bluuebunny/crossref_metadata_2025_split huggingface dataset:
A 300 Degree Celsius Directional Drilling System
Authors: Stefánsson Ari , Duerholt Ralf , Schroder Jon , Macpherson John , Hohl Carsten , Kruspe Thomas , Eriksen Tor-Jan 
Published: February 2018

Abstract
The typical rating for downhole measurement-while-drilling equipment for oil and gas drilling is between 150°C and 175°C. There are currently few available drilling systems rated for operation at temperatures above 200°C. This paper describes the development, testing and field deployment of a drilling system comprised of drill bits, positive displacement motors and drilling fluids capable of drilling at operating temperatures up to 300°C. It also describes the development and testing of a 300°C capable measurement-while-drilling platform.
The development of 300°C technologies for geothermal drilling also extends tool capabilities, longevity and reliability at lower oilfield temperatures. New technologies developed in this project include 300°C drill bits, metal-to-metal motors, and drilling fluid, and an advanced hybrid electronics and downhole cooling system for a measurement-while-drilling platform. The overall approach was to remove elastomers from the drilling system and to provide a robust "drilling-ready" downhole cooling system for electronics. The project included laboratory testing, field testing and full field deployment of the drilling system. The US Department of Energy Geothermal Technologies Office partially funded the project.
The use of a sub-optimal drilling system due to the limited availability of very high temperature technology can result in unnecessarily high overall wellbore construction costs. It can lead to short runs, downhole tool failures and poor drilling rates. The paper presents results from the testing and deployment of the 300°C drilling system. It describes successful laboratory testing of individual bottom-hole-assembly components, and full-scale integration tests on an in-house research rig. The paper also describes the successful deployment of the 300°C drilling system in the exploratory geothermal well IDDP-2 as part of the Iceland Deep Drilling Project. The well reached a measured depth of 4659m, by far the deepest in Iceland. The paper includes drilling performance data and the results of post-run analysis of bits and motors used in this well, which confirm the encouraging results obtained during laboratory tests. The paper also discusses testing and performance of the 300°C rated measurement-while-drilling components – hybrid electronics, power and telemetry - and the performance of the drilling tolerant cooling system.
This is the industry's first 300°C capable drilling system, comprising metal-to-metal motors, drill bits, drilling fluid and accompanying measurement-while-drilling system. These new technologies provide opportunities for drilling oil and gas wells in previously undrillable ultra-high temperature environments.
Real-Time Eye-Tracking System to Evaluate and Enhance Situation Awareness and Process Safety in Drilling Operations
Authors: Kiran Raj , Salehi Saeed , Jeon Jiwon , Kang Ziho 
Published: February 2018

Abstract
Lack of situational awareness in drilling operations has become an important factor in causing safety accidents or cause of non-productive time. Process safety is another critical aspect for such high risk operations and cannot be ignored. A review of testimony from offshore rigs worker suggests long working shifts and fatigue as one of the crucial issues impacting performance.
The study here presents results from experiments conducted in a Virtual Reality Drilling Simulator (VRDS) equipped with eye tracking technology. The eye tracking technology can be used to distinguish between less and more aware/alert participants which is most of the times related to fatigue or onsite distraction. The ocular activity can be used to obtain visual cues that can quantify the state of drilling operator while operating. These cues can help in generating some warning alarms to alert the driller. Therefore, the system can reduce not only accidents but can also save a tremendous amount of non-productive time by improving their efficiency. Since human eyes express the most direct reaction during less alert or distracted mental state, ocular activity data has been used as the basis for quantification of situation awareness by researchers. In recent years, eye tracking system has been developed in the form of static and dynamic devices. The camera installed in these devices capture different characteristics of the participants' ocular movement in real-time. These oculomotor data such as eye fixation count and duration and pupil size, has been implemented in several industries such as aviation and medical to assess the performance of participants in recent years.
In this paper, we use eye tracking techniques for investigation of alertness and awareness of participants while conducting different drilling operations on the simulator. Results obtained from this study indicate that the system can detect the distraction and alertness exhibited by humans. The results show the very promising application of this technology on the drilling rigs. The novelty in this work is the development of framework for implementation of real-time eye tracking technology in various drilling operations such as drilling rigs and Real Time Operation Centers (RTOCs).
The Barlow Equation for Tubular Burst: A Muddled History
Authors: Adams A. J. , Grundy K. C. , Kelly C. M. , Lin B. , Moore P. W. 
Published: February 2018

Abstract
The Barlow equation for tubular internal yield pressure is widely used in American Petroleum Institute (API) and International Organisation for Standardisation (ISO) standards, but its provenance and accuracy have never been established: indeed, until very recently, the original reference had been lost to the industry. This has led to doubt and confusion about its use. This paper presents the work done by ISO TC67 SC5 workgroup 2 to remedy this, and explains the background and technical basis for the upcoming revisions to ISO TR 10400.
It is shown that Barlow's 1836 derivation violates the 3D constitutive law, and the result is therefore incorrect as originally purposed (a thick wall hoop stress). Moreover, hoop stress is a uniaxial (1D) check: the modern approach is 2D or 3D checking, based on a material failure condition such as the Von Mises yield criterion.
However, the result also happens to represent the thin wall approximation to the VME failure pressure for plane stress (i.e., zero axial load), which gives an accurate measure of the yield pressure. Remarkably, this does not seem to have been recognised in previous work. The derivation is given, and the assumptions and limitations explained.
Present design practice is over-conservative for thick wall pipe, and potentially unconservative for thin wall. This is not the fault of the Barlow equation per se: it is caused by the difference in physics between the design equation (VME yield) and the ultimate limit state (ULS) behaviour (ductile rupture).
The industry should therefore consider revising OCTG burst ratings and accompanying design practice to achieve a more uniform safety level over the full D/t range of casing and tubing.
Annular Casing Seal Test Method
Authors: Fleckenstein W. W. , Baker R. , Eustes A. W. 
Published: February 2018

Abstract
A method and apparatus to test the annular seal of a casing string placed in a wellbore is presented. This method and apparatus, called the Annular Casing Seal Test (ACST), successfully measures the annular casing seal in the wellbore using a positive pressure test. Results presented document the experimental studies using prototypes under a variety of cemented casing conditions to determine the ability to detect effective and poorly cemented casing annular seals. When the interior of the tool is drilled out, an array of encapsulated bores is exposed, allowing pressure and flow communication between the interior and the annulus of the casing. Prototypes tested in experimental wellbores confirm the ability of the technology to detect casing annular conditions. A well-cemented casing annulus is easily detected, since the test pressure only encounters the annular cemented across the full circumference of casing. A poorly cemented annulus is similarly detected because pressure escapes the ports into the void in the cemented annulus. An important application of this method allows the annular seal at the surface casing shoe to be inexpensively and quickly tested, providing positive confirmation of the protection of the aquifer. This test is an improvement over the casing shoe test, which is in reality, a measure of formation strength and has demonstrated short comings in detecting poor cement jobs near the casing shoe in a variety of applications. This method is also an improvement over cement bond logs (CBLs), which are more expensive, time consuming, and do not provide a positive test of hydraulic isolation.
Real-Time Quantitative Composition of Formation Fluids While Drilling
Authors: Colombel Emilie , Guerriero Nicolas , Ringer Maurice 
Published: February 2018

Abstract
Mud-gas technologies for continuous PVT-like analysis of reservoir fluids in the drilling mud require a calibration procedure to determine the efficiency of the gas extraction process. This procedure is required because the efficiency of the hydrocarbons extraction process is strongly affected by the drilling mud type and properties, and so it must be performed any time the mud significantly changes.
The calibration procedure requires a sample of drilling mud that contains significant amounts of alkanes. Currently, this sample is collected while drilling during a gas peak and stored until the end of the phase, when the calibration can be performed. Thus, the gas extraction efficiency can only be determined at the end of each drilled section, and the quantitative analysis of the reservoir fluid in the mud is made available only at the end of each section.
This paper presents a new procedure, in which a Calibration Mud sample is built by injecting and emulsifying several alkanes into the mud. The calibration can then be performed at any time before drilling commences.
It is extremely difficult to inject and dissolve gaseous light hydrocarbons into a mud sample at the rigsite. For this reason, we inject a sample of six liquid alkanes into the mud and emulsify it to build a mud sample suitable for the calibration procedure. The extraction efficiencies for the lighter gas alkanes are then extrapolated from those of the injected alkanes using a model of the extraction process.
The new calibration process has been tested in several wells around the world. In each test, the new calibration process and standard calibration (performed at the end of the phase using mud collected while drilling) were performed. Validation of the new technique comes from ensuring the extraction efficiency coefficients using our new calibration mud match those coming from the standard calibration. The results were conclusive with similar coefficients obtained in each test. The uncertainty intervals overlap, and the calibration coefficients are statistically equivalent.
The new calibration procedure represents an innovative methodology enabling real-time, continuous quantification of the light hydrocarbons content (C1-C6) of the reservoir fluid, comparable to the PVT monophasic composition, while drilling, at surface. This is the first time that such data can be delivered in real-time while drilling. The resulting measurements have multiple applications such as enhanced geosteering and well placement, real-time identification of gas-oil contacts, and real-time selection of sampling points and can be integrated with downhole tool measurements to provide a true real-time understanding of the subsurface fluids.
Premature Failures of Rotary-Shouldered Connections RSC Due to Improper Re-Cut and Repair Procedures
Authors: Koneti Srinivasa , Gokhale Samit 
Published: February 2018

Abstract
Premature failures of rotary-shouldered connections (RSC) resulting from improper re-cut and repair operations performed on used connections can cause immense financial loss to oil and gas operators. One of the reasons for improper re-cut and repair procedures is the desire to limit the loss of tool length during thread repair operations. However, this leads to residual damage which can compromise the connection performance and lead to premature connection failures.
To study the issue, finite element analysis (FEA) modeling was utilized to determine the distribution of the stresses in RSCs and to map the stress profile at critical locations which could be affected by improper repair operations. In addition, two case studies where the connections of the components failed prematurely in their first run after the connections were freshly re-cut were investigated. The thread repair protocols and post-threading nondestructive inspections were reviewed. Visual examination and optical metallography were utilized to characterize the failure mechanism along with the location of the failures. The failures were not located at the last engaged threads of the connection, which is not typical. Both case studies indicated that the residual damage left from improper thread recut operations had led to the thread failures at non-standard locations.
The paper presents the case studies, the details of the metallurgical analysis along with the FEA simulation data. The paper lists the various options available for thread repair along with the commercial benefits associated with these repair options in terms of tool length savings. The paper also presents the failure risks associated with the thread repair techniques. Additionally, the paper discusses the correct re-cut and repair procedures for RSCs along with required NDE inspections that need to be performed after the repair of the connection. By applying and following the recommended repair and inspection protocols, premature connection failures resulting from improper thread repair may be eliminated.
Real-Time Well Construction Process Inference through Probabilistic Data Fusion
Authors: Chambon Sylvain , Venkatakrishnan Sai , Hamzah Mohammad Khairi , Belaskie Jim , Yu Yingwei 
Published: February 2018

Abstract
Well construction process automation systems rely on the tracking of the state of the world (equipment, wellbore, process) with a high degree of confidence for safe and efficient operations. Robust state detection algorithms are paramount as they depend on uncertain models and data from imperfect sensors. The proposed solution outlined here is a practical implementation for well construction state inference, focused on bit-rock interaction.
Probabilistic mixture models are learned from input sensor data stream, e.g. surface torque and hook load, accounting for noise and suitable priors. These models are then used for online classification of observations related to the underlying state of operations (e.g. on bottom drilling vs off bottom rotating). Multiple classified observables from different types of measurements are subsequently fused into system states using a Bayesian network, giving a robust state detection under uncertainty. The method required drilling mechanics knowledge in the interpretation of the classification as well as the design of the Bayesian network model.
The algorithm was applied on real sensor data (hook load and surface torque), for the inference of elementary states of bit-rock interaction (no interaction, bit fully engaged with formation, in transition). The use of streaming input data to continuously learn the mixture model allows the tracking of levels. For instance, hook load is modeled as the mixture of several distributions evolving as the well progresses, correlated to the drill string being in slips, out of slips off bottom, or on bottom rotating. Observations inferred from the mixture models have various levels of confidence. The Bayesian network allows their fusion into a robust system state.
The presented Bayesian network backed by mixture model is a fast, adaptive and robust solution to detect system state from drilling time series data with complex temporally correlated patterns. By learning from data and using priors from domain experts, the inference algorithms operate without user tuned thresholds or parameters. The probabilistic Bayesian approach provides a framework for dealing with uncertainty in drilling systems and can be extended in the future with additional observations drawn from new measurements.
Real-Time Downhole Data Resolves Lithology Related Drilling Behavior
Authors: Viens Christopher , Clark Tyler , Lightfoot Jonathan , Mercado Carlos 
Published: February 2018

Abstract
Utilizing azimuthal gamma imaging, continuous inclination, and downhole bending moment measurements to understand thinly layered shale lithology while maintaining the wellbore within the target formation has led to improvements in placement and drilling time reduction. A close examination of this approach in six wells in the Midland Basin demonstrates that utilizing a stabilized bottom-hole assembly (BHA) while drilling horizontally can result in a ‘locked-in’ phenomenon from contrasting hardness of the layers immediately above and below the wellbore. With proper interpretation of real-time downhole measurements, drillers are able to keep the well path in the target zone with minimal slide drilling. The ‘locked-in’ phenomenon was used most effectively in the Wolfcamp A formation where the thin beds are homogenous and laterally continuous. The phenomenon could not be leveraged as effectively in the Wolfcamp B, whose geology is a product of higher energy deposition when compared to the Wolfcamp A.
Offshore Well Intersection and Casing Pull Through to Deliver Pipeline Segment
Authors: Leonard B. A. , Pfeifer D. W. , Katuaga G. , Clark P. J. , Armistead G. T. 
Published: February 2018

Abstract
Due to technical and logistical challenges, an inovative solution was required to connect two offshore platforms in shallow water to allow gas transit as part of a pipeline network. A primary obstacle to conventional pipeline installation at this location was the presence of a large subsea canyon. As a result, the project team decided to utilize jack-up drilling rigs to drill a conduit and then install casing as a pipeline segment.
The project utilized some unusual drilling technologies and unique techniques to deliver the final gas conduit. These included a robust program design for a remote location, large diameter hole opening in horizontal wells, active magnetic ranging to affect wellbore intersection at very low incident angle, and synchronizing two rigs' activities as they latched drill pipe and then pulled casing as a single string. Execution was ultimately successful due to the extensive planning work and diligence of the operations teams, and a number of interesting observations and lessons were captured in the process.
A Cyber-Physical Approach to Early Kick Detection
Authors: Andia P. , Israel R. R. 
Published: February 2018

Abstract
This paper describes a novel approach to early kick detection. A cyber-physical approach is utilized to improve the speed and consistency at which a kick can be identified during drilling operations, thus automating the kick detection process. The proposed methodology combines physics-based modelling with Bayesian mathematics for detecting subtle changes in noisy and uncertain measurements. For early kick detection purposes, the physics model is that of a lumped parameter model that describes the fluid flow in a well and the noisy and uncertain measurements are the data streams from rig sensors available during well construction operations, which are used to fit/correct the results of the model via an extended Kalman filter approach.
A tool was built that is able to consume real-time and archived data, solve the lumped parameter model and Kalman filter implementation, and output the computed results for real-time viewing purposes. Historical datasets were used to demonstrate that the tool is able to detect kicks earlier than conventional methods, while providing an acceptable low false alarm rate. A real-time trial was conducted within a real-time monitoring center to evaluate the performance of the tool as an effective early kick detection technology via a set of key performance indicators and test the developed operational protocols and training materials with monitoring center personnel. The metrics put in place evaluated the tool in three categories: software robustness, data quality and early kick detection technical performance. A test plan was developed with test procedures and a workflow for utilizing the information given by the tool in the context of a real-time monitoring center. No kicks occurred during the construction of the well. However, certain operational events that resemble a kick demonstrated that the tool is able to identify them and trigger an alarm. The overall results of the real-time trial were favorable and potential enhancements to the tool were identified.
Probabilistic Real-Time Trajectory Control Considering Uncertainties of Drilling Parameters and Rock Properties
Authors: Liu Zhengchun , Samuel Robello 
Published: February 2018

Abstract
This work provides a probabilistic approach to proactively adjust drilling parameters (which can be uncertain) in real time to help ensure the actual drilling path overlaps the target drilling path to the maximum extent. The planned well path is initially adjusted by a probabilistic formation earth model (EM) for maximum production potential and then adjusted to help improve well path smoothness to allow the passage of tubular strings. Drilling parameters and EM data can be updated in real time during drilling operations.
Considering the uncertainty associated with petrophysical properties and drilling parameters, the overlap probability between actual and target well paths was computed for current and to-be-drilled locations. All position-related data were described as distributions. The mean value and standard deviation were computed in real time. Overlapping probability (between actual and target well paths) was used as feedback for drilling parameter adjustments.
This closed-loop feedback process enables proactive control of the actual well path. Here, it is illustrated using a horizontal well case study from a typical shale field. Based on log data, formation properties [Young's modulus, porosity (Φ), and total organic carbon (TOC)] are calculated using the real-time EM. At the current drill-bit location, those properties are described statistically as normal distributions rather than single values, as are the drilling parameters, including weight on bit (WOB), rotary speed (RPM), and flow rate (Q).
Statistical methods are applied to quantify the uncertainty of the predicted actual well path. All position-related data are described as distributions. The drilling path simulation indicates that the trajectory resulting from using this new control method provides better reservoir access and maintains dogleg severity (DLS) at an acceptable level.