bluuebunny/crossref_metadata_2025 huggingface dataset:
Source Characteristics and Lateral Migration of Middle Cretaceous Petroleum System in Western Abu Dhabi, Insight from Biomarker and Reservoir Investigation
Authors: Xiao Dengyi , Al Suwaidi Saeed K. , Ji Yingzhang , Al Blooshi Abdulla , Lv Mingsheng , Mao Demin , Al Shehhi Maryam , Shashanka Ashis , Wang Li , Hu Guangcheng , Hu Xinli , Zhao Wenhao , Ma Ren
Published: November 2020

In the western Abu Dhabi, oil fields have been discovered from the Mishrif reservoir (Cenomanian/Turonian). These fields are found in shoal/reef related stratigraphic prospects and composed of grainstone or packstone around platform margin setting. Regional understanding believes that the in-situ Shilaif mudstone is not mature enough to source the overlain Mishrif. So, it is inferred that the Mishrif reserves were charged from Shilaif kitchen of regional syncline through over 100km lateral migration from south to north. However, this accumulation pattern seems presumptive as little solid evidence was reported and little geochemistry measurement have been done previously.

To enhance understanding of the Shilaif source characteristics and figure out Shilaif-Mishrif accumulation rules, cuttings, cores from Shilaif and oil samples from Mishrif & Tuwayil were taken. Subsequently, geochemistry assay, oil-source correlation and related research were carried out. The results shows the in-situ Shilaif has abundant organic content with high TOC, HI and bitumen "A" with low maturity. Tmax of Shilaif mudstone yields an average value of 430°C and calculated vitrinite reflectance about 0.6, which means an early oil generation for in-situ Shilaif source. Oil-source correlation indicates a higher maturity of crude oil in the Mishrif & Tuwayil than the in-situ Shilaif. Furthermore, similarities of biomarkers between Mishrif oil and the Ghurab syncline Shilaif source are proved. All these evidences reveal the lateral hydrocarbon migration and accumulation northwards.

For the migration pathway, it is inferred the regional unconformity of TopMishrif plays an important role to transfer the hydrocarbon. In Western Abu Dhabi, truncation or depositional hiatus around TopMishrif are not as pronounced as Eastern Mishrif platform, but obvious exposure as well as leaching evidence could be observed from uppermost Mishrif and Tuwayil through core investigation. Besides, almost all the oil shows in Mishrif concentrate around the interface, which further proves the role of the unconformity.

The study on Shilaif source characteristics and hydrocarbon migration mechanism enhances the insight into accumulation rules of Cretaceous Petroleum system in Western Abu Dhabi and would guide the further exploration activity.
Managing 31% Dent Subsea Gas Pipeline, A Case Study from Operation and Integrity Approach
Authors: Zulfirmie Tris , Setiadi Dwi , Hernowo Widi , Purnawarman Faisal
Published: November 2020

Dent as a result of 3rd party damage during subsea pipeline operation, is causing a local stress and strain concentration and a local significant reduction in the pipe diameter. If failure as a result of a dent is not happened immediately, it is possible that the damage can deteriorate in service and cause failure at any time after the initial impact. The challenge to the pipeline operator is the identification of the dents that may threaten the future operation and integrity of the pipeline to avoid sudden pipeline failure.

A new approach developed where the simple pipeline re-assessment calculation and remaining life calculation produce negative results. An enhanced assessment technique using multiple methodologies such as Level 3 FFS assessment, flow assurance study, strain-based finite element remaining life assessment (RLA), detail corrosion and failure-mode analysis. Another approach is to prepare the repair plan to extend the chance of longer pipeline operation life.

From the enhanced assessment, pipeline are assessed from many criterias and fulfilled the requirements from the pipeline operation and integrity limit. The conclusion of the assessment is a conformity that even the engineering code and standard cannot fulfill the 31% dent presence, there are any other assessment methodologies that proved to be applied under the principle and safety rule. The result is the subsea pipeline is allowable to operate safely without high probabilities of failure and keep deliver the gas as per obligation requirement.
Pressure Index PI: A Practical Way to Normalize Formation Pressure in Offshore Malaysia
Authors: Sugiharto Yudiyoko Ega , Ralphie Benard , Johari Dzulfadly
Published: November 2020

Pressure analysis is concerned with the study of systematic variations of reservoir pore pressure with depth. The most common interpretation for pressure analysis is pressure-depth plot analysis, but other techniques that magnify understated pressure differences are also available. The measurement of formation pressure is of immense value in quantitative evaluation and prospect risk. Once the pressure data has been acquired, we need to understand how to interpret the data received because reservoir pressure data has numerous applications and misinterpreting it could make the results misleading. At equilibrium state (i.e. there are no net forces and no acceleration), a fluid in the system is called hydrostatic equilibrium. Hydrostatic pressure increases with depth measured from the surface due to the increasing weight of fluid exerting downward force from above. The traditional pressure evaluation is usually done in conventional unit such as psi, kPa, psi/feet, psi/m, kPa/m, ppg. The current work will introduce the concepts and definitions of formation pressure evaluation using Pressure Index (PI) with the unit g/cc. For better understanding of the application of PI, some reservoir studies are also discussed in this paper.
Expert Operation Assistance System
Authors: Fernandez Blanca
Published: November 2020

Cepsa has implemented an Expert Operation Assistance System, designed by and for users, based on a Knowledge-based system that implements production rules.

This implementation allows, through production rules defined in a knowledge extraction session, to make multiple comparisons with data taken from Cepsa’s datalake, and to generate a series of recommendations. The objective of these recommendations is to facilitate Operator’s work by warning of situations that may arise as an early warning system.

An expert system is a program that imitates human behavior, optimizing the information provided to give an opinion on a specific topic. It has some specific knowledge about an area using information from human knowledge for decision making.

Expert systems are the first operational result of artificial intelligence because they manage to solve problems through knowledge and reason in the same way that a human expert does.

Cepsa has developed an Expert System platform where business unit specialists can generate their modules implement their rules and get results. This platform allows to scale as many modules as business units need.

Many instances of Expert Systems rules have been implemented in some Cepsa units (Crude units, FCC, pumps, furnaces, vacuum unit …) with great acceptance by users and high revenues.

Converting human knowledge to the knowledge of AI, expert systems operate as the assistant of expert people increasing supervisory effectiveness.

Cepsa has been researching numerous options in the Expert Systems market, but we have chosen to develop our own platform for several reasons:

Expert systems have been used mainly for other businesses.

It allows giving recommendations on degrees of freedom in those units in which Machine Learning is not able to act due to there are no instrumented manipulated variables (manual valves…)

These systems allow to optimize our plants by handling this type of variables
Understanding Heat Transfer and Complex Buoyancy Driven Circulation in Sulphur Condensers
Authors: Ralston Thomas , Singapore Wala Abdulqadir Aziz , Van Vorselen Michel
Published: November 2020

Troubleshooting and Root Cause Failure Analysis (RCFA), of process equipment operations, is often hampered by an inability to measure all key quantities of interest. Frequently the only recourse is to utilise simulation techniques. The ease of use and accuracy of Computational Fluid Dynamics (CFD) continues to improve, however, successful CFD modelling frequently requires supporting analysis from process simulation and other analytical software.

When considering troubleshooting studies on process systems with similar complexity to that presented here, it is important to appreciate how different simulation and analysis techniques can complement one another in obtaining the necessary process insight.

Where the operator has not developed a simulation-based "digital twin" to properly characterise process streams and unit operations, it will be necessary to provide one. This may entail estimates and approximations needing verification. Here, commercial shell and tube heat exchanger modelling software was used in conjunction with the industry's leading process simulator to benchmark thermal performance predictions against those of the original process licensor.

Plant data historian records were used to define Reference Operating Conditions (ROC) and these were modelled by a commercial exchanger modelling program. From this a set of Agreed Modelling Conditions (AMC) were defined, to account for process upsets. The AMC conditions provided flow, temperature, and pressure boundaries for CFD simulations.

CFD modelling was conducted for the process side system to establish the magnitude and impact of tube side maldistribution in the condensers. This was found to be modest and was demonstrated to have minimal impact on thermal behaviour.

CFD simulation of the shell side circulation system, including fully coupled heat transfer representation of both process side cooling and evaporation on the shell side was central to the studies. This revealed disruption of liquid recirculation was occurring within the shells, attributed to the way BFW was distributed within the shell.
Wireless Completion Monitoring and Flow Control: A Hybrid Solution for Extended Capabilities
Authors: Bouman Marcel
Published: November 2020

For years downhole monitoring and control have been widely used technologies to improve production and reservoir management. At the same time drilling technology has evolved and resulted in a rise of deep and complex multi-lateral wells. A well path may cover multiple production zones and connectivity between, and performance of production zones are often difficult to quantify. These challenges have contributed to a growing demand for information and control directly at the reservoir. This paper will show a reliable method to bridge the gap between the upper and lower completion for both control and data flow.

The method is a combination of two well proven systems, namely a cabled permanent downhole monitoring system that is connected to the surface with a tubing encapsulated conductor and instrumentation and control tools that are placed in the production zones of the laterals and are operated wirelessly. Extending the capabilities of both systems, a new wireless interface incorporated at the lower end of the cabled monitoring system enables duplex communication with the wireless instruments and tools in the lower completion. Communication between the wired system and wireless operated instruments may be based on acoustic or electromagnetic signals.

The combination of the two technologies provides an innovative new method to overcome the challenge of making a physical connection between the upper and lower completion for monitoring and control data transmission and may also be adapted to access instrumentation and controls in multiple laterals. The adaption of the technology is straightforward as the standard interface card is placed in a surface acquisition unit for dry trees and in the subsea control modules for wet trees. The interface card can send commands and log data from both the wired instrumentation in the upper completion and the wireless operated instruments and controls in the lower completion.
Investigating Hole-Cleaning Fibers' Mechanism to Improve Carrying Cutting Capacity and Comparing Their Effectiveness with Common Polymeric Pills
Authors: Karimi Rad Mohammad Saeed , Kalhor Mohammadi Mojtaba , Tahmasbi Nowtarki Kourosh
Published: November 2020

In drilling oil and gas wells, hole cleaning in deviated wells is more challenging in comparison with vertical wells due to boycott effect or eccentricity of drill pipe. Poor hole cleaning can result in problems such as borehole pack-off or excessive ECD. In these circumstances, increasing drill pipe rotation & flow rate and simultaneously using polymeric sweeps are common treatments to remove cuttings from the borehole, but these sweeps are incompetence in removing bulky high-density cuttings or metallic debris in milling operations. Also, in the condition of zero or low flow-rates, settling of particles in polymeric pills are high.

In this paper, a specialized fibrous-type material (Fiber-1) for investigating hole cleaning effect of fibrous sweeps was used. The effectiveness of Fiber-1 in comparison with common polymeric pills (such as Xanthan gum and polyanionic cellulose) in different concentrations (1 to 3 lb/bbl) was investigated using rheological or cutting settlement tests. Mentioned tests were applied in synthetic well condition (2 hours rolling in 200°F).

Hole cleaning fibers' main mechanism is forming a fiber network in the fluid that prevents cuttings to easily settle. The other mechanism that was observed in laboratory results, was an increment in rheological parameters such as Low Shear Viscosity (LSRV) and Yield Point (YP) that have a direct influence in cutting carrying capacity which this one is hardly mentioned in previous research works. For instance, results showed yield point was increased 25% when 2 lb/bbl Fiber-1 material was added to a common Xanthan gum pill. Also, readings in RPM 3 and RPM 6 (120°F) were increased by 17% and 18% respectively when 3 lb/bbl Fiber-1 material were added to common Xanthan gum pill. Also, the optimum concentration for having the maximum YP and LSRV (without getting any flocculation or settlement issues) was 2 lb/bbl. The invasion time for settling a metallic cutting in a pill containing 2 lb/bbl Fiber-1 was about ten times more than settling time in the common Xanthan gum pill.

The main discussed issue in this paper is finding significant mechanisms of hole cleaning fibers and their merits in comparison with polymeric high-viscosity pills. Also, Fiber-1 as an environmentally friendly specialized fiber for reducing hole cleaning problems in challenging deviated holes were studied and was optimized for using in field applications.
Integrated Production Optimization using Implicitly Coupled Multi–Reservoirs and Facility Modeling with Miscible Gas Injection EOR in South Oman
Authors: Kumar Kamlesh , Pathak Varun , Agrawal Pankaj , Alias Zaal , Narwal Tushar , Hadhrami Abdullah , Eastick Rob , Krenz Ryan , Wong Jeffrey , Hamedi Yousef
Published: November 2020

An Integrated Production System Model (IPSM) is an essential tool to study the interactions between multiple reservoirs, wells and surface networks for any integrated optimal development. This paper describes a fully implicit IPSM for two interacting production system networks (critically sour facilities with >5% H2S) with multiple oil reservoirs and undergoing Miscible Gas Injection (MGI) for Enhanced Oil Recovery (EOR) using produced sour gas from oil and condensate fields in South Oman.

A range of up to 17 reservoir models, with different complexities, were incorporated in this IPSM. Larger reservoirs were modeled using 3D, fully compositional, numerical discretized models, whilst smaller ones were based on decline curves. A new production system is connected to an existing system, within a closed loop, honoring all nodal constraints, e.g. multi-stage separators, gas compression, gas sweetening, and heat exchangers. Priorities were assigned such that sweet gas export commitment is achieved first, followed by miscible gas injection to oil reservoirs and gas recycling to a condensate reservoir for production optimization. An Equation of State (EOS) model is used to model the complex interactions of different fluids, at reservoir and facilities levels.

This IPSM has been set-up to provide accurate and consistent short to long term forecasting, optimizing on oil/gas production and recycled gas injection. All surface network constraints are honored and cut-back logics based on different prioritizations are behaving reasonably. Current capabilities include determining the optimal strategy for development of these portfolio of reservoirs based on the different value drivers, tracking of composition for components like H2S that limits gas sweetening units and affects miscibility in reservoirs and longevity of the facilities. The IPSM is also intended for optimizing near-field potential in mature fields and developing new fields while operating under the facilities constraints. It can be used to analyse various business opportunities in the reservoirs and surface facilities (such as low-pressure operations) to the appropriate degrees of complexity.

This work involved integration and collaboration across multiple disciplines, identifying complex interactions between facilities constraints and reservoir performance (associated with produced gas reinjection), through an implicitly coupled EOS IPSM. Fluid blending in the surface network, and recycling and apportioning of produced gas from the seventeen reservoirs for re-injection after meeting export requirements and honoring all system constraints and priorities makes this problem quite unique and challenging
Improved Decision-Making, Safety and Reliability with Visual Asset Performance Management
Authors: Khoury George , Figueiredo Matheus
Published: November 2020

Asset Performance Management (APM) aims to improve the reliability and availability of physical assets while minimizing risks and operating costs, optimizing productivity to increase return on asset investment. Traditional APM combines IT data and OT data with big data analytics to define a course of action that will improve business outcomes.

This paper introduces a new concept for APM, Visual Asset Performance Management (Visual APM), that adds an asset information layer to APM. A Visual APM solution uses navigable 2D and 3D models to deliver "living" digital twins of equipment, machinery, and processes. It creates a centralized information repository to provide a seamless, contextualized view of data.

This approach integrates interactive visualizations of equipment and plants with real-time data and analytics that teams can leverage to inspect asset health and monitor business performance in real time.

Visual APM represents a paradigm shift for conventional Asset Performance Management, presenting a new way for engineers, operators, and maintenance teams to interact with asset information throughout its entire life cycle to reduce CAPEX and OPEX. The ability to quickly access asset and plant information and visualize asset performance can help increase the overall health of a facility significantly.

A top 10 Oil & Gas company that has adopted this approach achieved the following results:

Cut maintenance costs such as corrosion under insulation by 10–20% Shortened the time spent in the planning inspections process by up to 60% while improving the quality of the planning Achieved overall improvement in the effectiveness of campaigns and minimized rework Reduced health, safety, and environmental hazards Digitized the input of inspection results through handheld devices Increased the accuracy of data captures in the field Enhanced reporting capabilities
A New Effective Multiwalled Carbon Nanotube-Foam System for Mobility Control
Authors: Ramanathan Raja , Abdelwahab Omar , A. Nasr-El-Din Hisham
Published: November 2020

Nanoparticles have improved a surfactant's ability to create long-lasting foam. Recent studies have widely recommended the use of silica nanoparticles to enhance foam stability. This paper presents an experimental investigation of a new and highly effective Alpha Olefin Sulfonate (AOS)-multiwalled carbon nanotube (MWCNT) system for mobility control during gas EOR operations.

The new AOS-MWCNT system was evaluated for its foam stability at 150°F using a high-pressure view cell. The MWCNT was obtained as solid particles of aspect ratio up to 100 and silica nanoparticles of median size 118 nm. The foam system was optimized for its maximum half-life by varying the concentration of the AOS and the nanotube from 0.2-1% and 250-1,000 ppm, respectively. Compatibility testing with salts were done as well. Coreflood experiments with 1.5 in. diameter and 6 in. long Berea sandstone cores were run to calculate the mobility reduction factor at 150°F. Nitrogen foam was injected into the core at 80% foam quality in the tertiary recovery mode and the pressure drop across the core was measured. The formation brine had a salinity of 5 wt% NaCl and the foaming solutions were prepared with 2 wt% NaCl.

The optimal concentrations of the AOS solution and the nanotubes for maximum foam stability were determined to be 0.5% and 500 ppm, respectively. The optimized AOS-MWCNT system yielded 70% greater nitrogen foam half-life (32 minutes) than an optimized AOS-silica system at 150°F. The foam half-life of a standalone 0.5% AOS solution was 7 minutes. In presence of crude oil, the foam half-life decreased for all the tested systems. Coreflood experiments at 150°F showed a significant increase in the mobility reduction factor when the new AOS-MWCNT system was used as the foamer instead of standalone AOS or AOS-silica system. The new foaming system was stable through the duration of the experiment, yielding foam in the effluent samples. There was no formation damage observed. Salt tolerance for the MWCNT nanofluid was higher than the silica nanofluid.

Foam needs to be stable for long periods of time to ensure effective mobility control during gas injection for EOR. This paper investigates a new highly effective AOS-multiwalled carbon nanotube system that outperforms the AOS-silica foaming systems in terms of foam stability and mobility control at 150°F.
The Impact of Tailored Water Chemistry Aqueous Ions on Foam Stability and Mobility Control
Authors: AlYousef Zuhair , Ayirala Subhash , Almubarak Majed , Cha Dongkyu
Published: November 2020

The in-situ generation of foam while injecting gas is well recognized due to its effectiveness in lowering the gas mobility and, hence, improving the sweep efficiency in porous media. Therefore, generating strong and stable foam is necessary to achieve in-depth conformance control in the reservoir. Besides other parameters, the chemistry of injection water can significantly impact foam generation and stabilization. The tailored water chemistry (formulated low salinity water) was found to have good potential to improve foam stability. The objective of this study is to extensively evaluate the effect of different aqueous ions in the selected tailored water chemistry formulations on foam stabilization and mobility control.

In this experimental investigation, bulk and dynamic foam tests were conducted to evaluate the impact of different tailored water chemistry aqueous ions on foam generation and stabilization. For bulk foam tests, the stability of foams generated using anionic, amphoteric, and nonionic surfactants and different aqueous ions was analyzed and quantified using bottle tests. For dynamic foam test, the pressure drops and, accordingly, gas viscosity as a result of foam generation using different water formulations were measured using a microfluidic device (rock-on-a-chip).

The experimental results clearly demonstrated that the ionic content of aqueous solutions can significantly affect foam stabilization. The results revealed that the foam stabilization in bulk is different than that in porous media. Depending on the surfactant type, the divalent ions were found to have stronger influence on foam stabilization when compared to monovalent ions. The bulk foam results expressed that the aqueous solutions containing calcium chloride salt (CaCl2) showed longer foam life with the anionic surfactant and very weak foam with the nonionic surfactant. The solutions with magnesium chloride (MgCl2) and CaCl2 salts displayed higher impact on foam stability in comparison to sodium chloride (NaCl) with the amphoteric surfactant. Less stable foams were generated with aqueous solutions comprising of both magnesium and calcium ions. In the microfluidic model, the solutions containing MgCl2 salt produced more stable and viscous foams when compared to those produced using NaCl and CaCl2 salts. The foam solutions obtained using MgCl2 showed higher resistance to gas flow and subsequently higher mobility reduction factor for the injection gas.

This experimental study, for the first time, confirmed the impact of different aqueous ions in the tailored water chemistry formulation on foam generation and stabilization. Such a study focusing about the role of different aqueous ions in the injection water on foam could help in better understanding the foam stabilization process. The new knowledge gained can also enable the selection and optimization of the right injection water chemistry and suitable chemicals for foam field applications.
Wireless Advanced Nano-Devices for Well Monitoring
Authors: Ordonez Varela John Richard , Boero Rollo Jean Grégoire , Le Beulze Aurélie , Ochi Jalel , Vellaluru Neeharika , Dutta Partha Pratim , Benken Alexander , Gianchandani Yogesh
Published: November 2020

An innovative and practical solution for well monitoring of pressure, temperature, inertial, and magnetic parameters is reported. Tiny and robust systems integrating microscale technologies for telemetry, wireless charging, and physical sensing were developed, characterized, and ultimately deployed on a live installation. The microsystems were designed and developed by the University of Michigan and characterized by Total S.E., whereas the intervention protocols were designed and implemented by TOTAL in TOTAL E&P CONGO offshore facilities. This work demonstrates how regular downhole monitoring of assets can be performed at low cost, thus optimizing production while also de-risking future development plans such as infield wells. This novel approach also reduces risks associated with conventional downhole monitoring methods.
A New Insight into Modeling of Wormhole Propagation in the Presence of Asphaltene for Carbonates
Authors: Khurshid Ilyas , Al-Shalabi Emad W. , Al-Attar Hazim
Published: November 2020

Carbonate acidization is the process of creating wormholes in carbonate rocks by injecting acid to increase reservoir permeability and consequent oil production. Nevertheless, some reservoir oils might contain certain amounts of asphaltenes that affect the wormholing process. During acidization in the presence of these asphaltenes, the injected acid might not effectively react with rock. This study illustrates the processes of interactions between acid, rock, and asphaltene. It is found that a cumbersome and intricate compound known as acid-asphaltene sludge is formed when the acid reacts with the deposited asphaltene. The formation of this sludge would reduce oil productivity and acid injectivity. In this study, a numerical model is developed to predict the amount of asphaltene deposition, acid-asphaltene reaction, and formation of acid-asphaltene sludge.

A 1D numerical model was developed to predict the deposition of asphaltene and acid-asphaltene reaction in radial geometry. Then, the developed model was utilized to predict sludge formation and its related effect on reservoir permeability. Furthermore, the developed asphaltene deposition model was validated against two different sets of experimental data where various factors affecting sludge formation were determined. The detailed analysis showed that although sludge formation is few percent, its concentration increases with time and acid injection. The results also indicate that acid-asphaltene sludge causes an irreversible and permanent formation damage from 40 percent blockage to total pore blockage, depending upon the location of sludge deposition in pore body or pore throat, respectively. Hence, reduction in hydrocarbon productivity is expected at a much lower rate as opposed to that before the acidization job. In addition, the results showed that the amount of acid-asphaltene sludge formation depends on asphaltene percentage, acid concentration, acid flow rate, and flow period. To the best of our knowledge, there is no published work focusing on modeling acid-asphaltene sludge formation and its subsequent wormhole development. This paper provides more insight into the effects of asphaltene deposition and acid-asphaltene sludge formation on wormhole creation and propagation.
The Application of Reservoir Simulation in Reserves Estimation Methods to Estimate the Range of Technical Uncertainty
Authors: Dousi Niek , Syarkawi Fauzan , Ignatov Ivan
Published: November 2020

According to the latest SPE-PRMS guidelines, reservoir simulation may be applied in reserves estimation. However, no clear guidance is available (from SPE or public sources) on how dynamic models should be used. This paper addresses this gap by providing a practical overview of the application of reservoir simulation in reserves evaluations, based on the authors' experience and a literature review. Furthermore, a novel simulation-based reserves estimation method is presented.

SPE released an update of the PRMS reserves estimation guidelines in 2018. It is noted that the most common methodology applied is decline curve analysis (DCA). However, in many circumstances DCA alone is not sufficient for a reliable reserves estimate. To improve the reliability of the estimate, results from reservoir simulation and / or analogue reservoirs could be required. A dynamic model may be used in several ways in reserves estimation: To generate production forecasts based on a consistent physics-based model containing geology, and assuming different subsurface realizations, to establish a range of technical recoverable resources (TRR)To provide an estimate of recovery factor in order to validate the forecasts from other prediction techniquesTo establish oil/gas decline trends for comparison to the DCA resultsTo provide vital insights into the dynamic behavior of the reservoir that can be further used in DCA, material balance or sector models.

Several articles have addressed the use of reservoir simulation in reserves estimation. It is noted that the main challenge is to generate the range of uncertainties in the TRR, not only the "best technical estimate". Reserves assessors usually apply a combination of several methods to estimate the uncertainty in the remaining oil recovery. A novel reserves estimation method is introduced, which uses results from reservoir simulation on analogous reservoirs.

This paper provides a detailed overview of all the reserves estimating methods that can be applied with help and guidance from reservoir simulation models to determine 1P, 2P and 3P reserves, while honoring SPE-PRMS guidelines. Also, a novel technique is presented that can be used for reserves determination of a large number of small reservoirs. It is shown how this technique was successfully applied during a reserves assessment for a group of fields in the Middle East.

The paper provides a comprehensive yet practical overview of how reservoir simulation may be applied in reserves evaluations.

In addition, a novel method is described. It entails the estimation of the range of TRR's for a number of reservoirs using reservoir simulation and adopting a statistical approach while honoring SPE-PRMS guidelines. The spread in ultimate recovery factors can be combined with the maturity index to establish a technical uncertainty relationship, that can be applied to estimate the reserves of analogous reservoirs.
Integrated Debottlenecking Approach Revitalizes Aging Platform by Increasing Production 30% in Gulf of Mexico
Authors: Gandhi Ankur , McConkey Sara L. , Kimbrough Jeremy , Bolingbroke Hannah F. , Kapoor Yogesh , Walker Thor J. , Buquet Brandon , Beecher Richard E. , Tryon Benjamin R. , Rodrigues Neil , Kalich Kevin
Published: November 2020

Successful identification, evaluation, and management of bottlenecks in a complex, offshore production processing system—though challenging—can significantly increase daily production for the system owner. Historically, such optimization plans were developed in relative isolation of the entire production system from wellhead to export pipeline. That approach benefits simplistic systems with sufficient ullage and in which discrete changes do not affect other flow system components. However, the Constitution platform in the Green Canyon area of the Gulf of Mexico, which was commissioned in 2006 with a nameplate capacity of 70,000 BOPD, is a complex system with four fields in varying stages of development. These fields have both dry and wet tree wells with varying fluid compositions and pressures flowing through the facility, which necessitates varying process requirements, making it challenging to manage. Such a system requires a holistic and focused approach by all technical and commercial disciplines. This paper focuses on a multidisciplinary process developed to identify, evaluate, and eliminate interdependent bottlenecks on the Constitution platform and its flowline network during a 16-month period. A multidisciplinary study was kicked off in 2017 to address these complex bottlenecking issues, and the resulting project achieved a 30% improvement in deliverability of the process system.
Waste Management for 3D Metal Printing Using Nickel Based Super Alloys
Authors: Malkawi Ameen , Chinea Gonzalo , Sharrofna Hussain , Nair Asok , Aleid Zahra , Minhas Naeem
Published: November 2020

Additive Manufacturing (AM) or 3D printing is a relatively new manufacturing technology and Powder Bed Fusion (PBF) is one of the major modalities of this technology. There is a misconception that it is "plug-and-play" with no greater risks involved. The focus of this study is to raise awareness about the hazards associated with, AM operations and waste management, mitigation and change the mindset. In the AM processes a lot of chemicals are used in the whole AM cycle; feedstock, pre-processing and post-processing. Feedstock for metallic 3D printers is very fine metal powder (less than 100µm in size) with various health and fire hazards associated with it. This metal powder is spread on the build plate to create layers for selectively melting it until the whole structure is built. Un-melted powder is recycled for the next manufacturing job. However, some of the powder will remain on the manufactured part structure and some will go to multiple filters during the process. This powder is to be safely removed from the built part and managed as hazardous waste. Similarly, clogged filters are also to be safely removed and treated as hazardous waste. A well-defined chemicals waste management process for 3D printing is presented and discussed in this paper. Examples of waste sources are metal powder characterization, unloading printed jobs and contaminated tools and equipment.

In this paper, the authors have presented topics related to AM waste management, including but not limited to the sources of chemical wastes, waste types that generated by AM processes, waste control and management, waste disposal, international standards associated with hazardous waste management and some recommendations and remedies.
Digital Sedimentological Core Description Through Machine Learning
Authors: Mezghani Mokhles , Masrahy Mohammed
Published: November 2020

Describing subsurface geological core is a critical task in the oil and gas industry to understand hydrocarbon reservoirs and define the lateral and vertical variabilities in geomodels. This task is conducted by visually inspecting the core and recording important rock texture characteristics (e.g., grain size, roundness, sorting) and sedimentary structures (e.g., bedding, lamination, type of deformations, bioturbation). Figure 1 shows an example of the results. Due to the high level of detail and the amount of data to be recorded by such a task, a geologist typically spends a considerable amount of time observing and analyzing the core. The results will necessarily carry a certain degree of subjectivity, depending on the geologist's expertise. Moreover, this workflow requires the physical availability of both geologist and core in the same place (commonly in a core laboratory) in order to describe the core when it is needed. Knowing the high cost of the coring process, it will be very prejudicial to ignore such valuable data while building subsurface geological models. This challenge is actually well handeled in our company by leveraging on the digital transformation program that we are currently undertaking. The objective of this work is to develop a workflow to automate the core description task by using machine learning. A large set of core samples will be used to train the model using high-resolution core photos and their associated digital core description. The trained model can be used to predict core description for cores where only high-resolution core photos are available. This workflow is of high impact on our operations. Indeed, it can be applied for legacy core samples where the core photos have been acquired. It can be applied for the fresh core samples too. As soon as the core photography is completed, a real-time core description can be provided to the geologist for his review and approval.

This workflow is validated by predicting core description for cores already described (visual description). Ten wells have been used during this validation study. For these wells, both core photos and digital core description are available. This dataset includes approximately a total of 3,500 feet of core. The testing and validation was done using a blind testing approach, where eight wells have been used to train the model and two wells for prediction. A good agreement between the manual description and automated description is obtained. Even if the manual description is not unique and is impacted by the geologist experience and subjectivity, having this overall agreement is a very positive indicator regarding the robustness of this workflow. In addition to robustness, the automated workflow is offering consistent (repeatable) results without any subjectivity. Finally, the real-time aspect of this workflow is adding a new dimension to the workflow efficiency. Indeed, once the model is trained, few minutes (depending on the well core footage) are needed to generate the full well core description.
A Unique Use of New Generation Pulsed Neutron Tool Integrated with Advanced Production Logging to Evaluate Gas Production from an Oil Well: A Case Study from Offshore UAE
Authors: Al Afeefi Baraka Said , Bong Saudyano , Mustafa Hammad , Kuliyev Myrat , Chitre Sunil , Bazuhair Ahmed Khalid , Anurag Atul Kumar , Dasgupta Suvodip , Sookram Neil , Mosse Laurent
Published: November 2020

In a green field located in offshore Abu Dhabi, a new well was drilled in an oil-bearing zone and was completed with slotted liner inside a 6-in horizontal drain hole. Abnormally high gas rates were reported during the surface production testing of this well. This paper highlights the unique use of a new pulsed neutron tool combined with an advanced production logging tool for assessment of the well performance and identification of the source of gas breakthrough.

This combination of advanced technology tools with measurements from array flowmeters, optical gas holdup sensors, and a new generation pulsed-neutron tool was deployed in the well to provide reliable flow type, borehole, and formation measurements in a gas environment. A multidisciplinary approach involving production engineering, petrophysics, and well integrity was essential in diagnosing this unexpected issue of high gas production. An integration of the various results from production logging, the pulsed neutron measurements, and open-hole and cement log data has helped in confirming the source of the produced gas.

The acquired production log (PL) data revealed gas entry from the top of the lower completion and no presence of free gas below that depth. The zonal contributions from the horizontal lateral quantified from the acquired data also helped in assessing the productivity of the reservoir. The pulsed neutron log (PNL) measurements were acquired in the second run, which then helped confirm the borehole fluid properties and to identify and quantify the formation fluids. Combining the PNL and PL data helped identify the gas entry point accurately. Based on the integrated data interpretation, it was confirmed that the gas could not originate from the reservoir being produced through the lower completion and that there must be gas channeling downward through channels in the cement behind the casing from a gas reservoir above the oil reservoir.

The unique use of the advanced PNL data and its integration with other log data facilitated the successful identification of the gas source and quantified zonal contributions in a challenging logging environment.
Auto-Updated Virtual Multiphase Flow Metering System Using Neural Networks and Edge Computing
Authors: Torre Mario , Chen Julio , Sadek Nael
Published: November 2020

In oil and gas production, the multiphase flow rate is one of the most important measurements at the wellhead because it is essential for production allocation, flow assurance, and production surveillance. Multiphase flowmeter devices (MPFM) provide accurate measurements. However, this performance comes at high capital and operating costs that are not economically viable for all wells within aging or on mature fields. A real-time platform based on current technologies offers methods to deploy and automatically update the reduced-order models (ROM) to edge field devices. This approach is used specifically to provide a solution to estimate flow rates in real time at the field level, with and accuracy performance close to what the MPFM delivers, but at a reduced capital and operating costs.

Edge field devices can provide the required computing power to run data-driven ROM models on the field side using neural network algorithms, trained to calculate well multiphase flow rate with acceptable accuracy. Periodic updates are performed on the data-driven models on the cloud, and the updated models are downloaded to the edge field device. In this way, the models based on neural networks, deployed and running at the edge field device level, are automatically adapted to changes of the well flow regime over the well's life cycle.

An auto-trainable, machine-learning-based, multiphase estimated flow metering system running at the wellsite has been deployed and implemented. The system uses real-time and well test data, mathematical well models, neural-network-based data-driven models, which are automatically trained and updated on the cloud. The solution includes implementation in a real-time digital oil field automation system, which provides the technology platform required by this virtual flow metering system. The system offers a cost-effective way to obtain well flow rate measurement estimates with an acceptable accuracy. This virtual metering system can be used on hundreds or thousands of oil wells simultaneously using real-time data. The system provides oil and gas operators with good real-time flow metering estimates of their wells, accurate enough for production surveillance and allocation.
Investigation on Fouling During Application of EOR Polymer in Aishwarya Field
Authors: Zagitov Robert , Mathur Vinay , Subramanian Jaisankar , Selvam Venkat Panneer
Published: November 2020

Deposition of elastic fouling material on equipment for processing and transportation of crude was observed after EOR polymer breaking through to producing wells of the Aishwarya field. The objective of the study included analyzing polymer containing deposits, concluding on mechanism of precipitation and developing the solution for fouling control based on the novel laboratory test procedure.

Aishwarya field is in north-west part of India. Fatehgarh group is the main reservoir unit. Artificial lift in Aishwarya is mainly by ESP. An opportunity to improve the recovery of Aishwarya field via better displacement of oil was envisaged through implementation of EOR polymer flood. HPAM (partially hydrolyzed polyacrylamide) polymer injection was initiated in September 2017. Failures of ESP pumps, significant fouling of strainers of liquid transfer and PWRI pumps, pressure increase in Aishwarya production line which necessitate increased pigging frequency was observed soon after polymer breaking through to producing wells.

Detailed analysis of produced water containing back produced polymer and elastic deposits collected from different equipment were performed. Specific test methods have been selected for such analysis including SEC, XRF, XRD, SEM/EDS, FTIR, NMR etc. It was found that Aishwarya deposits contain high concentration of precipitated polymer (to 36%) and polymer was completely hydrolyzed, degree of hydrolysis or DOH at 100%. Chemical nature of polymer was evaluated as Calcium Carboxylates.

DOH of returned polymer in Aishwarya produced water was measured upto 79%, significant increase from the initial 25%. Such high DOH significantly dropped tolerance of HPAM to divalent cations and increases potential for precipitation with Calcium in Aishwarya brine having relatively high concentration of Calcium and high value of the relative hardness, the ratio of divalent cations to total cations.

Fast increase of DOH was attributed to the relatively high temperature of the Aishwarya reservoir (up to 77 deg C at the OWC zone).

Novel test method, accelerated aging test, has been used to investigate the long-term stability of the applied HPAM and more thermally stable polymers containing monomers of acrylamide tertiary butyl sulphonic acid (ATBS) for Aishwarya conditions. Laboratory tests represented 200 – 400 days travelling time at the Aishwarya reservoir temperature. The test results indicated on significantly better viscosity retention and higher polymer thermal stability, represented by the polymer cloud point, of ATBS co-polymers than HPAM for Aishwariya field conditions as more suitable polymer type for polymer flooding than HPAM.