bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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.
Effect of Solid Particle Concentration on Drilling Fluid Rheological Behavior and its Impact on Pressure Losses
Authors: Cayeux Eric , Leulseged Amare 
Published: February 2019

Abstract
Solid particles in suspension in a fluid, like barite, lost circulation material (LCM), cuttings or cavings, influence the pressure losses that are experienced when pumping or moving a drill-string in a borehole. As the volume fractions of those different solid particles varies along the hydraulic circuit, it is desirable to estimate the impact of local solid concentrations on pressure drops.
The influence of solid particles on the rheological behavior of fluid has mostly been studied for Newtonian fluids, but very little experimental work has been published for non-Newtonian fluids like drilling muds. For that reason, a series of measurements, made with a scientific rheometer has been conducted on a typical KCl/Polymer water-based mud. The experimental investigation covers the effect of particle concentration on the rheological behavior of the mix, in conjunction with the particle size.
The change of rheological behavior is slow at low solid concentrations but increases exponentially with larger proportions of solid in suspension. Furthermore, the increase of effective viscosity is larger with fine particles than with coarser ones. Empirical formulas are proposed to describe how the original Herschel-Bulkley rheological behavior of a base fluid can be modified to incorporate the effects of the variation of solid concentrations in the fluid mix.
All these results are based on measurements made with a scientific rheometer. As computerized and high precision rheometers are usually not available at the rig site, we describe a methodology to utilize standard model 35 rheometer measurements to estimate the pressure loss gradient as a function of the volumetric solid content.
Modeling the Effect of Axial Oscillation Tools in Torque and Drag Computations
Authors: Mahjoub Mohamed , Dao Ngoc-Ha , Menand Stéphane 
Published: February 2019

Abstract
When drilling complex wells, such as those with long lateral sections, the friction forces become significantly high, which can impede advancement of the drill string and reduce drilling performance. In these situations, Axial Oscillation Tools (AOT) could be used to introduce an axial vibration to the drill string. By locally reducing the friction forces, better transmission of weight to the drill bit is possible and an increase in the rate of penetration occurs. However, to optimize the use of these tools, predictive modeling is necessary to assess their effect on drilling characteristics.
A new modeling approach is proposed to accurately model the effect of the AOT on drilling operations without the need to carry out resource-intensive and time-consuming dynamic computations. To estimate the influence length (i.e. the extent of the axial vibrations) and the maximum displacement at the AOT, a study was performed to determine the most important parameters. Based on this study and on the theory of wave propagation, new analytic expressions are proposed. Once the influence length and the maximum displacement are calculated, an effective friction coefficient is estimated as the mean value of the instantaneous friction coefficient and used in a stiff-string torque and drag model.
The model was applied to a real case study, and an agreement between the modeling results and field measurements regarding the influence of the AOT was obtained. Moreover, the effect of the excitation force and rate of penetration on the drill string tension profile was investigated. This work should enable drilling engineers to better optimize the position of AOT along the drill string and to maximize its efficiency.
Modelling the 3D Bit-Rock Interaction Helps Designing Better PDC Bits
Authors: Pelfrene Gilles , Stab Olivier , Tilleman Danny , Gallifet Thomas , Cuillier Bruno , Carlos Julien 
Published: February 2019

Abstract
The bit-rock interaction has long been studied to assess PDC drill bit performance, which is driven both by cutting and non-cutting parts of the drill bit. While the cutter-rock interaction has been studied by many authors in the literature, only a few studies have focused on the interaction between the rock and non-cutting parts of the drill bit.
In this paper, we introduce a new method designed to model the interaction between the whole drill bit and the rock formation within a full three-dimensional framework. This approach is based on a generic computational geometry algorithm which simulates the drilling process considering both the drill bit and the hole being drilled as a set of 3D meshed surfaces. The volume of rock removed by the PDC cutters as well as the area and the volume of contact between the rock and the non-cutting parts of the drill bit can be computed with a high accuracy based on the 3D CAD model of the drill bit.
The in-house drill bit simulator implementing this algorithm primarily allows the engineer to estimate how bit-rock interactions distribute between cutting and non-cutting parts of the drill bit and to balance the bit design in the 3D space accordingly over a given range of drilling parameters. This approach has been brought to the field in order to address cutter breakage based on rubbing contacts optimization. Field results associated to some case studies in US shale plays and Canada are described and clearly show that contact points predictions closely match field observations. Moreover, design modifications applied following this process have led to an overall increase in bit performance and bit durability while preventing core-out issues.
The bit design methodology presented in this paper is dedicated to design drill bits whose interaction with the rock formation is predicted with a higher accuracy by accounting for the exact 3D shape of the drill bit.
Building a Rig State Classifier Using Supervised Machine Learning to Support Invisible Lost Time Analysis
Authors: Coley Christopher 
Published: February 2019

Abstract
This paper covers the development of a key component of an internal system to report invisible lost time (ILT) metrics across drilling operations. Specifically this paper covers the development of a generalizable rig state engine based on the application of supervised machine learning. The same steps used in the creation of the production rig state engine are appled here to a smaller data set to demonstrate both the tractability of the problem and the methods used to create the rig state engine in the production system.
The project objective was to provide efficiency and engineering metrics in a central repository covering operated regions. The system is designed to require minimal user configuration and management and provides both historic and near real time analysis to deliver a rich resource for offset comparison and benchmarking.
Identifying rig-state is at the heart of every performance and engineering analysis system. This can be thought of as a machine learning classification problem. A large supervised learning set was constructed and used to train classification models which were compared for accuracy. A key success metric was the ability to generalise the selected model across different operations. Output from the rig-state classifier was then used to derive KPI data which was presented through a web based front end. A pilot system was then developed using agile principles allowing for rapid user engagement. Testing demonstrated that the system can support all real time operations within the company simultaneously and rapidly process historic well data for offset benchmarking. The cloud-based architecture allows rapid deployment of the system to new groups significantly reducing deployment costs. The system provides a foundation for onward data science and more advanced functionality.
Minimal configuration, cloud storage and processing, combining contextual data with real-time rig data, near-real-time and historic analysis capabilities, rapid deployment, low cost, high accuracy and consistent metrics are all key and proven value drivers for the system. The output data is aso a valuable resource for additional machine learning and data science projects.
An Integrated Geomechanical Approach to Accurately Predicting the Fracture Gradient for Mitigating Drilling Losses of Challenging Wellbores
Authors: Fang Zhi , Zamikhan Norshah , Tarang Ravie-Tajit , On Chee Khong , Huver Pieter Hendricus 
Published: February 2019

Abstract
Fracture gradient (FG) of wellbores is the function of not only stresses, formation pressure and rock mechanical properties but also well trajectories. An accurate FG prediction is critical for safe well drilling. However, the existing methods do not account for the trajectory effects. An integrated geomechanical approach has been developed to more accurately predict the FG of wellbores subject to various trajectories. The approach deploys the Kirsch equations and takes into account the effects of formation pressure variations on stresses. It further integrates the elaborated individual procedures for deriving the geomechanical input parameters from regional field data to form a FG model. After verifying the losses test and offset well drilling data with necessary modifications, the calibrated FG model is then able to more accurately predict the fracture initiation pressure (FIP) of wellbores to mitigate the drilling losses for not only vertical but also deviated wellbores by guiding the equivalent circulation density (ECD) management.
The integrated geomechanical approach has been applied to the planning and drilling of more than 30 new wells at Brunei Shell Petroleum (BSP). It has significantly mitigated the drilling losses for the challenging wells of a field redevelopment project in which about 50 deviated wells were expecting narrow drilling windows due to penetrating heavily depleted reservoirs. In another drilling campaign, it saved the sidetrack of a lost hole section by revising the trajectory as instructed by the FIP predictions. The integrated geomechanical approach is an algorithm that can effectively mitigate drilling losses by accurately predicting the FG for any arbitrary wellbores.
Well Control Incident in the North Sea as Interpreted with Advanced Gas Influx Modelling
Authors: Skogestad Jan Ole , Bjørkevoll Knut S. , Frøyen Johnny , Linga Harald , Lenning Eivind , Håvardstein Stein T. 
Published: February 2019

Abstract

Objectives/Scope
Handling well control incidents during drilling operations safely and efficiently is of crucial importance, due to the potential danger to crew, rig and environment, as well as the economic aspects. In this paper, we study an actual incident from a North Sea drilling operation, using recent advances in gas influx modelling, which allows for improved understanding of the underlying physical processes, hence enabling more accurate well control simulations.

Methods, Procedures, Process
Data has been gathered from a drilling operation where a well control incident occurred, and put into a hydraulic drilling model. This model is enhanced with compositional modelling of PVT properties of the gas/fluid system, allowing for better description of the gas absorption capability of the drilling fluid. Furthermore, effects of non-instantaneous gas loading are handled by a novel kinetic model. Multiple simulations with varying model parameters are run in order to understand how different physical processes can explain the behavior observed in the dataset.

Results, Observations, Conclusions
Simulations of the case have been compared to the operational data, showing how the different modeling parameters of gas influx impact the simulation prediction performance. A key to safe handling of well control incidents is early detection, but relying only on recordings for topside process conditions limits accuracy and reliability as compared to using the topside data in combination with real-time downhole data and/or advanced mathematical interpretation software. The results show how, by using a combination of downhole modelling and observations, it is possible to obtain a more complete picture of the well conditions throughout the operation. The results also give an indication on early signs that may allow for faster reaction and more confident handling of a gas influx.

Novel/Additive Information
This case-study of a gas influx scenario with sophisticated gas absorption modelling is the first of its kind, providing useful insights relevant for well control handling and illustrating the benefit of digitalization of drilling operations. By implementing the technology for real-time surveillance, safer and more efficient handling of well control incidents is allowed for, thus reducing the risk of dangerous situations on the rig.
Design and Comparison of Two Drill String Solutions that Break Barriers in Extended Reach Drilling
Authors: Awad Ahmed , Carrois Fabien , Lafuente Marta , Matveyev Andrey 
Published: February 2019

Abstract
To date, extended reach drilling (ERD) wells drilled on one of the main UAE offshore reservoirs have been delivered by using a tapered drill string design that combines two sizes of drill pipe. To reduce the number of days per well, a one-size only drill string concept has been considered, but such an option required some improvements in torque and geometry to meet specific well design requirements.
An initial analysis of the drilling requirements in terms of torque, dimensions, tensile capacity, and hydraulics showed that the process limiter was the drill pipe connection as no option was available in the market that could meet the redesigned requirements. Two new technical solutions were separately developed that took into account the need for a reduced tool joint outer diameter (OD) for equivalent circulating density (ECD) and fishability in an 8½-in. hole. Once developed, the solutions were then validated for manufacturing and field trials.
The first solution consisted of designing and developing an ultra-high torque thread profile, while the second solution suggested to upgrade the tool joint material grade of a new 4th generation double shouldered connection. Both newly designed drill pipe strings successfully passed the shop stress tests and were mobilized for operations. The drill pipes were used for drilling within the tight hydraulic window of such ERD wells, further validating the original drilling simulation parameters. The successful trial of these two single size string solutions enabled the saving of more than five days of rig operating time per well.
This paper presents a detailed comparative evaluation of two innovative drill pipe design solutions that enable operators to run a single size string in challenging ERD wells. It also provides an insight into the operational benefits obtained by shifting to the new single size string.
Micro-Sonde Well Logging System; a Novel Method for Along-Well Measurements
Authors: Saelevik Gunnstein , Skadsem Hans Joakim , Kragset Steinar , Gardner Dave , Randeberg Erlend , Hjelstuen Magnus 
Published: February 2019

Abstract
The micro-sonde well logging system is a concept for obtaining along-well measurements of temperature, changes in fluid velocity and pressure while drilling. The micro-sondes are encapsulated, self-contained measurement devices designed to follow the flow from the bottom hole assembly to surface. Once retrieved at surface, the measurements can provide information about well conditions such as the presence of cuttings beds, washed out zones and gain/loss zones. Post-processing of the data requires knowledge of the forces acting on the micro-sonde and the resulting trajectories from the release point at the bottom hole assembly and to surface. The main objectives of the studies presented in this work are to understand the micro-sonde motion in the mud flow and to design and construct a demonstration device.
We have performed a literature study, CFD-modelling and experiments to better understand the behavior of a micro-sonde in a typical annular flow domain. The trajectory of a single micro-sonde has been investigated as it passes tool-joints under the influence of inner string rotation. Further, the experiments investigated the likelihood of transporting the micro-sonde intact to surface for a drilling application. For the experimental studies, two annular flow loops, one vertical without rotation of the drill-string and one horizontal with a rotating drill-string, including tool-joints and a model bottom hole assembly have been constructed and utilized.