bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bismuth Plugs Used to Cap All Wells During the Final Phase of the Valhall DP Abandonment Campaign, Offshore Norway
Authors: Thorstensen Egil , Vadset Kjetil , Straume Martin Knut , Delabroy Laurent , Abdelal Gasser , Carragher Paul , Fulks Jeff , Mason David Leslie 
Published: April 2022

Abstract
A premium bismuth-based alloy plug system has been developed to achieve a gas tight seal in annuli that cannot be achieved with traditional cement plugs, providing a new methodology for abandoning wells. To date, 35 plugs in total have been run in 30 wells, with this technique consented to by the offshore Norway regulator for Valhall conditions.
No surface pumping equipment is needed for this type of plug. The alloy – when molten – has a viscosity like water, but a very high density. It can therefore flow through perforations or section milled windows, with gravity, into the annulus or into multiple annuli. When the alloy solidifies, it expands to create an impermeable seal. The entire process, from melting to solidification, takes place in a matter of minutes and the seal is ready to test within a few hours.
The first at scale programme for abandonment applications has been done in the Valhall field offshore Norway. This was following an extensive plug and alloy development and qualification programme over a 4-year period, working in partnership with the local regulator from the outset. The testing programme demonstrated that the bismuth-based material is, in many ways, superior to cement. Following successful development of a system, a single well in Valhall was selected for a trial and tested for 2 years. Following success in the trial well, the operator extended the application to a total of 30 wells.
Three different tool sizes were required for the campaign. Section milling of inner casings of 13-3/8", 18-5/8" and 20" had to be performed. Significantly shorter lengths for section milling were required as the bismuth plug – set inside the window – contributed to the efficacy of the system. All plugs were set by running on pipe. The tools run in these wells resulted in the world's largest bismuth alloy plug ever deployed with the largest tool (20"x30") weighing in at nearly 16,000 kg (34,000 lbs) and over 9,000 kg (20,000 lbs) of alloy. After the tools were melted downhole, the heater was extracted resulting in a solid bismuth alloy barrier across the wellbore.
Extensive work was done to assess corrosion risk. Numerous tests were done according to industry standards and the bismuth-based plug substantially outperformed Inc 718 and 13Cr L80, thus a substantially longer lifetime is projected than had conventional materials been used.
The authors believe that this technique can – when coupled with appropriate engineering work and in partnership with local regulators – be more widely applied, leading to simpler operations, lower costs and better long term well integrity.
Break-Through in Elimination of High-Frequency Torsional Oscillations through New Damping Tool Proven by Field Testing in the US
Authors: Kueck Armin , Hohl Andreas , Schepelmann Cord , Lam Sui-Long , Heinisch Dennis , Herbig Christian , Kulke Vincent , Ostermeyer Georg-Peter , Reckmann Hanno , Peters Volker 
Published: April 2022

Abstract
The push in the drilling industry for drilling longer wells, and faster and more difficult trajectories leads to increasing challenges with the dynamics of the drilling systems in particular in expensive high end offshore wells. Dynamic effects are more severe and occur more frequently increasing load and damage to tools so that mitigation by dedicated tools or drilling procedures is necessary. Generally, downhole drilling dynamics effects can be categorized by their direction of action. Vibration excited in the axial direction, along the tool axis, mainly originates from the bit rock interaction, e.g. bit bounce (Dykstra et. al. 1994). Vibration in the lateral direction, perpendicular to the tool axis, can be generated from interaction with the borehole wall. Here forward and backward whirl motions are possible. In case of backward whirl the origin can be, for example, the whirling bit (Brett et. al. 1990) or a stabilizer. Low clearance results in high whirl frequencies accompanied by high loads (Oueslati et. al. 2014). The earliest identified torsional vibration phenomenon in the drilling industry is stick-slip where the entire string oscillates with a frequency close to its first eigenfrequency. Due to the drill string length this frequency is low, at usually less than 1 Hz. Due to more advanced dynamics measurement tools (Makkar et. al. 2012, Akimov et. al. 2018, Townsend et. al. 2021) that record data at higher sampling rates, another torsional dynamics phenomenon was identified in recent years: high-frequency torsional oscillations (HFTO) (Jain et. al. 2014, Zhang et. al. 2017). The vibration frequency of HFTO could be identified to be in the range between ~50 Hz to above 400 Hz depending on the bottomhole assembly (BHA) and string configuration. The root cause for this type of vibration is a self-excitation mechanism in the bit-rock cutting process in hard rock, when drilling with PDC bits onshore and offshore (Oueslati et. al 2013, Oueslati et. al. 2014). HFTO can result in high dynamic torque and rotational and tangential acceleration amplitudes stressing the drilling tools.
The combination of high frequencies and high amplitudes can quickly result in fatigue damage on tools and components. Examples are displayed in figure 1. The dynamic torque fatigues the material, and 45-degree cracks occur and grow (Zhang et. al. 2017). The acceleration leads to relative movement due to inertia forces which can vibrate cables off circuit boards or generate "vibration dust" where vibrating parts are in contact which each other.
Simulation of Subgouge Sand Deformations Using Robust Machine Learning Algorithms
Authors: Azimi Hamed , Shiri Hodjat , Mahdianpari Masoud 
Published: April 2022

Abstract
Ice gouging is one of the major menaces to the subsea pipelines crossing the Arctic (e.g., Beaufort Sea) or the non-Arctic (e.g., Caspian Sea) shallow waters. Burial of the sea-bottom-founded infrastructures is regarded as a feasible method for protection of the subsea assets against the ice gouging threat. These pipelines are commonly embedded underneath the deepest ice-scoured records in the area, whereas the pipeline system is still threatened by the ice-induced soil displacement developed into the ice tip owing to the shear resistance of the seabed soil.
Determination of the sub-gouge soil displacements is a governing design factor for the subsea structures in the Arctic offshore that commonly need costly laboratory studies and long-running finite element (FE) analyses to guarantee the operational integrity of the subsea pipeline against the ice-gouging event. Thus, the industry is still seeking more cost-effective, reliable, and faster alternative approaches for simulation of the iceberg-seabed-pipeline interaction process to minimize the collision risk of ice keels with the subsea structures. Recently, the application of machine learning (ML) in different fields has witnessed impressive growth since the ML technology is sufficiently precise, quick, reliable, and cost-effective to model various linear and non-linear problems.
In this study, three robust ML algorithms comprising the Decision Tree Regression (DTR), Random Forest Regression (RFR), and Extra Tree Regression (ETR) models were used for the first time to simulate the iceberg-seabed interaction process in the sandy seabed. Using the parameters governing the ice-seabed interaction mechanism, a set of the DTR, RFR, and ETR models were developed. To verify the ML models, a comprehensive dataset was constructed and the data was divided into two sub-samples including the training (70% of data) and testing (the remaining 30% of the data) datasets. Subsequently, for the DTR, RFR, and ETR models, several analyses such as sensitivity analysis, error analysis, and uncertainty analysis were performed. The conducted analyses demonstrated that the ETR algorithm had a reasonable performance to simulate both horizontal and vertical sub-gouge soil deformations in the sand. The soil depth ratio (y/W) and the horizontal load factor (Lh/γs.W3) had substantial significance to model the horizontal and vertical deformations in the present study.
The presented results provided a good notion of modeling the ice-gouging problem through the ETR algorithm. The outcomes may facilitate proposing new solutions to estimate the sub-gouge soil deformations in the sandy seabed. The present work can also be used for the planning of expensive field, laboratory, and FE simulations and to reduce the expenditures on future studies.
Techno-Economic Assesment for Carbon Capture Techniques
Authors: Poothia Tejaswa , Pandey Gaurav , Mehra Dipti , Rawat Prerna B. S. 
Published: April 2022

Abstract
This paper focuses on a techno-economic analysis for carbon capture technologies with a study of processes that apprise different grades of products purity. The cost evaluation of carbon capture and storage techniques has been discussed. It describes about the cost metrics, carbon storage and transport, aspects of energy supply, maturity, retrofitting cost of these techniques. Therefore, the three leading carbon capture techniques namely: pre-combustion, oxyfuel-combustion and post combustion carbon techniques are enlightened to review the development of carbon capture techniques and their techno economical aspects which can be beneficial for sustainable development. Carbon products streams that are generated by Carbon Capture and Storage (CCS) techniques, are observed to contain the impurities at some level. The effect of these impurities for the efficient and safe storage and transportation of carbon is fundamentally major issue. Acceptability and economic viability in terms of health risks and surrounding environment are also very critical factors. The paper aims to review the various technoeconomical aspects for carbon capturing technologies in industries and different power plants in order to increase the feasibility/efficiency of CO2 storage and transport for promising future.
Geomechanics Helps in Identifying Hydrocarbon Potential and Compaction Disequilibrium of Eocene Reservoirs – Case Study of a Geologically Complex Plateau in South Asia
Authors: Mahmood Azhar , Khan Mohammad Rasheed , Siddiqui Faraz Hasan , Khalid Perveiz , Ahmed Nisar 
Published: April 2022

Abstract
Reservoir geomechanics is essential for cost-effective drilling in complex areas, reducing risks related to wellbore stability problems, and other issues related to abnormal pore pressure, efficient reservoir modeling and enhanced oil recovery (EOR) plans. The information of major sources of overpressure generation like tectonics, under compaction, hydrocarbon accumulation and presence of an effective seal is necessary to apply reservoir geomechanics. The present study comprises of structural interpretation and comparative petrophysical evaluation of the Chorgali Formation with special emphasis on reservoir geomechanics for this Eocene reservoir in an oil field. This field is in the Potwar Plateau, included in the list of areas of the world containing over-pressured sedimentary rock.
The main objective of this research work is to determine the pore pressure using well log data for two wells. In this model sonic transit (DT) time is correlated to recognize the compaction history for more accurate pore pressure prediction and to analyze the dependence of compressional wave velocity on vertical effective stress, stiffness of material and pore pressure. Pore pressure prediction by using well log data is much more affordable and gives continuous and extensive range of data than direct measurement by modular dynamic tester, drill stem test and repeat formation tester, etc. One dimensional (1D) well concentric mechanical earth model (MEM) is developed for reservoir geomechanics of Eocene carbonates.
Seismic interpretation results reveal thrusting and popup structures in the area due to compressional tectonic regime. Petrophysical analysis discloses that the Chorgali Formation has better reservoir characteristics as compared to the Sakesar Formation. Compaction disequilibrium in argillaceous layers and hydrocarbon accumulation in reservoir zones are primary sources of overpressure. The well log-based pore pressure estimation shows good agreement with the in-situ measured formation pressure obtained from modular dynamic tester (MDT). The variation in rock physics properties such as bulk modulus, Young's modulus, shear modulus and Poisson's ratio are also modeled to delineate the high pore pressure zones. Reservoir geomechanics results illustrate that the predicted abnormal pore pressure is mainly due to significant hydrocarbon potential in the Chorgali Formation. On the other hand, shales deposited in the Sakesar Formation during Early Eocene are over-pressured due to compaction disequilibrium.
A Test Rig for Jetted Conductors in Soft Clays
Authors: Fernandes Bernardo Branco Lopes , Pinheiro Arthur Veiga Silvério , Guimarães João Henrique Diniz , Dias Rafael , Cutrim Fabio Sawada , Gonçalves Clemente José de Castro , Danziger Fernando Artur Brasil 
Published: April 2022

Abstract
This paper describes the design, construction and operation of a test rig for jetted conductors in soft clays. The rig was designed to produce repeatable tests under controlled conditions to evaluate the influence of operational jetting procedures on the conductor performance just after installation and at different periods after installation (set-up effect), underdifferent loading conditions. The test drilling rig consists of two main parts: an isostatic supporting structure and a jetting bottom hole assembly (BHA). All parts were designed to emulate real operational conditions found in offshore drilling rigs on a more manageable scale. A 7" (177.8 mm)OD and 6 m long conductor was used for this purpose and a 3.5" (88.9 mm) commercial drilling motor was fitted inside it. The design was such that several combinations of values of bit stick-out and flow rate are easily obtained in the field. The test rig showed up as a powerful tool for geotechnical research in which the influence of some drilling parameters on the axial and lateral bearing capacity of the conductor, such as: bit stick-out, flow rate and set-up can be evaluated.
Towards a Novel Approach to Consider Casing Wear in Well Designs
Authors: Mencaglia Xavier , Cazier Olivier , Feutry Vincent , Almeida Gustavo , Brillaud Loïc 
Published: April 2022

Abstract
This paper deals with an in-depth evaluation of the collapse pressure of a worn pipe (due to the casing wear) using a reliability-based approach (based on a 2D finite element analysis) combined with physical tests. In addition, a novel approach to evaluate the performances of a worn connection is proposed combining 3D FEA and physical tests.
The first step is to determine the maximum wear, due to the contact forces between the drillstring and the inner wall of the pipe while drilling. A stiff-string torque and drag model with contact management allows a very accurate estimation of these forces at each step of the well construction process, and the cumulative mechanical work is calculated at each cross section of the well. A wear model is then applied: the induced 3D wear is calculated, and a predicted maximum wear profile is obtained.
This maximum wear is incorporated in the pipe collapse reduction factor evaluation (referred to as CRF) and in the worn connection evaluation envelope (referred to as worn CEE) assessment. For the pipe, a 2D model has been developed. This model is fully parametric, and a variety of parameters can be changed such as: the ovality, the eccentricity, the pipe OD/t ratio, the tool joint diameter, the position of the wear groove, etc. A large DoE has been launched to evaluate the CRF of each individual pipe. This cloud of points allows for determining an equation to give a CRF in function of the casing wear level. This equation integrates the scattering that will be found in the reality considering a pipe population. Some physical tests were performed to cross-check with the equation. The equation shows a less severe CRF than the one computed with the API uniform wear model. For the connection, a 3D FEA model including the casing wear groove is created to evaluate the local stress gradient in the groove. The connection studied is a VAM® SLIJ-II. In addition, some physical tests (based on the API RP 5C5:2017) were performed to check the remaining performances of the connection and to correlate with the FEA. Through the test, the VAM® SLIJ-II 14" 115.00# 125ksi has demonstrated that the initial CEE was maintained during multiple rounds of a Series A with both 5% and 10% wear.
The litterature is centered on the casing wear of pipes comparing the API uniform wear model to other approaches such as analytical formulation or finite element analysis. In this paper, a casing wear profile is estimated with a stiff string model, and the CRF for the pipe is calculated thanks to a reliability-based approach. The important novelty is the assessment of a worn CEE on the VAM® SLIJ-II using a 3D FEA model and some tests.
Implementing A New Spacer System Capable of Curing Partial Losses Prior to Cementing While Depicting Remarkable Fluid Compatibilities
Authors: Shamsan Abdulmalek Ahmed , Nino Adriana Contreras , Hugentobler Kory , De La Cruz Sasso Alejandro , Zuleta Rodny Masoud 
Published: April 2022

Abstract
A cleaning system that effectively displaces movable and immovable mud from the wellbore prior to cementing is key for a successful cementing job and for long term zonal isolation. If in addition, the cleaning system can help in minimizing losses while showing proper compatibilities with mud and cement both, this will provide another assurance for a competent cement sheath in the wellbore. This new spacer system was tailored as per the actual wellbore conditions for Saudi operations.
To analyze the behavior of the new spacer system under different conditions, fluid compatibilities were performed with diverse drilling fluids and cement slurries. The stability of the new spacer was also verified under static and dynamic conditions. Furthermore, this spacer was tested with and without Lost Circulation Material (LCM) through different slot sizes ranging from 500-5000 microns along with a Particle Plugging Apparatus (PPA). This test was used in determining the spacer's capability to plug the slots under different pressure and temperature ranges.
In this study, spacer design was optimized to maintain the rheological and density hierarchy requirement between three fluids - drilling fluid, spacer, and cement slurry. Spacer design was tailored to maintain the above-mentioned hierarchies at both surface and downhole temperatures. It was found that the new spacer system has improved compatibility results with different drilling muds and cement slurry systems even without adding any additional viscosifier agents. The tailored spacer proved its stability under high pressure high temperature (HPHT) conditions using a consistometer with no settling and zero free fluid. In addition, it shows to effectively plug a 500-micron slot disk and was able to seal up to 5000 microns when LCM was added across different pressure ranges (100, 500 and 1000 psi). In addition, field trials for wells encountering dynamic and static losses were performed where spacer with LCM was pumped after considering critical flow path and minimum flow area restrictions. As a result, the new spacer proved to be compatible at multiple densities, demonstrated its ability to bring cement to desired depths, and helped in improving Cement Bond Logs (CBLs).
The application of this engineered spacer system is extremely valuable for the fields having low fracture density formations. Pumping this spacer, will not only help in the effectively cleaning of wellbores prior to receiving the cement but also in forming a seal to reduce any loss circulation issues. This will help in bringing the top of cement (TOC) to the desired depth and ensuring placement of a dependable barrier throughout the life of the well.
Offshore Co-Produced Critical Minerals and Geothermal Energy Generation
Authors: Nash Susan Smith 
Published: April 2022

Abstract

Scope
This paper presents the results of a study to determine the potential for coproduced critical minerals and geothermal energy generation in offshore production. The objective was to focus on high temperature produced water in locations likely to contain critical minerals such as lithium, rare earth elements (REEs), platinum group metals, arsenic, and others. The scope is global, and the offshore locations graded to prioritize in terms of geothermal energy and concentration of critical minerals.

Method
The method involved studying the tectonic history of the offshore production of the world and conducting reconnaissance basin analysis to create general maps of heat and location of critical minerals. A study of all publications that included information about the geochemical composition of reservoir fluids as well as samples / cores was also incorporated. Where available, geothermal information was gained by collecting the bottomhole temperatures of producing and test wells.

Results
The preliminary results indicate that some offshore production does have the potential to be converted to producers of geothermal energy, to be consumed locally, depending on needs and infrastructure. In some cases, platforms can be converted to battery charging stations. With respect to critical minerals, preliminary results have identified offshore producing fields with a potentially commercial concentration of critical minerals in the produced brine / reservoir fluids. Further study is being conducted to define the type and concentration of critical minerals, and to recommend the ideal production method for each high-ranking prospect.

Novel Information
Certain offshore reservoirs have the potential to coproduce geothermal energy and reservoir fluids. Further, there are locations in offshore basins that may have commercially producible levels of critical minerals. Novel methods of producing and concentrating brine will be necessary offshore to work within the constraints of the locally generated energy, and to preserve and protect the environment.