bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fiber Optics Improve Cement Performance and Drilling Cost in the Bakken
Authors: Jerrard Mark , Osborne Paul , Stark Price 
Published: March 2022

Abstract
The cement barrier represents the first line of defense to maintain well integrity on a multimillion-dollar asset, and an integral barrier for stage isolation for completion expenditures. The actual cement slurry design parameters are often based on historical precedent, trial and error, and simulation modeling but frequently have limited direct measured validation. What measurements have been completed, including wellbore static temperature measurements, are often known to be tens of degrees off from actual conditions. Cement placement effectiveness can be qualitatively evaluated via logging tools but is based on assumptions associated with the design and can be subjective based upon interpretation.
This paper will present a monitored cement slurry as, it cures in real-time, on two wells in the Williston Basin, H4 and H5.
The slurry designs were monitored via a fiber optic cable, pressure, and temperature gauges installed on the outside of casing. The pressure and temperature gauges were run concurrently with the fiber optic allowing further evaluation along the lateral during prejob circulation and the cementing operation.
The fiber optic cable and gauges were primarily deployed for completion evaluation and drainage mapping. Taking advantage of this equipment enabled monitoring of the heat of hydration of the cement slurry, and the annular pathways via gauges, from pump down through final curing along the entire lateral length.
The distributed temperature data provided visibility into the top of cement, curing temperatures, quality of circulation and curing behavior of the slurries. The observed Geothermal temperatures prior to cement placement were not consistent with previously reported temperatures via wireline or drill bit. The slurry design based on these temperatures responded to its actual downhole condition in a variety of surprising ways: (1) Slurry curing time was delayed beyond the heat of hydration predicted start time (2) heat of hydration of the slurry occurred at different depths along the lateral, possibly relieving hydrostatic pressure on the slurry column.
The wellbore itself, in one case, was observed to still contain obstructions in the annulus preventing a consistent slurry placement in both wells.
Adjustments to the design were necessary based on the data and implemented once observed. The implemented changes were cost neutral and significantly better results were observed in the fit for purpose, engineered cement slurry design.
The specific observations from this case study are not unique. In the last three years several cement monitoring programs have been conducted with similar results indicating a systemic issue in the industry regarding cement design.
Real-Time Estimation of Downhole Equivalent Circulating Density ECD Using Machine Learning and Applications
Authors: Robinson Tim , Gomes Dalila , Meor Hashim Meor M. Hakeem , Yusoff M. Hazwan , Arriffin M. Faris , Mohamad Azlan , Ezharuddin Tengku , Othman Eswadi 
Published: March 2022

Abstract
Despite many drilling technology improvements during recent years, hole cleaning remains a significant challenge. The variation of equivalent circulation density (ECD) is a symptom of borehole instability. Therefore, the ability to accurately estimate ECD is a key consideration for preventing hole cleaning problems that may lead to a stuck pipe, and well pressure management more generally.
In this work, we demonstrate a Machine Learning approach to estimating downhole ECD in real-time using a deep neural network. Surface measurements that are widely available from most rigs are used as the model inputs, hence less configuration information is required relative to hydraulic simulations for pressure loss. Mean Absolute Errors of ~0.3-0.4 ppg were achieved on 16 validation wells and 7 holdout wells (blind test); these wells were independent of those in the training data. Prediction errors often reflect offsets between reference and predicted values; however, even with these offsets, trends in ECD behavior can still be captured correctly. The model shows promise for real-time ECD monitoring purposes to complement existing numerical methods and downhole tools.
Beyond real-time estimation, other applications could include forecasting ECD a short time ahead to provide early indications of hole cleaning issues; case studies obtained from a real-time monitoring centre where this approach is used are presented as part of this work. The software tool was capable of detecting such symptoms in advance, giving the driller opportunity to take preventive actions to avoid a potential stuck pipe.
Behavior Anomalies Detection in Drilling Time Series Through Feature Extraction
Authors: Jeong Cheolkyun , Yu Yingwei , Patino Diego , Venkatakrishnan Sai , Mansour Darine 
Published: March 2022

Abstract
The industry has focused mainly on extracting key performance indicators (KPI) from its operational processes that aggregate data in different forms. The computation of average values has been one of the most important ways to measure process performance. However, averages or any other aggregate measures do not give a mechanism to identify how to improve a process. To detect abnormal activities with longer durations than normal (time anomalies), or not following the standard process (behavior anomalies), a drilling engineer has to manually review the drilling parameters individually. It is therefore essential to implement an automated mechanism to identify failures or anomalies within the process in real-time and provide feedback to field personnel in an efficient and easy-to-understand fashion to develop improvement plans.
To automatically identify time and behavior anomalies from the real-time surface data, the proposed workflow consists of three steps. First, the time sequence signal is split into drilling activities through data segmentation. Next, we extract features from the segmented activities and statistically convert the feature score into probability. Based on that, the system automatically judges whether it is an anomaly or not. The algorithm has successfully demonstrated its applicability in the field data with better interpretability.
Drilling Optimization in the U.S. New Mexico Permian Basin with a Compound Angle Motor in Monobore Wells
Authors: Borjas Francisco , Hollis Chris , Nabors John , Lopez Juan Ramon , Soberanes Juan Carlos , Feddema Chad 
Published: March 2022

Abstract
Drilling in the US Permian Basin is constantly evolving to optimize and reduce the total well construction cost. To be part of this fast-paced environment, operators and service companies should always engage in innovative thinking to find new ways to improve.
Several solutions are being tested every day in different disciplines of well construction that contribute to major breakthroughs in optimization. Examples of these are: novel technologies, different well designs, and artificial intelligence for automation, just to name a few. One known solution for cost savings in the well design category are monobore wells that have proven to save about 40% on average (Norwood et al. 2016).
Monobore projects utilize a single hole size to minimize different tool sizes for drilling and completions. While the reward is high, it should be carefully planned and analyzed to overcome any engineering challenges. For example, one major challenge an operator faced in Eddy County in conventional monobore wells is the geometry design for placement and optimum performance of an Electrical Submersible Pump (ESP). The well geometry required a specific design where within a curve section, a critical tangent section was required for optimum ESP operation. To accomplish this task several Bottom Hole Assemblies (BHA) with different bent housings are needed.
To solve this problem, a Compound Angle Motor was run in a conventional monobore application in the Permian Basin in New Mexico with great success. The concept uses a low degree internal tilt of the drive mandrel with a compound external bend (similar to conventional motors) but allowing the external bend to be much lower due to the existing pointed mandrel (Jones and Sugiura 2021). This translates in the ability to drill several sections with the same tool while having a more neutral BHA to improve trajectory control.
More than 19 wells utilizing the Compound Angle Motor have proven to provide substantial improvements in wellbore trajectory control, and asset utilization. In this Case Study we showcase these interesting results along with new challenges that emerge while pushing the limits.
Overcoming the Challenges for Cementing Salt Zones in Deepwater Top Hole Drilling in Brazilian Pre-Salt Wells: A Well Containment Barrier Approach
Authors: Moreira Rafael Peralta , Ribeiro Diego , Piedade Thiago 
Published: March 2022

Abstract
When a surface casing is set in front of salt zones, challenges such as hole enlargement and salt dissolution need to be addressed in the cementing design. This study compares the several possible solutions for drilling and cementing in deepwater top hole drilling with exposed salt formation, with the general objective to provide valuable insight on the relevance of cement integrity on well containment analysis in deepwater wells. Several studies reported in the literature have evaluated the different approaches that industry follows on drilling and cementing top hole sections when salt formations are present. In addition to a review on these practices, through a detailed analysis of field data from hundreds of wells in Santos basin pre-salt wells, we identify the main aspects of cement sheath quality and its ability to withstand well containment loads from cement slurry formulation to the drilling practices and geological conditions. From data in real scale, a new and robust design and its field results are presented. From the analytical study of several possibilities, it is shown that well geometry aspects - such as inclination, tortuosity, and hole enlargement – shall attend minimum requirements to obtain the desired cement sheath quality. These requirements were able to be established through extensive field data analysis and simulations for cementing in different conditions. When those requirements are not achieved, even the highest efforts on the sole cementing design does not mitigate the loss of well integrity. Another set of important conclusions are concerned the cementing slurry design and centralizer selection and placement: salt concentration in cement slurry, bond strength between salt formation and cement slurry stands as the key characteristic and the salt-based cement slurry with this property provided the best for specific field results. Since the industry is continuously discussing the best drilling and cementing practices on salt formations, this paper provides compiled results from a large field dataset on top hole drilling in deepwater wells. Furthermore, both theoretical and applied engineering considerations on the salt-based cement slurry design, its mechanical properties, and the placement environment (hole diameter, geology, and casing centralization) are addressed to bring on a discussion on general guidelines for cement sheath quality in well containment analysis.
Development of Online Drilling Fluid Property Logging System
Authors: Ge Yunhua , Mei Yunyi , Zhang Songjie , Zhang Yanlong , Liu Guanglai , Yang Hao , Wang Qi , He David , Zhang Josh 
Published: March 2022

Abstract
Continuously monitoring of drilling fluid properties and simulating of down hole hydraulics is critical and beneficial for safe and efficient drilling. However, the drilling fluids properties are generally taken once every regulated interval and the downhole wellbore conditions and drilling fluids performance are judged accordingly and sometimes experientially for lack of updated data. In this paper, we present a novel unit called On –line Drilling Fluids Properties Logging System (ODFPLS) for real-time measurement of drilling fluids property and software for downhole hydraulics modeling by integrating of these real-time measured data.
The ODFPLS unit consists of four testing modules, they are Density module, Rheology module, Funnel Viscosity module, and Ion Content module. During working, the fluid sample is sucked in and flowed first to the Density module, tested there and then flowed to other modules in above order and finally discharged into waste pits without any human intervention. The test data is stored in the database of well-site digital platform and shared to the Remote Operational Centers (ROCs) for drilling fluids performance diagnosis and downhole hydraulics modeling
The indoor and field pilot tests showed that the unit is capable of measuring fluid properties such as mud density, funnel viscosity, rheological behavioral parameters, calcium and chlorine concentration and so on properly and accurately while drilling compared with manual measurement by lab operators. The drilling fluids performance diagnosis and hydraulics modeling provides not only rheological mode identification but also the real time equivalent circulating density ECD and equivalent static density ESD at any point in the wellbore during drilling. It also delivers surge and swab pressure calculation as well as ECD data while tripping drill pipe or setting casing. The timely availability of the information enables the mud engineer and drilling engineer to aware the status and trends of the downhole conditions and improve efficiency in decision making.
Application of a Forced Vibration Modeling Approach to Better Quantify the Role of Downhole Vibrations and Excitation Tools
Authors: Nguyen Khac-Long , Mahjoub Mohamed , Dao Ngoc-Ha , Menand Stéphane 
Published: March 2022

Abstract
Drilling operations can induce several external excitations to the drillstring and bottom-hole assembly (BHA) due, namely, to the drillstring-wellbore contacts, bit-rock interactions, fluid flow, and mass imbalances. On the one hand, such undesirable excitations may lead to excessive vibrations and damage to the drill bit, BHA, or drill-pipes. On the other hand, some vibration tools are used to intentionally introduce a source of lateral vibrations in the drillstring to reduce the friction effects and enhance the rate of penetration. Whether these vibrations are undesirable or intentional, efficient models are necessary to predict them accurately to help optimize the drilling parameters and vibration tools placement in the drillstring.
The time-domain analysis can give a detailed portrayal of drillstring vibrations, but usually requires a lengthy computational time, especially for the simulation of long structures. This paper focuses on an alternative analysis using a forced vibration model based on a linearized frequency analysis. It consists of studying the magnitude of the displacement, velocity, acceleration, and internal efforts, when the drillstring is subject to an external harmonic excitation at a given frequency. This numerical model is based on the beam finite element method, where the wellbore-drillstring contact effects are considered using a Jacobian matrix approach.
The forced vibration model is applied to study the lateral vibrations produced either by mud motors or lateral vibration tools. The comparison between the results of frequency and time-domain analyses shows that the forced vibration model can describe the global behavior of drillstring vibrations with a fast computation. When varying the excitation frequency, critical values giving large vibrations could be identified and avoided by the driller thanks to a heat map representation of the vibration magnitude as a function of the position and excitation frequency.
The novelty of this work is in showing the capacities and limitations of the forced vibration analysis compared to time-domain analysis. The fast computation of the frequency analysis can provide efficient and accurate predictions and, therefore, could be employed to optimize the BHA design and drilling parameters, and therefore reduce the harmful vibrations and improve the performance of any drilling systems equipped with downhole excitation tools.
Construction of a Reference Well to Support the Qualification of Cement Evaluation Logging Tools and Data Processing
Authors: Beltrán-Jiménez Katherine , Merciu Ioan Alexandru , Gardner Dave , Govil Amit , Bose Sandip , Lomeland Stig , Hemmingsen Pål Viggo , Kuragina Olga , Godøy Rune , Mitelshtet Konstantin , Berg Eirik 
Published: March 2022

Abstract
Verification of annular well barriers is a critical process that can significantly affect the cost and complexity of plug and abandonment (P&A) operations, deep sidetracks, or any other drilled wells. Sonic, acoustic, and ultrasonic logging tools are nowadays used to evaluate the cement bond to the casing and infer information about the quality of the annular barrier seal. Nevertheless, as the comparison of the real annular condition and the log response can be uncertain or difficult to establish in a real well scenario, a well was drilled and completed with well-defined engineered defects introduced in the cement with the aim to establish a reference for assessing vertical and azimuthal sensitivity of the data delivered by logging tools. During the execution of this joint project between industry representatives and researchers, the first challenge was to select an appropriate material to simulate appropriate cement defects. Such material should have an acoustic response similar to water, be suitable for installation on the outside surface of a 9 5/8-in. casing, be robust enough to survive a trip downhole, and withstand the cement placement and curing process. After a screening process, four different synthetic rubber materials were selected as potential candidates worthy of further investigation. The characterization executed to select the material used included acoustic measurements and mechanical observations, as well as a detailed description of the well-designed and well construction procedure.
The reference well has a 12 ¼-in. section drilled to 214 mRKB and was completed with 9 5/8-in. casing. The completion design comprises the shoe, the float collar, and 17 casing joints fully centralized. Ten casing joints were run into the well with defects installed on the outside wall of the pipe simulating defects in the annular cement. The defects mimicked water channels of 10°, 20°, 30°, and 45° width. After landing the casing, a cementing operation was executed utilizing Class G cement of 1.90 SG. The first logging run confirmed all engineered defects had survived the trip downhole and that the goal of creating defects with well-defined geometries had been achieved.
The novel well facility was constructed with the aim of establishing a reference for the qualification of logging tools that can allow a direct comparison between log response and annular seal quality. This well provides the industry with the opportunity to compare different logging technologies to detect and evaluate cement defects and their performance to describe defects with specific lengths and sizes.
Accurate Prediction of Casing Collapse Resistance by 3D Finite Element Modeling
Authors: Lin Bisen , Coe David , Harris Richard , Klever Frans 
Published: March 2022

Abstract
Three-dimensional (3D) outside diameter (OD) and wall thickness mapping of a casing joint include synchronized OD laser scanning and wall UT (ultrasonic testing) measurement at a resolution of every 1-inch along the length and every 1 or 2 degrees around the circumference. This full-length mapping data can then be used to construct a 3D finite element analysis (FEA) model that captures the geometric attributes, including OD, wall thickness, OD ovality, and wall eccentricity of a casing joint. Together with the actual nonlinear material plasticity model and the measured residual stress, the 3D FEA model can accurately predict the casing collapse strength. Also, the Klever-Tamano ultimate limit-state (KT ULS) collapse equation per API TR 5C3 [1] together with a calibrated moving-average scheme was used to calculate the joint's collapse strength.
Results predicted by 3D FEA and KT ULS collapse models were then compared to the actual full-scale collapse test results. A 3D FEA model generally produces more accurate results than the KT collapse equation. In addition, both 3D FEA and KT collapse models predict slightly lower than actual collapse pressure, which therefore is on the conservative side.
The accurate prediction of casing collapse strength can be beneficial to the end user in sorting and ranking the casing joints by collapse resistance, and therefore provides valuable information that can be used in the end user's risk assessment with the consideration of the worst-case discharge scenario. Furthermore, the end user may potentially select the joints with the highest predicted collapse strength for the bottom portion of the casing string where the highest collapse resistance is desired.
In addition, the OD and wall mapping data together with the actual material tensile properties (yield strength, ultimate tensile strength, and strain hardening parameters) can be used in estimating the internal yield and ductile rupture pressures and other performance properties. This is outside the scope of this paper and can be pursued in future work. These predicted casing performance properties may then be used in sorting and ranking the joints based on a specific performance property of interest or combination of performance properties.
IADC Code Upgrade: Bit and BHA Forensics Using Rig-Based Photographic Documentation Practices
Authors: Watson William , Dupriest Fred , Witt-Doerring Ysabel , Pastusek Paul , Sugiura Junichi , Procter Ray , Daechsel Dustin , Abbas Raafat , Shackleton David 
Published: March 2022

Abstract
This paper establishes uniform recommended industry practices for bit and bottom hole assembly (BHA) photo documentation. In addition to standardizing photo documentation this reference document contains a discussion and example photos which may be used as training material to aid the rig site team in determining the cause of the damage observed in the photos.
Effective field photo documentation and training to identify the causes enables the team to modify parameters used in real time or make other immediate changes in the BHA or drilling system with a higher degree of confidence they will increase drill rate or extend bit and BHA life. The field documentation also provides the basis for more detailed post-drill assessment or extensive redesign if needed.
While other data should be analyzed to confirm the cause, the damage that's observed in the photo documentation is the most important in directing the actual redesign effort. For example, downhole accelerometer data may indicate the presence of BHA whirl but whether this damages the bit in a given situation is unpredictable. Whirl may not be the priority of redesign unless the photo documentation shows a pattern of damage that is known to be specifically due to BHA whirl.
These photo documentation practices were developed specifically to support real time drilling forensics. The guidelines were compiled from the practices of multiple operators, bit manufacturers, and service companies with significant experience in utilizing similar photo documentation practices to support real time decisions. The photo documentation is not complex and experience has shown that within a short period of training and daily discussions the collection of high-quality photos becomes a routine, sustainable practice.
The work described in this paper is part of a joint International Association of Drilling Contractors (IADC)/ Society of Petroleum Engineers (SPE) industry effort to revise the IADC dull grade manual.