bluuebunny/crossref_metadata_2025_split huggingface dataset:
Results from the Introduction of a Well Construction System
Authors: Rowatt John David , Jourde Alexandre , Pemmasani Vinay Krishna , Barbosa Beatriz , Yepez Juan-Carlos , Thow Paul 
Published: February 2020

Abstract
Historically the industry has siloed each part of the drilling process—workflow, hardware, and crew—limiting the impact of innovative technologies introduction. This paper describes the results from the introduction of a new drilling system, built from the ground up to achieve a step change in efficiency and consistency. It uses a holistic and disruptive approach, based on a full-system analysis of the drilling process. The systemic approach allows to fully harvest the value brought by software and hardware platforms and downhole technologies through a new organizational structure and processes.
The approach first focused on the Permian basin, analyzing over 4,000 steps to drill a typical well, cutting across all technical and operational disciplines and mapping them into more than 200 multi-disciplinary workflows. While connecting these workflows, opportunities were found to change activities, remove unnecessary steps and resources, and align job scopes to the tasks instead of using the usual service providers perspective.
The system was tailored to meet the specific demands of the operating market. The digital platform seamlessly orchestrates new workflows, shares and links data across multiple domains and technologies, drives intelligent automation and combines surface and subsurface data for insight analysis. The hardware platform integrates the surface systems (MPD, casing running, cementing), the downhole tools and the digital platform. The workflow-driven organization accounts for the new system capabilities. It includes an integrated crew, centralized process management, remotely executed operations and technical support. This system has drilled several wells and has successfully tested all these components.
Improved Channeling and Gas Migration Issues Using Foam Cement: Case History, Montney Formation
Authors: Ahmady Afshin , Turton Simon , Lewis Sam , Grant Mark , Murphy Brian 
Published: February 2020

Abstract
Wells in the Montney Formation area, British Columbia, Canada, were designed as monobores and include surface and long lateral production casings. The decision to modify the openhole (OH) completion to a cemented sleeve system presented some concerns. A comprehensive data set from all prior cement operations was compiled and analyzed. This data showed severe gas migration to surface for both an OH completion and cemented lateral well.
Computational fluid dynamics (CFD) and a finite-element simulator were used to evaluate both conventional and foam cement options using actual centralization and caliper log data. The results from this analysis identified a gas-flow potential factor (GFP) was of an order of magnitude where only compressible, foam cement would provide the required properties to achieve competent, long term zonal isolation.
The characteristics of foam cement include a high kinetic energy that assists removing immobile mud trapped on the low side of the casing. Additionally, in this case, using a foamed spacer further improved mud removal from the annulus, resulting in improved displacement efficiency, as observed in the final cement evaluation logs. Filtrate loss and reduced hydrate volume can allow gas migration, giving rise to surface casing vent flow (SCVF) while the cement is curing. Foamed cement helps create a highly compressible cement system that can compensate for these volume decreases and reduce the potential for SCVF. The ductile properties of the set foam cement help mitigate the likelihood of cement debonding and cracks forming during hydraulic fracturing operations, which also helps to reduce the potential for SCVF.
Recurrent Auto Encoders for Automatic Sensor Validation; Tomorrows Data with Yesterday's Sensors
Authors: Gupta Soumya , Chatar Crispin , R. Celaya José 
Published: February 2020

Abstract
Since the early 1920s, sensors have been used on drilling rigs to enable making operations decisions. Drilling operators have always relied on human intervention whenever the data were questionable. Automation, remote operations, smart systems and digital technology are all words which describe the recent directional change for well construction. These changes can have a huge impact on the efficiency, safety and cost of operations. The drilling industry needs real time validation of data. With the volume of data being generated on today's rigs, this requires measures beyond human capacity. There are many gaps which need to be addressed if the industry is to make this standard in the future. For example, to make automation to work, the data fed into the smart systems for decision making must be cleaned, corrected and calibrated.
This paper presents how machine learning techniques from other industries can be modified and applied to the data from drilling rig sensors. There are numerous strategies employed in medical, space and government agencies where validating data has been important to success. Of these strategies, a few were selected for drilling operation applications. An auto-encoder was used to study low dimensional data representations in an unsupervised manner. This algorithm was then adjusted to allow for partial reconstruction and handling processed drilling data. Reconstruction errors were used as a metric to identify potential errors and highlight them for the domain experts. Additionally, to identify errors, artificial potential errors were injected into the system and then the system was tested to understand if the errors could be identified by our methods. The results show that we can correctly identify anomalies such as missing data, outliers and sensor drift, using reconstruction errors. The model presented in this paper is based on drilling data from thousands of wells and tested on additional data as well as simulated data.
Automated Evaluation of Rocks Physical Properties to Enhance Drilling Efficiency and Reduce Non-Productive Time
Authors: Al-Rubaii Mohammed Murif , Mahmoud Mohammed Ahmed , Gajbhiye Rahul N , Al-Yami Abdullah , Al-Awami Mohammed B , Alafnna Saad 
Published: February 2020

Abstract
Evaluating physical properties of rock while drilling can improve and optimize drilling operations and save time and cost of the drilling operation. Logging tools, correlations, mini-frac test, micro-frac test, and coring operations are used to have required parameters of physical properties of rock to have a clear image about features of drilled formation. However, most of them are expensive, consumed time, decelerate wells’ deliveries and have impact of error influence. In this paper, physical properties of rock were calculated by using surface drilling parameters and fluid rheological properties to ensure delivery of wells with efficient drilling operations in optimum time and cost. Surface drilling parameters and fluid rheological properties were collected to evaluate rock physical properties. The drilling parameters and mud rheological properties in certain hole sections were analyzed first to determine the effect of rate of penetration (ROP) and cuttings concentration in annulus (CCA) on physical rock properties of rock. Evaluating physical rock properties while drilling from surface drilling parameters and fluid rheology properties will help and enhance the drilling operations, minimize drilling problems and has a major impact on cost optimization. The data selected are from the same hole size, formation type and mud type. The relationship between collected drilling parameters, fluid rheological properties and physical rock properties were then evaluated to determine the relationships of the correlations strengths. This is the first time to evaluate physical rock properties from drilling surface parameters and fluid rheological properties and showed acceptable calculated values. The results of this work include a developed model of rock bulk density that has been validated and compared with sonic and bulk density logs. The model has shown very low absolute error (less than 2%). Other physical properties of rock were determined based on developed bulk density model by using strong correlations that are applicable for same scenario. Evaluation of physical rock properties in the hole sections was tested and helped estimate bulk density, porosity and Ultimate Compressive Strength (UCS).
A Physics Model Embedded Hybrid Deep Neural Network for Drillstring Washout Detection
Authors: Jeong Cheolkyun , Yu Yingwei , Mansour Darine , Vesslinov Velizar , Meehan Richard 
Published: February 2020

Abstract
One of the practical challenges in the oil and gas industry is the lack of quality data for applying machine learning techniques. A way to tackle this problem is to build a hybrid system that combines physics models with machine learning workflows. To demonstrate the applicability, the proposed hybrid model has been applied to drillstring washout detection which is relatively a common but severe and very expensive failure in drilling.
We propose a hybrid deep neural network (hybrid-DNN) composed of three components – Parameter Network (PNet) for estimating model parameters, Residue Network (RNet) for predicting regression or classification results, and a physics model appropriate for the problem at hand. PNet learns the system behavior based on the embedded physics model, which it controls through adjusting model parameters. RNet utilizes the outputs from the PNet and physics model as input and is being trained for predicting the residual. Once trained, the hybrid system can control the parameters of the physics model and predict the desired results in real-time.
The proposed hybrid system has been applied to drillstring washout detection. Traditionally, drillstring washouts have been detected by monitoring the trends of hydraulic coefficients between standpipe pressure and flow rate of the circulated drilling fluid. Several data-driven methods based on statistical change detection have been tried to automatically detect the occurrence of abnormal trends. However, most current applications struggle to identify true washout events since they largely overlap with normal drilling patterns in noisy measurements.
The hybrid-DNN has been verified by augmented drillstring washout cases and actual field events. When fed with a real-time data stream, it is able to extract the optimized model parameters and identify normal drilling conditions and potential washout situations. It also demonstrates that the hybrid-DNN predicts more reliable results without false-positives compared to the data-driven approach without a physics model. The proposed physics model embedded hybrid-DNN provides a general-purpose framework for many different domain problems based on physics.
An Approach to Autonomous Drilling
Authors: Cayeux Eric , Mihai Rodica , Carlsen Liv , Stokka Sigmund 
Published: February 2020

Abstract
To date, solutions for drilling automation have focused on assisting functionalities to the drilling process by the mean of fault detection, isolation and recovery (FDIR) functions, safe operating envelopes (SOE), control methods applied to a few parameters, and automated standard procedures. Yet, the decision to execute different functions has been left to a human operator. In this paper, we address the next level in drilling automation: a method to achieve autonomous drilling.
Autonomous drilling requires that the software solution is capable to adapt itself to unexpected situations, to learn both online and from experience, all this in a timely fashion and with incomplete information. Our approach to autonomous drilling is based on the minimization of a "cost" function that incorporates both performance evaluations and risk assessments, in order to reach a certain goal. Here, our objective is to minimize the drilling time to arrive at the section total depth (TD). This time evaluation also includes possible delays that could be incurred in case of drilling incidents.
Since the drilling system is non-holonomic, it is necessary to consider all past states in order to evaluate the current state of the system. Thus, the method relies on the propagation of uncertainties for the evaluation of the current situation and foreseeable alternative developments of the drilling operation to reach the section TD. Therefore, the availability of well distributed measurements in space and time, with acceptable accuracies, allows for driving the drilling operation more aggressively than in the case of sparse information of poor quality. On the other hand, when the drilling downhole conditions start to deteriorate, the autonomous drilling function applies, by itself, remedial procedures to keep the time to TD as low as possible.
The novel autonomous drilling method is built on top of existing drilling automation solutions. The necessary adjustments to these systems are also described. A virtual test rig environment that is a replicate of an actual full-scale test rig, is used to develop and qualify the new autonomous drilling solution, before a final demonstration on an actual full-scale test rig.
The automatic management focusing at the same time on short, medium and long-term horizons when balancing between performance and risk is the key factor to obtain a software solution that adapts itself to unexpected situations. Concomitantly, the use of systematic error propagation enables to learn from past measurements what are normal and abnormal states of the drilling system, therefore fulfilling the main requirements of an autonomous system.
The Nature of the Interaction Between Stick/Slip and High-Frequency Torsional Oscillations
Authors: Hohl Andreas , Kulke Vincent , Kueck Armin , Herbig Christian , Reckmann Hanno , Ostermeyer Georg-Peter 
Published: February 2020

Abstract
The drilling process is impacted by vibrations through limited drilling efficiency and rate of penetration, reduced reliability and increased non-productive time. The understanding of the mechanisms and physics that lead to high levels of vibrations is extremely important to elaborate vibration mitigation strategies. A typical vibration excitation mechanism is forced response excitation, e.g., caused by the imbalance of the mud motor that can lead to lateral resonance with severe impact on tool life. Self-excitation is prominently caused by the bit-rock interaction and mainly excites torsional oscillations if PDC bits are used. Representations are stick/slip with low frequencies (&lt;1 Hz) and high-frequency torsional oscillations (HFTO) with frequencies up to 500 Hz.
The large frequency gap between stick/slip and HFTO allows for different effects and excessively increasing loads. The nature of this interaction is diverse and requires different strategies to reduce the loads associated to HFTO and stick/slip to a minimum.
The interaction between stick/slip and HFTO is analyzed and appropriate drilling optimization strategies are proposed. Several scenarios are discussed by examination of high-frequency downhole data (1000 Hz) measured in different field applications and physical modeling. It is shown that averaged statistical data or diagnostic data that are typically available can lead to misinterpretation of the drilling conditions. The first scenario is pure HFTO. The second scenario is stick-slip with superimposed HFTO that can lead to an amplification (up to factor two) or reduction of HFTO loads compared to the first scenario. Influencing parameters are discussed that determine either an amplification or a reduction of the loads in the second scenario. The third scenario shows the interaction in the context of stability measures that are determined by the operational parameters. The increased rotary speed in the slip phase of stick/slip can lead to a stabilization of HFTO and actually decreasing amplitudes.
The observations in the field are further validated using theoretical drilling scenarios. For each scenario different strategies are presented to reduce the field loads associated to HFTO and the compromise of the strategies to the drilling efficiency and rate of penetration is discussed. The nature of the interaction between stick/slip and HFTO is analyzed and unveiled.
Clearly, the necessary depth of understanding can only be achieved by analysis of high-frequency downhole data. The physics-based interpretation of the problem allows the development of very specific drilling optimization strategies. Depending on the scenario a complete mitigation of HFTO or at least a significant reduction of loads can be achieved. Ultimately, the drilling process can be optimized leading to a reduced cost of the well delivery since HFTO can be a major cause for non-productive time if not handled properly.
Fluid Migration Characterization of Cemented Sections Retrieved from a North Sea Production Well
Authors: Skadsem Hans Joakim , Gardner Dave , Beltrán-Jiménez Katherine , Kragset Steinar , Delabroy Laurent , Ruckert Frank 
Published: February 2020

Abstract
The annulus cement sheath between casings is an important well barrier element for ensuring zonal isolation and preventing cross-flow of formation fluids. Understanding the migration path geometry and how hydrocarbons and treatment materials flow in such paths are important for diagnosing and treating leaking annulus cement. We study the seepage properties of gas and liquid through two cemented annulus sandwich sections recovered from the upper vertical part of a North Sea production well during a permanent abandonment operation. Studying physical and mechanical properties of these sections can provide unique insights about the sealing properties of annulus cement that has been exposed to downhole conditions and more than thirty years of operation.
The sandwich sections are each nearly a joint length long and comprised of a 9 5/8-in casing inside a 13 3/8-in casing that was originally cemented by bullheading cement slurry down the annulus. One of the sections contains the top-of-cement while the other is from approximately 140 meter below top-of-cement. A series of seepage experiments have been performed to better understand variations in sealing potential along the assembly, including settled solids above the top of cement.
Visual inspection of the annulus cement at the bottom and top ends of the section reveal full cement coverage around the eccentric inner casing. Minor local imperfections in the form of pockets of fluid trapped in the hardened cement are also observed, presumably originating from the original cementing operation. The settled solids above the top-of-cement were found to act as an effective barrier against fluid migration initially but yielded irreversibly once exposed to higher test pressures. Seepage rates through the cemented section are consistent with previous measurements in full-scale annulus test assemblies.
The gas and liquid seepage experiments performed on the retrieved section improve our understanding of well cement quality close to the top of cement, including possible sealing potential of the material above the top of cement. Comparing the cement log from the well to seepage measurements helps correlate log response and annulus cement seepage potential which can benefit both remediation design and future abandonment operations.
Nonlinear Dynamics of a Drillstring Immersed in a 3D Curved Well, Simulations and Experiments
Authors: Nguyen Khac-Long , Mahjoub Mohamed , Tran Quang-Thinh , Andrianoely Marie-Ange , Manin Lionel , Dufour Régis , Menand Stéphane 
Published: February 2020

Abstract
During drilling operations, the bit-rock and drillstring-wellbore contacts with stick-slip phenomena, fluid-structure interaction, and mass unbalances distributed along the drillstring yield nonlinear dynamics coupling axial, torsional, and lateral vibrations. Excessive and uncontrolled vibrations may induce drilling equipment damage due to fatigue, cracking, and ruptures. Understanding and predicting the drilling dynamics become necessary to avoid those harmful vibrations.
The drillstring dynamics is modelled in the time domain using the beam finite element method. The contact between the drillsting and borehole is accounted for using radial elastic stops and the fluid effect on the drillstring dynamics is considered by two models. The initial position is obtained from a static equilibrium computation that takes into account the drillstring pre-load. The dynamics is then calculated by applying a time-integration scheme.
The dynamic model is applied to a real case of a quasi-vertical well with field measurements of downhole vibrations along with surface data. Numerical simulations are carried on a drilling assembly of several kilometers length. The obtained results are compared to the experimental data to analyze the structure vibrations such as forward and backward whirling and stick-slip. Knowing the various uncertainties of some physical quantities like the friction factor and fluid damping, a series of simulations varying the model hypotheses are conducted and the results are compared to clarify the importance of each phenomenon.
The novelty of the proposed dynamics model is its ability to consider a realistic geometry of drilling assembly in 3D curved wells with fluid flows, and to give a complete study of the coupling phenomena between axial, torsional, and lateral vibrations.