bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium Sulfate Dissolution Using Lactic Acid
Authors: Alqahtani M. F. , Alissa F. M. , El-Demellawi J. K. , Bamigdad S. A.
Published: November 2023

There has been a global surge in scale challenges across the oilfield industry, surpassing other flow assurance challenges. In principle, scale refers to the deposition of mineral solids (primarily inorganic), such as calcium carbonate, calcium sulfate, or barium sulfate, that can accumulate and obstruct flow pathways in various industries, including oil and gas production, water treatment, and other industrial processes. Scale formation can lead to reduced production rates, increased energy consumption, equipment damage, and operational disturbances. Hence, the mitigation and prevention of scale deposition have become pivotal for maintaining high-performing production processes. In this regard, among the known scales, the calcium sulfate scale, in the form of gypsum (CaSO2.2H2O), is deemed challenging for many applications. This type of scale is usually caused by mixing incompatible waters. CaSO2.2H2O is an acid-insoluble scale; thus, it requires an effective scale dissolving recipe. Herein, we demonstrate the use of lactic acid (C3H6O3) as an emerging green chemical to remove gypsum deposits in the presence of different bases, including potassium and sodium carbonates and hydroxides. Different scale removal recipes were developed comprising mixtures of lactic acid with individual bases or a mixture of two bases. We show that, generally, hydroxide bases have exhibited lower performance, particularly potassium hydroxide, compared to their carbonate counterparts. Nonetheless, potassium carbonate, in particular, has offered a better performance compared to sodium carbonate. Incorporating lactic acid with the experimented bases has further improved the performance of the developed recipes, thanks to the induced synergistic effect, specifically with potassium carbonate. The latter has also demonstrated the ability to polymerize lactic acid when coupled with another base, such as sodium hydroxide or potassium hydroxide. Noteworthy, using sodium carbonate has resulted in much lower performances when coupled with the other hydroxide bases. Therefore, mixing two bases when dissolving calcium sulfate is not always the optimum choice as it brings other negative consequences.
Estimation of Gamma Ray Values with Deep Learning from Seismic
Authors: Karimli J. , Yeleskina T. , Shafiyev A. , Asgarov H. , Malikov R. , Mammadov O. , Shahsenov I.
Published: November 2023

Seismic inversion is pivotal in the oil and gas industry, aiding geophysicists in understanding reservoir characteristics. Despite its widespread use, the limitations of seismic data, like low resolution, introduce uncertainties that impede direct application. This study introduces an innovative method to estimate 3D Gamma Ray data from seismic reflectivity, reshaping reservoir understanding and management.

The study's goal was to predict 3D Gamma Ray data and its uncertainty via seismic reflectivity. This was achieved by employing Functional Convolutional Neural Networks (FCNNs) and Continuous Wavelet Transform. By merging well data and seismic information using signal processing and deep learning, accurate forecasts of Gamma Ray values were accomplished. It's worth noting that this manuscript constitutes as a continuation of the scientific research project initiated by Shahsenov et al. in 2022. The authors describe the updated methodology, the improvements achieved in the results, as well as any alterations made to the methodological framework.

The quality of prediction was validated through several statistical techniques, ensuring robustness. Blind wells were thoughtfully integrated into various analyses to facilitate a comparison between actual and predicted log values. The outcomes of these evaluations, promising in nature and showcasing notable advancements over the earlier work, are represented visually and in detail through the report.

In summary, this research pioneers a seismic inversion shift and builds upon prior research (Shahsenov et al., 2022). The combination of seismic reflectivity and deep learning allows precise prediction of 3D Gamma Ray values. By combining well and seismic data, the challenge of sparse logs is addressed, empowering geophysicists for more effective reservoir management. This enhanced reservoir understanding promotes data-driven decisions in the oil and gas sector.
Characterize to Stimulate: A Novel Field Development Approach in Tight Cretaceous Mishrif Reservoir, Minagish Field, Case Studies from West Kuwait
Authors: Ziyab Khalid , Patra Milan , Abu-Eida Abdullah , Akbar Bader
Published: November 2023

To unlock Mishrif reservoir potential in West Kuwait, a new development strategy involving analysis with Distributed Temperature Sensing (DTS) and downhole intervention with instrumented coiled tubing (Active CT) followed by high-rate stimulation by bull-heading has been applied to the tight carbonate formation. The goal was to find a cost-effective stimulation strategy that would increase the number of productive wells through an integrated production enhancement project approach.

The operation encountered various challenges, primarily driven by a high-permeability areas across the open hole, which was detected by DTS. Modifications were made to the CT stimulation procedure, including diversion techniques such as high-pressure jetting, dual injection and the pumping of a near-wellbore fully degradable diverter composed of a customized blend of multimodal particles and degradable fibers to temporarily isolate the highly permeable streaks. Real-time downhole telemetry had a paramount importance in ensuring the injection rate was kept below preset pressure limits and in monitoring downhole dynamics for optimal use of the high-pressure jetting tool. In most of the interventions, following the CT stimulation, a second post-stimulation DTS log was conducted to evaluate the fluid coverage and effectiveness of the diversion strategy allowing for further adjustment of the bullhead stimulation program for an optimum fluid coverage and avoiding the high-intake zones.
Wellbore Stability Analysis Using Stochastic 1D Geomechanics and Plane of Weakness (PoW)
Authors: Abdi Hadi Ashtiani , Alward Wassem
Published: November 2023

Wellbore stability models traditionally rely on inputs derived from rock physics models and empirical correlations, often iteratively adjusted using drilling observations and Mechanical Earth Models (MEM) predictions to obtain deterministic solutions. Given the inherent uncertainty in these parameters, scenarios with varying levels of uncertainty are commonly considered. Previously, assessing the impact of planes of weakness (PoW) on wellbore stability predictions in one-dimensional (1D) scenarios was challenging. Weak planes exhibit lower cohesion and friction angles compared to intact rock, affecting the stability of the wellbore. This paper introduces a stochastic approach that integrates PoW into existing workflows, allowing for the evaluation of inconsistent and non-intact rock masses’ influence on wellbore stability within the stable mud weight window. This approach can be employed across an interval, or just for a single depth, incorporating several sets of weakness planes.

The method presented in this paper employs Monte Carlo simulation to provide deterministic solutions for Plane of Weakness failure and incorporate individual uncertainties associated with key variables of MEM. Outputs include standard deviations and means, enabling the calculation of probability logs for various mud-weight window limits (e.g., breakdown pressure, kick pressure, shear failure). Additionally, image log-identified fractures are considered as Planes of Weakness, providing insights into the behavior of inhomogeneous or non-intact rock masses during drilling when drilling parameters fall outside the stable mud weight window.

This approach proves invaluable in addressing complex geomechanical environments characterized by uncertain subsurface pressures, stresses, rock properties, and the presence of PoW such as natural fractures. It aids in identifying significant sources of uncertainty, and guiding data acquisition, and rock-testing efforts. Furthermore, it enhances wellbore stability predictions in scenarios with limited calibration data. The paper showcases examples of its application in optimizing wellbore stability boundaries for proposed trajectories in the South of Iraq, highlighting its practical utility in real-world drilling scenarios.
A Guide to Safe and Economical Lighting Circuiting Design for Offshore Facilities
Authors: Pragasam Sathishkumar
Published: November 2023

Lighting circuiting design is often perceived as a simple exercise in a project. However, there are many factors that influence this design, which may lead to a poor overall design if not properly addressed. Like in any other engineering design, both technical and commercial aspects play a vital role in the lighting circuiting design. Safety in design is also dependent on the technical aspect of design. Also, since this design needs lot of close coordination between the engineers who work on the equipment design and sizing and the designers who take care of the physical aspect of the circuiting, a clear work process is required to be followed. With the added constraints in an offshore Oil & Gas facility in terms of space availability, weight restrictions and schedule pressure, required attention is required on the lighting circuiting design right from the beginning of a project. The intent of this paper is to discuss about the various technical aspects that go behind the lighting circuiting design and the comparison of different technically viable options in terms of commercial aspect through a qualitative approach.
Oil & Gas Exploration and Development with the Reverse Time Holography Technology
Authors: Erokhin G. , Erokhina M. , Safran K.
Published: November 2023

The article analyzes methods for constructing seismic attributes, which are based on two-stage data processing: on decomposition the initial common shot gathers in common image gathers, using the time-reversal algorithms and on synthesis a seismic attributes. It is shown that a detailed analysis of the joint behavior of two vectors: the velocity vectors in forward wave and the velocity vectors in time-reversed backward scattering wave provides detailed information about the medium. This is the essence of a new approach called RTH, which allows the acquisition of various seismic attributes at high spatial resolution. The new approach provides the solutions of prediction problems in oil and gas exploration, as well as problems in development using the drilling data and AI algorithms, at a new qualitative level.
Improving the Technology of Complex Hydrogen Thermobarochemical Treatment CHTBCE for Effective Use in Oil Wells With Weakly Consolidated Sandy Reservoirs
Authors: Kravchenko O. , Veligotskyi D. , Agaev U.
Published: November 2023

Today, it is common practice to produce oil from failure-prone, weakly cemented reservoirs. The operators’ desire to increase production requires operating wells at their maximum capacity, and therefore leads to more aggressive drainage of the reservoirs with high oil flow from the pay zone to the well bore. At the same time, the oil filtration rate increases significantly, especially in the near well bore zone. This promotes the active movement of rock particles together with the production from the bottomhole formation zone to the well bore. Sand movement to the well bore and removal into the well itself leads to many unfavourable consequences, such as reservoir disintegration, up to the collapse of the reservoir roof, blocking of filtration channels in the bottomhole formation zone (BFZ), accumulation in the well bore with an overlap of the productive interval. All this prevents the product from entering the well, leading to abrasive wear, pumping equipment failure, etc.

These factors affect the quality of the filtration properties of the bottomhole formation zone, disrupt the hydrodynamic link between the productive formation and the well bore, resulting in its productivity drop. To date, there are several technologies aimed at consolidating the bottomhole formation zone and preventing sand removal. They are used depending on the design of the bottomhole, the time of operation, the geological and temperature parameters, the mechanical, and the chemical and combined methods of securing the formation rocks in the bottomhole zone of the wells. As a rule, the use of these technologies leads to a decrease in the filtration-capacitance properties (FCP) of the reservoir. These technologies fail to solve other common problems of well flow rate reduction, such as colmatization, asphalt-resin-paraffin deposition (ARPD), FCP reduction by oil-water emulsions, etc. At the same time, the methods of complex impact on the reservoir are now widespread to increase well productivity. Their application during one technological treatment exertsa multifactor physical and chemical effect on the rock and its saturating fluids, with several flow rate reduction factors being eliminated simultaneously. The controllability of the physicochemical processes employed in the oil production enhancement methods (OPEM) opens up prospects for their use to improve FCP with simultaneous reservoir consolidation.
Methodology of Creation of Artificial Core Reservoir Formations Using Geometric Design Methods
Authors: Kravchenko O. , Romanova T. , Veligotskyi D. , Homan V. , Agayev U. , Yaskov G. , Chuhai A.
Published: November 2023

During the operation of oil wells, their flow rates decrease not only due to a reservoir pressure drop but also because the permeability of the bottomhole formation zone (BFZ) decreases because of the fall-out of asphalt-resin-paraffin deposits, colmatization by process fluids, formation of fracture particles, salt deposits, etc.

The productivity of such wells can be restored by applying various oil production enhancement (OPEM) methods. Choosing the most effective OPEM, developing the treatment design and predicting well productivity increase is currently done, as a rule, by being based on experimental studies with subsequent application of physical and computer modeling methods. At the same time, to determine experimentally the permeability change coefficient of the reservoir rock by implementing one or other OPEM, using natural cores is a desirable option. They are a source of unique information about the reservoir rock and the character of fluid filtration there-in. Natural cores are extracted from the well at the drilling stage and, as a rule, they are available either in limited quantities or are completely absent. In this case, experimental studies are carried out on artificial cores made by special technologies. At the same time, it is very important and relevant that they have morphological, mineralogical, and filtration-capacity properties (FCP) as close as possible to those of natural cores. Only in this case, we can talk about the adequacy of the physical model and the accuracy of the results of experimental studies, which, in turn, are the initial ones for mathematical modeling. Body text 2 paragraphs.
Key Takeaways from Mobile, Self-Contained Multiphase Pumping Package Designed for Efficient Unloading and Production Boosting of High Gas Volume Fraction and Heavy Liquid Wells
Authors: Yudin K. , Kurimov D. , Benther A. , Putra E. , Nurmukhanbetov A. , Bekishev A. , Shugayev N. , Valdivia P. , Ivkin A. , Maximov P. , Hajjoubi H.
Published: November 2023

Tengiz Field has been in production for over 30 years period and as a result, some wells are not capable of producing fluids to the current system pressure. Several wells were shut in because of insufficient wellhead pressure, changes in well flow regimes, and in reservoir conditions leading to unexpected well loading and unplanned shutdowns. Tengizchevroil (TCO) has historically unloaded wells primarily by depressurizing the production line connected to the loaded well, lowering the wellhead pressure, and enabling the well to start up by itself without the need for further assistance. To kick off the well when flowline depressurization is insufficient, a fullbore nitrogen bullhead is injected through the kill line. This makes the hydrostatic column lighter and enables the reservoir to push it more easily. Both methods are costly and pose HSE risks associated with equipment movement, production line depressurization, pressure management, Joule-Thomson effect, brittle fracture risks, H2S gas leak risks, and CO2 and methane emissions due to fuel gas flaring. The Multiphase Pumping Package (MPP) project was initiated to develop a new solution to unload wells that stopped producing. The project required an agile solution with a high level of mobility, ensuring safe and faster deployment between metering stations reducing idle time, and minimizing the loss of production.

This paper shares lessons learned from using a Multiphase Pump (MPP) for unloading and boosting wells with heavy liquid at the bottom and gas at the top. It covers the MPP's fit-for-purpose design for mobile and self-contained applications, as well as its ability to operate under extreme conditions like high GVF (up to 98%) and heavy liquids. The paper will cover the following aspects of MPP applications:

The design aspects and criteria for MPP, including business requirements and limitations. MPP's surface tie-in locations and its mobility between different sites Operational challenges during well startups and unloading, as well as practical methods developed, and lessons learned.
Open Hole Packer Movement – The Last Piece of the Puzzle, Tubular Design
Authors: Kuswiranto A. , Cooke D.
Published: November 2023

Open hole packers for multi-stage fracturing completions have long been deployed with open hole anchors with a philosophy that these anchors will enable achievement for a successful well stimulation. The general perception in the industry is that the open hole completion in the well should be anchored to avoid open hole packer movement during a fracturing job. However, some questions are still unanswered such as: Are the open hole packers moving during the fracturing job? When are the open hole packers likely to move? This paper takes looks at several open hole packer movement analyses during stimulation.

To analyze the objective of this study, the focus was kept on the analytical open hole packer force and the movement tendency during a stimulation job. To answer the questions above, it is essential to evaluate analytically the effect of these induced axial loads during fracturing with open hole packers, which have been set with and without use of open hole anchors, in the completion string. Hence, this paper discusses the study and influence of; 1) high pressure and cooling effect during stimulation, 2) friction force associated with open hole packers, and 3) maximum force required for open hole packer movement, and 4) packer movement lab test data.

The results from open hole packer movement analysis performed for several cases has successfully estimated the maximum force needed for packer movement. The study addressed the un-answered questions and showed the requirement for either complete anchoring of all open hole packers or total elimination of open hole packer anchors during hydraulic fracturing.

Uncertainty of potential tubular failure, due to misinterpretation of open hole packer movement, can be determined earlier during the concept design stage, to avoid well integrity issues during the stimulation operation.
Pore-Scale Study on the Flow Dynamics of Coupled Low Salinity and Nanofluid Flooding in Carbonate Formations
Authors: Khalilinezhad Seyed Shahram , Duan Xili , Singh Kuldeep
Published: November 2023

A significant volume of annual world oil production comes from carbonate reservoirs like the giant Middle East and Caspian Sea reservoirs. However, the production enhancement is complicated by geological heterogeneities of carbonate formations, such as a complicated network of natural fractures leading to highly permeable paths or shale streaks leading to discontinuous flow barriers. The primary objective of this paper is a feasibility study of coupled low salinity and nanofluid flooding for oil recovery enhancement from carbonate reservoirs. Accordingly, diluted seawater and two different types of nanoparticles (NPs) were exploited to prepare low-salinity nanosuspensions to understand the synergistic effects of low-salinity nanofluid (LSN) injection on oil droplet remobilization. As the multiphase flow experiments were performed using glass micromodels, surface wettability analysis was also conducted on flat glass plates to clarify the role of NPs at the interfaces. The fluid flow around shale barriers and fracture/matrix interactions were qualitatively scrutinized at the pore scale using multiphase flow tests on the oil-wet microfluidic chips inspired by the pore structures of rock samples of carbonate reservoirs. The results of contact angle experiments showed that the inclusion of NPs into low-salinity water can ameliorate the ability of the aqueous solution to reverse the surface wettability of the oil-wet samples to a more water-wet state due to the improved adsorption isotherm of NPs into the glass surface. Microscopic and macroscopic observations of the porous media flow tests also disclosed that the LSN injection could significantly improve breakthrough time as well as microscopic and macroscopic sweep efficiencies. In other words, a slight viscosity improvement of injected water due to the presence of NPs could relatively diminish the extension of fingering patterns in porous media and create a better displacement front, resulting in a higher breakthrough time of displacing fluid. Furthermore, due to surface wettability reversal, LSN injection reduced the amount of untouched oil behind the shale streaks and showed better intrusion into the matrix and a higher fluid exchange rate between the matrix and fractures. This study proves the effectiveness of LSN injection in improving the efficiency of enhanced oil recovery from carbonate formations. Besides, we highlighted the flow characteristics of LSN around the shale streaks and high permeable fractures.
Application of Drag Reducing Agent DRA in Tengiz Field Gathering System to Reduce Frictional Pressure Drop in the Pipelines and Increase Production: Best Practices and Challenges
Authors: Nadirov Maruan , Moldabekov Bayan , Benther Arnoldo , Kurimov Dauren , Subramanian Sivakumar , Zhumagulov Kanat , Aitkazin Mirkhat , Nemanic Mike , Suleimenov Olzhas , Gubashov Rustem , Shorabek Zharas , Bekov Samat , Kuatov Asan , Orazov Baurzhan , Beisebayeva Ainur , Bopiyev Chingiz , Yeschanov Ilyas , Tauyekelov Medet , Kaiyrgaliyeva Zaira , Dyussenova Madina
Published: November 2023

Drag reducing agents (DRA) have been used in the oil and gas industry for decades to increase flow capacity of pipelines transporting petroleum products or crude oil over long distances. Injection of DRA reduces the flow turbulence, thereby reducing the frictional pressure drop in the pipelines and increasing pipeline throughput. Most of the time DRA is used in single phase flows, but application in multiphase flow conditions is growing. The surface gathering system of Tengiz oil field is complex and consists of more than 300 km of gathering lines and trunklines, some of which are bottlenecked due to their smaller diameter or high flowrates from the wells. TCO decided to implement continuous injection of DRA in parts of the production system to lower the frictional pressure drop in the bottlenecked pipelines and increase production from the wells.

The selection of DRA chemical was based on laboratory testing of the additive's compatibility with other liquids (such as caustic solution, produced water, corrosion and hydrate inhibitors) used in the field and plant processes, and on field trials. The obtained field test data was used to calibrate the network model in IPM GAP to simulate the reduction in pipeline friction losses due to DRA injection, and this approach helped to find future locations for continuous injection of the additive. As a result, continuous DRA injection was implemented at four injection points, which increased the total oil production from the field by 3%.

The purpose of this article is to share TCO's experience with the application of DRA injection in a multiphase flow system and describe all stages from selection of DRA and laboratory testing to modelling and actual execution of DRA injection in the pipelines of the Tengiz oil field. The paper discusses an overview of the current status of the DRA project, results obtained, best practices and lessons learned from field applications.
Feasibility of Foam-Enhanced Water-Gas Flooding for a Low-Permeability High-Fractured Carbonate Reservoir. Screening of Foaming Agent and Flooding Simulation
Authors: Derevyanko V. K. , Bolotov A. V. , Minkhanov I. F. , Varfolomeev M. A. , Usmanov S. A. , Saifullin E. R. , Egorov A. N. , Sudakov V. A. , Zhanbossynova S , Sagirov R. N.
Published: November 2023

The carbonate reservoirs of the Alekseevskoye field (Russia, Republic of Tatarstan) are complicated by high heterogeneity and the presence of fractures, which make development difficult due to early water or gas breakthrough depending on the injected agent, as well as low of the productive horizon. To increase sweep efficiency and introduce fractured reservoirs into development, it is necessary to use gas enhanced oil recovery (EOR) technologies. To find the optimal technology in terms of technological complexity and efficiency, three technologies were compared: Water Injection (WI), Water-Alternating Gas (WAG), and Foam Assisted Water-Alternating Gas (FAWAG). Series of core-flooding tests were implemented under reservoir conditions on carbonate cores, and cores with artificial fractures, saturated with original reservoir fluids. For FAWAG method compatible with high-mineralization water surfactant was chosen. Total recovery factor for each test was calculated. It was equal to 33%, 76% and 53% respectively for WI, WAG and SWAG, on the original core models. Therefore, WAG and SWAG were chosen as most effective techniques to improve oil recovery for in comparison with CWI. In artificially fractured cores, the WAG method recovery rate was 40%; subsequent injection of a foaming active substance mixed with FAWAG formation water proved effective, increasing the oil recovery rate to 47% due to partial blockage of the fracture.
Non-Matrix Uncertainty Management Through the Integration of Drilling, Production, and Seismic Data in the Supergiant Kashagan Field
Authors: Gabdullin A. M.
Published: November 2023

The Kashagan supergiant oil field is a naturally fractured and karstified carbonate reservoir located in the Precaspian basin of Kazakhstan. Karst manifests itself in multiple forms within the reservoir, but the most important forms are geobodies, which are presumed to represent paleocaves (Figure 1). The distribution and properties of the reservoir geobodies are highly uncertain since they can only be ascertained through the use of 3D seismic and well penetrations. The current wells show a high degree of variability in production performance (e.g. PI, rates) despite the relative proximity of the wells. This variability is assumed to be influenced primarily by the proximity to geobodies and associated non-matrix permeability. Therefore, a more robust validation of geobodies calibrated with production data will support updates to reservoir architecture in geological models and enable optimization of future well placement.
Hydraulic Fracture Propagation with Complex Natural Fracture Network in Lacustrine Shale Oil Reservoirs
Authors: Li Jie , Li Jian , Ma Fujian , Guo Zixin , Luo Yin , Liu Changchun , Niu Li , Chang Rui , Huang Zheyuan , Lei Qihong , Bukovac Tomislav
Published: November 2023

The challenges of lacustrine shale oil reservoirs include not only heterogeneity of reservoir quality, but also the effect of natural fractures on propagation of hydraulic fractures and associated fracture hits. The intercalated sandstone and shale in a gravity deposit setting result in significant variation of the reservoir quality both vertically and horizontally. The subsurface conditions become even more complicated when the reservoirs are naturally fractured. This study aims to characterize the natural fractures with seismic data and diagnose hydraulic fractures with microseismic data, fracturing data, and simulation data.

An ant-tracking algorithm was used with variance of the seismic data as the input to delineate natural fractures and to build the natural fracture model. A geological model and a geomechanical model were built integrating all available data, including logs, core data, and seismic data. The quality check was performed by analyzing various data and comparing these data with the three geoscience models. The data included drilling data, such as the mud loss; microseismic data and fracturing data, such as the observed neighboring wellhead pressure and pressure decline G function analysis; and, eventually, production data. A distributed fracture network (DFN) model was built with the ant-tracking results. Fracture stability analysis was performed based on the natural fracture model and geomechanical model.

The fracturing design was customized and optimized with the models mentioned above and understanding obtained from the analyses. High fracturing efficiency and positive production performance impact are benefits of the workflow.

The hydraulic fracture propagation is diagnosed mainly by microseismic data and fracturing data. Additionally, interaction between nature fractures and hydraulic fractures can be identified by fracturing simulations using an unconventional fracture model simulator for a complex fracture network with the inputs of the DFN and the geomechanical model derived from the 3D geological models.
Development of a Hydrate-Free Operating Mode Model for Gas Lift Wells
Authors: Andrianova A. , Yudin E. , Shestakov A. , Mosyagin G. , Polinov M. , Gudilov M. , Kobzar O. , Isaev D. , Ganeev T.
Published: November 2023

The purpose of this work is to create a model to ensure hydrate-free operation of gas lift wells based on data on pressure and temperature at well sites most prone to hydrate formation, inhibitor concentration, as well as historical information about previous hydrate formation at the site.

To achieve the objectives, first of all, statistical methods of high-frequency data analysis were used in order to automatically identify hydrate formation intervals at an early stage. Information about temperature and pressure at the time of the intervals identified algorithmically and confirmed in the field, was used as points of adaptation of the hydrate formation curve. Information on inhibitor concentration was also taken into account when constructing the curve. The resulting curve allows calculating the risk of hydrate formation at a particular node and recommending the optimal inhibitor concentration to ensure a hydrate-free regime. All results of the algorithm are displayed in the user interface in tabular and graphical form and are supplemented with information about the well and relevant nodes of the inhibitor pipeline system.

The result of this work is an implemented system for determining the risk of hydrate formation and making recommendations for the concentration of injected hydrate inhibitor. The methodology based on the use of historical data on hydrate formation in the node as points of curve adaptation allows to take into account the inaccuracy of empirical correlations in view of the possible irrelevance of information about the component composition of the fluid or the presence of components, which are not a parameter of the correlation relationship. The model can be used as a tool for online monitoring of hydrate formation risk in the node, depending on the current values of telemetry, and as a recommendation tool for drawing up the technological mode of the well and the selection of optimal planned concentration of inhibitor, which provides hydrate-free mode for all the nodes of the well. Using this system simplifies technologists work and allows them to focus their attention only on wells that require recommendations to adjust inhibitor concentration or are at risk of hydrate formation.

The novelty of this work is to build a system for planning or ensuring hydrate-free operation using the methodology based on the method of adapting the hydrate formation curve on the historical data.
Seismic Facies Clustering via Spectral Decomposition using Machine Learning
Authors: Mammadov O. , Shafiyev A. , Malikov R. , Asgarov H. , Karimli J. , Shahsenov I. , Yeleskina T. , Karimli I. , Abdullayev N.
Published: November 2023

Analyzing seismic data, particularly when engaging in attribute analysis and spectral decomposition is time-consuming and requires human resources involvement. Usually, interpreters manually select and blend frequencies to identify geological patterns in seismic data. To do a proper analysis, hundreds of combinations should be generated, which introduces notable human bias.

The study objectifies the automation of spectral decomposition interpretation through the application of machine learning techniques aiming to identify and classify distinct seismic facies.

The proposed algorithm includes an integrated approach of Self-Organizing Maps (SOM) and K-Means. The input data is the frequency, spectrally decomposed from seismic data and projected on a target seismic horizon. To ensure geological relevance, a broad frequency range is considered, and steps are computed using the Structural Similarity Index Measurement algorithm. The normalized data goes through the SOM algorithm and clusters similar patterns along the frequency axis. To reduce the number of clusters, SOM nodes go through the K-means algorithm. The quality of clustering is evaluated by analyzing the unified distance matrix with weights colored by the relevant cluster.

The proposed algorithm generates a single horizon containing clustered seismic patterns. These patterns are then compared to the geologist's interpretation outcome, which was based on the "best matching" spectral decomposition RGB blending. The algorithm successfully identifies and clusters mud volcanoes along with their invasion zones and chimneys into separate clusters. It also clusters channelized facies into 2-3 distinct clusters, automatically separates floodplain areas, and identifies poor data areas.

Due to the input of a wide frequency range, the algorithm goes beyond expected geological features. It enhances channel continuity and automatically identifies thinner channelized features that were not depicted on manually created maps. The algorithm's capabilities provide valuable insights and improve the overall accuracy of seismic data interpretation.

This paper introduces a novel algorithmic approach for interpreting seismic data that goes beyond traditional methods, and offers a fresh perspective on seismic data interpretation, by enabling fully automated and quick seismic facies clustering, reducing human bias, and improving feature identification. It offers practical applications in reservoir characterization and hydrocarbon exploration, as well as valuable insights for industry professionals, researchers, and decision-makers involved in seismic data interpretation and exploration activities.
Digital Transformation of Well-Engineering: Deploying an Integrated Cloud-Based Solution for Enhanced Performance and Collaboration
Authors: Morrison A. , Rakhmetov Z. , Vij J. , Huang J. J. , Mulyukova Y.
Published: November 2023

In 2022, Tengizchevroil (TCO) adopted and transitioned to a cloud-based well-engineering solution (combination of multiple engineering engines), an adoption that was built upon the successful implementations and learnings from other asset locations. The primary objective is to achieve enhancements in performance, integration of data and applications, and improved collaboration targeted for factory or pad well planning. This paper outlines the deployment process, significant milestones, utilization of agile methodology, and the benefits derived from this digital transformation.

After an initial agile workflow mapping and optimization exercise, offset well survey and drilling data were centralized in an integrated database to enable automation. Digital well planning templates were established, an optimized subsurface data integration workflow was implemented, and one-click drilling program capabilities were deployed. Additionally, a well-structured and prioritized backlog was created to define the minimum viable product (MVP). Prior to the final deployment, a dedicated 3-week bubble support/hypercare phase was conducted to ensure a smooth transition to the new engineering solution.

Due to the well-coordinated efforts throughout the journey, TCO successfully trialed and launched the integrated cloud-based solution in September 2022. User feedback was captured throughout the integration process and adjustments implemented within the templates. Full implementation for future factory and pad drilling planning is planned based on the milestones and benefits that were noted during the trial phase.

From an optimization standpoint, the implementation of advanced tools such as "copy basis of design", stick chart analysis, and automated trajectory, hydraulics, torque & drag (T&D) and anti-collision, has significantly reduced well-planning times. Interaction with sub-surface teams, and with other applications, has been significantly improved. The inclusion of inbuilt quality checks and automated engineering validation engines has ensured consistent well planning. And the fully interconnected engineering system provides automated adaptation after any re-planning modifications. Each development requirement underwent a thorough review, following an agile methodology, to implement TCO's requirements. On a global scale it has also been recognized that the Software-as-a-Service (SaaS) model leads to reduced operational expenditures.
Sexual Support Experiences of Australian Adults Living with a Spinal Cord Injury
Authors: Doig Connor , Allen Andrew , Mason Jonathan , Heck Marita , Cudmore Timothy
Published: November 2023

Objectives: Sexuality is a key domain of wellbeing that is significantly compromised by SCI but often left unaddressed during rehabilitation, with a typical focus being genital functioning and fertility. Using a theory-driven qualitative methodology and applying Material, Discursive, Intrapsychic Theory (encompassing multiple dimensions of sexuality), this study explored the support experiences of nine Australian adults with an SCI.
Design: This qualitative methodology took a deductive, critical and constructionist theoretical perspective, which prioritised the collection of information-rich data over acquiring a large sample size, and utilised a contextual approach to understanding the facets of sexual wellbeing.
Setting & Methods: Male (N = 8) and female (N = 1) participants with varying levels of SCI completed an online interview which was primarily participant-led.
Results: Participants’ responses reflected previous research on sexuality in SCI, noting an emphasis on physical aspects (e.g., erection and ejaculation ability) to the neglect of the psychological and interpersonal. The three core components of Material, Discursive, Intrapsychic Theory were mapped onto themes from the data, with multiple sub-themes comprised in each, demonstrating that aspects aside from sensation loss like gender identity, self-confidence, and disability stereotypes all effect sexual wellbeing. An additional fourth theme of relationship dynamics was also identified, including aspects such as connectedness and perceived safety in relationships.
Conclusions: This provides practical implications for support experiences such as the inclusion of partner support in rehabilitation. Further investigation is recommended to provide specific interventions for regaining sexuality in the context of a SCI.
Giant electric field-induced second harmonic generation in polar skyrmions
Authors: Li Qian , Wang Sixu , Li Wei , Deng Chenguang , Hong Zijian , Gao Hanbin , Li Xiaolong , Gu Yueliang , Zheng Qiang , Wu Yongjun , Evans Paul , Li Jing-Feng , Nan Ce-Wen
Published: November 2023

Electric field-induced second harmonic generation (EFISH) allows electrically controlling nonlinear light-matter interactions crucial for emerging integrated photonics applications. Despite its wide presence in materials, the figures-of-merit of EFISH are yet to be elevated to enable novel device functionalities. Here, we show that the polar skyrmions, a topological phase spontaneously formed in PbTiO3/SrTiO3 ferroelectric superlattices, exhibit an outstanding comprehensive EFISH performance. The second-order nonlinear susceptibility and modulation depth, measured under non-resonant 800 nm excitation, reach ~54.2 pm V-1 and ~664% V-1, respectively, and high response bandwidth (at gigahertz scales), wide operating temperature range (up to ~400 K) and good fatigue resistance (>1010 cycles) are also demonstrated. Through combined in-situ experiments and phase-field simulations, we establish the microscopic links between the exotic polarization configuration and field-induced transition paths of the skyrmions and their EFISH response. Our study not only presents a highly competitive thin-film material platform ready for constructing on-chip devices, but opens up new avenues of utilizing topological polar structures in the fields of photonics and optoelectronics.
Cenozoic India-Asia collision driven by mantle dragging the cratonic root
Authors: Li Yanchong , Liu Lijun , Peng Diandian , Cao Zebin
Published: November 2023

The driving force behind the Cenozoic Indian-Asia collision remains elusive. Using global-scale geodynamic modeling, we find that the continuous motion of the Indian plate is driven by a prominent upper-mantle flow pushing the thick Indian lithospheric root, originated from the northward rollover of the detached Neo-Tethyan slab and sinking slabs below East Asia. The maximum mantle drag occurs within the strong Indian lithosphere and is comparable in magnitude to that of slab pull (1013 N/m). The thick cratonic root enhances both lithosphere-asthenosphere coupling and upper-plate compressional stress, thereby sustaining the topography of Tibetan Plateau. We show that the calculated resistant force from the India-Asia plate boundary is also close to that due to the gravitational potential energy of Tibetan Plateau. Our findings suggest that this mantle flow is key for the formation of the Tibetan Plateau and represents part of a hemispheric convergent flow pattern centered on central Asia.
Deciphering the influence of centrosome-related genes on osteosarcoma to develop a prognostic signature
Authors: Zhong Yujian , Wei Sixing , Zeng Xiaoshuang , Jin Wenyi , Chen Junwen , Zhong Changheng , Huang Liangkun , Zhu Zhengjie , Xu Hanzhe , Zhou Jianlin , Peng Hao
Published: November 2023

The centrosome, a vital component in mitosis in eukaryotes, plays a pivotal role in cancer progression by influencing the proliferation and differentiation of malignant cells, making it a significant therapeutic target. We collected genes associated with centrosomes from existing literature and established a prognostic model for 85 osteosarcoma patients from the TARGET database. Genes associated with prognosis were identified through univariate Cox regression. We then mitigated overfitting by addressing collinearity using LASSO regression. Ultimately, a set of five genes was selected for the model through multivariable Cox regression. Model performance was assessed using ROC curves, which yielded a training set AUC of 0.965 and a validation set AUC of 0.770, indicating satisfactory model performance. We further identified genes with differential expression in high and low-risk groups and conducted functional enrichment analysis using KEGG, GO, Progeny, GSVA, and GSEA. Results revealed significant variances in various immune-related pathways between high and low-risk cohorts. Analysis of the immune microenvironment using ssGSEA and ESTIMATE indicated that individuals with unfavorable prognoses had lower immune scores, stromal scores, and ESTIMATE scores, coupled with higher tumor purity. This suggests that high-risk individuals have compromised immune microenvironments, potentially contributing to their unfavorable prognoses. Additionally, drug sensitivity and molecular docking analysis revealed increased responsiveness to paclitaxel in high-risk individuals, implying its prognostic value. The JTB-encoded protein exhibited a negative binding energy of -5.5 kcal/mol when interacting with paclitaxel, indicating its potential to enhance the patient's immune microenvironment. This framework enables patient prognosis prediction and sheds light on paclitaxel's mechanism in osteosarcoma treatment, facilitating personalized treatment approaches.
Predictive value of spectral dual-detector computed tomography for PD-L1 expression in stage I lung adenocarcinoma: Development and validation of a nomogram
Authors: Wang Tong , Fan Zheng , Yue Yong , Lu Xiaomei , Deng Xiaoxu , Hou Yang
Published: November 2023

Background
Programmed death ligand 1 (PD-L1) expression is a predictive biomarker for the efficacy of immune checkpoint inhibitors in treating early-stage lung adenocarcinoma (LA). Given that studies on the relationship between PD-L1 expression and spectral computed tomography (SDCT) quantification, qualitative parameters, and clinical biomarkers are limited, we aimed to explore this aspect for stage I LA and developed a nomogram to aid in preoperative individualized identification.
Methods
We analyzed SDCT parameters and PD-L1 expression in patients with invasive non-mucinous LA diagnosed by postoperative pathology. Based on the expression of PD-L1 (threshold, 1%), the patients were divided into positive and negative groups.
Results
Overall, 356 participants were included in the analysis. After univariate analysis, 18 parameters were associated with PD-L1 expression. Multiple regression analysis was performed on the significant parameters with AUC > 0.6, further, CT.value, CT40kev.a, Zeff.a, ED.a, ED.v, TK1, and Dsolid were found to be independent risk factors for PD-L1 expression in stage I LA. The clinical decision-making curve of the SDCT parameter-clinical nomogram had the highest net benefit over a wide range of threshold probabilities, and the clinical impact curve indicated its clinical validity. Model comparisons revealed the higher discriminatory accuracy of the nomogram than that of any individual variable.
Conclusion
Quantitative parameters based on SDCT can predict the expression of PD-L1 in early-stage LA, with Zeff.a playing a prominent role; our nomogram showed excellent predictive performance and good calibration. This approach may promote better non-invasive prediction of PD-L1 expression.