bluuebunny/crossref_metadata_2025 huggingface dataset:
Why are Some Listeria monocytogenes Genotypes More Likely to Cause Invasive (Brain, Placental) Infection?
Authors: Vazquez-Boland Jose , Wagner Martin , Scortti Mariela
Published: November 2020

Although all isolates of the foodborne pathogen Listeria monocytogenes are considered to be pathogenic, epidemiological evidence indicates that certain serovar 4b lineages are more likely to cause severe invasive (neuromeningeal, maternal-fetal) listeriosis. Recently described as L. monocytogenes “hypervirulent” clones, no distinctive bacterial trait has been identified so far that could account for the differential pathogenicity of these strains. Here we discuss some preliminary observations in experimentally infected mice suggesting that serovar 4b hypervirulent strains may have a hitherto unrecognized capacity for prolonged in vivo survival. We propose the hypothesis that protracted survivability in primary infection foci in liver and spleen –first target organs after intestinal translocation– may cause L. monocytogenes serovar 4b hypervirulent clones to have a higher probability of secondary dissemination to brain and placenta.
Exercise as an Adjuvant to Bone and Cartilage Regeneration Therapy
Authors: Smith John
Published: November 2020

Abstract: This article provides a brief review of the ontogeny of chondrocytes and the pathophysiology of osteoarthritis (OA), and details how physical exercise improves the health of osteoarthritic joints and enhances the potential of mesenchymal stem cells for successful transplantation therapy. In response to exercise chondrocytes increase their production of glycosaminoglycans, bone morphogenic proteins and antiinflammatory cytokines and decrease their production of proinflammatory cytokines and matrix degrading metalloproteinases. These changes are associated with improvements in cartilage organization and reductions in cartilage degeneration. Studies in humans indicate that exercise increases peripheral blood recruitment of bone marrow-derived mesenchymal stem cells (BM-MSC) and upregulates BM-MSC expression of osteogenic and chondrogenic genes, osteogenic micro-RNAs, and osteogenic growth factors. Rodent experiments are uniform in demonstrating that exercise enhances the osteogenic potential of BM-MSC while diminishing their adipogenic potential, and that exercise done after stem cell implantation may benefit stem cell transplant viability. Physical exercise also exerts a beneficial effect on the skeletal system by decreasing immune cell production of osteoclastogenic cytokines interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and interferon (INF)-γ while increasing their production anti-osteoclastogenic cytokines IL-10 and transforming growth factor (TGF)-β. In conclusion, physical exercise done both by stem cell donors and recipients may improve the outcome of mesenchymal stem cell transplantation.
EVALUASI KEPUASAN MAHASISWA TERHADAP PELAYANAN AKADEMIK FAKULTAS TARBIYAH DAN ILMU KEGURUAN IAI MUHAMMADIYAH SINJAI
Authors: Nurjannah Nurjannah
Published: November 2020

This research was descriptive with a quantitative approach. Quantitative research involves measuring the level of certain characteristics. The subjects of the study were all students of the Faculty of Tarbiyah and Teacher Training, Islamic Institute of Muhammadiyah Sinjai. Data collection techniques using questionnaires and documentation. Based on the research results obtained that the evaluation of student satisfaction with academic services in the Faculty of Tarbiyah and Teacher Training based on 6 aspects of assessment namely tangibles aspects of 3.29, assurance aspects of 3.85, reliability aspects of 3.88, empathy aspects of 4.04, the responsiveness aspect is 3.81 and the information system aspect is 3.80. Based on these values, the six aspects are categorized as good. of the 6 aspects of the assessment, the highest assessment is on the assurance aspect while the aspect that needs to be improved is the tangibles aspect. Whereas the assessment of each study program the highest is Tadris Mathematics and the lowest is Arabic Education.
A Coupled Diffusion Model for Gas Transport in Tight Unconventional Reservoirs
Authors: Yuan Meng , Jing Yu , Wang Ying Da , Armstrong Ryan , Mostaghimi Peyman
Published: November 2020

Tight unconventional reservoirs are being developed in the global natural gas market. Gas production from unconventional tight reservoirs such as coalbeds or shales is a multi-physics process where diffusion and sorption are coupled. Gas diffusion, the complex flow mechanism in the tight unconventional reservoirs, is crucial during gas production, of which the mechanisms have not been well understood. Gas diffusion in rocks is a complex process, especially when gas is adsorbable to rock surfaces, where surface diffusion cannot be ignored. This paper aims to analyze the sensitivity of rock and gas parameters during gas diffusion and provide insights into the physics of gas transport in tight rocks. We develop a dual-diffusivity model for tight rocks at the continuum scale. We study the impact of two types of diffusions under different conditions and include the adsorption-induced swelling within this model. Also, the free and adsorbed gas concentration fields are simulated in a coal core. The simulation results show that compared with surface diffusion, free gas diffusion is more likely to dominate the diffusion process at relatively low pressure, high temperature and high porosity. In addition, the results indicate the importance of the level of coal swelling on the diffusion process in coal.
Directional Difficulty Index Across Different Offshore Fields in a National Oil Operating Company in the Middle East Reveals Market Variations and the Adoption of Disruptive Technologies Impact in Drilling Operations
Authors: Ness Knut Johannes , Exposito Gonzalez Juan Jose , Iftikhar Choudhry Bilal , Torres Premoli Javier Ernesto , Couzigou Erwan
Published: November 2020

The main objective of this study is to validate the market variations and the adoption of disruptive technologies effects on Drilling Operations through the analysis of Directional Difficulty Index (DDI) for historical and current wells with a common framework, allowing demonstrating the variations caused by the deployment of disruptive technologies as well as the impact of the market behavior.

The methodology used here is predicated upon three main steps:

First, historical drilling data for exploration and development wells for Abu Dhabi National Oil Company Offshore has been evaluated using the Definitive Survey listings.

Second, this data has been correlated against the market historical data and with the introduction of disruptive new technologies that have dramatically changed the technical limit as well as in the standard operational practices has been observed.

Third, a detailed analysis has been made of the correlations of market and introduction of technologies with their impact in the complexity of the wells.

The study is an attempt to document correlation of the following elements to the main parameter analysed i.e. the directional difficulty index: Oil and gas market behaviour towards a direct impact in the complexity of the wells drilled:▪  During market downturn, the complexity of the wells is reduced▪  During the market uptick, the complexity of the wells increasedIntroduction of new disruptive technologies have a direct impact in the complexity of the wells, we focused on three technologies that changed the traditional practices increasing the technical limit, and its effect on the directional difficulty indexTwo additional observations were considered relating to the directional complexity index:▪  The development stage of the field: green or mature and its effect on the complexity of the wells▪  The field structure which determine the development strategy: i.e. drive line or rim developments and its effect on the complexity of the wells

This study involving market behaviour, the introduction of new technologies and how they affect the directional difficulty index is a maiden attempt in its league; determining this correlation helps to better address the influence of these elements in long term strategic planning and predict change.

In addition, if the findings associate the development stage of the field and the field structure with the directional difficulty index, this opens the door for future studies to better determine their influence.
Novel Technology to Improve Recovery of Remaining Oil in Tight Glutenite Reservoir of Junggar Basin: Employing Chemical Diverting Agents in Refracturing Operation
Authors: Wang Yong , Zhao Xubin , Shang Jianlin , Tang Chuanyi , Deng Jiasheng , Xing Yangyi
Published: November 2020

The production wells in tight glutenite reservoirs have great potential for refracturing, because most of fracturing fluid and proppant flow into the first-class layer with lower initiation pressure during initial stimulation with multi-layer simultaneous fracturing treatment. However, layer segmentation during refracturing can be a challenge, especially in vertical wells. Using only mechanical segmentation tools is of high risk and sometimes ineffective. This paper presents a new refracturing technology for vertical wells employing diverting agents. The segmentation tools are rarely needed in the new refracturing technology. The implementation procedures are as follows: First, reservoir characteristics, remaining oil distribution and water content are evaluated to identify the target layers of refracturing. Second, through the classification of predicted initiation pressure, number of temporary plugging and diverting fracturing are determined. The dosage of chemical diverting agents is designed. Finally, refracturing treatment are performed with an injection procedure of "fracturing fluid and proppants (dredging existing fractures) + granular plugging agents (blocking existing fracture entrances) + fracturing fluid and proppants (creating new fractures) + powdery plugging agents (blocking new fracture tips) + fracturing fluid and proppants (creating complex fracture networks)". The refracturing treatment was performed in Well B1401 located at Junggar Basin in China using the method presented in this paper. The fracturing construction curve of Well B1401 shows that obvious pressure increase was observed when the diverting agents was added, and the initiation pressure or propagation pressure of subsequent fracture was monitored higher than that of previous fracture. It is suggested that proper agents or combinations can effectively plug the opened fractures and generate high enough pressure in the fractures to initiate branch fractures. The production log data indicate that five new layers begin to produce oil after refracturing operation, and the daily oil production of Well B1401 remarkably increased from 1.5 t/d to 9.8 t/d in the field test, which verifies the validity of the tool-free refracturing of vertical wells employing diverting agents. This study provides a new refracturing technology for vertical wells in tight glutenite oil reservoir employing diverting agents is presented. The segmentation tools are rarely needed in the new refracturing technology. It has been applied to hundreds of low-yielding oil wells in tight glutenite reservoirs of Junggar Basin, China. The average annual oil production per well has increased by 950t. It also provides guidelines to the engineers with respect to refracturing design and commercial viability. In addition, this technology is not only suitable for vertical wells, but also for horizontal wells.
Technologies for Energy Transition
Authors: Bedani Omar , Depetri Valentina , Ruggeri Fabio
Published: November 2020

The production of fuel and chemicals in many countries is based on fossil sources but concerns about reservoir limitations and greenhouse gas emissions are shifting the focus towards solutions to increase the efficiency of processes and decarbonise these markets: the objective of this paper is to provide an overview on low-carbon intensity technologies that are instrumental to the decarbonisation of the energy industry.

Hydrogen is the most promising low-carbon intensity energy vector. However, it is mainly produced through hydrocarbon steam reforming which generates 9 to 12 metric tons of CO2 per ton of produced hydrogen. A key factor in driving the energy transition and achieving a low-carbon future is therefore the potential to obtain low carbon intensity hydrogen – through carbon capture solutions producing blue hydrogen, using biofeedstocks within adapted steam reforming applications to produce biohydrogen, or via water electrolysis utilizing renewable power.

The blue hydrogen technology described in this paper results in more than 90% CO2 emissions reduction due to the integration of an advanced steam reforming solution with pre-combustion carbon capture. While blue hydrogen, which is produced from hydrocarbons, is able to significantly reduce the emissions to the atmosphere, but still produces some CO2, biohydrogen is instead a carbon neutral solution achived via modified steam reforming of liquid biofeedstock. This technology has the potential to be carbon negative when enhanced with a carbon capture system.

Another aspect of the decarbonisation process, Substitute (or Synthetic) Natural Gas (SNG) from biomass gasification, biogas upgrading and power-to-gas systems is the most promising and immediate solution among the hydrocarbon-based fuels. SNG product has great market possibilities in refining, and automotive sectors or for injecting into pipelines for the upgrading and re-purposing of distribution networks. The product is a clean carbon alternative to conventional natural gas that can be distributed using the existing grid infrastructure.

Wood is pleased to present this paper to introduce the above-mentioned technologies for hydrogen and SNG, with the aim to provide viable and alternative solutions to industrial operators who are looking to support the economy decarbonisation securely and create a more sustainable future.
A Geochemical Technique for Formation Evaluation and Oil Water Contact OWC Identification in a Mature Tight Carbonate Reservoir Field in Abu Dhabi, UAE
Authors: Ahsan Syed Asif , Dantla Vijaya , Firmansjah Mochamad Arief , Koksalan Tamer
Published: November 2020

Direct hydrocarbon measurement on extracts of core and cuttings and SARA (Saturate, Aromatic, Resin and Asphaltene) compositional analysis integrated with mud log and petrophysical data provide a high confidence reservoir saturation assessment and oil-water-contact (OWC) identification where testing and perforation decisions can be timely and cost effectively achieved.

A suite of forty eight (48) core plug and cuttings samples from seven (7) wells were analyzed. SARA composition were determined on extracted samples to assess hydrocarbon saturation and OWC through the reservoir of interest. Log and core data comparison with a vertical well, drilled nearby previously, may help to provide hydrocarbon saturation assessment of the section drilled in the horizontal section. However, despite detailed core studies on the vertical well drilled nearby, encountering surprises in the horizontal section due to the complexity of geology is not un-common. In order to circumvent these surprises, here we propose a cost optimized quasi real time formation evaluation and OWC identification using analytical and interpretive protocol that has proved extremely helpful in X reservoir in an oil field in Abu Dhabi. Data and interpretive protocol adopted in this study, although applied to an appraisal scenario, has equally good application potential for development drilling for the selection of an optimal perforation interval.

The novel integrated approach presented here utilizing mud log, extract yield normalized to rock weight and SARA composition, though present and utilized independently for decades in the industry, has been adopted concurrently to assess hydrocarbon saturation and OWC identification. Coupled with conventional open hole logs, mud log and extracts geochemical data on core and cuttings samples provide a robust perforation or completion interval selection. Such perforation interval selection or isolation of high water zone in a horizontal well scenario is particularly very critical in thin and tight reservoirs where improper well completion may severely impact reservoir performance and project's economics.
Challenges in Benefit Realization of the Smart Instruments Diagnostics Capability
Authors: Valasubramanian A..
Published: November 2020

Smart field instruments (sensors & valve positioners) are the main digital data source required for modern day predictive data analytics tools and frameworks. Apart from communicating the measurement value, there are many additional features available within the smart field devicessuch as sensor diagnostics, remote set up, commissioning, trouble shooting and calibration, all within the same 2 wire used for the signal communication.

This paper summarizes the challenges faced in the journey of realizing the benefits of smart field instruments diagnostics using Highway Addressable RemoteTransducer (HART)open protocol as part of Instrument Asset Management System (IAMS).
Multi-Tubular Electromagnetic Corrosion Inspection Tool – Performance Demonstration using Yard Testing
Authors: Fouda Ahmed , Dai Junwen , Hu Yunyun
Published: November 2020

A multi-frequency electromagnetic pipe inspection tool with multiple transmitter and receiver arrays was designed to accurately estimate the individual wall thicknesses of as many as five nested pipes. The new tool enables monitoring well casing integrity without having to pull out production tubings, therefore minimizing inspection time and cost. This paper demonstrates the performance of the tool using yard mockups with known defects. The principle of tool operation and the methodology for data processing are also detailed in the paper.

The tool relies on eddy current principle in its operation. It comprises two sections of transmitting and receiving coil antennas and operates in continuous-wave mode at multiple frequencies. The configuration of strategic transmitter-receiver spacing and multi-frequency operation delivers a suitable range of information to evaluate individual pipes for the majority of well configurations. An advanced inversion-based data processing workflow is executed to estimate pipe parameters, including electrical conductivity and magnetic permeability, wall thickness, and eccentricity.

The proficiencies of the technology are confirmed by performing yard tests with two long test mockups. Each mockup has multiple combinations of overlapping and non-overlapping man-made defects distributed along sections consisting of three, four, and five nested pipes, which mimic typical corrosion progression. The measurement data from the mockups are validated against synthetic data generated from a 2D electromagnetic forward solver. Then, a procedure including pipe material property estimation, calibration, and inversion algorithms is performed to retrieve pipe thickness.

Results from the yard tests reveal that this tool is fully capable of detecting various kinds of corrosions concurrently across five strings of pipes, even on the outer pipes with high severity. The impact of pipe eccentricity on the accuracy of thickness estimation is also shown by deliberately decentralizing the innermost pipe over a length of the testing setup.

The information provided by this tool can improve the efficiency of well intervention operations, especially in areas with high-corrosion rates, and could result in significant cost savings to the operator.
Epoxy Resins-Cement Slurries for Primary Cementing Application
Authors: Hashmi Ahmad Atef , Al-Yami Abdullah Saleh , Dahmoush Abdullateef Ahmed , Wagle Vikrant , Alanqari Khawlah Abdulaziz , Alshaikh Saber Y , Gumsani Abdullah M , Ali Wajid , Al-Turki Faisal Abdullah
Published: November 2020

Polymer resin systems have many advantages over conventional cement. Since resins are solids-free particles, they can be used in low injectivity zones such as narrow fractures where conventional cement cannot be squeezed through. Besides, the resins can be used in combination with cement to enhance casing/cement bonding for improved wellbore isolation. To ensure the success of a field application, the lab testing must be performed at downhole conditions.

The objectives of this paper are to study the performance of epoxy resins and their curing agents. Also, to examine cement-resin slurry formulation testing and field application.

Cement Slurry was designed with suitable rheology and thickening time. This was done by utilizing enough curing agent into the cement-resin slurry. This study also highlights a successful field deployment to cement a 9 5/8-in liner tie-back job.
An Automated Diagnostic Analytics Workflow for the Detection of Production Events - Application to Mature Gas Fields
Authors: Poort Jonah , Shoeibi Omrani Pejman , Vecchia Adrian Luciano , Visser Gerlof , Janzen Mathijs , Koenes Jimmy
Published: November 2020

Detection of production and well events is crucial for planning of production and operational strategies. Event detection is especially challenging in mature fields in which various off-normal events might occur simultaneously. Manual detection of these events by an engineer is a tedious task and prone to errors. On the other hand, abundance of data in mature fields provides an opportunity to employ data-driven methods for an accurate and robust production event detection. In this study a data-driven workflow to automatically detect production events based on signatures of events provided by experts is demonstrated. In the developed workflow, state-of-the-art data-driven methods were integrated with the domain knowledge for an accurate and robust detection. The methodology was applied on several case studies of mature fields suffering from production issues, such as scaling and liquid loading. It was found that the workflow is accurate, robust and computationally efficient which could detect new events (verified by the expert). The demonstrated method could be implemented both in the real-time or offline fashion. Such a workflow is sufficiently generic which can be applied for detection of different events and anomalies than tested and verified in this paper, such as leakage, production losses, …
Advanced Analysis of CO2 Storage Development Plan and its Unique Compared to Field Development Plan
Authors: Widyanita Ana , B W Zairudin W Ahmad
Published: November 2020

There will be future development of hydrocarbon fields with high CO2 content in Malaysia. Carbon Capture and Storage (CCS) is required in order to develop these fields, since venting and flaring of CO2 to atmosphere is not allowed. Reducing CO2 emission will impact to environments and climate change. On the storage part, integrated study needs to be conducted to ensure the field is suitable as storage site. The main objective of this paper is focusing on the important advanced analysis and assessments for maturing potential CO2 storage sites, which is called Storage Development Plan (SDP).

The evaluations and analyses will cover 4 major areas, which are Storage Capacity/Injectivity; Containment; Well Integrity; and Monitoring, Measurement and Verification (MMV). These evaluations and analyses are conducted in order to assess the subsurface risk, reduce uncertainties and mitigation plan in maturing the fields as storage sites. Integrated screening and maturation assessments of potential storage sites must be conducted in order to identify the most suitable CO2 storage sites.

The Storage capacity/injectivity analyses will cover estimation of CO2 storage capacity, optimum injectivity strategy, sensitivity on CO2 injection scenarios, and study on porosity-permeability changes, trapping mechanism and long-term fate study. Containment analyses will cover assessment of containment/seal integrity, possible leakage risk pathways, evaluation of compaction and subsidence to hold injected CO2 as long-term storage solution. Well Integrity analyses will cover the evaluation of well integrity and leakage assessments through existing wells, assessment of existing wells for conversion and propose cost-effective mitigation plan. Monitoring, Measurement and Verification (MMV) will cover monitoring and verification of CO2 injection performance and behavior consistent with prediction on capacity and injectivity, monitoring seal integrity, monitoring compaction and subsidence, and ensuring containment that address health, safety and environment. This advances analysis and maturation assessments provide solution to mature the best suitable storage sites for development of hydrocarbon fields with high CO2 content.

This Storage Development Plan (SDP) would form a benchmark of advance analyses and assessments for maturing the CO2 storage sites in Malaysia and elsewhere in the world. This will be integrated study consists of overburden, reservoir, laboratory, well integrity and MMV studies. This integrated study will reduce the subsurface uncertainty and mitigate the identified risk for any fields that are selected as storage site. This greatly aids to optimize and commercialize the future development of hydrocarbon fields with high CO2 content.
Reservoir Structural Imaging Using Azimuthal Dipole Sonic And Vertical Seismic Profiling
Authors: Van Kleef Franciscus , Verma Ravi , Waqas Muhammad , Donald Adam , Benett Nicolas , Suliman Israa , Al-Kharusi Saif , Hirabayashi Nobuyasu
Published: November 2020

Offshore Abu Dhabi a deviated well, with a dip of 51 degrees over the logged section, was logged using modern full waveform sonic tool with monopole and dipole sources. By using the individual single receiver sensor polarized shear reflections from dipole source, the dip and azimuth of the reflector were determined. The reflections recorded matched very well with the structure recorded from a walk-above VSP and the resistivity image also acquired in the same well and with the 3D seismic.

In another field offshore Abu Dhabi, standard dipole data was used to image layering and natural fractures using a modified workflow. In this horizontal wellbore, the relative dip of the events from the 3D-STC were used to place the migrated images appropriately above and below the wellbore.

The described method using sonic tools detects reflections up to 30 m away from the wellbore at meter scale resolution. As such this fills the gap between seismic which records reflections at 30-100 m scale resolution, VSP at 10 m scale resolution and micro resistivity images at millimeter scale.
Advancing Relative Permeability Estimation Through Data-Driven Modeling
Authors: Kalam Shams , Khan Mohammad , Khan Rizwan Ahmed , Alam Mir Muhammad , Sadeed Ahmed , Mahmoud Mohamed , Abu-Khamsin Sidqi A.
Published: November 2020

Availability of large amounts of data helps in developing data-driven models using state of the art Artificial intelligence (AI) methodologies. Relative permeability is an important parameter used by reservoir engineers and are usually accurately obtained from laboratory experiments, which are relatively expensive. Therefore, AI can play an important role in developing models to predict relative permeability accurately without extensive lab procedures. Accordingly, this work presents application of two AI algorithms namely, Artificial Neural Network (ANN) and Adaptive Neuro-Fuzzy Inference System (ANFIS). Furthermore, two novel mathematical correlations are extracted from the ANN model to predict relative permeability of oil/water in oil- and water-wet environments. The input data, obtained from literature, for the development of AI models include porosity, rock absolute permeability, initial water saturation, residual oil saturation, wettability index and water saturation.

A customized workflow is applied to ensure proper data is fed into the AI models. In addition, a rigorous sensitivity analysis is performed within the framework of this workflow. This analysis involves running multiple realizations with varying number of neurons, resulting in various weights and bias for the ANN model. Moreover, ANFIS model is tuned using various cluster sizes to result in the most optimum value. Finally, the optimized ANN and ANFIS models are compared using the Root Mean Squared Error (RMSE) and correlation coefficient (R2) analysis when applied to a blind dataset comprising of more than 300 data points. The analysis illustrates that the ANN model is relatively better in predicting relative permeability values to both, oil, and water. On the other hand, analysis of the ANFIS model shows that it yields high error values when tested on unseen dataset. Also, unlike the ANN mode, it does not provide an actual mathematical correlation. This work presents alternate data-driven artificial intelligence models which will lead to quicker and cheaper relative permeability estimates.
Insights of Processing Early-Outs from New High-Quality 3D Seismic Data for Exploration Prospectivity: A Land Case Example from Abu Dhabi
Authors: Caeiro Maria Helena , Cambois Guillaume , Mahgoub Mohamed , Al Hammadi Miaad , Smith Cara L.
Published: November 2020

Currently ADNOC is conducting the world's largest continuous 3D seismic acquisition campaign of approximately 90 000km2 with the aim of covering the entire Abu Dhabi emirate subsurface (both onshore and offshore) with 3D seismic. The main objective of this campaign is to provide high quality seismic data to explore conventional and unconventional resources. The new 3D covers areas that were under-explored in the past and is of excellent quality to apply advanced technologies for interpretation and reservoir characterization. The new 3D seismic data has high-trace density, broadband frequency content, full-azimuth and long offsets, which provides paramount information for detailed subsurface imaging and characterization of complex reservoirs.

This study is focused on a 3D land seismic survey recently acquired that is currently at the time and depth imaging stage. The early-out volumes obtained from processing consist of valuable preliminary data that can be used to infer some possible exploration prospectivity features while final processing is still ongoing.

A significant benefit of the pre-stack depth migration (PSDM) method is the construction of a detailed anisotropic subsurface velocity property model. Therefore, it accounts for lateral velocity variations, which are related to geological features especially attractive to explorationists, and has a more accurate overburden representation than historical time imaging workflows. Herein, we present some examples on how the 3D PSDM volume reveals more confidence in geological features that are not so clear in a pre-stack time migrated (PSTM) volume. The preliminary results indicate how shallow hydrocarbon presence can interfere with the PSDM velocity model and how it can be solved to reveal possible exploration potential in deeper sections.
Casing Wear Modelling: A Comparison between MFCL and 3D Stiff String Model
Authors: Aichinger Florian , Nobbs Benjamin , Couliou Florent , Dao Ngoc-Ha , Brillaud Loic , Medrano Silfredo
Published: November 2020

A stiff-string torque & drag & buckling model has been coupled to a 3D meshed casing wear calculation to model the effect of drilling operations on casing wall thickness reduction. Results of the numeric simulation are compared to MFCL for field cases and provide an understanding of possible well integrity issues during the well life cycle. A Hall wear model and 3D rigid stiff string model is used to predict casing wear. Using Wear Factor Coefficients obtained for several hard-banding, casing grade and mud-types, the process was tested against numerous field cases. For each field case, a history of drill string runs were modelled and filtered into operations in which the drill string rotates such as Drilling, Reaming, Back reaming and ROB. Initially, the calliper log was not analysed to ensure the results are non-biased using experimentally found Wear Factors. In a second phase, the Wear Factors were calibrated against the measured calliper log. This paper provides a methodology that was used to successfully quantify the effect of casing wear against numerous field cases. The 3D orientation of the casing wear was found from an un-calibrated MFCL. After calibration of the new Wear Factor, the casing wear can be predicted before and after well construction. When used as a post analysis tool, the methodology helps determine if casing wear was a root cause of loss of well integrity. This process also helps reduce the uncertainty in Wear factor as a major unknow in the contact force, is now properly modelled. When used in a post analysis process, the results where quantitative (groove depth vs 3D orientation) but also qualitative, providing a post-mortem description of the state of the well to operation's personnel. The methodology presented here can be used to both predict excessive casing wear and determine if excessing casing wear was a cause of failure. It can be used to help determine the state of well for workover operations or plug and abandonment operations. Accurate casing wear prediction at planning stage allows the anticipation of costly but fit for purpose mitigation means & measures.
What Test Environment for the Qualification of OCTG Sour Service Grades – Means and Consequences of pH Control
Authors: Florian Thebault , Julien Pennequin , Hervé Marchebois , Christelle Gomes
Published: November 2020

Many worldwide Oil & Gas fields are sour with H2S partial pressures (PPH2S) above 0.05 psi. For such situations, it is critical to employ Oil Country Tubular Goods (OCTG) qualified for sour service, meaning resistant to Sulfide Stress Cracking (SSC). More especially when very high strength grades are required for producing high pressure O&G reservoirs. For instance, a quenched and tempered sour service low alloyed steel with 125 ksi Specified Minimum Yield Strength (SMYS) has been investigated through various standardized test solutions. As corrosion processes in acidic environment with dissolved H2S make the testing solution to drift, some of the standardized test solutions are highly buffered with the acid-base couple acetic acid / acetate. Another method for limiting the pH drift consists by frequent additions of strong acid as hydrochloric acid during the test. The objective of this work is to compare the electrochemical of such high strength steel in NACE TM0177 Solution B, EFC 16 solution with and without pH adjustment. Thermodynamic calculations for predicting the saturation pH, hydrogen permeation tests, corrosion rate measurements and fine characterizations of iron sulfide scales (composition, morphology and defectology) were performed for being correlated to SSC test results. Build a better understanding of test methodology impact on the hydrogen uptake and the protectiveness of corrosion products is also an aim of this work.
An Accurate Model for Prediction of Hydrocarbon Gas MMP Based on a Large High-Temperature Data Set
Authors: Mogensen Kristian
Published: November 2020

Minimum miscibility pressure (MMP) is an important parameter when designing a miscible gas flood. Traditionally, the MMP is evaluated using slimtube tests, which are time-consuming and expensive. Since it is typically not feasible to test more than a few injection gases on a subset of relevant reservoir fluids, reliable methods are required to estimate the MMP. The most popular correlations are often based on data from low-temperature reservoirs and are not always very reliable.

In this work, we make use of the new, comprehensive ADNOC PVT database, which contains more than 100 slimtube MMP measurements for a variety of injection gases, including sour gases. We then complement this data source by performing equation of state (EOS) based miscibility calculations covering a large temperature range with appropriately tuned EOS models. The combination of measured and simulated data is then used as input for development of a general correlation.

The new correlation is a modification of the Eakin-Mitch formulation. It has been tuned to a large variety of injection gases and reservoir fluid compositions, and covers a wider temperature range. The average deviation is 5% and the maximum error is less than 20%. Results show that the MMP exhibits a maximum versus temperature, a feature also noticed previously during development of CO2 miscibility (Yuan et al., 2005; Alshuaibi et al., 2019).

One of the novelties of this work is the identification of a more complicated temperature-dependency of the MMP. Furthermore, the new correlation considers not just lean gases but also rich gases and sour gases, which develop miscibility based on the combined condensing-vaporizing mechanism. We believe that this model is more robust because it covers a much larger parameter range compared to existing correlations.
An Integrated Approach to Optimise an Offshore Field Development Plan
Authors: Kasekar Hiren , Ghauri Usama , Nevin Michael , Mel Raphaele , Uijttenhout Mattheus , Alblooshi Jamal , Draoui Elyes
Published: November 2020

The ADNOC Offshore oilfield located in the Arabian Gulf is being developed utilising various wellhead towers, infield pipelines and a standalone super complex. The field development team devised an updated subsurface plan to achieve production targets beyond the original plan. The incremental oil necessitated assessment of original surface facilities design to identify any bottlenecks and unlock constraints.

A set of production forecasts were initially provided as basis for assessment covering various scenarios and range of reservoir uncertainties. To manage these uncertainties, the facilities and subsurface development teams worked in an integrated and iterative way. The production profiles were used to assess and develop understanding of surface facilities such as oil flowline network, water injection supply and network, gas lift networks and the major equipment.

The assessment results provided guidelines on the process facilities constraints which were feedback to subsurface team. An optimised subsurface development plan was then generated respecting the facility constraint and leveraging the existing facilities design to utilise ullages.

An initial view of investment to produce incremental oil considered installing three new wellhead towers, a new manifold platform and a new water injection platform both linked to the super complex and a new main oil line installation to transfer partially stabilised oil from super complex to oil processing plant. The technical evaluations and the decision analysis resulted in a low-cost solution that was needed to ensure that the field's incremental oil production is economically viable.

The integrated approach not only allowed selection of techno-commercial robust solution but also allowed optimisation of investment providing flexibility to accommodate the key project uncertainties. This was achieved by deferring the investment to future by descoping the overall development plan in two separate projects - achieve production plateau and sustain plateau. The interim period between the two projects would provide time to resolve the subsurface uncertainties and an opportunity to revisit future development strategy without committing any investment. In addition, the original UTC was significantly improved. This approach emphasised the importance of having a flexible surface facilities solution in accommodating the developments in the subsurface field development strategy especially in an offshore environment and during the early field production period.

This paper presents an approach followed for optimisation of an offshore oilfield development plan under various surface facilities constraints.
A Rapid and Cost Effective Geochemical Pyrolysis Technique Sh_Pyroil for Direct Hydrocarbon Saturation Evaluation in a Carbonate Reservoir in Abu Dhabi, UAE
Authors: Koksalan Tamer , Ahsan Syed Asif , Hanif Rehan , Baudot Pascal
Published: November 2020

In tight carbonate and clastic reservoirs, log interpreted saturation is often challenging. Archie derived Sw values involve “a”, “m” and “n” factors which are measured on samples that are quite variable within a core. Nevertheless, typically a constant “a”, “m” and “n” factor values are assumed for saturation measurements for the whole reservoir section or for a given rock type of a reservoir section which may still yield inaccurate hydrocarbon saturation having an impact on volume estimation among others. We propose an alternative solution that is real time, cost-effective and provides high confidence sweet spot identification for the selection of perforation zones in a vertical well and plugging of high water saturation zones in a horizontal well. The modified pyrolysis technique we present here and term “Sh_Pyroil” can provide high confidence direct hydrocarbon saturation rapidly (3 minutes) at a very low cost. Sh_Pyroil, measured in miligram HC per gram of rock weight (mg HC/g rock), can be conveniently converted into hydrocarbon saturation in percentage. We used modified pyrolysis on 90 core plugs, at one foot interval, from the dense and oil bearing zones. The objective of this study was to compare the thermally extracted core hydrocarbon saturation “Sh_Pyroil” to the log derived (Archie) saturation in order to assess its applicability as a rapid, cost-effective and high confidence direct hydrocarbon saturation tool that can assist in: Time sensitive drilling and completion decisions (e.g. selection of optimal perforation zones and plugging of high water saturation zones),Keeping the horizontal well in sweet spots and,In-Place hydrocarbon volume estimations, in conventional and unconventional reservoirs.
Artificial Intelligence Application for Just in Time Maintenance
Authors: Choudhary Debal D , Bist Shivprasad , Koirala Raju
Published: November 2020

In the present digital era, artificial intelligence (AI) backed decision-process can transform the way asset-failures could be managed. A Proof-of-concept of scalable AI algorithm has been developed and field-verified, to demonstrate potential to implement "Just-in-time" (JIT) maintenance. The model has ability to absorb configuration variations; it is run on periodic basis, to reassess the findings, and identify changes in the operating behavior of the asset. It is a robust tool, for the field engineers.

The objective of this research paper is to establish fundamentally different thought process for maintenance decision-makers for dynamic-diagnosis of faults using normal operating data. Each category of equipment has unique behavior, and hence must have customized solution. When linked through IIoT, the automated business decision for maintenance cost reduction can be applied on mass scale. The experimental results & field validations show that AI based diagnostics methodology outperforms traditional maintenance cost-management practices. It is a system which is self-learning, and therefore, as the model matures, dynamic strategy will evolve; and maintenance cost saving can extend beyond targeted 4% of net operating cost. The concept can be equally applied for any data-intensive-complex machineries and static-assets (Heat exchanger, Pipeline, Rotating equipment, etc.) across process industries.
Debottlenecking of Supply Chain Management Process with Blockchain Technology and Automation: A Case Study of a Typical Sub-Saharan African Oil and Gas Company
Authors: Odachi Kenechukwu
Published: November 2020

This research addresses the bottlenecks experienced in supply chain management (SCM) in an African hydrocarbon company, which slows down processes and makes the procedures tedious, this leads to operational inefficiencies. This paper discusses the security of the supply chain management data and the overall automation of procurement value chain, providing transparency to the stakeholders involved in the entire supply chain management process. It also provides a system that is not prone to malware or data alteration. The existing system lacks trust and greater transparency. A new technology will be developed using Blockchain Hyperledger which is a distributed ledger technology (DLT). The SCM application/portal serving the request and procurement process will utilize the Hyperledger Fabric SDK or REST web service to interface with the Hyperledger Fabric network. The organizations that participate in developing the Hyperledger Fabric network are known as the "members". Every member organization in the blockchain network is capable to set up their peers for taking part in the network. All these peers’ needs are configured with suitable cryptographic materials like Certificate Authority and other data. Chaincode will be actualized in peers to initiate transaction invocation request. This process will result in the chaincode providing an executable smart contract. The system executes the terms of the contract (agreement) by all necessary stakeholder's peer; for example: when goods or services are completely delivered, work Completion Certificate will be issued. This will be on the blockchain network and will be transparent to all stakeholders so once invoice is presented, the verification will be automatically ascertained and payment will be made. Procurement data like invitation to tender (ITT), request for proposal (RFP), request for quote (RFQ), contract award, work completion certificate (WCC), and invoice will be distributed among the nodes uniformly at the same time, making it impossible for cyber-invasion on all the nodes at the same time. Blockchain has been identified industry-wide as the next level in SCM operations because of its greater transparency, increased efficiency, enhanced data security, reduced costs, improved traceability, smart contract and unbroken chain of transaction history. It was observed that the blockchain implementation will further enable easy audit trail, automated and transparent Issuance of ITT/RFP/RFQ to Vendors, end-to-end SCM automation with secured data, and quality reporting system. In conclusion Blockchain Technology will enhance Supply chain manpower efficiency and hydrocarbon production. Blockchain Technology in Supply chain management will present a new knowledge in the area of integrated supply chain management for procurement process transparency and end- to-end data security