bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bit-Rock Interaction for PDC Drill Bits: A Review and an Open-Source Library
Authors: Ghaly E. , Shor R. J. 
Published: February 2025

Abstract
The polycrystalline diamond compact (PDC) bit is the most used bit type in deep drilling with a global market worth over $3.13 billion USD in 2023. Numerous models, ranging in complexity from a simple linear equation to fully coupled computational fluid dynamics discrete element method models, have been proposed in literature, yet no open-source implementation exists that includes a choice of fidelity and complexity. In this paper, we review the existing bit-rock interaction models, summarizing assumptions, construction methodology, validation data, prediction capabilities, and performance. A Python library of bit-rock models is also detailed and published via the Open-Source Drilling Community. An extensive literature review of published models starting from 1985 through today is conducted. Models ranging from single cutter models to full bit models are considered. High fidelity coupled finite element models constructed for specific geologic environments are included with the benefits and limitations of using this approach are discussed. The focus of the study is generalized physics-based models which can be coupled with a drillstring model to provide general performance guidelines. Model formulations, assumptions, limitations, and available validation are systematically presented to establish a clear understanding of the study's framework. The selected models, implemented in Python, are compared with downhole data across several scenarios. A workflow is then proposed to couple open source drillstring models with bit models, emphasizing the critical aspect of timestep synchronization. The bit models primarily describe the forces between the bit face and rock, considering the underlying physics of the drilling process. Additionally, current gaps in knowledge are highlighted to encourage future research and development in this domain.
An Innovative Water-Based Reservoir Drill-In Fluid Solution Customized to Withstand the Extreme Thermal Boundaries of the Perth Basin While Minimizing Formation Damage
Authors: Freschi Yasmin Lee , Rincon Chavez Andres Camilo , McCartney Richard Murray , Wenk Andrew , Manzoleloua Cedric , Li David , Vickers Damian Richard , Motta Marcelo Dourado , Derkach Edward 
Published: February 2025

Abstract
Selecting and designing a reservoir drill-in fluid (RDF) for wells with openhole standalone or gravel pack as lower completion strategies can be complex, especially for high-temperature reservoirs. In addition to minimizing formation damage and maximizing well performance, the RDF must meet drilling and logging requirements, including stability for several days at elevated bottomhole temperatures. For reservoir temperatures exceeding 149°C, most operators prefer nonaqueous RDF systems because, when properly designed and maintained, they meet drilling and logging requirements and are less damaging than conventional synthetic polymer-based aqueous systems. However, with a growing emphasis on minimizing environmental impact, a technically competent aqueous-based system is preferred wherever practicable.
Contrary to most operators, Beach Energy committed to achieving the Perth Basin drilling campaign objectives by challenging the status quo. The challenges involved drilling Perth Basin gas reservoirs, where formation temperatures reach as high as 200°C, using a high-temperature water-based reservoir drill-in fluid (HT WB RDF) system, and completing the wells with an openhole standalone and premium mesh screen as the lower completion strategy.
In response to these challenges, an HT WB RDF system using a novel synthetic polymer was customized with optimal chemical concentrations and sized calcium carbonates to bridge reservoir pores while building a high-quality acid-soluble filter cake. This approach minimized formation damage while drilling and achieved up to six days of static stability at bottomhole conditions. Furthermore, a low-corrosive breaker was formulated to dissolve and disperse the filter cake after running the lower completion string to the bottom and setting the packer.
The process of selecting and qualifying an environmentally friendly RDF to satisfy both thermal stability and formation damage requirements, as well as its performance during and following field deployment, is examined in detail.
Distilling Time Lapse Borehole Images (4D Callipers) Into Geomechanics Solutions
Authors: Market J. , Øy L. , Lauritzen M. , Barrouillet B. , Bye I. , Chemali R. 
Published: February 2025

Abstract
Time lapse borehole images provide a wealth of geomechanics information, visualizing structures, lithology, and borehole shape minutes, hours, and days after drilling. To make this wealth of 4D data practicably usable in a mechanical earth model, a method is presented to distill the rich dataset into concise geomechanical parameters.
LWD borehole images are acquired using ultrasonic imagers (which work well in water-based muds and smaller diameter holes) as well as with recently introduced radar-based tools (which work well in oil base muds and large diameter holes). The data can be acquired in multiple passes or in multiple sensors along the drill string to characterize the borehole changes under drilling and production stresses. Time lapse videos are used to present such data varying with time. However, data in a video format is not always easily digestible to the geomechanics team. By distilling the images into hole shape vs depth, the information can be integrated into the mechanical earth model.
Several examples are presented showing hole shape vs time as well as ultrasonic/electrical images vs time to show structure. Snapshots from the 4D videos are shown alongside hole shape and ultrasonic/electrical image logs vs time plots. These illustrate not only the stress changes with time/drilling activities but also the growth of natural and induced fractures during the drilling process.
This method is novel in that it captures time lapse borehole shape information at several measure points along the drill string as well as at multiple passes during the drilling activities. It presents the data not only as 4D movies but also in digestible hole shape and stress direction logs.
Increasing Driller's Situational Awareness Through Haptic Feedback
Authors: Pavlov A. , Visser J. , Maas W. , Hashemi A. , Ødegård O. , Steur E. , Imsland L. 
Published: February 2025

Abstract
This paper presents a concept of a system for increasing the driller’s situational awareness. The system is based on haptic feedback provided by joysticks in the driller’s chair. In this system, the conventional joysticks in the driller’s chair are replaced with actuated joysticks that give the driller the feeling of force and vibrations. Coupled with sensors, digital twins, automation systems, and/or advanced analytics tools like Machine Learning or Artificial Intelligence, they allow the driller to feel various conditions topside and down the wellbore and interact with automation systems through hands and joysticks. This approach addresses the bottleneck of the driller’s visual perception of large data streams from the screens; it addresses the problem of drillers' trust in automation systems, and it allows for low-cost integration of automation systems. In addition to the concept of the system, the paper presents the system’s prototype, its testing, and several use cases of its applications.
Dynamic Simulation of the Bullheading Process in Pressurized Mud Cap Drilling: Considering Gas Dissolution
Authors: Liu Yaxin , Zhou Lei , Upchurch Eric. R. , Anfinsen Bjoern-Tore 
Published: February 2025

Abstract
A comprehensive analysis of the bullheading process in Pressurized Mud Cap Drilling (PMCD) operations under various drilling parameters and flow conditions is presented in this study, with a specific focus on the role of gas dissolution in oil-based mud (OBM) - a topic not thoroughly explored in existing literature.
Using a commercial multiphase flow simulator, the interactions between formation fluids (specifically gas or oil kicks) and different types of drilling muds, such as water-based mud (WBM) and OBM, during PMCD operations are investigated. Well-scale experiments for gas bullheading were replicated for validation. The sensitivity analysis covers variables like kick composition (gas or oil), kick size, gas kick solubility, gas kick contamination, drilling fluid base oil composition, drilling fluid oil/water ratio and wellbore inclination. The effects of these parameters on the dynamics of wellbore pressure, fluid behavior, and bullheading efficiency through a series of simulations tailored to mimic real-world PMCD scenarios are assessed.
Compared to WBM, gas dissolution in OBM leads to a reduction of surface pressure during the shut-in period of PMCD. The volume of free gas becomes considerably reduced, which requires a lower bullheading rate and therefore reduces fluid usage. Our findings also indicate that larger kick sizes result in notable surface pressure increases, consequently leading to observable migration of the residual gas after the bullheading process. Wellbore pressure dynamics for gas kicks contaminated with 10% of carbon dioxide (CO2) and hydrogen sulfide (H2S) are only slightly different from that of pure dry gas. Changes in drilling fluid base oil composition and oil/water ratios can impact their ability to dissolve gases, which in turn influence the overall gas removal efficiency. Moreover, wellbore inclination influences fluid stratification and movement, with higher inclinations (i.e., greater departures from vertical) challenging effective gas removal due to gravitational impacts on fluid layers, causing uneven gas distribution and trapping within the wellbore. Oil influx is miscible with OBM and is less likely to migrate along the wellbore. This miscibility enables a more homogeneous fluid mixture, contributing to more efficient bullheading. This study also addresses how adjustments to choke openings during bullheading process can optimize the management of unexpected influxes, thus safeguarding the PMCD operation.
New insights into the role of gas solubility in OBM within PMCD operations are provided, a significant knowledge gap in existing literature. The comprehensive analysis of how various drilling parameters and flow conditions influence wellbore pressure and bullheading efficiency offers actionable strategies that can enhance safety and operational efficiency for drilling engineers in the field.
Longer, Smoother Laterals Enabled by Novel Traction Drill Collar
Authors: Ancketill M. , Profit J. , Clegg J. 
Published: February 2025

Abstract
A downhole traction drill collar (TDC) is presented that demonstrates an improvement in weight on bit (WOB) transfer in long, high inclination lateral sections and an associated reduction in overall drilling dysfunction. The resulting improvements in drilling mechanics and nascent potential to improve rotary steerable system (RSS) tool life, as evidenced from downhole sensor data, highlights a potential step change in drilling performance at a time when both longer and lower cost laterals sections become more valuable to operators.
A TDC tool uses sets of orientated rollers to convert collar weight into axial traction to improve weight transfer to the bit. The solution selected comprises a single tool, with a specific requirement that it does not create any new vibration downhole or have any pressure drop that would result in an increase in standpipe pressure. The improved weight transfer reduces lateral vibration of the bottom hole assembly (BHA), mitigates pipe buckling, reduces stick/slip and polycrystalline diamond compact (PDC) cutter damage, provides a more consistent depth of cut and therefore more consistent torque.
A prototype TDC tool was designed and run on a test bed which proved that rotation through the orientated rollers would provide significant axial traction, improving WOB transfer.
To ensure that the rollers would remain captive and present no risk of junk, the TDC tool was made in two pieces with a proprietary service connection. An early iteration of the connection design was fatigue tested, and although the connection did not fail, the fatigue testing revealed a minor area that showed signs of stress. As a result, the connection was subjected to rigorous analysis to ensure both strength and adequate resistance to fatigue during multiple bending cycles. Design changes were proposed, and repeat fatigue testing was successful with no failure, or incipient failure, observed during the testing.
Initial field testing was conducted which showed significant improvements in WOB transfer and borehole quality resulting from use of the TDC tool. These improvements, combined with the rigorous analysis and fatigue testing described above, provided confidence to begin a campaign of field testing. The results of these field tests will be described in detail.
This paper will describe how a simple BHA tool with no significant energy requirements of its own can convert the natural force of gravity into useful axial force which can help to improve weight transfer while drilling. At the same time, undesirable drilling dysfunctions including lateral vibration and stick/slip are mitigated. This combination of factors will allow drilling of significantly longer lateral sections at reduced cost.
Successful Casing Size Recovery: Milling Expandable Liner Hanger to Overcome Gulf of Mexico Well Challenges
Authors: Soltero A. , Klein A. , Hanks C. 
Published: February 2025

Abstract
This paper presents a case study detailing the successful recovery of a casing size in a deepwater Gulf of Mexico (GOM) subsalt development well. By milling an expandable liner hanger and recovering part of an 11-7/8 in. liner, the team enabled a whipstock sidetrack below an unstable salt inclusion and the installation of a 9-7/8 in. production liner across the reservoir target. The solution was achieved through a carefully coordinated milling and recovery operation prioritizing safety, well integrity, and compliance with regulations. Collaboration with service providers, industry experts, and partners validated the feasibility of this innovative approach, with proven tools and operational parameters tailored to the wellbore's unique requirements. The operation preserved the well's production goals, maintained well integrity, and mitigated further operational setbacks, while averting significant costs and risks associated with an alternative plan requiring a 7-3/4 in. liner. The milling operation itself was completed in 11 hours, far faster than anticipated. This paper provides unique insights into milling an expandable liner hanger and conducting casing recoveries in complex deepwater environments, serving as a valuable reference for teams addressing similar challenges in adverse wellbore conditions.
Reducing and Optimizing Well Cost and Time by Implementing a Technical Collaborative Partnership in Roncador, an Ultra Deepwater Brownfield in Brazil
Authors: Jesus Y. , Goncalves B. P. , Castro V. Y. , Vanzan V. , Pioli R. M. , Figueiredo De Oliveira G. L. , Moura E. , Da Silva Costa R. 
Published: February 2025

Roncador is an ultra-deepwater field, ranging from 1400 to 1900 m water depth, located at Northern area of the Brazilian Campos Basin, about 125 km from the coast (Figure 1). The field was discovered by Petrobras in 1996 and first oil was in 2002. Over 22 years more than 150 wells have been completed and in 22 years with peak production of 400 kboe/day in 2009 and 2015. Accumulated production is more than 1.7 Bboe. The field is currently producing from four production units (Figure 2) and started to face production decline.
In 2017 Equinor and Petrobras formed a strategic partnership were Equinor acquired a 25% stake. Petrobras got 75% stake. The STAA - Strategical Technical Alliance Agreement project aims to maximize value creation and the longevity of the Roncador field utilizing the best of technology, competence, and experience from Petrobras and Equinor in a collaboration.
As part of the STAA, both operators have been working side-by-side to improve efficiency and reduce well cost. Working with simplification, standardization and focusing on operational efficiency it was possible to reduce the construction duration by more than 50% and the well construction cost by more than 60%.
Experiences from More Than 30 Years of Safe Drill Cuttings and Waste Injection at the Valhall Field
Authors: Kristiansen T. G. , Flatebø R. E. 
Published: February 2025

Abstract
Re-injection of drill cuttings and wastewater have been performed at the Valhall field in the southernmost part of the Norwegian Continental Shelf (NCS) for over 30 years. This is a quite unique documentation of such a long successful re-injection project in the industry. The injection of more than 16 million barrels water and cuttings have been performed safely and environmentally friendly to date. The only unscheduled event has been a water kick in an offset well when the procedures for injection was not adhered to. The injection started following an opportunistic strategy where dead wells waiting to be sidetracked were used for injection. Most injection has been performed in Tertiary shales in the overburden, but also horizontal wells in the chalk reservoirs have been used. The perforations have been placed mainly in Tertiary shales to reduce risk of screen-out. Leak-off taking place in shallower more permeable formations over time. The cost per barrel has varied through time. It was very low when following an opportunistic strategy using dead wells waiting for sidetracks. Later in the project life the need to control the injection locations more stringently, to avoid significant anti-collision work, resulted in the use of dedicated injection wells. The cost went then up towards 5 USD/barrel. To remain competitive with the current costs of offshore treatment, a dedicated re-injection well must accommodate waste volumes from approximately 30 wells. In comparison, for cost-effectiveness against onshore treatment, it would need to handle waste volumes from around 20 wells. A low-cost, environmental and HSE friendly alternative with no disposal to landfills, or the sea, may be dedicated injection wells as used at Valhall that can take the drilling waste for re-injection in a larger area around the field. This volume may then also include waste volumes from other licenses, CCS wells and exploration drilling. The paper covers the main observations from this over 30-year long period and discuss the basis of design, the waste domain concept, the monitoring techniques and procedures developed to follow up expected and non-expected injection behavior.
Successful Utilization of a Floatation Collar Tool to Reduce Drag Force and Enhance Running Completions in Unconventional Long Lateral Wells
Authors: Almomen Hassan , Alkhaldi Yara , Alkwiter Abdullah 
Published: February 2025

Abstract
Unconventional wells with long laterals have great potential to further extend their lateral length to maximize reservoir contact. Torque and drag simulation and operational observations showed that current design suffers extreme drag, resulting in buckling-risk and insufficient hook load to run a completion to target depth. This paper highlights the achievement of running completions in the longest lateral wells (12,000 ft lateral) using a floatation collar for unconventional drilling.
Buoyancy technology, specifically the floatation collar tool, was deployed within a 45-90° inclination. This device traps air between the floatation sub and the shoe, reducing the frictional forces acting on the casing through buoyancy effects. The floatation collar has a calibrated glass barrier, which is ruptured with surface applied pressure once the casing reaches the target depth, allowing suitable well circulation prior to the cementing operation. The floatation collar placement is optimized for maximizing the hook load available while crossing the curve section that has the highest dogleg severity.
Using the floatation collar tool with the original completions and casing design across 12,000 ft of lateral length was successfully achieved. This is the longest horizontal drilled section for partial cementing of long string applications to date. Furthermore, multiple positive attributes were observed, including smooth deployment of the drill string over a curve section of a 7 deg/100 ft dogleg while the string reaches the bottom without lockup. In addition, the compressive forces improved by approximately 88 Klbf in comparison to simulated actual value with a mud weight of 12.83 ppg when the floatation collar (rated with 8000 psi) was placed within the mentioned inclination. These results were all accomplished while still maintaining the original casing design, and allowed for the possibility of more extended reach laterals. This method significantly improves the probability of reaching the target depth in challenging wells, while maintaining the original completion and casing design.
This paper illustrates the benefits of utilizing a floatation collar to overcome the challenges of reaching the target long-lateral wells when running completions, by minimizing the risk of buckling and reducing the drag forces on the casing. Hence, the running time and cost of the well are reduced significantly.
Breaking the Casing-Cement Bond and Cement Structure to Aid Casing Recovery
Authors: Speagell Malcolm 
Published: February 2025

Abstract
One of the main issues surrounding any casing recovery operation is the integrity of the cement and cement-bond behind or between casing strings. To successfully retrieve casing to surface the integrity of this bond must be either removed entirely or reduced to a level where the casing pulling equipment has enough available force to be able to either pull the casing free or move the free point of the casing to a depth where additional cuts can be made that will allow the retrieval of the casing.
A new approach to breaking the casing-cement bond is to apply alternating compression and tension forces to the inner casing wall to deflect the metal of the casing from the inside, manipulating the structure of the metal within its elastic deformation limit to break the cement-bond on its outside without deforming the casing shape.