bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Triple-String Cement Approach in Redefining Well Plug and Abandonment Techniques
Authors: C. Attawit , H. Phonlawit , K. Sineenat , N. Apiwat , D. Suwit , S. Suwin 
Published: August 2024

Abstract
Well Plug and Abandonment (P&A) process stands as the primary phase in decommissioning activities. Compliance with country regulations and industry standards is imperative for P&A methods. With over 2,000 wells requiring abandonment post-concession by the Operator, costs extend beyond P&A to encompass waste handling, logistics, scrap disposal, and SSHE concerns.
To enhance cost-effectiveness, a novel barrier placement technique, the triple-string cement balance plug, has been innovated, trialled, and assessed. This paper introduces a novel technique, the triple-string cement balance plug, enhancing well Plug and Abandonment (P&A) processes. The primary objective is to establish well barriers across necessary sections via Off Rig operation (Phase 1 using a slickline/electric line and a cementing unit) as much as possible. The procedures for the first and second barriers are similar to Operator's best practices. The additional procedure involves the placement of the third barrier across three annuli. It is achieved by limited penetration perforation and placing a cement plug simultaneously across tubing (2-7/8" or 3-1/2" × 7" casing) and the 9-5/8" casing annulus. Then a well barrier is verified through pressure testing to the required test pressure. The tubing is cut below the SSSV, followed by circulating the well with kill-weight fluid and suspension. Phase 2, by utilizing a Rig/Rigless unit to retrieve tubing, cut and retrieve remaining casing and conductor, if any, and finally the placementof environmental plug.
With successful trials during the 2021-2023 campaign and subsequent adjustments, this technique proves successful in perforation, circulation, cement placement, and meeting pressure testing criteria. Implementing this technique anticipates substantial cost savings in the Operator's extensive well P&A operations. Considering the Operator's potential 2,000 wells for P&A post-concession and non-usable wells, this technique could yield total savings of up to 12% for P&A operations alone. Moreover, minimizing the extraction of tubing and casing reduces waste handling, particularly hazardous materials like Mercury, Arsenic, and radioactive substances. However, the potential cost savings from reduced tubing and casing extraction are not factored into the cement balance plug in 3 annulus technique's estimated savings.
Casing Drilling Successful Application Case Histories and Best Practices in Gulf of Mexico
Authors: Sanchez A. , Duque E. , Lugo M. , Torres J. , Rojas E. , Marcano L. , Peralta O. , Garcia S. 
Published: August 2024

Abstract
The Casing Drilling technique is used in the Gulf of Mexico area, to drill the top of the salt dome located in the Upper Miocene Formation at an average of +/- 4,500 meters, which is a high pressure zone preceded by abnormal pressure zones, this increases the risk of fluid loss, stuck pipe and fracturing the formation by requiring to increase the control fluid density.
This dual step drilling process looks to deepen into the salt dome at a desired interval between 20 and 30 meters. This challenge is encountered during the drilling of the 14 ½" × 16" section, which is first drilled with a 16" or 14 ½" PDC (Polycristalline Diamond Compact) type bit with an underreamer to the top of the salt dome. The drill string is then pulled out of the hole to allow for the second step, to drill and set the casing within the saline dome with the Casing Drilling technique using an Internal Casing Running Tool (CRTi) in conjunction with a Drilling Casing Shoe and Casing String.
The Casing Drilling technique is used to reduce time and costs associated with the risks of drilling in stratum with different types of gradients, minimizing the possibility of stuck pipe, loss of circulation and even a fracture of the formation, thus isolating abnormal pressure formations, while introducing the casing string. In addition to these advantages, this technique allows the casing to be ran with a drilling casing shoe and use the casing as a working string without exceeding its operational limits. A final benefit is being able to cement the casing even if the casing string is trapped or cannot run within the saline zone and /or reach target depth with successful results up to 52 meters drilled into the salt dome.
The ultimate goal of this technique is to increase the successful rate reaching the target zone.
The Casing Drilling technique is uncommon worldwide, presenting great challenges in its application. This paper will showcase the advantages and good practices of this application based on deepening the 13 5/8" Casing within the salt dome in the Offshore Southern Zone of the Gulf of Mexico.
A Solution for Running Liner Less Single Trip Completion in Wells with a Short Section of Open Hole Reservoir: Reducing Rig Time, Simplifying Operations, and Optimizing Tools and Services Compared with Conventional Upper and Lower Completion
Authors: Amorocho A. , Al Nuaimi M. , Iglesias D. , Fernandes P. 
Published: August 2024

Abstract
The purpose of this paper is to summarize the experience gained during the design stage, and the technical and operative considerations for a new concept of liner less well construction with a single trip completion in wells with a short section of open hole reservoir, instead of running 7in liner hanger and completing the well with a lower and upper completion as a current practice. The solution keeps the flexibility to disconnect the upper completion part above the production packer for any workover and provides the ability to reconnect a new upper completion section expediting the well to production.
Combining different phases during the well construction and completion streamlines operations and communications, improves operational efficiency, and reduces cost during initial production and further interventions, while extending the well life and productivity.
Wellbore Strengthening – An Operators Evolution from Conceptual Well Problem Solving to Operational Success
Authors: Manson James Hunter 
Published: August 2024

Abstract
Inadequate hole section formation strength, either known within detailed engineering planning or encountered unexpectedly during operational execution, can lead to downhole losses, high NPT, contingency casing string running and failure to achieve key well objectives. Several technologies and strategies can be utilized and executed, to work within narrow PPFG windows, avoiding formation breakdown and enable successful drilling, casing running and loss free cementing. This paper outlines the operators’ evolution, in relation to one of those technologies, Wellbore Strengthening, from initial concept well problem solving through to operational success.
Wellbore strengthening has been around for many years, with success achieved, across many applications, to strengthen the formation above the original in-situ minimum horizontal stress. This is accomplished through the incorporation of a formulated blend of sized particles, previously typically calcium carbonate and graphitic material, but now also often including cellulose and fibrous material within the drilling fluid. By inducing pressure, the rock is fractured, the solids in the drilling fluid plug and seal the induced fracture, holding the fracture open, as the fluid is bled off behind the bridge, thereby creating additional strength via a hoop stressed zone. The formation strength, primarily of weak sands, has been increased by low 10’s of psi, to 100’s of psi, or ultimately pushed by specific drivers, up to many 1000’s of psi.
The detailed design and testing of potential and selected wellbore strengthening formulations has been documented and considerable expertise is available within the oil and gas well drilling fluids companies to fully support the successful application of this technology. Wellbore strengthening application techniques can really be split into either of two types: Dynamic or Static, where the design of the wellbore strengthening formulation has common aims and technical objectives. However, the difference in complexity between the two techniques is significant, with static wellbore strengthening being little more than the combination of two common rig operations of open hole pill spotting and performing a LOT or FIT. However, dynamic wellbore strengthening is a much more complex, heavier on time and cost and more onerous to execute.
This paper will present detailed examples of wellbore strengthening success, across several wells, what has been achieved, outlining practical lessons learnt, including some common wellbore strengthening misconceptions. Wellbore strengthening formulations are optimally developed where detailed geological input parameters, such as Dynamic Young’s Modulus, Poisson’s Ratio etc. are known, however a practical approach is outlined for where this data is unavailable, particularly applicable to exploration wells in new basins.
Principles for Best Practice Geomechanics for CO2 Sequestration in Depleted Reservoirs
Authors: Chatterjee A. , Sinaki A. Younessi , Ghosh A. 
Published: August 2024

Abstract
As the world is facing challenging climate targets, one of the initiatives is to reduce carbon dioxide (CO2) emission through carbon capture and storage (CCS). However, to understand the viability of CCS study, field scale geomechanical risk assessment is key to determine short- and long-term injection and storage capacity. A comprehensive study was carried out to investigate the geomechanical risks associated with injection in the depleted reservoirs. This was done by preparing well-centric (1D) geomechanical models using inputs from petrophysical, drilling and production data of historical wells. This was then extended to a 3D geomechanical model for the entire area of interest in the field. The model was then used to investigate the caprock integrity (threshold of maximum injection pressure), reactivation of the existing faults (caprock & reservoir) and thermal stress effect on caprock & reservoir,
A caprock integrity analysis was carried out for all the storage layers, and it was found that the storage layer pressures (reservoir pressure increase during injection) did not exceed the fracture pressure values of the caprock that will cause tensile failure. A fault stability analysis was carried out for the modelled faults and the Tau ratio for the maximum reservoir pressure (close or greater than initial reservoir pressure) was calculated. Results shows that there is no risk of fault stability using the current injection design (injection pressures close to the initial reservoir pressure). The stress changes induced by the thermal expansion/contraction of the rocks are calculated from the thermoelastic equations for the start of injection stage for both the reservoir and caprock. The caprock fracture pressure incorporating the thermal stress effect at the well location reduced significantly for the shallowest storage layer. With the focus of managing carbon emissions, this is one of the best principal practices and fit for purpose methodology which can be adopted for field scale geomechanical risk assessment to evaluate the short- and long-term CO2 injection risk and storage capacity in any field of interest.
Innovative way of 1.25" CT Clean Out Job Beyond the Norm
Authors: Yap Y. H. , Chua H. L. , Mokhtar M. K. , Choi Y. X. , Intang E. D. , Isik F. S. , Dasan L. M. , Haslan M. H. , Nicholas F. K. H. 
Published: August 2024

Abstract
Debris cleanout in well is a common coiled tubing operations worldwide with the simple objective to clear a flow path in the tubing for either production fluid to surface, injection fluid.
This paper documents a distinctive approach to executing a coiled tubing (CT) sand clean out operation without establishing any fluid or gas return to surface, by methodical and calculated procedure of hard penetration into Holdup Depth (HUD). The subject is Well H, which was completed with 2-3/8" 4.6 ppf dual completions tubing and of which production from both strings is flowing with sand. The short string and long string have both been set with the Thru-Tubing Sand Screen (TTSS) at the X-Nipple profile. Tubing Clearance Check (TCC) run conducted by wireline confirmed the HUD. The high sand interval column above the TTSS is deemed as beyond the effective capability of slickline sand bailing. Instead, coiled tubing was proposed to execute the clean out of well until End of Tubing (EOT) with a 1.25" OD coil, allowing for replacement of the TTSS downhole. Initially, coil run in hole (RIH) and tagged the sand HUD. At this depth, bottoms up of Treated Fresh Water (TFW) was pumped into well to circulate the sand particles out of tubing, but no solid return of fluid was observed at surface. Nitrogen gas was introduced into well with TFW to improve lifting efficiency of cleanout fluid. Sand return was not observed at surface with this attempt, but nitrogen return was. Risk assessment was conducted at this point due to the acknowledgement that the absence of solid fluid or sand return at surface runs the risk of coil being stuck downhole under accumulation of sand debris that did not successfully circulate out of well during cleanout operation. Decision was then made to continue clean out based on a precautious regiment of pumping nitrified TFW while hard biting or penetrating HUD at 50 ft interval.
Adopting this precautious method to conduct sand cleanout, the job was safely executed and coiled tubing was able to tag onto the TTSS. The well was handed over to wireline to retrieve the TTSS assembly, comprising of XN-lock mandrel and 10 ft Sand Screen. Sand cleanout allows for wireline access to retrieve the old TTSS and install a newer TTSS downhole. The success of this novel approach is the ability to deliver the coiled tubing sand clean out job beyond the normal sand clean out practices, but still within the safe working envelope and without jeopardizing technical safety.
Implementing Eccentric String Reamer With Enhanced Wellbore Strengthening Practices – A Case Study
Authors: Hanjawanich S. , Tangcharoen N. , Sukarasep W. , Suphawechraksakul P. , Worrawongwanna C. , Siripan T. 
Published: August 2024

The legacy concession comprises mature fields with a well-known wellbore problem, lost circulation while drilling. Highly depleted reservoirs and pressure ramps at deeper sections are the main contributing factors inducing drilling fluid loss events. This case study describes a technique for lowering equivalent circulating density (ECD) in the Gulf of Thailand (Got), specifically in PTTEP’s legacy operating area, while drilling with a combination of using eccentric string reamers (ESR) and adjustable gage stabilizers (AGS) bottomhole assembly (BHA) and enhanced wellbore strengthening (WBS) practices. Since lower borehole pressure might lessen or postpone drilling fluid loss events, lower ECD in the slimhole is preferred when drilling depleted reservoirs in mature fields. In order to maximize reserves capture and perhaps penetrate otherwise unrealized pay horizons, it may be possible to further progress in deepening well depth by delaying losses.
While there were a number of approaches to lower ECD, the majority of these involved costs related to significant modifications to the drillstring and/or casing design specifications, so there was a need for a low-impact, low-cost operational solution. Hole-opening is one of the approaches to increase annular clearance. A one-trip approach that does not significantly affect a holistic way well factory is limited.[SJ1][SH2] Rather than using ESR, other alternatives are evaluated but are not fit for purpose, such as reducing drill pipe size and lowering intermediate casing wall thickness.
Additionally, the chosen course of action must not jeopardize the operational dependability of the drilling equipment and be suitable for a high-temperature reservoir drilling environment. ESR is a straightforward but contentious hole-opening tool. ESRs are straightforward because they have cheap running costs and no moving parts or cutting blocks to relocate. The reason they are problematic is that it is uncertain if the drilling dynamics and tool eccentricity will properly open the hole to the target diameter. An eccentric reamer solution was selected for field trial and possible development, as this hole-opening application is confined to annular clearance for fluid, not mechanical clearance. A reamer design with the required enlargement ratio (6⅛-in. to 6⅞-in.) was specifically designed and built along with placement software to help locate the tool optimally in the BHA.
Placing the Wellbore in Complex Geological Succession Covering the Maximum Reservoir Contacts
Authors: Espinoza I. Baca , Szczawinski W. A. , Popescu M. , Al Riyami N. H. 
Published: August 2024

Abstract
The drilling and placement of Maximum Reservoir Contact (MRC) wells can be challenging in areas where there is scarcity of available data and/or poor correlation between offset wells. This is especially true for reservoirs with complex geological structural setup, where formation dips may vary significantly within the same lateral drain. Logging while drilling sensors are located away from the bit, which introduces delay and potential errors in evaluating the current bit position. To achieve the well objectives, proactive approach is necessary.
Prior to geosteering the forward modeling is conducted based on geological data, using the expected targets, and accounting for the potential uncertainties such as tectonic environments, target thickness variations, thin target layers, and formation lithology variations. The expected trajectory for MRC may feature dog leg severity limitations to assure successful completion placement, so the drilling Bottom Hole Assembly (BHA) design limitations must be carefully evaluated. To address the complexity of the project it is recommended to place the most important sensors as close to the bit as possible.
The study discusses four wells drilled and completed in the Middle East and covering up to 9,000ft of the drain completed in one run. The major objectives were to land the well as per the provided targets and to stay away within pre-assigned limits such as water level stand-off, etc. For most of the cases, the density, acoustic or resistivity image were the primary mapping means for cases with sufficient contrast allowing to keep the trajectory within the porous target. The near-bit Gamma Ray (GR) with the azimuthal image was used for early reaction to the lithological variations and correlation for the stratigraphic position determination. The rate of penetration and weight on the bit coefficient were used as the earliest indicators for the soft-to-dense transition in contrasting formations. The results allows the revision of the pre-defined Limited Entry Linear (LEL) placements with allocated spacing targeting the highest productivity.
The case study presents various tools and methods that when combined allow to improve wellbore structure and maximize the reservoir targets contact. The use of a pre-job forward model and real-time stratigraphic feature identification using a fit-for-purpose bottom hole assembly allows for the accurate placement of the drain and avoidance of missing targets. The results from Logging While Drilling (LWD) allows the confident well completion as per targets while maximizing the production from MRC wells.
Prediction of postoperative infections by strategic data imputation and explainable machine learning
Authors: Beldi Guido , Guillen-Ramirez Hugo Armando , Sanchez-Taltavull Daniel , Perrodin Stephanie , Triep Karen , Endrich Olga 
Published: August 2024

Abstract

Infections following surgery drive patient morbidity and mortality, making early detection essential. Traditional predictive models utilize preoperative patient characteristics and features of the surgical procedure. This study enhances these baseline determinants by incorporating postoperative responses. We have designed and tested a procedure-agnostic workflow to forecast infection and generated baseline predictions from preoperative and intraoperative phenotypes extracted from electronic health records. Laboratory values were then strategically imputed to build a prediction model that incorporates both their static and kinetic properties, achieving high recall for infection. The integration of kinetics revealed unknown informative combinations of routine markers among hepatic, renal, and bone marrow functions. Applying explainable machine learning ensures clinical applicability by elucidating how different organ systems respond to and predict infectious complications. By enabling earlier detection of postoperative infections, this work enhances patient outcomes and optimizes resource utilization in surgical care.
Growth responses and accumulation of osmoprotectants under salinity and drought in woody plants: insights from Parkinsonia praecox (Ruiz &amp; Pav.) Hawkins
Authors: Villarreal Valeria , Sosa Laura , Calvo Juan Armando , Posetto Paola , Llanes Analia 
Published: August 2024

Abstract

This study was performed to analyze the growth and biochemical responses in P. praecox plants exposed to salinity and drought. The results indicate that increased root biomass and length occur in high salt and drought conditions (30% FC and 700 mM). This root response ensures water acquisition to maintain plant water status under arid and saline conditions, a strategy observed in other woody species. Moreover, the study highlights proline, glycine betaine (GB), and carbohydrates as vital osmoprotectants. P. praecox accumulates these compounds primarily in roots and shoots under drought conditions, suggesting significant metabolic adaptations to water deficit. However, under salinity, the roots and leaves of P. praecox plants did not accumulate GB. The accumulation of soluble carbohydrates in P. praecox was pronounced in roots under severe water deficit conditions (30%FC). This metabolic response, along with the accumulation of proline and GB, indicates a strategy to cope with stress-induced damage. Moderate increases in these compounds under high NaCl concentrations suggest an effective osmoregulatory mechanism to mitigate salt conditions. This study enhances our understanding of the mechanisms underlying tolerance in woody plants, particularly P. praecox, and underscores the importance of osmoprotectants and soluble carbohydrates in mitigating adverse environmental conditions.
Microstructure and mechanical properties of diffusion bonding joints of 42CrMo steel and tin bronze with nickel interlayer
Authors: Ye Junyang , Li Xianfen , Li Siyuan , Jiang Ruize , Hua Peng , Liu Dashuang 
Published: August 2024

Abstract

Diffusion bonding technology was used to realize the connection of 42CrMo steel and tin bronze, and the effects of bonding time and nickel interlayer on the microstructure and mechanical properties of the joint were studied. The results show that: When 42CrMo steel and tin bronze are directly diffusion bonded, at 850 ℃ and 4MPa, the shear strength of joint first increases and then decreases with the increase of bonding time. When the bonding time is 60 min, the thickness of the diffusion layer is about 0.5μm, the shear strength of the joint reaches a maximum of 152MPa, and the fracture shows mixed fracture characteristics of brittleness and ductile. After adopting Ni foil as the interlayer metal, both 42CrMo steel/Ni and Ni/tin bronze interfaces formed obvious diffusion layers of about 11 μm and 50 μm, respectively, a granular discontinuous distribution of (Cu,Ni)3Sn formed on the Ni/tin bronze side, the shear strength of the joints is elevated up to 221 MPa, and the fracture is characterized by ductile fracture.