bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of Four Cytokine/Chemokine Genes in Peripheral Blood Mononuclear Cells infected with Dengue Virus
Authors: Sri Masyeni Dewa Ayu Putri , Hadi Usman , Kuntaman Kuntaman , Yohan Benediktus , Margyaningsih Nur Ita , Sasmono R Tedjo
Published: February 2019

Overproduction of numerous pro-inflammatory cytokines, during dengue virus (DENV) infection, has been related to plasma leakage in the vascular endothelium and studied elsewhere with conflicting results. The current study objective is to evaluate the expression of four cytokine/chemokine genes following DENV-2 infection within peripheral blood mononuclear cells (PBMC) isolated from a healthy donor. Venous blood was drawn,  and PBMCs were isolated using Ficoll density gradient centrifugation. Cells were maintained in culture medium and infected with Indonesian isolate of DENV-2. Cells were harvested and followed by total RNA extraction and reverse-transcription into cDNA using oligo d(T) primers and Reverse Transcriptase enzyme system. The SYBR Green-based quantitative qRT-PCR was used to calculate the relative expression of IL-6, IL-8, IP-10 and MIP-1β- encoding genes during infection time points, compared to uninfected cell controls. The observation of the cytokine was on the 6 and 18 hours post-infection. The different expression profiles of cytokines/chemokines were observed. The up-regulation of gene expression was observed for IL-8 and IP-10. In contrast, the down-regulatory of IL-6 and MIP-1β genes expression was documented during the infection period. The cytokine IL-8 and IP-10 are potent chemoattractants  in the recruitment  of neutrophil, basophil, and lymphocytes in response to an infection. The highlight of this study is on the up-regulation of IL-8 and IP-10 genes expression which may confirm the roles of these chemokines in the pathogenesis of dengue infection.
ANALISIS KESESUAIAN GAYA BELAJAR MENURUT MBTI (MYERS-BRIGGS TYPE INDICATOR) TERHADAP PENGUASAAN KONSEP KIMIA LOWER ORDER THINKING (LOT) DAN HIGHER ORDER THINKING (HOT)
Authors: Kurniawati Dwi , Ridwan Achmad , Sihombing Sondang N.
Published: February 2019

Penelitian ini bertujuan untuk menganalisis gaya belajar yang terdapat pada siswa terhadap penguasaan konsep kimia. Penelitian ini dilakukan pada semester genap tahun ajaran 2012/2013 di SMA Negeri 2 Tangerang. Penelitian ini merupakan penelitian deskriptif untuk menemukan kesesuaian antara gaya belajar siswa dengan penguasaan konsep kimia. Metode yang digunakan dalam penelitian ini adalah deskriptif analisis kuantitatif non-parametrik. Data yang dihasilkan dari tahap uji kelayakan instrumen dan tahap pengambilan data penelitian terhadap siswa sehingga diperoleh gaya belajar yang dimiliki subjek penelitian. Kemudian siswa dengan gaya belajar yang konsisten diuji penguasaan konsep kimianya melalui instrumen konsep kimia berdasarkan CCI (Chemical Concept Inventory). Hasil penelitian menunjukkan bahwa terdapat 13 gaya belajar berdasarkan pemetaan gaya belajar MBTI. Hasil pengujian terhadap skor tes konsep kimia menunjukkan bahwa terdapat kesesuaian antara gaya belajar terhadap penguasaan konsep kimia LOT dan HOT. Setiap gaya belajar tidak terdapat perbedaan yang signifikan terhadap penguasaan konsep kimia.

Kata kunci: Gaya Belajar, MBTI, LOT and HOT konsep kimia
Pengembangan Media Pembelajaran Berbasis Chemo-Edutainment Melalui Model Instructional Games Pada Materi Konfigurasi Elektron
Authors: Bahriah Evi Sapinatul , Feronika Tonih , Suharto Hari
Published: February 2019

Penelitian ini bertujuan untuk menghasilkan media pembelajaran berbasis chemo-edutainment model instructional games pada materi konfigurasi elektron serta mengetahui respon guru dan siswa terhadap media yang dikembangkan. Metode penelitian yang digunakan adalah deskriptif kualitatif melalui tiga tahap, yaitu tahap pra-produksi, produksi, dan pasca-produksi. Data yang diperoleh dianalisis secara deskriptif. Pada tahap pra-produksi dihasilkan perancangan media pembelajaran berbasis chemo-edutainment yang telah diintegrasikan dengan model dari instructional games. Pada tahap produksi dihasilkan media pembelajaran yang telah divalidasi oleh 4 orang dosen. Tahap pasca-produksi media pembelajaran diujicobakan kepada 3 orang guru kimia dan 35 siswa kelas X di salah satu SMA di Tangerang. Produk di respon berdasarkan aspek kualitas isi, kualitas teknis dan kemasan bahan ajar. Hasil penelitian menunjukan bahwa media pembelajaran yang dikembangkan memiliki nilai edukatif dan bersifat menghibur serta menyenangkan bagi penggunanya. Hasil uji coba terbatas mendapatkan skor respon guru sebesar 84,09% termasuk dalam kategori sangat baik. Hasil respon siswa mendapatkan total skor sebesar 82,88% dengan kriteria sangat baik.

Kata Kunci: Media Pembelajaran, Chemo-Edutainment, Instructional Games, Konfigurasi Elektron
Dynamic Stress Analysis of Critical and Cyclic Loads for Production Casing in Horizontal Shale Wells
Authors: Mitchell Robert F. , Zwarich Nola R. , Hunt Hai L. , McSpadden Albert R. , Trevisan Ruggero , Goodman Malcolm A.
Published: February 2019

Recent development of a new dynamic model for tubular stress analysis is now extended to the design challenges and failure modes characteristic of long production casing strings in extended horizontal shale wells. In particular, the issue of cyclic loading due to repeated sequences of multi-stage fracturing has not been addressed until now. The new model provides the ideal means of analysis of cyclic thermal loads as well as critical impact of compression due to initial running friction.

The new dynamic model of tubular stress solves the one-dimensional momentum equation over a time step sequence initiated from the original running of the string into the wellbore. Friction is modeled in a fully history dependent manner, with damping provided naturally by the wellbore fluid viscosity. Local pipe velocity as well as magnitude and orientation of sliding friction is solved at each node with friction aggregated at the connection upset and joint mid-point.

Unconventional shale wells pose critical design challenges especially in regard to the long production casing strings run in extended horizontal or lateral sections. Compressive frictional loads accumulated during running are trapped in the string by cement, packers and the wellhead. Thus the initial load state must fully account for the initial frictional state in order to be realistic and conservative. Hydraulic fracturing at high flow rates and significant pump pressures, including the possibility of screen-out, represents a critical design load on the casing which can also significantly alter the orientation and magnitude of tubular/wellbore frictional contact. The particular phenomenon of repeated fracturing treatements in a multi-stage stimulation compounds the design challenge. Cycles of cold stimulation followed by renewed hot production can lead to unexpected migration of axial loads and localization of critical stresses.

The cyclic nature of loading due to repeated sequences of multi-stage re-fractures and renewed production has not received industry attention due to the unavailability of appropriate models. Lack of adequate models has perhaps resulted in the problem being overlooked. A dynamic model is ideally suited to the analysis of cyclic loads because of its inherent ability to account for a full history of friction loads. The dynamics of loading and unloading are also critical to this new ability to address the design problem. Previous static-based stress models have been unable to provide a comprehensive basis of design.
Determining Wellbore Stability Parameters Using a New LWD High Resolution Ultrasonic Imaging Tool
Authors: Ciuperca Constantin-Laurian , Di Tommaso Davide , Dawber Mike , Tidswell Jonathan
Published: February 2019

A new LWD ultrasonic imager for use in both water- and oil-based muds uses acoustic impedance contrast and ultrasonic amplitude measurements to obtain high-resolution structural, stratigraphic and borehole geometry information. Following extensive testing in the Middle East and the US, this paper presents results from the first European deployment of the new 4.75-in. high-resolution ultrasonic imaging tool.

An ultrasonic transducer, which operates at high frequency, scans the borehole at a high sampling rate to provide detailed measurements of amplitude and traveltime. A borehole caliper measurement is made, based on the time of arrival of the first reflection from the borehole wall. A second measurement detects formation features and tectonic stress indicators from the change in signal amplitude. The amplitude of the reflected wave is a function of the acoustic impedance of the medium. Resulting impedance maps have sufficient resolution to detect sinusoidal, non-sinusoidal and discontinuous features on the borehole wall.

Breakouts, drilling-induced fractures, and tensile zones were used for stress direction determination. Breakout identification was obtained both from amplitude images and oriented potato plot cross sections derived from traveltime measurements.

The orientation of natural fractures is parallel at the maximum stress direction, indicated by drilling-induced fractures and tensile zones. The World Stress Map confirms the maximum stress direction determination.

It was also possible to detect certain key-seat zones and investigate borehole conditions to prevent issues during the subsequent casing job.

The new LWD ultrasonic imaging technique represents an important alternative to density and water-based mud resistivity imaging, which has several limitations. Unlike the resistive imaging LWD tool that is very sensitive to standoff, the higher tolerance of the ultrasonic imaging tool enables the amplitude and traveltime ultrasonic images to contain fewer unwanted artifacts.
Calculating a Tortuosity Index Metric Using Machine Learning Techniques
Authors: Noshi C. I. , Schubert J. J.
Published: February 2019

Extremely tortuous wells pose many wellbore quality repercussions and poorly affects several well drilling and production-based operations. To date, many indices have been developed for accurate tortuosity identification, but few have had the capability to efficiently mirror and quantify micro-tortuosity in real-time. This study applies a previously-proposed novel algorithm studied by some researchers to quantify well trajectory tortuosity using simple and readily available survey data. The process is followed and validated using twenty wells located in the Permian Basin.

Python code was written to identify proper inflection points at the mid-point of the curve turns and using inclination and azimuth indices, a 3D overall TI index was generated for each well. The technique is inspired from the discipline of ophthalmology, specifically a method to determine tortuosity from retinal blood vessels.

The approach successfully produced a tortuosity metric with three different risk categories characterizing three ranges of the index. The indices generated were matched against operator reports of drilling incidents and NPT. The methodology matched highly tortuous wells with greater downhole tool failures rates ranking it in the high-risk zone.
Simulated Drilling Testing of an Active Wellbore Sealing System on a Full-Scale Test Rig
Authors: Johnson Austin , Nichols Jess , Ameen Kareem , Fraczek Justin
Published: February 2019

Objectives and Scope

An active wellbore sealing system has undergone simulated drilling tests in a full-scale, purpose-built test rig facility. The active wellbore sealing system contains wellbore pressure during all drilling operations with an active, direct-hydraulic control system to actuate the dual non-rotating seal sleeve elements. The test rig facility enables simulated drilling testing including the use of drilling mud, simultaneous drillpipe stripping and rotation, production topside equipment, and application of wellbore pressure.

The active wellbore sealing system test program operates the equipment under realistic field conditions and enables control parameter optimization. Test procedures have been developed based on historical well data with careful consideration given to the application of test results. Analysis of the test data is provided and discussed.

Methods, Procedures, Processes

This paper shares test results from the active wellbore sealing system test program. An overview of the system and test environment will be shared. Test procedures and technical considerations will be discussed. Data and analysis from the test program will be shared.

Results, Observations, Conclusions

The active wellbore sealing system offers distinct operational advantages over passive systems in deepwater. An active control system enables extended seal life and active seal integrity management. Rigorous simulated drilling tests provide a technical basis for comparison to real wells. Seal element condition monitoring allows the rig to replace the seal assembly only as required, saving rig time.

Novel and Additive Information

The active wellbore sealing system is operated with the chamber pressure between the seal elements higher than the wellbore pressure, forming three mechanisms to ensure wellbore pressure is contained. Further, testing demonstrates that minimal human input is required to operate the system.
An Active Return Flowline Sensor for Onshore Drilling Rigs
Authors: Lambie Patrick M , Sampaio Jorge H
Published: February 2019

This paper presents the concept, construction, and test of a small scale volumetric flow rate sensor using the simple principle of mass conservation with the purpose of accurately measure the flow return in onshore drilling operations. The results demonstrate that the solution is accurate, extremely sensitive to flow variations, and capable of identifying and measuring flow variations caused by influx or loss of fluids in the wellbore.

The solution uses the principle of mass conservation and is limited to low compressibility fluids which corresponds to the larger portion of onshore operations in US and abroad. Under this assumption, the principle of mass conservation is replaced by volume conservation, which allows the appropriate measure of the return flow rate. The principle is realized using off-the-shelf equipment. The solution is installed as a bypass of the regular flowline on conventional drilling rigs and does not require the use of special equipment like rotating head and expensive Coriolis systems.

The small-scale sensor system constructed and tested is capable of handling up to 40 gpm with a footprint of about 4 ft2. Considering the scale to handle typical flow rates up to 1,000 gpm the size of the equipment in real scale is roughly in the linear ratio of three, which corresponds to a footprint of 36 ft2 (3’x12’), compatible with the available area between the rig structure and the mud pits. Several tests indicate that the system can sense changes in flow rate in the range of ±1% of the maximum nominal flow rate in few seconds after a flow perturbation/variation occurs and obtain accurate readings of the actual flow rate in less than 30 s (5 s to identify, 10 s to measure, 15 s to stabilize). This means that the time to identify influx of gases or loss of fluid is reduced substantially compared to traditional differential methods used in onshore rigs, and are comparable to solutions using Coriolis methods, at a fraction of the cost. The system can also provide a real-time measurement of the return fluid density. The use of this system in onshore rigs brings to these scenarios the same level of safety as the case of offshore operations using Coriolis systems.

This new measuring system uses sound principles and is implemented using off-the-shelf equipment, although for higher efficiency and optimized reliability the use of a design-for-fit equipment is advisable. The invaluable benefit is to bring the same level of safety as the case of more expensive systems usually affordable only in offshore scenarios. By reducing substantially the influx volume of kicks or the volume of fluid lost before appropriate actions are taken makes this system economically and environmentally attractive.
Cementing an Irregular Annulus Geometry: Full-Scale Experiments and 3D Simulations
Authors: Skadsem Hans Joakim , Kragset Steinar , Sørbø Jostein
Published: February 2019

Primary cementing involves displacing the drilling fluid from the annulus outside the casing and replacing it by cement slurry. Incomplete displacement can compromise zonal isolation, impacting both productivity and abandoning costs of the well. Washouts and similar irregularities are often generated during drilling, but their effect on displacement and cementing is poorly understood. We report results from full-scale cementing experiments and numerical simulations for an eccentric annulus geometry with a washout.

Inclined annulus test assemblies were constructed by placing 7-in tubing inside 9 5/8-in casing and letting the inner tubing rest on the low side of the casing, supported by the tubing collars. The geometric irregularity is in the form of a 16-in casing segment welded onto the assemblies to represent a local washout. The assemblies were cemented by displacing a water-based spacer by denser, more viscous conventional cement slurry. Numerical simulations of cement placement have been performed using an open-source computational fluid dynamics platform.

The quality of the hardened cement was investigated by leakage testing followed by visual inspection of the annulus after cutting the assemblies open at designated positions. Leakage paths are visible along the interface between cement and the outer wall along the upper side of the annulus. There is no obvious contamination of the cement after the washout due to mixing with the water-based spacer. Numerical simulations are in good qualitative agreement with experimental observations, including correctly predicting the presence of residual spacer fluid inside the washout.

The experiments were performed at modest flow rates so the density difference between the fluids will largely compensate for downward casing eccentricity in the regular part of the assemblies. Buoyancy becomes even more pronounced inside the washout due to lower axial fluid velocity, resulting in strong downward slumping of the dense fluid and a fully three-dimensional displacement flow.
Slide Drilling Guidance System for Directional Drilling Path Optimization
Authors: Pehlivantürk Can , D'Angelo John , Cao Dingzhou , Chen Dongmei , Ashok Pradeepkumar , Van Oort Eric
Published: February 2019

The amount of uncertainty related to directional drilling makes it challenging to accurately model and predict the results of drilling actions, leaving much to human know-how and interpretation. Additionally, few path planning methods in the literature consider the directional steering tool being used which results in a loss of optimality when sliding and rotating instructions are fitted on a geometric optimal path. The formulation of the optimization problem varies greatly between rotary steerable systems (RSS) and mud-motor configurations. Additional cost functions and constraints are present for mud-motor use, which significantly increases the problem complexity. A slide drilling guidance system is proposed to combat this issue and to help automate directional drilling. The guidance system leverages three main modules. The first is a computationally efficient, non-linear wellbore propagation model. The second is a set of cost functions that aims to quantitatively represent the actual value of the well, representing production loss, drilling time, completion cost, and wellbore quality. The last module is a Genetic Algorithm (GA) solver that generates sets of optimal drilling instructions. The guidance system is built into a software package that utilizes an intuitive, easily-accessible Graphical User Interface (GUI) to be an effective advisory tool for the directional driller. The software is currently being implemented into the Real Time Drilling (RTD) system by an operator.
Real Time MPD Optimization in Challenging Scenarios
Authors: Siqueira Vanni Guilherme , Alonso Fernandes André , Tacio Teixeira Gleber , Vieira Martins Lage Antonio Carlos , Leibsohn Martins André , de Souza Terra Felipe , de Souza Cruz Marcelo , Rodrigues G. da Silva Fabio , Édio Dannenhauer Cristiano
Published: February 2019

Given the complexity related to deepwater drilling with narrow operational windows, any effort to increase the confidence on the safety guidelines should be encouraged. There are many procedures in MPD operations that can be verified and validated during the operations, in order to avoid unforeseen situations.

As initiatives to optimize the drilling process in real time are extremely important, the present study focuses on the development of specific methodologies to support MPD operations, which are implemented on a real time drilling diagnosis software [5].

It is very useful to review the drilling plan in various situations. With the use of MPD monitoring module is possible to obtain, from the DPPT (Dynamic Pore Pressure Test) and DFIT (Dynamic Formation Integrity Test) procedures, more precise values to compose the operating window. As a consequence of appliying it together with precise hydraulics, cutting transport and torque and drag models, the developed methodology proposes, as output, the ideal operating parameters, such as choke pressure, pump flow rate or adjustments related to the drilling fluid properties. The methodology always considers the best approach to meet the restrictions imposed by the operational window, avoiding drilling problems. Alternatively, if a change on the operating parameters is not sufficient, it also simulates the best position for the Anchor Point.

The developed methodology was successfully applied in a number of MPD wells recently drilled in distinct deepwater locations, in Brazil. The real time optimization procedures proposed in the present paper are a further step to ensure the reliability of MPD operations in challenging scenarios, aiming enhanced efficiency and safety.
Improving Accuracy of Well Depth and ROP
Authors: Kyllingstad Åge , Thoresen Karl Erik
Published: February 2019

This paper presents a theory and formulas for correction of the drillstring length as a function of loads, such as tension force, fluid pressures and temperature. The effects being specifically addressed are static and dynamic tensional stretch, pressure ballooning, hydrostatic shortening, flow lift shortening, and thermal expansion. Many of these corrections increase progressively with the drillstring length and the sum of all correction can reach several meters for long drillstrings.

The corrected, load dependent drillstring length is the key to estimate both the measured well depth and the short-term rate of penetration (ROP) more accurately. Accurate short-term ROP is important both for calculating mechanical specific energy (MSE) and for monitoring and optimization of the drilling process.
Real-Time Drilling Advisor Appstore – An Agile Development and Deployment Program
Authors: Liu Yu , Wu Xianping , Baumgartner Theresa , Zimpfer Douglas , Wedgwood Denver , Teff Cody , Zhu Jiaqi , Jia Yuying , Zhao Yucheng , Tao Lei
Published: February 2019

In the new wave of digitization, real-time advisory mode drilling data analytics is both an intermediate step to achieve long term vision of autonomous drilling and an agile response to the need of delivering beyond best in class wells. An operator has constructed an agile program for drilling data analytics to lead the development of analytics solutions, deployment to collect business values, and handover to productization. The product under development is a Real-Time Drilling Advisor (RTDA) Appstore, which is both an R&D template for prototyping and a hosting environment for rapid field trials and early deployments.

The RTDA Appstore consists of a witsml data pipeline, template of drilling data analytics functionalities, modularized computational kernels, machine learning packages for historical data analysis, an in-memory database for both historical and real-time processed data, customized drilling visualization widgets, and an open-source web app deployment framework. A hybrid methodology combining conventional engineering practice, data-driven approaches, novel visualization formats, and physics-based modeling is adopted to develop real-time data analytics solutions. It focuses on three areas: failure detection, performance improvement, and advisory directional drilling. A list of applications and features in the RTDA Appstore includes: interactive offset data map, drilling parameter roadmap, drilling efficiency monitoring, bit/reamer wear prediction, smart torque/drag, payzone tracking, auto slide sheets, sliding KPI, real-time casing wear, real-time BIC benchmarking, etc.

So far, about 30 wells of the company's Deepwater wells and about 150 of the company's unconventional wells were drilled using RTDA applications. RTDA deployments generated time and cost savings through early warnings or bespoke visualization of information for improved decision making. The RTDA Appstore is built in-house and thus provides flexibility and modularization options and heavily focused on the analytics layer. The agile program creates an interactive channel to not only meet business demand, but also to use feedback from operations to steer the digital R&D strategy. As the half open-source nature of this program, the digital capability cultivated through the development and deployment of RTDA will also be cascaded to local wells teams through format of digital training, code repository, and a single portal Appstore.
Dump, Condition, Dilute: Utilizing High Voltage Technology to Extract Solids from Drilling Fluid
Authors: Chandler Kody , Dykalski Michael , Wolfe John , Frisky Sean , Duffy William
Published: February 2019

This paper presents data from a full-scale field trial on multiple drilling rig sites. On these sites high voltage technology (HVT) was utilized to process invert emulsion drilling fluids (IEF). HVT was developed and deployed for the removal of drilled solids, conditioning the fluid back to a targeted density or to a state close to base-oil quality. This process assists in minimizing dilution and waste, while maximizing cost savings.

To start the process, a set volume of IEF was either "dumped" from the circulating system or recovered by secondary recovery equipment, such as drying shakers. This volume was then processed with the HVT to a desired condition (i.e. density) dictated by the drill site manager or drilling fluids engineer. The conditioned IEF was then reintroduced into the active mud system as dilution or refined make-up volume. The methods in the field trial applied standard calculations from the API RP 13B-2. Results for IEF processing rates, fluid properties, volumes treated, recovered volumes, and subsequent waste volumes are represented graphically. Detailed explanations and illustrations of trends are included.

Over the course of the six-month trial, the HVT processed volumes in three different modes. All produced positive separation results, which were verified with third party analysis. The application of each mode was dependent upon the IEF property objectives and the time frame window for processing. The HVT successfully and consistently achieved targeted IEF densities with improved fluid quality (i.e. decreased low gravity solids content) and minimal waste volumes. Additionally, the HVT achieved IEF densities close to or below 7.0 pounds per gallon (ppg), which illustrates a state of near base-oil quality. Key operational factors were found to influence HVT performance. These included proper flow pressure, processing time windows, IEF emulsion stability, and the migration of the separated solids within the HVT unit.
Prediction of Penetration Rate Ahead of the Bit through Real-Time Updated Machine Learning Models
Authors: Li Yuanjun , Samuel Robello
Published: February 2019

Rate of penetration (ROP) in petroleum engineering refers to the speed of forward motion of the drilling tools during the drilling process. This is an important parameter that has long been optimized for maximization, keeping in mind human, safety, and environmental factors along with consideration to downhole tools. Its importance is validated by estimating the drilling. Longer estimates of drilling time translate to increased costs.

Drilling costs are affected mainly due to the following contributing factors: non-productive time, idle time, and invisible time. Attempts have been made to reduce these times to reduce costs. Simultaneously the time taken for drilling can also be reduced by effectively increasing the ROP. Drilling depths, on average are between 5,000 to 10,000 feet, coupled with a formation that has complex properties are major factors contributing to non-productive time covering a high proportion of drilling time. Thus, a large non-productive time leads to longer drilling cycles, and eventually, a low ROP.

In an attempt to reduce the non-productive time, there is a need to optimize the ROP. Higher ROP facilitates a decrease in time and thus costs.

In this paper, ROP is effectively predicted using artificial neural networks not at the surface, but at the bit. The artificial neural network has several advantages that overcome the limitations of the conventional models. By effectively predicting ROP, estimation of the whole drilling process time and cost, identification of specific reasons that slow down the drilling process are possible, and proper measures to avoid these issues can be implemented. The target of any ROP optimization strategy should be to have the highest ROP mechanically possible, considering human health, safety, and environment, and factoring in conditions of the well and drilling state.
Curing stick-slip: Eureka.
Authors: Dwars Sicco , Lien Morten , Øydna Søren , Baumgartner Theresa
Published: February 2019

This work investigates the results of the first deployment in the industry of technology Z on an offshore drilling rig with a heavy top drive. The study uses a quantitative analysis of downhole data to confirm the benefits of Z.

Z expands the stick-slip free operating envelope and does not require tuning. Following a dozen or so Z land rig deployments since 2015, the technology was added to a heavy offshore rig, a newbuilt, with modern hi-end variable frequency drives that enable near-zero control loop latencies. A study validates the effectiveness of the system with downhole rotary speed data.

The Z system was used for multiple sections in the Barents Sea, where the overburden traditionally causes troublesome torsional vibrations. The users of the technology gave a positive feedback from their first experiences. This work aims to verify qualitative surface observations with a quantitative analysis of downhole data. Downhole sensors captured the dynamics of multiple locations in the drill string over the course of about 3 weeks. Stick-slip severity was quantified using downhole rotary speed data. Periods when Z was turned on were compared to periods when Z was turned off.
Toward Seamless Interoperability Between Real-Time Drilling Management and Control Applications
Authors: Cayeux Eric , Daireaux Benoît , Saadallah Nejm , Alyaev Sergey
Published: February 2019

Real-time signals exchanged during a drilling operation are in constant evolution and provided by multiple stakeholders that have distinct perspectives on the drilling process. To achieve an improved drilling management and control, it is desirable that real-time drilling data can be exchanged seamlessly without necessitating any human intervention to configure software applications.

By utilizing a shared drilling semantic model, drilling data-producers can expose the meaning of their real-time signals in a computer readable format. On the other hand, data-consumer applications can discover programmatically which data streams are the most appropriate for their functioning, therefore achieving seamless interoperability. This paper presents a drilling semantic framework that allows software solutions to achieve automatic and versatile self-configuration. Yet, the data exchange performances are compatible with the requirements of high-end applications involved in the management and control of drilling operations.

The semantic framework relies on few but important concepts for the drilling domain. It allows to qualify the physical quantity associated with the signal, to define its dimensionality and to specify necessary references. Another important notion is the differentiation between measurements, set-points, commands, estimated values, parameters, etc. Derived measurements are explicitly described as a function of direct ones. The semantic definition encompasses how signals are related to each other in a semantical network. Relationships between signals and their logical position, in a topological description of the drilling system, are also important. Finally, the conditional validity of signals may be semantically described.

A semantical model for drilling is presented together with its implementation in the OPC-UA real-time data exchange standard and will be made available to the drilling community for free usage.
Combining Drilling Big Data and Machine Learning Method to Improve the Timeliness of Drilling
Authors: Zhao Ying , Sun Ting , Yang Jin , Yin Qishuai , Wei Hongshu , Liu Zhengli , Li Zhong , Huang Yi
Published: February 2019

For an oil well, we can determine the working conditions of drilling wells and whether there is an accident by logging data. However, it takes a long time to analyze logging curves by traditional manual work. Therefore, this paper proposes a new method combining logging big data (BD) and machine learning (ML), which can train and study a large number of logging curves and form a data base. Then this data base can be used to judge the working conditions of the well being drilled and whether there is an accident automatically.

In the proposed method, firstly, due to the large span of data and different detection methods, there will be some differences in data accuracy, so the data need to be preprocessed to avoid these influences. Secondly, the preprocessed data is input into the artificial intelligence method, and trained by cyclic iterations; meanwhile the rule of judging working conditions is also learned from the data. Thirdly, we get a training set containing all kinds of working conditions and common accidents through artificial intelligence learning method. Finally, the logging data that need to judge is input into the training set after preprocessing, and then we can determine the working conditions and whether there is an accident according to the output of the procedure.

For the proposed method, we used the logging data of Bohai Oilfield to verify that a total of 200 logging data including 4 conditions were preprocessed and input to the artificial intelligence method to randomly generate a training set (160 sets) and the test set (40 groups) is output after the training set. The results show that the relative error of the four kinds of working conditions output by the proposed method is less than 5%, and the average calculation time is faster than traditional method, saving a lot of manual processing time.

This article introduces the methods of big data and artificial intelligence into the field of drilling, which have been tested by actual data. The time for judging drilling conditions by manpower can be greatly saved, and the common accidents during drilling can be found in time, which show that this method is of great significance.
Evaluation of the Elevated Temperature Performance and Degradation Mechanisms of Thread Compounds
Authors: Ernens Dennis , Westerwaal Diana , Roijmans Roel F. , van Riet Egbert J. , Daegling Stefan , Wheatley Alan , Worthington Edward , Kramer Henk , Van Haaften Willem Maarten , De Rooij Matthijn Bas , Pasaribu Henry Rihard
Published: February 2019

Thread compounds play an important role in the sealing ability of casing connections in the oil and gas industry. Next to their lubricating role during assembly, most of these thread compounds make use of nonbiodegradable or persistent particle additives to aid in the sealing ability. Soon, these additives need to be replaced by benign alternatives as agreed in the proceedings of the Oslo-Paris Commission. This is, however, a challenge in high temperature (>150°C) well environments. This paper presents an investigation of the high temperature failure mechanisms of thread compounds with the aim to develop biodegradable high temperature resistant thread compounds. To this end, the performance of commercially available, environmentally acceptable thread compounds was investigated with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), high temperature rheometry and high temperature pin-on-disc experiments. The compounds are assessed on their stability, consistency, lubricity, and the resulting wear at high temperature. The results indicated that, without exception the commercially available thread compounds investigated in this study fail by adhesive and/or abrasive wear at around 150 degrees Celsius because of thermally induced degradation. To remedy this and to validate the mechanisms, a prototype thread compound was developed which exhibits strong film forming. The conclusion is that a successful high temperature resistant environmentally acceptable thread compound can likely be developed. The key property of this thread compound should be the ability to form a tribofilm during make-up which protects the surface at a later stage when the lubricant has lost its consistency and the base oil is fully evaporated.
Quenching of Self-Excited Vibrations in Multi Degree-of-Freedom Systems: Application to Stick-Slip Mitigation in Drilling
Authors: Ramakrishnan Ganesh
Published: February 2019

Surface-based damping mechanisms are the most commonly used method to mitigate stick-slip vibration in drilling systems, and their parameters are typically chosen based on low-order models of the drilling system. Field experience indicates that these low-order models do not capture all deformation mechanisms, and there is a need to include higher-order modes of deformation in the model. As a result, it is also imperative to delineate the effect of the surface damping mechanism on the higher-order modes of deformation, and vice versa. This work investigates this interplay using a combination of analytical methods, numerical simulations, and field data analysis.

The effect of surface-based damping mechanisms, in principle, is similar to that of vibration absorbers used to quench self-excited oscillations in nonlinear systems. Therefore, to determine the stability of the drilling system as a function of the surface damper parameters, a torsional model of the drillstring with a negative damping boundary condition at the bit is considered. For this system, the stability chart determining the rate of growth of amplitude of the natural modes as a function of the surface damper parameters is shown to depend on the operational parameters and on the configuration of the drillstring. These analytical observations are then evaluated using transient numerical simulations of a coupled axial-torsional model of the drillstring, with a realistic bit-rock interaction law. Finally, the efficacy of the analytical and numerical model in reproducing field results is demonstrated by analyzing downhole rotational speeds of the bit acquired using high-frequency data acquisition sensors.

The results described in this paper provide a mechanism to determine the effect of the surface damper parameters on the higher-order dynamics of the drilling systems, and provide a rationale to determine consistent damping parameters that do not adversely affect the higher-order dynamics of drilling systems.
The Specialty of Push-the-Bit Rotary Steerable Tool Dynamics
Authors: Xue Qilong , Huang Leilei , Wang Jin , Li Lixin , Liu Baolin
Published: February 2019

Drillstring vibrations are an important cause of premature failure of drillstring components and drilling inefficiency, in particular, torsional vibration is more important. A large amount of research on torsional drillstring vibrations has been conducted in the last few decades. Stick/slip is a severe type of torsional drillstring oscillation that affects the efficiency of the drilling process and can cause bit damage as well as drillstring failure.

For rotary steerable system (RSS), the stick-slip vibration is introduced as a new mechanism to explain the large amplitude torsional oscillation of the drillstring. we aim for an improved understanding of the causes for torsional vibrations in RSS and torsional vibrations with and without stick-slip are observed.

We show that the RSS implementing agencies pushing the borehole wall caused the drill bit torsional vibration more serious. The results contribute to the better understanding of the dynamics of the push-the-bit RSS. Chaotic vibration is mainly caused by elasticity of the drillstring and changing frictional forces at the bottom tool, static frictional forces are higher than the kinetic frictional forces which make the bit act in a manner where it sticks and then slips, and presents complex dynamic behavior, which makes down-hole dynamic responses difficult to predict.

In the Rotary Steerable System (RSS), frictional force between the pads and borehole wall will make the drill bit instantaneous rotational speed reduces. The pads of the implementing agencies in RSS constantly pushed against the borehole wall, making bottom hole by a cycle of nonlinear damping force, which is lead to the bottom drilling tool movement of chaos and disorder.
Novel Aromatic Polyamides and its Application in Enhancing the Integrity of Oil Well Cement Sheath
Authors: Contreras Elizabeth Q. , Rasner Diana , Martinez Roland F. , Thaemlitz Carl J.
Published: February 2019

Quality of cement is an integral part of well integrity. To ensure and improve cement quality, innovative polymers, based upon a family of polymers known as polyamides, are synthesized to improve the mechanical properties of Portland cement. This results in cement systems that have high resistance to impact breakage in set cement.

With the addition of polyamides into cement, mechanical properties such as unconfined compression strength (UCS), confined compression strength (CCS), Young's modulus, and the effect of temperature on cement performance are used to show significant improvements to set cement elasticity and compression strength. Under dynamic force loading conditions, up to 30 MPa (4,350 psi) and at temperatures ranging from 20 to 180°C (68-356°F), a tri-axial load cell offers a more comprehensive method of measuring mechanical properties, of designing competent cement systems, and predicting cement integrity. These measurements are further compared to analyses from more traditional methods, such as confined acoustic and unconfined load cells, for information such as compressive strength.

The polymer additive is a solid comprising of a polyamide that enhances the mechanical properties of set cement by rendering it high-strength and more elastic to reduce plastic deformation. Findings show that the new polyamide-cements exhibit unconfined compressive strength improvements greater than 25% when compared to latex-treated cement. Furthermore, tri-axial load cell measurements are able to quantitatively analyze the reliability of cement by measuring cumulative fatigue damage which predicts cement failure (Reddy, 2007). Strain-controlled cyclic tests to measure mechanical properties at 20°C show that polyamide cements resist deformation better because of higher durability than latex cements. Polyamide cements had only an 11% permanent strain when compared to latex cement, which had a 27% permanent strain. It is important to assess the mechanical performance of oil well cement, which is subject to cyclic loading due to dramatic changes in pressure and temperature during production (Ravi, 2004).

Lastly, the effects of temperature on cement performance is well-documented to cause phase changes at different scales and a decrease in cement strength (Reddy, 2016). With polyamide-cements, the rate of cement strength retrogression is less at temperatures up to 180°C allowing the cement to have increased strength in comparison to latex cements, as well as to cement with no additives. Collectively, the data on elasticity and high compressive strength shows the value of this new polymer additive for cement systems on long-term zonal isolation in gas and oil wells. These polyamides maintained all favorable characteristics, proving to be the best performing additive that imparts the desired mechanical properties essential to extending the endurance of wellbore cement sheaths.
Self-Adjusting PDC Bits Reduce Drilling Dysfunction, Increase Drilling Efficiency in Gulf of Mexico Wells
Authors: Rodrigue Wayne , Callais Ryckman , Roy Chowdhury Ashabikash
Published: February 2019

Drilling interbedded formations can induce torsional vibrations that result in inefficient drilling and damage to drillstring components. A common bit choice for these applications is a standard polycrystalline diamond compact (PDC) drill bit; however, PDC bits due to its shearing action often exhibit some level of torsional dysfunction.

Historically, the most effective method to mitigate torsional vibrations in PDC bits is to use fixed depth-of-cut (DOC) control technology that restricts the PDC bit formation engagement at a pre-determined ratio of rate of penetration (ROP) and drillstring RPM. The challenge with using fixed DOC control is finding a compromise between limiting vibrations through targeted sections without limiting ROP in others. To address this, a self-adaptive DOC technology was developed. The self-adaptive DOC technology automatically adjusts the DOC engagement threshold as drilling conditions change, eliminating manual parameter adjustment required at surface to manage torsional dysfunctions.

This paper will cover self-adaptive bit runs from deepwater Gulf of Mexico wells. In a recent run, a 12¼-in. bit drilled past 30,000ft measured depth (MD) in an abrasive and interbedded section. The self-adaptive bit delivered a 48-percent improvement in ROP over the best offset, saving 23 drilling hours while exhibiting 97-percent smooth drilling concerning stick-slip and 100-percent smooth drilling to axial and lateral vibrations. Another application yielded excellent results in a section featuring bottom-hole coring work. In three separate runs, the self-adaptive bit drilled a sand/shale formation with 98-percent smooth drilling concerning lateral vibrations, axial vibrations, and whirl. It also exhibited 97-percent smooth drilling concerning stick-slip. The self-adjusting technology helped to return to drilling despite the coring disrupting the bottom-hole pattern.

Real-time drilling dynamics data measured downhole is used for demonstrating the effectiveness of self-adaptive DOC control technology for sustained drilling performance improvement in deepwater wells.