTO susceptibility of bit-rock interactions, the full-scale laboratory drilling rig consists of a mud circulation system, hoisting system, bit, and BHA coupled with high-frequency instrumentation to measure torsional vibrations on a millisecond scale. Finite element models (FEM) built to characterize the drilling simulator are used to correctly interpret the results of drilling data. An experimental modal analysis (EMA) is used to validate and refine the FEM models. Next, PDC-bits are used to drill several rocks under varying pressures, RPMs, and weights on bit (WOB). The resulting high-frequency torque and tangential acceleration data are compared to a checklist of necessary criteria to prove that self-excited HFTO occur in the lab. These measurements, when considered with their axial sensor positions, are used to reliably identify HFTO and compare bit-rock combinations by their susceptibility to HFTO.\u0000 Results of the FEM-models and the EMA agree on the characteristic mode shapes and dominant frequencies which match dynamic measurements. Recorded data show that self-excited HFTO are reliably excited when the criteria for self-excitation are fulfilled. Vibration energy is concentrated in one dominant mode, the vibration amplitude is scaled by the RPM, and the frequency of torsional oscillations is independent of the rig RPM. HFTO-prone rocks are identified using segmented rock specimen tests. The excitation mechanism in the laboratory test rig corresponds to the mechanism in the field. Stability maps show that bits differ in excitability allowing a comparison based on bit features and subsequent bit improvements. Methods and tools tested in the lab environment form a framework for developing anti-HFTO field solutions and operational guidelines.\u0000 The upgraded full-scale drilling rig reliably generates HFTO in a laboratory environment under realistic drilling conditions. When coupled with extended research into the combination of bit, rock and BHA variables that lead to HFTO susceptibility, this rig will enable faster and cost-efficient product and procedure development cycles for proven and validated anti-HFTO tools and field guidelines. An HFTO suppressing bit or an HFTO suppressing damping device will have a significant impact on BHA r","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"27 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131790946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detailed Dynamics Modeling Helps to Assess the Effect of Stabilizer Design on Drill String Vibrations","authors":"K. Nguyen, M. Mahjoub, N. Dao, S. Menand","doi":"10.2118/212549-ms","DOIUrl":"https://doi.org/10.2118/212549-ms","url":null,"abstract":"\u0000 Various stabilizer types are used in the industry, such as bladed stabilizers with straight or spiral blades, roller-reamers, and other emergent forms. Their designs are proved, via many in-field measurements, to have a significant impact on vibration levels. Although experimental data is extremely valuable to rank the available design options, testing the different stabilizers can be costly and sometimes risky. In addition, in-field conditions can be difficult to control making the comparisons between stabilizers even more complicated. Assessing the design impact using numerical simulations represents an interesting alternative to provide objective comparisons based on tests in a controlled environment.\u0000 When a stabilizer is rotating, the contact forces between its different blades and the wellbore are transient. A static approach like torque and drag or directional models is then insufficient to properly investigate the stabilizer's design characteristics. Therefore, a time-domain dynamics approach is adopted in this work. A detailed modeling of bladed stabilizers including the blade geometry (number of blades, spirality, and blade width) and friction characteristics are introduced in an existing time-domain model. These characteristics are used to compute the contact forces between the wellbore and each individual blade.\u0000 This numerical model is applied to quantify the effect of stabilizer design in terms of vibration, from straight blades to highly spiraled blades. First, a parametric study of blade design and wellbore inclination effects on stabilizer vibrations is presented by considering different stabilizers in straight well conditions. Simulations of an actual drill string configuration in an unconventional well is discussed. For vertical, curved, and horizontal sections, the acceleration levels, contact forces, and rotation speeds are investigated. These analyses can constitute guidelines about stabilizer design to minimize vibrations.\u0000 The novelty of this work is to introduce the geometry details of the stabilizers in the time-domain dynamics to differentiate designs in terms of likelihood to trigger vibrations.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122071927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Lightweight Drilling Fluids for Stability, Properties, and Performance at Downhole Conditions Through a Novel Pilot Facility","authors":"S. Bhagwat, Angel Wileman, Luis Gutierrez, S. Rao, V. Gupta","doi":"10.2118/212554-ms","DOIUrl":"https://doi.org/10.2118/212554-ms","url":null,"abstract":"\u0000 This paper describes the methods developed for testing and qualification of novel lightweight drilling fluids (foams, glass-bead fluids) using a unique pilot-scale test facility (PSTF). The performance criteria included fluid stability, rheology, pressure transmission, and gas migration under downhole conditions. Test results demonstrating the methods developed are provided, along with the capabilities of the facility, custom fixtures, and equipment that were built to study the performance of these fluids.\u0000 A set of performance criteria and testing requirements were initially developed, which were then used to design and fabricate a novel pilot facility. The PSTF could generate downhole drilling conditions of 7,500 psig and temperatures above 300°F. Three custom-instrumented test articles were built to simulate wellbore geometry; one 10-ft long and one 18-ft long, both with a 2.62-in ID. The third article had a 10-ft long 6-in × 4-in annulus, with the eccentric internal pipe capable of 100-rpm rotation to mimic the drill string. The test articles could incline up to 45° to simulate deviated wells. Gas could be injected, and its migration rate measured in static and countercurrent flow using a video camera with full-bore sight glass, and gamma-ray densitometers. Dedicated sections for foam generation, measuring density, rheology, pressure transmission, and fluid sampling and imaging were provided.\u0000 Upon commissioning of the PSTF, a 1 1/2 year test program was successfully carried out using lightweight foams and hollow glass-bead fluids. Due to the novel nature of the tests, best practices and procedures were developed through experimentation to quantify static and dynamic fluid stability, gas migration, foam generation techniques, fluid imaging and characterization, pressure transmission, and rheology. A variety of measurement techniques and instrumentation were trialed in the test articles to determine the best methods for tracking gas migration. Experiments in the test articles yielded a large amount of performance data, including fluid stability over time at different temperature and pressure conditions, the impact of drill string rotation on fluid stability, migration velocities of gas bubbles (i.e., gas kicks) within the drilling fluids at stagnant and countercurrent flow conditions, and the impact of drill string rotation. Pressure transmission speeds were measured in the foam with varying gas fractions. Example datasets from the testing program are provided, along with detailed descriptions of the test methods.\u0000 The methods and test facility used to study lightweight drilling fluids are unique to the authors’ knowledge. For the first time, drilling fluids were analyzed in an annulus with a rotating pipe at downhole conditions at a pilot scale, and fluid stability along with gas migration were studied. These provide for rigorous testing of lightweight drilling fluids; the application of these fluids is expected to increase with declining r","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122320549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Safe, Robust and Efficient Through Tubing Abandonment","authors":"Egbert van Riet, Alex Lucas, Roel F. H. Roijmans, Wout J. G. Keultjes, Alistair Agnew, Mohamed Oukil Benmesbah, Simon Houghton-Evans, Caroline Evans-Guthrie, Robert Jan Potze, J. Keenan, M. Meng","doi":"10.2118/212530-ms","DOIUrl":"https://doi.org/10.2118/212530-ms","url":null,"abstract":"\u0000 There is a growing need for robust and efficient abandonment approaches with many oil and gas reservoirs nearing their economic lifetime. The Through-Tubing Abandonment (TTA) approach can deliver safe, robust and efficient isolation and reduced environmental footprint in keeping with ‘As Low as Reasonably Practicable’ (ALARP) principles. This paper provides guidance on how to select TTA candidate wells, including wells with gauge cables present in the permanent isolation interval, and provides operational advice to obtain a quality abandonment.\u0000 The industry has been abandoning wells via through tubing cementing methods for decades which has resulted in significant progress in the understanding of the applicability of the methodology and commensurate development of suitable technologies to deliver reliable long-term isolation. This paper will present the latest on selection criteria to screen wells for TTA. It will further propose cement placement and verification methods, necessary barrier lengths and risk-based decision making on the acceptability of gauge cables as part of the final permanent well barrier element.\u0000 The recent insights in TTA technologies and their use are described. These include demonstrated technologies such as expanding cement and vibration tools to enhance cement placement and options to log and verify the isolations. Testing results on cement sealing with gauge cables incorporated in the cemented annulus are also presented. Furthermore, promising emerging technologies such as methods to centralize the tubing to improve cement placement will be described.\u0000 Recent TTA applications in Europe, onshore and offshore, are presented as examples to illustrate current industry experience and the viability and reliability of such approaches.\u0000 A generally accepted, safe, robust and reliable approach towards TTA in keeping with ALARP principles common to the industry is pursued within this paper in order to enable acceptance and growth of TTA and associated technologies, and thereby further enable the wider application of rigless abandonment across the industry.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127820836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time Series Analysis for Digital Twins in Green Shipping","authors":"Lazaros Avgeridis, Konstantinos Lentzos, Dimitrios Skoutas, I. Emiris","doi":"10.5957/some-2023-028","DOIUrl":"https://doi.org/10.5957/some-2023-028","url":null,"abstract":"A promising way for the waterborne industry towards decarbonization and emissions reduction is through digitalization and in particular via Digital Twins (DTs) technology. In this context, the DT provides insights for optimal decision-making, predicting potential future events, or even detecting irregularities in the behavior of the ship to reduce its carbon emissions and energy consumption. To achieve this, we propose an architecture for automated data capture, processing, and analysis. The analysis component of this infrastructure leverages machine learning (ML) algorithms for time series data, such as anomaly detection and forecasting. Importantly, to understand how these algorithms make a certain prediction we also provide a detailed look at current approaches used to interpret these models. Finally, we demonstrate a practical use case, where time series analysis can prove especially useful when applied to real-world vessel data.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125937510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Potential of Methanol and Ammonia to Decarbonize Shipping: Impact on GHG and Other Pollutants","authors":"G. Voniati, A. Dimaratos, S. Kyklis, G. Koltsakis, L. Ntziachristos","doi":"10.5957/some-2023-035","DOIUrl":"https://doi.org/10.5957/some-2023-035","url":null,"abstract":"Decarbonization of the maritime sector towards the achievement of the ambitious IMO targets requires the combination of various technologies. Alternative fuels with low or zero carbon content can play a significant role. This work makes a preliminary assessment of the potential of methanol and ammonia to contribute to the decarbonization of shipping, analyzing their benefits and highlighting the main challenges before their extensive application.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122957010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stringer Detection and Drilling System Significantly Reduces the Invisible Lost Time (ILT) Caused by Reaming","authors":"A. Hohl, Glen Houghton, Danial MacFarlane","doi":"10.2118/212557-ms","DOIUrl":"https://doi.org/10.2118/212557-ms","url":null,"abstract":"\u0000 Drilling hard stringers that are erratically distributed in an underlying rather soft formation is challenging from different perspectives. An unforeseen change of the drilled formation from soft to hard and dense rock can cause impact damage to the bit, deflect the bottom-hole assembly (BHA), result in high bending loads, increase vibration, and cause wear/tear on BHA components. If not properly managed, this leads to non-productive time (NPT) and increased maintenance costs. Further, a deflection caused by a stringer away from the planned well path that is detected late results in high local doglegs (HLD) and requires time-consuming correction through reaming with invisible lost time (ILT).\u0000 Recently, a stringer detection method based on vibrations, namely high-frequency torsional oscillations (HFTO), has been presented. A case study with 21 sections in the North Sea based on this solution is shown that demonstrates a reduction in ILT by 80%.\u0000 The system is based on a timely and reliable detection of stringers, an optimized mud pulse telemetry scheme, and an automated advisory system. The downhole algorithm embedded in a measurement while drilling tool is consistently interpreting HFTO based on tangential acceleration and dynamic torsional torque measurement. By defining thresholds for the amplitude and the localization with respect to frequency content of HFTO, the algorithm results are translated into a binary value with 1 – stringer currently drilled or 0 - no stringer is drilled. The low bandwidth consuming 1-bit value and downhole measured bending moment are sent in 10 to 15 second intervals to the surface by mud pulse telemetry. Once the stringer is detected, the bending moment data is closely monitored to react correctly and efficiently to a stringer in different scenarios.\u0000 This solution is discussed in a case study in Norway covering 21 sections with and without the system deployed. The offshore application is challenged by frequently occurring stringer layers and nodules of different geometry. Based on the stringer content, the reaming time has been typically high in this application. The system, however, enabled a timely detection of the stringers and an optimal stringer drilling enabled by the frequently sent bending moment information. Therefore, stringer drilling was done without having to pull off-bottom frequently and ream the transition area between soft and hard formation thereby saving time and reducing wear on the BHA and drill pipe, ultimately ending up with a smoother/straighter wellbore.\u0000 By using the system, a faster reaction to any stringer and the use of appropriate parameters to avoid costly HLDs are achieved. The case study demonstrates a significant and consistent improvement in ILT. The reaming hours per 1000 m as a benchmark have been reduced from 2-5 hours without to 0.3-0.6 hours with the system resulting in an average saving of 12 hours per reservoir section.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131600868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intelligent Tracers for Fluid Invasion Tracking During Coring Operations","authors":"Abdulaziz Alqasim, Atul Godbole, Deena Tayyib, Marie Wurtz, S. Hartvig","doi":"10.2118/212518-ms","DOIUrl":"https://doi.org/10.2118/212518-ms","url":null,"abstract":"\u0000 Core analysis, if conducted successfully, can provide accurate assessment of the original reservoir fluid properties, however, it is challenging to retrieve an uncontaminated core, due to mud components contaminating the fluids originally present in the reservoir. Due to invasion, the liquid extracted from the cores, does not necessarily represent the native liquid, but rather a mixture of drilling and reservoir fluid, thus affecting the results, conclusions and decisions that were based on the analysis. Therefore, deploying advanced water-based mud (WBM) tracers, during coring operations, can mitigate this issue and lead to a significant cost-reduction in field development.\u0000 Tracer technology is an efficient monitoring and surveillance tool, that was proven to help in tracking and understanding the injection flow paths, and estimating the remaining oil saturation (Sor) in the reservoir, through inter-well and single-well tracer tests. Utilizing water-based tracers in the drilling mud, during coring operation, can help in quantifying the degree of invasion in the retrieved cores, therefore proper correction and more accurate assessment of the reservoir rock and fluid properties, can be made.\u0000 The accuracy of the data plays a pivotal role in guiding the way forward and the future development of oilfield projects. A WBM tracer was utilized in the drilling mud, during the sidetracking of an observation well at the first and largest CO2-Project in the middle east. The objective of sidetracking the well was to obtain sponge core samples to assess the residual oil saturation (ROS) and evaluate the sweep efficiency of the CO2-flood.\u0000 This report provides an overview of tracer technologies and the lessons learnt from deploying advanced water-based mud (WBM) tracers during the coring operation of a CO2 observation well, including theoretical and experimental considerations, engineering design and field test issues. The objective of this tracer survey was to estimate the invasion of the drilling mud-filtrate and correct water saturations. It will be useful to use this deployment in some of the relatively mature fields, however, it may have some limitations and challenges that need to be addressed first.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133231459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transient Modeling of Tripping Operations Enables Closed-Loop Limit Control of Tripping Processes to Reduce ILT While Maintaining Wellbore Safety","authors":"Pedro J. Arévalo, G. Becker, R. May, M. Forshaw, S. Grymalyuk, Glen Houghton, Morten Lien, S. Hovda, Kim Evensen, Randi Reber","doi":"10.2118/212513-ms","DOIUrl":"https://doi.org/10.2118/212513-ms","url":null,"abstract":"\u0000 Tripping operations can take up a significant portion of well construction time and the associated cost. In the last decade, there has been extensive development and deployment of real-time tripping applications to optimize tripping parameters while maintaining formation integrity. This paper presents a system that utilizes transient modeling of tripping behavior to determine the optimum parameters that safeguard the integrity of the formation and the mechanical equipment at the rig site. The system delivers tripping boundaries to automated drilling control systems (ADCS) for every stand.\u0000 A digital twin of the wellbore, equipped with physics-based transient models, estimates the permissible axial velocities and accelerations developed when running drillstring in and out the wellbore. These motions develop pressure waves which travel along the wellbore and which can compromise formation integrity. The digital twin, prepared in the planning phase and deployed in the real-time drilling environment, uses smart triggering algorithms to automatically update the models and refine simulation results. Automation systems consume the predicted limits via an aggregation layer to refine fit-for-purpose tripping applications. The automation system finds optimum proposals of tripping limits and updates them directly in the rig control system in real-time.\u0000 The trip monitoring system automatically and continuously publishes optimum velocity and acceleration tripping limits per stand and transmits them as set points to the ADCS to define a safe operating envelope (SOE). This approach can greatly reduce the overall tripping time in comparison to non-automated deployments. Furthermore, the reduction of invisible lost time (ILT) takes place while maintaining the integrity of the formation, and the integrity of the surface equipment. Finally, reduction of the energy required to perform the tripping process consequently decreases the amount of carbon emissions involved in the process.\u0000 A set of case studies confirm the effectiveness of the approach and illustrate its benefits. A case study addresses the topic of adoption of drilling automation applications such as the tripping advisor. Another case presents the concept of interoperability using as example a deployment on a rig simulator setup in Europe to perform closed-loop control using the tripping application to write velocity and acceleration limits continuously to the ADCS.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130774145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"2nd Mode Shape Torsional Vibration - Observation, Identification, Mitigation","authors":"S. Keshiyev, T. Naterstad, Ross Murray","doi":"10.2118/212473-ms","DOIUrl":"https://doi.org/10.2118/212473-ms","url":null,"abstract":"\u0000 This paper investigates the drill pipe twist-offs that occurred while drilling an S-shaped well in the 12 ¼\" section. The presence of the 2nd mode shape of torsional vibration was observed and linked to the failure. Conditions that lead to a 2nd mode shape being triggered and sustained are discussed in addition to recommendations to prevent fatigue failures.\u0000 2nd mode shape torsional vibration is a standing wave with two nodes created along the drill string, with the first one being the top drive and 2nd located along the drill string. The drill pipe experiences the highest torque fluctuations in the rotational nodes during torsional vibration.\u0000 A high-resolution drilling dynamics recorder was utilized to record a spectrum of torsional vibration frequencies, confirming the presence of the 2nd mode shape of torsional vibration. The multiple degrees of freedom spring-mass model was used to identify the node location, which was later compared to the locations of the actual twist-offs.\u0000 The presence of the 2nd mode torsional vibration, its transition from the fundamental mode to the 2nd mode, and the conditions for the transition to happen were observed.\u0000 Recommendations were developed on how to recognize the 2nd mode shape with the surface instrumentation, on the drill string design, and preventive inspection.\u0000 Knowing the location of the node gives a possibility of selective inspection of the drill pipes once the 2nd mode shape was observed while drilling, minimizing the risk of fatigue failures. Also, the drill string design could be revised by increasing drill pipe strength within the nodes.\u0000 The twist-off locations were found to match the calculated location of the node caused by the 2nd mode shape with a high degree of accuracy.","PeriodicalId":382692,"journal":{"name":"Day 1 Tue, March 07, 2023","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122361853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}