bluuebunny/crossref_metadata_2025_split huggingface dataset:
Source Rocks of the Thamama Hydrocarbon in Abu Dhabi
Authors: Taher Ahmed 
Published: November 2018

Abstract
More than 80% of Abu Dhabi oil reserves are accumulated in the Thamama reservoirs. However, its source rock locations, thickness and richness distributions are not fully understood.
Thamama hydrocarbons were generated and migrated from different source rocks including Diyab, Rayda, Thamama dense and Shuaiba basinal facies, in addition to a contribution from the deeper Paleozoic, Silurian Qusaiba and the Pre-Cambrian Huquf source rocks.
The Oxfordian, Diyab high-energy Oolitic belts are prograding in westward direction, and have resulted in the development of Diyab intrashelf basin in west Abu Dhabi. At the end of the Kimmeridgian time, Abu Dhabi basin was tilted towards the east due to the opening of Arabian-Indian Suture. This tilting had completely shifted the high-energy Oolitic belts to prograde in eastward direction, which resulted in the development of Rayda source rock in east Abu Dhabi.
The Thamama dense layers were deposited during the highstand system tract, which allowed some organic matter to be preserved; especially in intervals deposited below the wave base. The Shuaiba basinal facies were deposited in an intrashelf basin that was surrounded by the Shuaiba shelf facies. This resulted in restricted water circulation and anoxic conditions. Such depositional environment is reasonable for source rock preservation.
The hydrocarbon generations from these different sources were mainly accumulated in a super-giant Paleo-structure that was located in the northeast onshore Abu Dhabi. This Paleo-structure was segmented by the Late Tertiary tilting, which resulted in remigrating its trapped hydrocarbon into the prominent Abu Dhabi fields.
The development of Rayda source rock will increase the potentiality of finding additional unconventional hydrocarbon resources in east onshore Abu Dhabi. The high unconventional potential in this area can be attributed to the advanced level of source rock maturity and to the highly faulting and fracturing found in east onshore Abu Dhabi. The Rayda source rock maturity map confined the unconventional gas potential to the foreland basin while the unconventional oil potential is located to the south of this area (figure-10).
Understanding the locations of Thamama source rock kitchens will facilitate the delineation of its migration pathways. This will reduce the exploration risk and help in detecting prospective areas for stratigraphic traps potential along the Thamama migration pathways over all Abu Dhabi.
Significant Increases in Turnaround Maintenance Performance and Safety through Powerful Digital Integration
Authors: Tol Michel M. 
Published: November 2018

Abstract
More and more leading companies are moving to digital systems to support their operations, maintenance and turnarounds. This marks huge progress and sees impressive results: incidents and injuries decrease, risk becomes more understandable, and processes streamline and simplify. But if the information used within these digital systems is not connected or up to date, the concept simply does not work effectively.
Collaborating closely with major industry players such as Shell, BP, RasGas, Borouge, and others, eVision Software developed bespoke daily maintenance and turnaround management solutions, which address and mitigate many common turnaround and maintenance challenges. The enterprise-ready tool combines powerful Permit to Work, Risk Assessment, Isolation management and advanced (Mobile) visualisations, and integrates these into the client ecosystem. This study pertains to a major derivatives manufacturer in the UAE, in which a platform was implemented to help achieve ambitious hands on tool time increases during their planned shutdown.
Integration gets the most out of existing client data and solutions. From preparing digital permits and risk assessments in eVision's software using up-to-date equipment and location information from Maintenance Management Systems (MMS); to creating context-sensitive work execution packs linked to Oracle Primavera, which can be mass signed, enabling continuous scheduling optimisation; to effective and efficient maintenance execution empowered by mobile tools for front-line crew; to monitoring real-time data through connected dashboards. Data and systems are connected, information is shared in real time, reducing Turnaround time and improving capacity planning and Hands on Tool Time, thereby decreasing the number of contractors required for the next shutdown. This continuous feedback loop further enables the client to take lessons learned and improve their next turnaround, getting maximum return out of their digital solutions.
By taking a platform approach to shutdown preparation and execution, and utilising the vast amount of data available across systems throughout the asset, challenges could be met head-on and mitigated, without large-scale changes to infrastructure or methodology. Creating a synergy between existing systems, new solutions and effective and improved procedures allowed staff to focus on what really matters: quick and safe turnarounds. During the 2016 planned shutdown, a core goal was to increase the HoTT of staff and contractors by a minimum of 7%. eVision was able to improve HoTT by more than 17% overall, by tackling key challenges, such as permit cycle duration, work instruction time, and vast reduction of indirect productive hours. By implementing the integrated software platform, the workforce was able to more effectively utilise their time on plant.
Maintaining Flare Tip Health
Authors: Bakthavachsalam Venugopal , Buendia Gerald , Hashimi Haitham Al 
Published: November 2018

Abstract
Maintaining flare tip health is essential to ensure safe disposal of flammable hydrocarbons in any oil and gas industries. This paper presents best practices (from operation, to maintenance and inspection) to ensure the health of large flare tips. The flare tip mixes flammable fluids and air into the required concentration and velocity to maintain stable ignition and combustion. These flare tips are vulnerable to damages caused by burn backs that may result in serious threats to plant safety & integrity, as well as exorbitant replacement costs.
We will outline how we comprehensively mitigated thermal buckling failures in HP flare tips to improve the asset life and availability of these safety critical flare systems. In the past, we recorded frequent flare tip failures in the four stage HP flare system of trains 3 & 4. Replacement of these expensive tips was planned during major turnarounds. Meanwhile, the root cause analysis revealed that the thermal bucking tip failures can be attributed to "burn back". Inadequate purge gas flow, poor reliability of burn back detectors, inadequate design, control measures and project specifications were identified as causes for the burn back.
It was recommended to replace the fuel gas as a purge gas medium with nitrogen. This permanently preserved the integrity of the flare tips, while avoiding fuel gas wastage. In addition, the following best practices were recommended to maintain a healthy flare system. Improve the design and reliability of burn back detectorsChange the inspection approach to thermographic surveysImprove the pilot flame, burn back detectors and alarm system to provide low flow alarms for purge gas
The implementation of these recommendations enhanced the asset life and availability of the safety critical flare system, as proven by the thermographic survey, which shows colder operating conditions of the flare tips.
Influence of Pressure and Temperature on CO2-Nanofluid Interfacial Tension: Implication for Enhanced Oil Recovery and Carbon Geosequestration
Authors: Al-Anssari Sarmad , Arain Zain-UL-Abedin , Barifcani Ahmed , Keshavarz Alireza , Ali Muhammad , Iglauer Stefan 
Published: November 2018

Abstract
Nanoparticles (NPs) based techniques have shown great promises in all fields of science and industry. Nanofluid-flooding, as a replacement for water-flooding, has been suggested as an applicable application for enhanced oil recovery (EOR). The subsequent presence of these NPs and its potential aggregations in the porous media; however, can dramatically intensify the complexity of subsequent CO2 storage projects in the depleted hydrocarbon reservoir. Typically, CO2 from major emitters is injected into the low-productivity oil reservoir for storage and incremental oil recovery, as the last EOR stage. In this work, An extensive serious of experiments have been conducted using a high-pressure temperature vessel to apply a wide range of CO2-pressure (0.1 to 20 MPa), temperature (23 to 70 °C), and salinity (0 to 20wt% NaCl) during CO2/water interfacial tension (IFT) measurements. Moreover, to mimic all potential scenarios several nanofluids at different and NPs load were used. IFT of CO2/nanofluid system was measured using the pendant drop method as it is convenient and flexible technique, particularly at the high-pressure and high-temperature condition. Experimentally, a nanofluid droplet is allowed to hang from one end of a dispensing needle with the presence of CO2 at the desired pressure and temperature. Regardless of the effects of CO2-pressure, temperature, and salt concentration on the IFT of the CO2/nanofluid system, NPs have shown a limited effect on IFT reduction. Remarkably, increased NPs concentration (from 0.01 to 0.05 wt%) can noticeably reduce IFT of the CO2-nanofluid system. However, no further reduction in IFT values was noticed when the NPs load was ≥ 0.05 wt%. Salinity, on the other hand, showed a dramatic impact on IFT and also on the ability of NPs to reduce IFT. Results showed that IFT increases with salinity particularly at relatively low pressures (≤ 5 MPa). Moreover, increased salinity can eliminate the effect of NPs on IFT. Interestingly, the initial NP size has no influence on the ability of NPs to reduce IFT. Consequently, the potential nanofluid-flooding processes during EOR have no negative effect on the later CO2-geosequestration projects.
A New Method for Diagnosing Caves in Fault-Karst Carbonate Reservoirs
Authors: Xu Yandong , Hu Wenge , Pang Wei 
Published: November 2018

Abstract
Shunbei block is nearly the deepest oilfield in China with formation buried about 8000 meters. Good production performance is gained with rate as high as 100t/d per well. The formation belongs to fault-karst carbonates and is composed by caves, natural fractures and matrix. The current well testing models that assume dual or triple mediums cannot give reasonable interpretation such as the volume of caves and the connectivity between caves.
We proposed a new model for the well connected to one cave in the carbonate formation based on the three laws of mass conservation, momentum conservation and energy conservation mechanics. The concept of wave propagation is introduced and the model incorporating fluid flow and pressure wave propagation is built in the caves. For the cave connected to the wellbore, its volume can be obtained by history match of the log-log plot of the pressure and pressure derivative. The matrix is viewed as storage medium and it provides fluid to the caves by crossflow. Field cases are conducted to validate the proposed method.
Results show that the sequent flow regimes including wellbore storage, transition from wellbore storage to cave storage, wave propagation and fluid flow in cave, formation flow can be diagnosed in the log-log plot of the pressure and pressure derivative, therefore, the new method can characterize the features of fault-karst carbonate reservoirs such as the volume of caves. For the field case, from pressure buildup test, the volume of the caves connected to the wellbore is estimated as 37281.41 m3. Log-log plots of the pressure and pressure derivative show good agreement with the pressure buildup data, therefore, the models are validated and the results interpreted are accurate and confident.
A New Approach to Well Construction Cost Saving, The Success of Drilling Long Departure Dual Lateral Wells in United Arab Emirates Onshore Field
Authors: Morales Annie , Al Yamani Sultan , Salem Gamal , Nava Jose , El Barbary Abdalla , Pham Dang Le Khoa , Diaz Nerwing , Adams Adeniyi 
Published: November 2018

Abstract
Drilling wells with long departure for extended reach applications is indeed a difficult task. Adding dual lateral sections involves increased risks, thus feasibility studies for wells design and execution purposes are critical. However, the success of this challenging campaign has enabled a new way of cost saving for wells construction.
This case study demonstrates the solutions during drilling and completion by using a single surface slot with two strings for deep water and gas injection wells in shallow coastal water field in UAE.
Dual laterals with long departure involve risks associated with drilling and completion, especially for long sections at high inclinations.
The process involves optimization of the well trajectory to minimize the inclination at whipstock setting depth in order to reduce the drilling footage in the dense formations. Optimizing the Bottom Hole Assembly and drilling parameters to improve the rate of penetration (ROP), always targeting shoe to shoe runs; optimizing the retrievable whipstock type selection together with retrieving procedure; improving the completion design in high inclination at nipple depth to be able to set the packer and test the tubing successfully.
Drilling one for two is the most beneficial point that this well construction practice has offered. Exiting from a congested surface location expose to the highest risk of Anti Collision, now reducing to 50% the exposure minimizing HSE risks. Saving surface facility while delivering two reservoir drains for better productivity is the key element for cost reduction. Most importantly, the concept is feasible and proven.
Surface location has become increasingly more congested in this field thus much higher collision risk, drilling and completion technical constraints are being pushed beyond their limit to target deeper and further reach reservoirs. Lessons learnt and recommendations have been captured to establish the basis for continuous performance improvement. This paper presents a novel approach to well construction with increasing efficiency, integrity from all involved parties, reducing operational risks while significantly reducing cost, and ultimately increasing productivity and profitability.
Novel Assessment of Hydraulic Fracturing with Geomechanical Characteristics in Tight Carbonate Formations
Authors: Jang Youngho , Yoo Hyunsang , Sung Wonmo , Lee Jeonghwan , Lee Won Suk 
Published: November 2018

Abstract
Hydraulic fracturing in naturally fractured tight formations causes complex fracture geometry corresponding to the existence of natural fracture as well as geomechanical characteristics. It is extremely important when stimulating fluids such as water, brine, and CO2 are injected into tight carbonate reservoirs for increasing recovery. For fracture propagation modeling, several models have implemented multiple planar fracture with only opening mode, which have a problem in representing realistic fracture behavior.
In this regard, we proposed a hydraulic fracture propagation model implementing multiple planar approach with mixed mode including opening and sliding modes for being able to describe fracture propagation more realistically. When hydraulic fracture encounters natural fracture non-orthogonally, fracture tip slides first along the natural fracture face, and then propagates into rock mass. That is why sliding mode also needs to be considered. With the use of the model, this study analyzed the effects of the brittleness on fracture propagating behavior and gas recovery for tight formations with respect to Poisson's ratio and Young's modulus.
We investigated the modeling results for examining the importance of the sliding mode newly employed in the hydraulic fracture model. In the case of a formation having a high brittleness index, which presents greater deformation longitudinally rather than transversely, called the formation A, the effect of sliding mode was not critical on the fracture propagation. Meanwhile, in a formation having an intermediate brittleness index, named the formation B, the hydraulic fracture less easily crosses natural fracture because Young's modulus of this formation is lower comparing to the formation A, and consequently, implementation of the sliding mode is more dominant. In a formation representing higher Poisson's ratio and Young's modulus compared to formation A, which denotes a low brittleness index, since it shows larger deformation in transverse direction, hydraulic fracture hardly crosses the natural fracture, and thereafter, the propagating direction of the crossed fracture is highly deviated. The larger brittleness index, the greater in stimulated reservoir volumes by up to 17% because fracture crossing occurred easily.
Therefore, the model with the mixed mode proposed in this study was found to be extremely important in the analysis of fracture propagation behavior resulting the stimulated reservoir volumes and gas recovery differently in tight carbonate reservoirs.
Development of In-House Novel Process Scheme to Mitigate BenSat Unit Oxygen Stripper Overhead System Corrosion with Reduced CAPEX
Authors: Chaudhuri Rajib Kumar , Rauof Raji A. 
Published: November 2018

Abstract
As part of the worldwide drive to produce cleaner fuels via Benzene reduction in the Gasoline Pool, ADNOC Refining utilizes the Innovative Benzene Saturation Technology which selectively targets saturation of only the benzene fraction to minimize the loss of octane number. The Benzene Reduction Unit (BenSat Process)is designed to process combined full reformate stream from two existing reforming units and comprises of the Oxygen Stripper, Reformate Splitter columns and BenSat Process unit. Severe corrosion and leaks were observed in the Overhead Circuit of the BenSat Unit after 2 Years of operation. Detailed Root cause analysis indicated to variations and contaminants in the feed stream as the main cause for the corrosion. Based on lab result of corrosion deposit analysis, which showed a presence of 78% of Iron & 9.8% of Oxygen, and morphology of failure i.e. presence of pits and tubercles it was concluded that the most probable reason for the failure is Oxygen corrosion aggravated by the presence of chloride.
As the contributing causes were identified to be continuous in nature, a comprehensive solution was required at ADNOC Refining to ensure that similar failures do not re-occur. An upgraded and expensive metallurgy for the entire overhead circuit was the obvious solution for such a problem. However even this solution only prolongs the effects of corrosion and does not mitigate the corrosion at the source. The Technical Team at ADNOC Refining (RRW) developed an economical and continuous chemical injection system to resolve the issue at the source itself. Given the sensitive nature of the platinum Catalyst in the downstream of the Oxygen Stripper System, the selection of appropriate chemicals was a challenge. A unique combination of Corrosion Inhibiting filmer and a Neutralizing Amine was selected while ensuring overall compatibility with the system. A Chemical Injection Skid Framework was designed, engineered and built in-house in record duration for immediate commissioning. Upon implementation of the chemical injection system, it was observed that corrosion halted completely within one month. The paper explains in detail the troubleshooting and implementation methodology. These methodologies further highlight how efficient team work is able to deliver in-house solutions in the shortest possible durations.
Analysis of Diffusion Coefficient and Fracture Aperture in Coal using Micro-Computed Tomography Imaging
Authors: Lu Xiao , Armstrong Ryan , Yuan Meng , Zhang Yulai , Mostaghimi Peyman 
Published: November 2018

Abstract
Coalbed methane (CBM), also known as coal seam gas, is becoming an increasingly important energy resource in the global natural gas market. Gas transport in CBM reservoirs remains a crucial research topic that has not been fully understood. Two scales of gas flow are identified in coal cores: flow in fractures and diffusion within matrix. The diffusion process is quantified by the gas diffusion coefficient while flow in fractures is governed by fracture apertures. This paper aims to explore the diffusion process in coal using X-ray microcomputed tomography (micro-CT) imaging. The experiments are conducted at 100 psi effective stress to eliminate the impact of pressure. The images obtained are registered for visualisation and analysis of the diffusion process and comparisons of fracture. In the paper, the impact of increasing effective stress on fracture aperture is demonstrated. Also, the diffusion coefficient of Krypton in coal matrix is estimated and discussed.
Prediction of Hydraulic Properties in Carbonate Reservoirs Using Artificial Neural Network
Authors: Khalaf G. Salem Khalaf Gad , Abdulaziz M. Abdulaziz Abdel Aziz , Abdel Sattar A. Dahab Abdel Sattar 
Published: November 2018

Abstract
An accurate estimation of porosity and permeability are extremely essential for designing an ideal and efficient program of an oil and gas field development. Numerous methods have been developed to determine the porosity and permeability including laboratory measurements and log derived models. Artificial neural network (ANN) provides an efficient technique that successfully addressed several engineering and geological challenges. In the present study ANN is applied to help in predicting porosity and permeability in carbonate reservoirs using back propagation neural network (BPNN) with high accuracy on well log data from numerous fields worldwide.
ANN has the ability to understand a highly non – linear relationship and to perform simulation studies in a rapid manner. The BPNN model of porosity and permeability is developed using a set of well logging data as input layers and core porosity and core permeability as output layers. Two scenarios are considered to develop by ANN.
The first scenario considers using all available logging data directly as input for ANN. In the second scenario an additional input, diagenesis parameter, is added as input to ANN which is essentially calculated from logging data. In each scenario two models are developed; the first for porosity prediction and the second predicts permeability in carbonate reservoirs. The optimal learning rate and momentum constant used in the BPNN model are achieved after serial combinative trials. The available data was assigned 80% for training and 20% for verification.
The results of the developed porosity and permeability models are well compared to core data in verification. In the first scenario, cross-plot of the actual porosity versus ANN predicted Porosity exhibited a good match with a correlation coefficient equal to 0.97. Cross-plot of the actual permeability versus ANN predicted permeability exhibited a good match with a correlation coefficient equal to 0.80. In the second scenario, cross-plot of the actual porosity versus ANN predicted porosity exhibited a good match with a correlation coefficient equal to 0.97. Cross-plot of the actual permeability versus ANN predicted permeability exhibited a good match with a correlation coefficient equal to 0.98. Such data indicate that the developed models are successful in predicting the porosity and permeability for carbonate reservoirs.