bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Machine Learning Approach to Forecast Reviving Unconventional Oil Reservoir Production
Authors: Ursegov Stanislav , Zakharian Armen , Taraskin Evgenii
Published: November 2020

For many unconventional reservoirs, the initial oil saturation is extremely low (around 30 %). In such circumstances, it is necessary to use alternative geological and hydrodynamic simulators to forecast production levels. A novel adaptive modeling approach based on cascades of fuzzy logic matrices was proposed and implemented for a mature carbonate oil reservoir in the Permian basin of Texas where next generation waterflooding was considered to revive development process and increase oil recovery.

The proposed approach is a variant of machine learning to solve the classical analysis and synthesis problem. At the analysis stage, the input and target parameters are normalized in order to equalize their significance. For each pair of input parameters, a fuzzy-logic matrix is formed and populated with actual values of the target parameter. The set of matrices forms a cascade in which every component is characterized by its own membership function. At the synthesis stage, forecasted results of the target parameter are calculated taking into account all membership functions and correspond to the maximum values of their superposition.

By means of the proposed approach, geological and hydrodynamic models of the unconventional reservoir were successfully created, which made it possible to estimate the distribution of its initial and remaining oil reserves for all reservoir formations. The options for further reservoir development were also considered including the reactivation of non-operating wells, drilling new wells, and initiation of waterflooding. The obtained results confirmed that waterflooding was able to enhance the cumulative oil production of the reservoir compared with the base case without waterflooding, and its role became more significant as the number of operating production wells increased. The calculated results also showed that the proposed approach was quite sensitive to the changes of input parameters, for example, to the number of production and injection wells. The cumulative oil production varied several times depending on the considered option. The calculated results justified the ability of the proposed approach to forecast the development results and to choose the proper strategy for the reservoir reviving. A distinctive feature of the proposed approach was its ability to adapt to any of geological and field conditions, such as the extremely low initial oil saturation that most reservoir simulators do not take into consideration.
Underbalance Coiled Tubing Drilling in Tight Gas Reservoir Study Case Onshore Field, Abu Dhabi
Authors: Ladmia Abdelhak , Culen Martin , Al Katheeri Abdulla Bakheet , Al Hosani Fahad Mustfa Ahmed , Edmonstone Graham F. J. , Mantilla Alfonso , Baslaib Mohamed Ahmed , Nabil Ihab Mohamed , Yousfi Fawad Zain , Al Hosani Mariam Ahmed , Almenhali Salem Saleh , El Shahat Ayman , Abdulsallam Fouad , Al-Khatib Haitham Mohamed , Al Jaberi Fawzi Omar , EL Beshr Huda , Mcneilly Kevin Dean
Published: November 2020

Coiled Tubing Drilling (CTD) has been growing and developed rapidly through the last two decades. There have been numerous highly successful applications of CTD technology in Alaska, Canada, Oman and the United Arab Emirates (Sharjah Sajaa and Dubai Murgham fields), among other places. Currently, Saudi Arabia has undertaken a campaign for the last seven years that has shown successful results in gas reservoirs.

ADNOC initiated a trial Coiled Tubing Underbalanced Drilling (CTUBD) project in the onshore tight gas reservoirs in Abu Dhabi, United Arab Emirates beginning operations 1-December-2019. The initial trial will consist of three (3) wells. The purpose of the trial is to assess the suitability of CTUBD for drilling the reservoir sections of wells in these fields, and further application in others.

The reason for choosing coiled tubing for drilling the reservoir sections is based upon the high H2S content of the reservoir fluids and the premise that HSE can be enhanced by using a closed drilling system rather than an open conventional system.

The three wells will be newly drilled, cased and cemented down to top reservoir by a conventional rig. The rig will run the completion and Christmas tree before moving off and allowing the coiled tubing rig to move onto the well. The coiled tubing BOPs will be rigged up on top of the Christmas tree and a drilling BHA will be deployed through the completion to drill the reservoir lateral.

The wells will be drilled underbalanced to aid reservoir performance and to allow hole cleaning with returns being taken up the coiled tubing / tubing annulus. The returns will be routed to a closed separation system with produced gas and condensate being primarily exported to the field plant via the production line, solids sparge to a closed tank or pit and the drilling fluid re-circulated. The primary drilling fluid will be treated water; however, nitrogen may be required for drilling future wells in the field and will be required regardless for purging gas from the surface equipment during operations. A flare will also be required for emergency use and for start-up of drilling. If the trial proves a success, a continuous drilling plan will be put in place.
A Thermodynamic Robust Model to Assess Hybrid Solvents for CO2 Capture
Authors: Alkhatib Ismail , Al-Hajaj Ahmed , Abu Zahra Mohammad , Vega Lourdes
Published: November 2020

The molecular-based soft-SAFT equation of state has been applied to describe the chemisorption of CO2 in non-aqueous hybrid solvents of mixtures of AMP and glycols. The reactive nature of the CO2 absorption process in non-aqueous amines was implicitly modelled by the formation of CO2-amine physical aggregates bounded by strong and localised intermolecular interactions. This modelling framework only required VLE data on the absorption of CO2 in amine solvents, without the need for additional information such as speciation reactions or equilibrium constants. Subsequently, the developed models were used to examine the CO2 capture performance of these hybrid solvents in terms of absorption cyclic capacity and heat of regeneration as key performance indicators using a simple and short-cut estimation method. Results show that for the same total amine mass concentration, non-aqueous AMP solvents possess a 30-40% decrease in total heat of regeneration compared to their aqueous counterparts at the expense of a 20-50% reduction in cyclic capacity. These results validate the reliability of the molecular modelling approach as an attractive and valuable tool for the screening of chemical solvents and process modelling.
Impact on Corrosion of Different Types of EOR Polyacrylamides in Various Conditions of Salinity and Temperature
Authors: Bonnier Julien , Martin Vincent , Rivas Christophe
Published: November 2020

Fossil fuels currently supply more than 85% of world's energy, and global energy demand and consumption is forecasted to go up rapidly over the next 20 years [Jamaloei et al., 2011]. Such demand can only be satisfied by sustaining the production of energy in existing fields.

Therefore, Enhanced Oil Recovery from existing fields has become increasingly important. Polymer flooding is one of the most efficient EOR technologies that started as early as the late 1950s [Standnes et al., 2014]. Adding polymers increases the viscosity of the injected fluid downhole, which helps to push out viscous crude oil for better oil recovery (up to 10-15% over water flooding) [Standnes et al., 2014] [Taylor et al., 1998]. Among them, Hydrolyzed polyacrylamide (HPAM) is gaining popularity in EOR: inexpensive, it can also withstand high mechanical forces during water flooding [Li et al., 2016] [Wever et al. 2011]. Depending on salinity and temperature, co and ter-polymers of PAM with ATBS may be more relevant to be efficient in highly stressed conditions.

Depending on process conditions, industrial equipments such as water pipelines and flowlines are built in seamless carbon steel (CS), stainless steel (SS) and especially duplex (DSS) or superduplex stainless steel (SDSS), capables of transporting fluids at high temperatures and pressures. Since produced water or seawater used in EOR processes bring species prone to induce corrosion (most notably carbon dioxide, hydrogen sulfide and sulfate, dissolved oxygen), several corrosion modes are possible : uniform corrosion of CS, pitting and crevice corrosion of SS, Microbiologically Influenced Corrosion (MIC). Technologies such as upstream deoxygenation of the fluids, addition of oxygen scavengers and corrosion inhibitors and/or addition of biocide are used [Voordouw, 2011].

The corrosion mechanisms of CS in synthetic and industrial brines in presence of CO2 and H2S are often studied, but the effect of viscosifying polymers on corrosion is not well documented. This study aimed to improve the knowledge on the effect of PAM based viscosifying polymers on corrosion of CS and SDSS.
Enhancement of Sub-Surface Completion Integrity by Mitigation of Complex Layered Scale/Asphaltene Deposition in Gas Wells
Authors: Al Jaberi Fawzi Omar , Albadi Mohamed Mubarak , Al Zaabi Saleem Salman , Ahmad Zeeshan Ahmad , Gadelhak Abdelrahman Mohamed , Cristea Zaharia Cristea , Ansari Saad Wajih
Published: November 2020

This study established the detailed root cause of complex layered scale deposition along the completion jewellery and production tubing, qualitative and quantitative scale composition, special design of the scale treatment and future mitigation plan to handle the scale/asphaltene issues in ADNOC Onshore gas wells. Gas producers are having scale problems due to corrosion products with mixture of organic material deposition which may be from produced gas and condensation of heavier hydrocarbon due to change in pressure temperature profile along the tubing. Gas injectors are having scale/asphaltene deposition indicating the lubricant components thus suggesting an exogenous source of scaling (i.e. external sources such as oilfield tools, seals, valves, upstream equipment).

Two stage chemical scale treatment designed after conducting extensive lab test to reach the 75 – 80 % solubility cost effectively. Mechanical treatment with sterling beads evaluated for hard scale by considering the tubing integrity. Scale treatment operation executed with coil tubing at 3 wells and successfully achieved the desired results.

Identified the root causes of scale build up and chalked out future mitigation plan to maintain the well integrity, flow assurance and cost optimization. In short term, scale issues can be handle by evaluating the suitable chemical with reference to well type, improving chemical injection system to minimize the corrosion products and improving the quality of injected gas for gas injection system. In the long term, scale formation can be avoided by squeeze inhibition treatment (scale/corrosion), mechanical treatment of scale removal for hard scale and improving in downhole completion jewellery maintenance.
First Real-Time Fiber Optic Surveillance and Analysis of a Bullhead Stimulation of an Extended-Reach Horizontal Lateral in a Giant Offshore Carbonate Oil Field
Authors: Seabrook Brian , Kiyoumi Ahmed , Sau Rajes , Othman Alaa , Almarzooqi Laila , Altamimi Ahmed , Wheatley Edward Jason , Correia Gladwin , Lolla Sri , Campbell Bryce , Shuchart Chris , Angeles Renzo
Published: November 2020

A giant carbonate field offshore is being redeveloped using extended-reach horizontal laterals, up to more than 20,000 ft. with open-hole un-cemented liners, drilled from artificial islands. Previously, SPE171800 introduced an innovative Limited-Entry Liner (LEL) design that enables high rate aggressive stimulation of these wells by bullheading. These wells provide significant profitability in unit development cost, though it is critical to effectively stimulate the entirety of the long laterals to maximize reservoir recovery. Recently, Sau et al. 2019 presented our first application of real-time fiber optic surveillance during the successful stimulation of a water injection well with a 12,000 ft LEL lateral section. Fiber optic distributed temperature and distributed acoustic sensing (DTS/DAS) data were collected. Qualitative analysis of the real-time data were compared with a subsequent production logging tool (PLT) to confirm the effectiveness of the LEL completion and also the validity of the real-time fiber optic data.

This current paper describes the detailed analysis of the DTS/DAS dataset collected and the information that can be extracted from it regarding the effectiveness of the well stimulation. Also presented here is how DTS/DAS can be used to monitor the completion performance during injection; quantitative DTS/DAS analysis provides detailed insight into the acid volume injection into each compartment as well as post-stimulation water injection profile over time and at different injection rates. Recommendations are made regarding how to use the data from future DTS/DAS enabled stimulation jobs to extract the most value from real-time measurements and how permanently installed fiber optic DTS/DAS systems can be used to monitor the health and performance of such extended-reach injection wells.
Maximizing Hydrocarbon Recovery and Water Injection Support through Pattern Reviews Between Injector Producer Pairs in a Large, Complex, and Faulted Brown Field in SE Asia
Authors: Ali Arfan , Gupta Manish K. , Salleh Reza , Bong Charlene
Published: November 2020

Large, complex and faulted structures often pose substantial challenges in maximizing hydrocarbon recovery. This is largely due to limited understanding of field wide connectivity of reservoir sands, across fault communication, and uncertainty in reservoir fluid contacts due to a fewer well penetrations in early life of the field. In addition, secondary recovery through water injection support brings further complexities in such fields, particularly in stacked reservoirs with multiple sands completed across individual production zones.

The work presented in this paper has utilized ‘pattern reviews’ technique in a brown field containing over 500 well penetrations in South East Asia. Pattern reviews have made use of reservoir pressure data, fault maps, sand/shale correlations, salinity variations between formation and Sea water, and injection and production data by carving out specific sections of the field containing injector-producer pairs. The integrated data and analyses have helped establishing connections, or otherwise, between injector-producer pairs across various parts of the field. Time lapse Production Logging (PLT) campaigns were executed to provide additional supporting evidence on flushing of certain reservoir sands in producer wells and preferential injection zones in injector wells.

Systematic selection of patterns containing injector-producer pairs across the field has provided a substantial support in our static and dynamic modelling work to establish reservoir/fault connectivity within fault blocks and across the field. This has subsequently helped in history matching production data as well as identifying infill opportunities for bypassed oil. The present work has also helped in optimizing water flood and choosing certain injectors/zones to open/close for pressure support.

An understanding on the connectivity between injector-producer pairs has also helped in identifying areas with low recovery and poor sweep. This has paved the way in initiating a pilot project for Polymer injection in this field to help understand incremental recovery in addition to water flood. A successful outcome would initiate field wide polymer injection with a potential of 10's of mmboe incremental recovery from the field.

For the first time in field history, pattern reviews have been extensively used as a tool to understand reservoir connectivity and dynamic fluid movements across the field. An additional attempt has been made to use ant track maps to help identify potential baffles and sub-seismic faults. An integrated effort between the various data and disciplines have provided fresh insights into the reservoirs and which would have otherwise been difficult in heterolythic nature stacked reservoirs.
Brownfield Projects Cost & Schedule Optimization
Authors: Mahmood Syed Faisal
Published: November 2020

The brownfield projects deal with existing facilities/assets to upgrade or modify. These projects can be minor (e.g., change a few cable trays) to major (e.g., remove an old gas turbine). These projects are smaller in Capex spending compared to new greenfield projects, and sensitive to completion schedules, because of the facility's operational/production state. Normally some of the work is performed during shutdown of the facility, so there is economic pressure to resume operations as soon possible.

Eighty percent of these projects are schedule-driven, and cost is relatively high if benchmarked with green field projects, which are usually cost-driven projects. There is a need to plan and execute these projects to optimize the cost and schedule, to achieve company's financial goals and production targets simultaneously. These strategies may vary from project to project, and there are many common actions that can be applied to all brownfield projects.

It is a challenge for the project management team (PMT) to execute a brownfield project within the planned budget and schedule, due to uncertainties and constraints. In this paper we will discuss the risks and challenges faced by brownfield PMTs, and how to mitigate risks with planning and execution strategy at different stages of the project life cycle: i.e., concept selection, FEED, detail engineering, project proposal, contract award, execute construction, and commissioning of the facility.
Reduce the Gap Between Planning and Operation : More Reliable Planning by Predicting Downtime
Authors: Jain Piyush , Ouldzmirli Oussama
Published: November 2020

Typical Planning Process

There is different level of planning:

Operation planning is one of the key activities which planners do, it plays a crucial role in overall profitability as planner tried to make most profitable production plan considering various internal and external factors.

External factors can be for feedstock availability and pricing, freight cost, product specs & demands whereas internal factors are unit's availability, operational conditions, blending etc.
SWCTT Data Simulation and Sensitivity Analysis of Measured Residual Oil Saturation
Authors: Felix Servin Jesus Manuel , Shi Nan , Abdel-Fattah Amr
Published: November 2020

Single-well chemical tracer tests (SWCTT) have received burgeoning interest as in-situ methods to measure the remaining oil saturation (S_or). The test not only involves field operations and lab measurements, but also relies on curve fitting of the data acquired from these procedures. Despite various types of errors and uncertainties arising in SWCTT, their effects on data analysis, and in turn the accuracy of S_or measurements, remain unclear. Here, we present a robust SWCTT simulator and use it to perform sensitivity analysis of different parameters over a wide range of reservoir and tracer properties. We find that accurate determination of tracers’ partition coefficients is crucial for estimating S_or, whereas errors in concentration measurements or pore volume characterization have less dramatic effects. More importantly, we demonstrate that matching the SWCTT data is only a necessary condition for the accurate estimation of S_or. In fact, a good data fitting without correct values of parameters such as partition coefficient could yield substantially deviated values of S_or. This sensitivity analysis and the "what-if" capability of our simulator provide in-depth understanding for the design and optimization of SWCTT.
Resolution of Repeatable Bearing Failure of a Gas Re–Circulation Fan
Authors: Ashour Mohammed , Shalabi Mustafa
Published: November 2020

A double suction centrifugal fan with rated power 1120 KW driven by variable speed motor using VFD (variable frequency drive) through flexible coupling (shim pack), fan rolling element bearings vibration is monitored by two seismic vibration sensors (one per bearing) connected to the control room. the fan is one of two gas re-circulation fans of water tube boiler generating steam to drive 650 MW power turbine. on 1st of July 2019 after power plant steam turbine major overhaul, fans started with acceptable vibration levels. Within August to September 2019 the fan bearings showed vibration and temperature increase higher than acceptable limits. Customer inspected both fan bearings and replaced the damaged inboard bearing. After one month of normal operation, the same fan inboard bearing failure occurred with the same characteristics based on the previous history, this plan was implemented: Fan bearings’ housings clearances measuring.Old (failed) bearings visual inspection.Fan inboard bearing replacement.Modal impact test to measure the fan natural frequencies.Startup. vibration data collection and analysis.

It was observed that, fan inboard bearing radial clearance between bearing and housing was 0.22 mm exceeding the maximum allowable limit 0.01 mm. (clearances adjusted as per manufacturer limits) as the fan inboard bearing is double row type, however the both failed bearings showed the same failure pattern on the closest row to the motor mean while the other row was clear. after fan inboard bearing replacement and machine startup, vibration data collected using online vibration analyzer and voltmeters installed on both fan bearings and motor inboard bearing, fan bearings velocity spectrum showed high vibration component at 141 Hz which is close to the bearing outer race fault frequency, and doesn't coincide with any of the fan natural frequencies. motor inboard bearing horizontal sensor showed severe fluctuations and Ski-slope in the spectrum. visual inspection showed damaged ground brush, and after its replacement, all vibration levels decreased, and the 141 Hz component decreased. based on previous observations it was concluded that, as a result of damaged ground brush, ESD (electrostatic discharge) generated and was responsible for fan inboard bearing housing clearances increase overtime, which led to repeatable bearing failures.

this case study is focused on how the root cause analysis performed to avoid the repeatable bearing failure, and the importance of preventive maintenance activities to avoid unplanned failure. also, how the ESD problem was detected through steady state vibration data and applying the appropriate maintenance plan.
Risk Based Maintenance Management System Achieving Operational Excellence
Authors: Abuelenin Marwan Hassan
Published: November 2020

The aim of this abstract is to focus on the Maintenance Management System (MMS) that was implemented at ADNOC LNG to accomplish operation excellence, effective decision-making regarding maintenance activities, and utilization of the Risk Management Process to assure asset integrity and major production revenues.

Risk-based MMS is a continuous improvement (CI) system to proactively prevent failures through the early identifications of risks, failure modes, failure criticality, and risk mitigation by utilizing cost effective predictive maintenance tasks and routines. Risk-based MMS effectively provides support for high critical decisions to assure asset integrity, minimize plant trips, avoid unnecessary forced shutdowns, and guarantee safe operations.

Asset Integrity Management (AIM) is important in the oil and gas business because it ensures reliable assets, performance, efficiency, cost effectiveness, sustainable production revenues, and achieve business objectives and operational excellence. Maintenance, Operations and Engineering are the key partners and custodians to assure asset integrity in compliance with HSE. The very close interface between the three result in high levels of asset reliability and availability.

In 2016 ADNOC LNG's Maintenance Division deployed the Maintenance Management System (MMS) driven by the Risk Based Reliability Approach. The objective was to perform consistent maintenance activities and asset integrity assurance by identifying risks and mitigations to reduce the risks in early stages to As Low As Reasonably Practical (ALARP).

The MMS Policy and Strategy was developed on the foundation of the risk-based approach in line with ADNOC LNG's corporate objectives, ADNOC's code of practice, and internationally accepted best practices.

The alignment of MMS with the Risk Based Approach was achieved by ADNOC LNG through successful implementation of Streamlined Reliability Centered Maintenance (SRCM) as a risk-based reliability asset integrity management tool. SRCM implementation achieved +98% reliability, cost reduction, work force utilization, proactive maintenance, and sustainable production. SRCM is mainly for rotating equipment, electrical equipment, and instrumentation. RBI (Risk Based Inspection) is already utilized for static equipment. The combination of both RBI and SRCM are successfully assuring the integrity of all assets at ADNOC LNG.

The key topics, which will be focused on, are criticality assessment, risk management, and asset integrity management reliability system SRCM (Streamline Reliability Centered Maintenance). The main challenges to implement MMS were: receiving the team's buy in, making sure the team was aligned with MMS policy and strategy, and cultural challenges. The system was successfully deployed with consistent processes and procedures helping maintenance end users perform in accordance to best practices.
A Novel Comprehensive Hysteretic Relative Permeability and Capillary Pressure Correlation
Authors: Cig Koksal
Published: November 2020

Relative permeability and capillary pressure (KR-PC) measurements from cores for a reservoir are a complex, labor-intensive and time-demanding job. Mathematical representation of KR-PC curves due to complicated multiphase flow mechanisms in situ is also a difficult task. Our objective is to achieve a comprehensive hysteretic KR-PC correlation in order to provide a better representation of the core driven KR-PC curves and apply them seamlessly for KR-PC history matching processes in numerical reservoir simulations.

The complications may arise from different rock types, wettabilities, transitional zones, saturation end-point differences, directional flow reversals and much more. For these reasons, there have been many KR-PC correlations developed to describe vast subtleties of reservoirs as well as to represent the KR-PC measurements from cores. KR-PC curves are later used in a variety of reservoir engineering, description and management applications.

The correlation proposed addresses difficulties observed in the commonly used correlations, such as: curve flexibility due to degrees of freedom to follow the measured data, hysteresis option by introducing scanning curves and satisfying the envelope of bounding curves, meaningful visual control points of complex curves, multiple flow reversal options from imbibition to drainage curves or vice versa, negative capillary pressure (Pc) values, which may occur in mixed-wetting conditions.

We have designed KR-PC curves from a simple parametrized cubic Bézier polynomial. The Bézier polynomial was further rationalized to provide weight factors to create required curvatures of the KR-PC curves. Hysteresis curves (either bounding or scanning curves) then added with a logical manner.
Generative Well Pattern Design Applied to a Giant Mature Field Leads to the Identification of Major Drilling Expenditure Reduction Opportunity
Authors: Lepphaille Maddalen , Thenon Arthur , Bergey Pierre , Salley Baptiste , Ben Sadok Abdelaziz , Koeck Charles
Published: November 2020

Well pattern design is difficult due to the very large number of possible solutions, the complexity of constraints deriving from drilling and completion, the nonlinear nature of fluid flow in porous media, the difficulty in ascertaining reservoir properties and, for mature reservoirs, development history. What matters the most is case dependent. This task is therefore traditionally conducted through manual processes with little or no help of computers, leading often to exceedingly conservative or simplistic designs whatever the reservoir heterogeneities.

The increase in computational power and algorithmic advances are opening the door to a new "Generative Design" approach, already used by other industries (car, aerospace). It consists in exploring a larger number of computer generated design possibilities more quickly and efficiently than what human can do by combining: i- "technical and experience" rules to automatically build a large number of "designs candidate", ii- workflows that qualify the performance of the designs, iii- selection criteria to identify the best design(s).

An innovative Generative Well Pattern Design Workflow named GWPD-WISH was benchmarked against traditional "manual" designs to leverage three reservoir development planning opportunities applicable to a giant mature middle eastern carbonate field already developed by hundreds of wells for which a reliable model was available:

Locate 2×15 in-fill producers to be drilled from 2 freely chosen platform locations Locate 2×15 in-fill producers to be drilled from 2 pre-determined platform locations Select 16 multi-string water injector wells for re-drill to improve recovery through better control of local reservoir pressure balance

The study was conducted using a large operational compositional model considering complex constraints in a limited time. The workflow proved able to identify substantially better patterns than the traditional approach for each of the three opportunities at the costs of only few hundreds of simulations. Pattern improvement was measured in term of reserves per incremental well and plateau duration extension. It corresponds to an opportunity for reducing drilling expenditures on a rolling basis by 30% or more.
High Accuracy Underwater Visual Measurement
Authors: Medagoda Lashika , Jolly Jordan , Bargoti Suchet , Kazzaz Abraham , Khan Junaid , Morgan Hamish , Altamimi Waleed , Ahsan Nasir , Naqshbandi Masood
Published: November 2020

Inspection of underwater assets on oil and gas offshore platforms are required to assess asset integrity, and whether intervention is required. These assets include mooring chains, fairleads, anodes and ballast tanks. Typically, calipers are used for taking measurements of these objects. Limitations of this technique include inaccuracy, inefficiency and potential damage to the asset. Compact underwater camera systems, including imaging sensors and lighting, are proposed to solve limitations of caliper measurements. Data processing creates scaled 3D models for measurement analysis and automatic fault detection. This paper presents Lantern Eye-S, a stereo-based visual measurement system developed by the authors. It is a stereo imaging system, which includes a stereo camera pair linked to a set of underwater strobes. It is extremely compact and can be deployed on very small ROVs, down to the 30kg class. Results are available as quickly as 5 minutes for in-situ analysis and assessment. Final results are available in 8 hours for detailed inspection. Calibration accounts for the water environment the images are taken, primarily to account for salinity in the water. Measurements can be automatically extracted, and comparisons are made to as-built drawings. Validation of the measurement is also undertaken with a known ground truth object placed in the water, to ensure integrity in the measurement.

Results include offshore integration and deployment on a mini-ROV (30kg class) and working class ROV (multiple tons). An important result from this work is that calipers were found to typically overestimate dimensions on mooring chain diameters. High accuracy measurements of small objects, with a compact camera system, was shown to be possible with the work in this paper. The use of a novel validation apparatus and uncertainty analysis allows appropriate levels of confidence to be attributed to the acquired analytics.
Identification & Mapping of Water Slumping Fronts by Ultra-Deep Electromagnetic Logging While Drilling Technology in Lower Cretaceous Reservoirs of Adnoc Onshore
Authors: Singh Maniesh , Al Arfi Saif , Boyd Douglas , Gerges Nader , Fares Wael , Clegg Nigel , Aki Ahmet , Diab Emad , Pandey Vikram , Mansoori Maisoon M. , Seddik Ibrahim A. , Reddy Rathnakar
Published: November 2020

ADNOC's limestone reservoirs suffer from the phenomena of injection water traveling preferentially at the top of the reservoir placing injection water above oil held there by capillary forces. Horizontal wells placed below areas of water override, cause the water above to slump unpredictably, increasing water cut and eventually killing the horizontal. Ultra Deep Directional Electromagnetic (EM) Logging While Drilling (LWD) tools provide the measurements to identify and map these water zones, improving reservoir management and design optimal well placement.

1D & 2D EM inversion modeling was conducted on two of ADNOC's largest oil producing reservoirs to evaluate the ability of an Ultra Deep Directional EM LWD Resistivity tool to identify water slumping in the presence of formation bed resistivity contrasts and predict depths of reliable detection (DOD) under various well trajectory scenarios. The inversion was run using depth of inversions up to 150 ft, the maximum expected vertical distance of tool to injection water. Modeling provided an optimized tool configuration (frequency, transmitter-receiver spacing's) to meet objectives. The inversion results further provided guidance for Geosteering, Geomapping and Geostopping decisions.

The inversion results in these reservoirs indicated that the Ultra Deep resistivity tool has a DOD of 50-150 ft to pick reservoir tops and water slumping or non-uniform waterfront boundaries. The real-time inversion will optimize landing and drilling long horizontal section to increase net pay for production and even through sub-seismic faults, measuring changes in the reservoir fluid distribution, reduce drilling risk and exceed well production life. This information will aid in updating static model with water flood areas, reservoir tops, faults and structure, designing better infill well spacing and trajectories within bypass oil regions, designing proactive and not reactive smart well completions to delay or reduce water production and ultimately extended plateau and improve ultimate recovery factor. Furthermore, it will aid resistivity mapping of underlying or overlying reservoirs for future development plans.

The encouraging results of this study confirmed to move forward with a field trial in these challenging reservoirs for better reservoir and fluid characterization and its management.
Feature Selection for Real-Time Drilling Sensing Systems Based on Linear Discriminants
Authors: Ramirez Ricardo , Soukup Ian Michael , Tapia Rafael , Cardona Carlos A. , Boudreaux Michael Sandford , Peterson Jacob Christian
Published: November 2020

Robust sensing frameworks such as high-speed inline drilling sensors provide a better understanding of drillingstring dynamics for a complete picture of the drilling processes. This understanding comes mostly from having a robust data analytics platform where clear understanding of the downhole phenomena is represented using either physics models or digital twins. Most of the current analytical, based on a comprehensive review of technical per-review papers, have been carried out using cloud computing resources. The proposed data processing approach provides a suitable methodology where analysis of multi-channel heterogeneous sources, such as the outputs of high-speed inline drilling sensors, are processed within a given window of time. Feature selection is attained using linear discriminants which provides an accurate assessment of the type of patterns the machine learning framework needs to use as a reference. Linear discriminants have shown feature selection provides a clear path towards the synthesis of real-time deterministic synthetic sensors.

Measurements for torque and bending share same units and use similar evaluation of the physical phenomena. There are additional measurement devices in the sensing suite those provide rotational speed, acceleration, pressure and temperature. The data this heterogeneous framework provides needs to be properly aligned using the system's embedded clock as a reference. A machine learning framework tuned to the features found using linear discriminants can discern and predict signal behaviors. At this point, it is possible to provide feedback in case of abnormal activity while generating relevant key performance indicators (KPI) suitable for drilling optimization and torque modeling.

This paper offers two major novel ideas. Firstly, evaluation of machine learning approaches using linear discriminants for real-time deterministic systems has not been documented as part of any automation effort in the oil & gas vertical. Secondly, the use of inline drilling sensors data makes it an important milestone towards the implementation of control frameworks using surface instrumentation data based on a highly desirable set of data points and assured data quality. For readability purposes, the paper has been organized in three sections: 1) description of data flows considering current machine learning (ML) methodologies used in O&G and evaluation of their approach towards deterministic behaviors; 2) comparison of current vs ideal sensor architectures and their influences on data analytics approaches; 3) description of approach used for time series analysis assuming an on-sensor analytics implementation.
Maintenance Outsourcing Strategy
Authors: Al Messabi AbdulRahman , Pande Girish , Al Ameri Fatima
Published: November 2020

ADNOC's business strategy has dynamically changed in response to the rapidly changing and increasingly complex business issues. One of the critical components of ADNOC Gas Processing's maintenance strategy is to have a clear strategy for outsourcing maintenance work. The Maintenance Outsourcing Strategy precisely fulfils this requirement. It serves as the basis for all future initiatives to reduce maintenance costs, increase productivity, improve the quality of service, and generate higher returns for shareholders without jeopardizing safety, integrity and reliability.

ADNOC Gas Processing shall use a phased decision model to take more informed outsourcing decisions, rather than using a defensive strategy to try and fix performance issues. The outsourcing selection model provides the sequence of analyses for the model. During the first phase, the strategic evaluation consists of a core competency analysis to determine if a component is a Production Critical Equipment (PCE) maintenance activity, and activity significance analysis that takes other important strategic factors like OEM requirements into consideration. In the second phase, the economic analysis looks at the economic feasibility of the outsourcing strategy using the Cost-Benefit Analysis (CBA) tool. In the third phase, the risk analysis is carried out using the risk evaluation tool to determine if the activity is of high or low risk. And in the last phase, the final decision is arrived at by combining the outputs from the strategic evaluation, economic analysis and commercial risk analysis, and formulating the best decision for the ADNOC Gas Processing. Results, Observations, Conclusions: The main goals of implementing this strategy are to reduce maintenance costs, increase productivity, improve the quality of service, and generate higher returns for shareholders without jeopardizing integrity and reliability. The primary goals of outsourcing are Improve Business Focus, Reduce Cost, Control Risk, Optimize Planning and Scheduling, and Improve Maintenance Performance.
How a Major Gas Compression Station Cut Construction Costs, Risks, and Time to Maximize Investment Returns
Authors: Sehgal Chirag , Khan M. Zeeshan
Published: November 2020

This paper explains how advanced digitalization concepts were employed in the development and construction of the Taweelah Gas Compression Plant in the United Arab Emirates (UAE). The plant began operation in late 2018 and is one of the largest and most modern compression facilities in the world. It is owned and operated by the Abu Dhabi National Oil Company (ADNOC) and comprises three compression trains, each with a processing capacity of 225 million standard cubic feet per day (mmscfd). Two operate at any one time, with the third on standby, giving the plant 450 mmscfd of total production throughput.

Using the Taweelah Gas Compression Plant as an example, the paper describes how onshore oil and gas compression stations can be built efficiently and economically by leveraging advanced digital technologies, such as Digital Twins. Other concepts/strategies that the paper will discuss which can help accelerate project schedules and reduce costs include:

Sophisticated hydraulic modeling software; Large power blocks to reduce the number of compression trains; Sole-source provisioning of compression drive trains; ‘Plug and play’ equipment packages that required minimal onsite commissioning; Remote diagnostics and analytics for condition monitoring and condition-based maintenance to ensure maximum uptime and availability;

Using the combination of the above concepts, along with extensive collaboration/co-creation between Siemens Energy and ADNOC, the Taweelah plant was able to achieve first gas just 16 months after front-end engineering design (FEED).
Extending the Life of a Storage Field Through Full Integrity Characterization
Authors: Loizzo Matteo , Bonnier Nicolas , Maurin Christian , Guenel Louis , Singh Kamaljeet
Published: November 2020

The implementation of a well integrity management system in a mature liquid hydrocarbon storage field brought to light essential questions about the present condition and likely evolution of the barrier elements in the years to come. Are there defects in the cement sheaths that were not detected at the time of site construction more than 50 years ago? Are there aging processes, such as casing corrosion or cement degradation, that could limit the field's useful life or even present an immediate risk? And, finally, what were the exact properties of cement and casing, given that the information available in drilling reports is very limited?

At the start of the campaign, the perceived need and available technology meant using a logging tool requiring pressure, and therefore the inspection would typically involve 2 workovers and a period of 3 weeks. However, tool selection focused on the actual aging risks, together with the use of new transmitters and relentless operational optimization improved operational efficiencies allowing two wells to be logged in two consecutive days, with important savings in direct and indirect cost as well as minimization of operational risk. The cost reduction did not come at the expense of actionable information: the wireline tools selected, together with detailed preparation and carefully supervised execution led to outstanding data quality being collected.

The implementation of a consistent method of absolute log calibration and quantitative evaluation allowed us to characterize cement properties and defects, as well as their evolution with time. A salient signature, common to most storage sites in salt, is high cement quality across the salt, with a sudden unexpected, partial loss of bond across the anhydrite that overlies the rock salt formation. This was recognized as a benign form of "sulfate attack": The precipitation of secondary ettringite within the cement matrix results in expansion and thus debonding across the stiff anhydrite, whereas creeping salt pushes cement back on the casing. Lead cement densification was also observed near shallower aquifers, also rich in sulfates, with clamping provided by marls in this case. After optimizing the logging suite, it was concluded that there was no risk of erosion, wear or corrosion, external as well as internal. The analysis also improved understanding of cement behavior across salt and the role of creeping formations.

A streamlined approach at integrity assurance, whereby the right questions are asked by the management system, optimum inspection protocols are selected and carefully carried out, and acquired data is processed using advanced quantitative techniques, allowed us to understand characteristics and dynamics of barrier elements and to conclude that safe operation of the site is possible and that there is no fixed life span.
Microscale Investigation of Dynamic Wettability Alteration Effect on Oil Displacement by Smart Waterflooding Using Synchrotron-Based Microtomography
Authors: Qin Tianzhu , Fenter Paul , AlOtaibi Mohammed , Ayirala Subhash , AlYousef Ali
Published: November 2020

Chemical additives have often been added to injection water for enhanced oil recovery (EOR) from geologic formations in the oil industry. The oil clusters in porous mediums commonly remain in the microsized capillary elements such as pores and throats due to high capillary pressures or negative capillary pressures, which is a function of pore topology, interfacial tensions, and wettability. Recent studies show that tailoring the ion composition in the injection brine can be an effective way to alter the wettability of carbonate reservoirs, reverse the capillary pressures to positive values, and improve oil displacement efficiency. There are limited studies on the impact of dynamic wettability alteration on multiphase fluid flow in heterogeneous carbonate rocks. The dynamics of pore-by-pore displacement by smart waterflooding is still unclear.

The objective of this research is to examine the process of wettability alteration in a natural carbonate rock by smart waterflooding and understand its impact on the microscale oil displacement. A carbonate rock sample was flooded with various amount of smart water within the first hour and after twelve hours, and the flooding cycles were visualized using synchrotron-based microtomography. The pore-scale observations demonstrate that the oil phase initially remains in the corner of the oil-wet pores after contacting with the smart water solution. After twelve hours, the oil droplets were remobilized to the center of the pores due to wettability alteration and favorable interfacial energies. This transition in the fluid occupancy enables the oil phase to form high-connectivity flow channels and subsequently resulting in oil mobilization and extraction from the porous medium.