bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Introduction of Drilling Data Space
Authors: Merciu Ioan-Alexandru , Kjørholt Halvor 
Published: March 2021

Abstract
Traditional well planning and drilling risk management requires revisiting past experiences for a given drilling volume and it is expected that new well project evaluation requires multidisciplinary teams and plurality of data usage and access. To date, there is little integration of drilling data and mud logs into decisional data space used for well planning. Integration of drilling data and mud logs into models used for well planning allows for the data to be analyzed and used for evaluation in order to answer questions such as: will we encounter stringers? What is the expected ROP during the project? How can I de- risk the project in planning phase?
We have developed a methodology to allow well planning and associated subsurface models to be created in geo-referenced drilling data space. At the heart, the method requires to build the static subsurface model using historical well trajectory, drilling data and mud log data. From this point of view the subsurface mathematical data space becomes pure drilling space where first the drilling data will populate the virtual space coordinates, allowing all otherwise standard 3D interpolation and intersect techniques to be used. Our approach provides flexibility and completeness for the data distribution as all the wells have past recorded drilling data while other sources of data may be very sparse such in the case of petrophysical or seismic data.
We have tested this approach on data from one field and the methodology is robust for using historical data to populate the model and plan new wells. Using driller definitions, we have built an expedite method to detect stringers and match the new observations with sub-seismic events and petrophysical evaluations. The potential application of this method beyond what we have tested is the possibility for scale up and perform rapid comparative exercise with other information and data sets. Sources of uncertainty and possible propagation of such through drilling data space is briefly introduced.
Having a historical database of drilling data in geo-referenced space gives confidence to well planning, helps the drilling team to get updated drilling information and perform risk management prior to drilling.
Novel Surfactant for Spacer-Less Cementing Compatible with Non Aqueous Fluids
Authors: Wee Joseph K. , Gomes Paulo , Huang ShanShan , Therond Emmanuel , Dieker Ansgar Heinrich, , Daulton Daniel J. , Doan Angela , Kellum Matthew Grady , Perez Cresencio 
Published: March 2021

Abstract
A novel, non-ionic surfactant is presented that alters typical cement incompatibility with non-aqueous fluids, effectively removing synthetic/oil-based mud (SOBM) from the wellbore and changing wettability of casing and formation from oil-wet to water-wet. The change in wettability eliminates the need for cement spacers conventionally deployed between the preceding non-aqueous fluid and the ensuing cement slurry. The entirety of spacer fluid interface can therefore be removed from operation, improving operational safety and efficiency, reduce waste and simplify wellsite logistics. The paper discusses the selection and evaluation of the proprietary surfactant in various laboratory testing. The main characteristics of the surfactant is its non-foaming, non-retarding, compatible with SOBM, ability to change oil-wet surface to water-wet, stable while minimizing environmentally impact. Scaling up, a yard test and a field trial in an offshore rig was successfully performed to evaluate the mixing, compatibility and pumpability using rig equipment.
Real-Time Lookahead Imaging Using the Drill Bit as Seismic Source
Authors: Goertz Alexander Valentin , Thiem Tatiana , Bergfjord Endre Vange , Libak Audun , Atkinson Brian , Bussat Sascha 
Published: March 2021

Abstract
We monitor the seismic signal emitted from a rotating drill bit in real time with an array of seismic sensors at the seafloor. Drill-bit seismic signals provide information to locate the drill-bit position itself and to image geological objects ahead and around the drill bit for geosteering purposes during drilling operations. The data can be obtained in real time without the need to stop drilling for logging and without any additional downhole instrumentation in the bottom hole assembly. Drill-bit positioning accuracy is independent of measured depth and with meter level lateral precision. This is significantly better than conventional downhole gyro-based methods, especially for long horizontal wells. With sources along the drilled well path approaching a target reservoir we obtain a 3D reverse VSP (RVSP) image around the well for prediction ahead of the drill bit. This paper presents a case study from the Grane reservoir in the North Sea, where we utilize a permanent reservoir monitoring (PRM) array for listening to signals emitted from drilling with a PDC bit. We present imaging results from a highly deviated well and compare them to 3D seismic. The field example shows the ability to look ahead several hundreds of meters below the drilled well trajectory.
A Study on the Impact of Rheological Measurement Technique on Pressure Loss Estimation Uncertainty
Authors: Iversen Fionn , Brevik Jan Ove , Taugbøl Knut 
Published: March 2021

Abstract
Drilling fluid rheology measurements provide input to flow frictional pressure loss calculations during drilling operations. This study compares the impact of uncertainty of different rheology measurement methods on pressure loss estimation through a series of flow-loop experiments.
The rheological properties of drilling fluids are measured using a high precision Anton Paar rheometer, in-line pipe rheometer and conventional model 35 lab viscometers. The derived viscosity is used to calculate the frictional pressure loss with uncertainty, comparing with in-situ pressure loss observations from flow-loop experiments. The experiments are performed for steady-state, laminar horizontal pipe flow at atmospheric pressure.
The results illustrate the impact different measurement techniques have on the accuracy of the modelled frictional pressure loss. The potential of the pipe rheometer is investigated with respect to use of measured frictional pressure loss data to predict pressure loss in wells and annulus directly. Finally, the effect of variation in the rheological properties have been illustrated on a simulated case downhole.
This study highlights differences in uncertainty range for conventional viscometers in comparison to a high precision rheometer and the propagation of uncertainty to the frictional pressure loss estimation. Quantification of the uncertainty of the modelled frictional pressure is essential information for application of downhole pressure estimation in managing the drilling process. The existing procedure of using conventional viscometers may not be sufficient when accurate pressure control is needed.
A Novel Approach to Drill Stem Selection for Drilling in Sour Fields
Authors: Plessis Guillaume , Muradov Andrei , Bordet Laurent , Griffin Richard , Hehn Lucien 
Published: March 2021

Abstract
For years the drilling industry has used sour service drill pipe within a narrow set of specifications and industry guidelines. That left room for original equipment manufacturers (OEM) to have customization on an iterative basis, which resulted in a wide product offering to fulfill operator needs. While this method worked, it did not lead to building the product in the most efficient and economical manner.
As a result of this product diversity, drilling engineers could specify the best product to deliver their projects when running drilling models, only to have to redesign it around what is effectively available on rigs or for rental. This disconnect puts pressure on the industry players and is the result of a lack of standardization.
We wiped the board to provide a simple solution that is more suited to allow alignment between operators, contractors, and rental companies. The new philosophy is based on the National Association of Corrosion Engineers (NACE) MR0175-2015 severity diagram, where environmental severity is defined in regions (1, 2, and 3), which have been used by oil companies’ engineers for their oil country tubular goods (OCTG) product selection. Even though the drill string will not be exposed to the well fluid for the same extended time and is surrounded by a more forgiving medium, the drilling fluid, the diagram allows a segmentation of customer's needs.
This framework helped define targeted product properties. A research and development (R&D) and industrialization test campaign could then be started to confirm that sound product configurations could be offered with targeted properties.
The study also explored the limitations imposed on connection make-up torque in a sour gas environment relative to the NACE severity diagram. Emphasis was given on methods to increase the make-up torque, which is needed to deliver the most extended reach wells that are now commonplace.
The result of this two-year development campaign is a short list of grades with an optimized balance between pipe subcomponents strength and sulfide stress cracking (SSC) resistance. Region 1 (mild severity) products will offer as much tension and torque as possible, matching or exceeding these of API products, including excellent resistance to SSC, thus making drilling operation safer. Region 2 (medium severity) will offer products with medium to high strength and enhanced SSC resistance. Finally, region 3 (high severity) products will be aligned with the industry specifications for maximized SSC resistance and lower strength.
This paper discusses a proactive approach that contrasts with a historical, more reactive one. As the drill stem technology leader, we saw an opportunity to drive this initiative that will benefit the drilling industry by offering a more natural way to select drill stem products.
For the first time a sour service product range aligns with the needs of drilling engineers and the inventory of their selected service companies.
Drilling Advisory for Automatic Drilling Control
Authors: Lahlou Kenza , Oedegaard Sven Inge , Svendsen Morten , Weltzin Tore , Bjørkevoll Knut Steinar , Rudshaug Bjørn 
Published: March 2021

Abstract
This paper describes a system being developed for providing an optimized real-time decision support with automatic forward-looking and what-if simulations. It will address the challenge of achieving automation, better performance, and avoidance of non-productive time (NPT) in drilling operations. It will additionally address the demanding human support currently required in the entire decision support workflow.
The approach includes utilization of Model based reasoning in Artificial Intelligence (AI) with a Digital Twin combined with Machine Learning (ML) and advanced 3D visualization which is a key enabler for operation alerts and optimization. Multiple forward-looking and what-if simulations will also be run in real-time to find optimal parameters for flow, rotation and running speed. A Diagnostic module will detect abnormalities and trigger safeguards.
Auto-configuration and auto-calibration will be the key elements for Drilling Advisory system and deployment without the need for back-office support. The personnel involved in the operation (drilling contractor, service provider and operator) will be able to quickly provide the necessary operational input and then the system will be auto-calibrated during the operation.
Results will be an Advisory Tool providing the operation with an optimal flow, rotation speed and running speed during Drilling, Tripping, Casing/liner/screen running and cement operations in two applications areas:
In front of the driller as an Advisory tool for rigs with legacy drilling control systems not capable of receiving automated instructions. Base for providing direct commands and safeguards to rigs with control systems capable of receiving automated commands of optimal flow, rotation speed and running speed.
Automatic Measurement of the Dependence on Pressure and Temperature of the Mass Density of Drilling Fluids
Authors: Cayeux Eric 
Published: March 2021

Abstract
Drilling fluids are subjected to large variations of pressure and temperature while they are circulated in a well. This span of pressures and temperatures is so large that the mass density of the drilling mud differs from one depth to another. For a precise estimation of the hydrostatic and hydrodynamic pressures, it is therefore important to have a good estimation of the pressure and temperature dependence of the mass density of drilling fluids.
Usually, the mass density of drilling fluids is manually measured with a mud balance. The pressure and temperature dependence of the mass density of the fluid, i.e. its PVT behavior, is then estimated based on the PVT behavior of its components and their relative proportions. However, variations in the composition of the fluid mix and uncertainties on the PVT behavior of each components, may lead to inaccuracies. To circumvent these limitations, an apparatus that measures directly and automatically the PVT behavior of the drilling fluid contained in a pit has been designed.
The setup measures both the mass density and the speed of sound in the fluid at specific conditions of pressure and temperature. From the speed of sound in the liquid mix, it is possible to estimate the adiabatic compressibility. The device also utilizes a heat exchanger from which the thermal conductivity and specific heat capacity of the drilling fluid can be estimated. Combining the specific heat capacity, thermal conductivity and the adiabatic compressibility, the isothermal compressibility can be calculated. By combining measurements made at different conditions of pressure and temperature, a PVT model of the drilling fluid is estimated.
By providing automatically, and on a continuous basis, the actual PVT behavior of drilling fluids, drilling automation systems can gain in precision and at the same time, their configuration can be simplified, therefore making them more accessible to any drilling operation.
Well Control 4.0: Integration of a Transient Model in Automated Well Planning Workflows
Authors: Anfinsen Bjoern-Tore , Mosti Inge , Szemat-Vielma Waldemar 
Published: March 2021

Abstract
Low oil prices are forcing the oil and gas industry to reduce the well construction cost. This calls for new and more efficient technologies and methods. Cost optimization may have negative impact on the risk level as less resources are available. Even with a strong focus on risk and new regulatory requirements, the well control risk level is not decreasing, but rather shows an increase.
A new workflow has therefore been introduced in a collaborative cloud-based well planning system that combines the most advanced transient, multiphase engine with an automated procedure based on drillers method.
The workflow will improve the quality of the well control planning as it will enable a simple way of automatic recalculation when the project context is changing. The data flow and quality control of data will also be improved and result in more up to date planning results. The automation of the process removes a huge amount of manual work that up to know has been required to keep the well control calculations synchronized with the project plan.
New engine features unique to well control modeling like transient temperature and full compositional tracking adds resolution and accuracy to the well control planning results and helps deliver consistency in the results.
The new workflow will deliver well control calculations with better resolution and accuracy with much less effort than what is normal today and should therefore help to reduce risk and cost associated with well planning.
Rotating Control Device Sealing Element Customization for Ultra-Deepwater Gulf of Mexico
Authors: Dow Blaine , Pazziuagan Dexter , Vaczi Ken , Chima Chima , Guidry Jason , Kamps Charley , Gallo Fernando , Ham Jeff , Likki Srinivas 
Published: March 2021

Abstract
As the Managed Pressure Drilling (MPD) systems for deepwater drilling rigs mature, operators are applying the technology on more complex prospects. Wells are encountering higher pressures in deeper water depths, pushing against the boundaries of technical limits not previously encountered.
A prospect in the US Gulf of Mexico required drilling to measured depths exceeding 31000 feet in water deepwater. Under such demanding depth, a non-typical drillstring was required to manage the tensile loading. Typical drill pipe connections on 6 5/8" S-135 tool joints are 8.5" diameter. This drill string would require V-150 landing string, with a 6 5/8" FH tool joint diameter of 8.875". Hard banding would bring the tool joint nominal OD above 9".
The depth of the well and planned string RPM presented risk of casing wear, therefore drillpipe protectors would also be required.
The depth of the reservoir and size of the drillstring meant pipe would need to be stripped out of the well with up to 900 psi backpressure in order to maintain constant bottom hole pressure.
All well challenges were used to determine design specifications for a custom sealing element. The scope of work was to design, validate through finite element analysis, then validate in a test fixture per API16RCD test procedures. On conclusion of the product validation, a land test rig trial, with mock-up of the planned system, including dual sealing elements in the Rotating Control Device (RCD), the required non-rotating drill pipe protectors on the planned drillpipe, was executed. The development schedule from start to finish was compressed to less than 6 months also, targeting completion ahead of the rig's drilling program.
This paper will recount the various phases of the design-build-validate-test effort that went into resolving these technical limits. It will conclude with field results and lessons learned from first deployment.
As operators pursue more challenging deepwater wells, this systematic approach, through alignment of the operator, drilling contractor and MPD technology company, serves as a model to expand the operating envelope of drilling systems, improving safe performance in a cost-effective manner.
Real-Time Classification of Drilled Lithology from Drilling Data Using Deep Learning with Online Calibration
Authors: Arnø Mikkel , Godhavn John-Morten , Aamo Ole Morten 
Published: March 2021

Abstract
Decision making to optimize the drilling operation is based on a variety of factors, among them real-time interpretation of drilled lithology. Since logging while drilling (LWD) tools are placed some meters above the bit, mechanical drilling parameters are the earliest indicators, although difficult to interpret accurately. This paper presents a novel deep learning methodology using mechanical drilling parameters for lithology classification. A cascade of multilayered perceptrons (MLPs) are trained on historical data from wells on a field operated by Equinor. Rather than an end-to-end approach, the drilling parameters are utilized to estimate LWD sensor readings in an intermediate step using the first MLPs. This allows continuous updates of the models during operation using delayed LWD data. The second MLP takes the virtual LWD estimates as input to predict currently drilled lithology, similar to manual expert interpretation of logs. This configuration takes into account case dependent (mud, BHA, wellbore geometry) and time varying (bit-wear, wellbore friction) relationships between drilling parameters and LWD readings, while assuming a constant rule when utilizing LWD data to classify lithology. Upon completion of training and validation, the system is tested on a separate, unseen wellbore, for which results are presented. Visualizations for true lithology alongside the estimates are given, along with confusion matrices and model accuracy. The system achieves high accuracy on the test set and presents low confusion between classes, meaning that it distinguishes well between the lithologies present in the wellbore. It can be seen that the borders between successive layers of lithology are detected rapidly, which is crucial seen from an optimization standpoint, so the driller may adjust accordingly immediately. It shows promise as an advisory system, capable of accurately classifying currently drilled lithology by continuously adapting to changing downhole conditions. Although we cannot expect perfect estimates of lithology purely based on drilling parameters, we can obtain a preliminary map of the subsurface this way. This novel configuration gives a real-time interpretation of the currently drilled lithology, allowing the driller to take proper actions to optimize the drilling operation in terms of rate of penetration (ROP) and best practices for different lithologies.
Evaluation of New Innovative Cement Blend for Enhanced CO2 and H2S Resistance
Authors: Lende Gunnar , Clausen Jill Angelique , Kvassnes Astri Jager 
Published: March 2021

Abstract
Achieving zonal isolation is incumbent upon preventing undesirable flow of hydrocarbons, carbon dioxide, and hydrogen sulfide, as well as other fluids. The risks associated with zonal isolation being compromised come from different mechanisms, such as insufficient displacement efficiency, tubular corrosion, cement cracking, micro-annuli from hydration shrinkage or pressure changes as well as erosion. It is therefore important to understand how CO2, H2S and other factors interact with cement under downhole conditions. The cementing materials are important to the short- and long-term integrity of the well and helping to ensure that no unwanted flow paths are formed that can threaten the safety, health and environment, and also the impact on the profitable life of the well. Thus, pathways for CO2 and H2S as well as other fluids should be avoided and blocked if they occur.
Described herein is the evaluation of a novel cement admixture developed for improving the resistance of the cement matrix to chemical attack from CO2 and H2S, and its incorporation in a tailored cement design. The development of this design focused on applications in wells in the Norwegian Waters where CO2 and H2S are present. A comprehensive test program using customized equipment provided the necessary information to evaluate the performance.
Further discussed are methods developed to test and evaluate the performance of this new design as effectively as possible by using available test equipment in new ways and new combinations.
Test results support the novel cement admixture combined with ordinary Portland cement (OPC) in terms of pumpability, curing time, permeability and mechanical properties is technically and financially viable given that necessary blend optimization is done. Hence, the cement blend can be used without changing the existing cement infrastructure, methods, vetting and procedures that exist for well cementing today.
Finally, the outcome of the first field test on an offshore permanent abandonment plug as part of a mature field plug and abandonment campaign is briefly referenced.