Skip to main content

Modern Chemical Enhanced Oil Recovery

In Order to Read Online or Download Modern Chemical Enhanced Oil Recovery Full eBooks in PDF, EPUB, Tuebl and Mobi you need to create a Free account. Get any books you like and read everywhere you want. Fast Download Speed ~ Commercial & Ad Free. We cannot guarantee that every book is in the library!

Modern Chemical Enhanced Oil Recovery

Modern Chemical Enhanced Oil Recovery Book
Author : James Sheng
Publisher : Gulf Professional Publishing
Release : 2010-11-25
ISBN : 9780080961637
Language : En, Es, Fr & De

GET BOOK

Book Description :

Crude oil development and production in U.S. oil reservoirs can include up to three distinct phases: primary, secondary, and tertiary (or enhanced) recovery. During primary recovery, the natural pressure of the reservoir or gravity drive oil into the wellbore, combined with artificial lift techniques (such as pumps) which bring the oil to the surface. But only about 10 percent of a reservoir's original oil in place is typically produced during primary recovery. Secondary recovery techniques to the field's productive life generally by injecting water or gas to displace oil and drive it to a production wellbore, resulting in the recovery of 20 to 40 percent of the original oil in place. In the past two decades, major oil companies and research organizations have conducted extensive theoretical and laboratory EOR (enhanced oil recovery) researches, to include validating pilot and field trials relevant to much needed domestic commercial application, while western countries had terminated such endeavours almost completely due to low oil prices. In recent years, oil demand has soared and now these operations have become more desirable. This book is about the recent developments in the area as well as the technology for enhancing oil recovery. The book provides important case studies related to over one hundred EOR pilot and field applications in a variety of oil fields. These case studies focus on practical problems, underlying theoretical and modelling methods, operational parameters (e.g., injected chemical concentration, slug sizes, flooding schemes and well spacing), solutions and sensitivity studies, and performance optimization strategies. The book strikes an ideal balance between theory and practice, and would be invaluable to academicians and oil company practitioners alike. Updated chemical EOR fundamentals providing clear picture of fundamental concepts Practical cases with problems and solutions providing practical analogues and experiences Actual data regarding ranges of operation parameters providing initial design parameters Step-by-step calculation examples providing practical engineers with convenient procedures

Chemical Enhanced Oil Recovery

Chemical Enhanced Oil Recovery Book
Author : Patrizio Raffa,Pablo Druetta
Publisher : Walter de Gruyter GmbH & Co KG
Release : 2019-07-22
ISBN : 3110640252
Language : En, Es, Fr & De

GET BOOK

Book Description :

This book aims at presenting, describing, and summarizing the latest advances in polymer flooding regarding the chemical synthesis of the EOR agents and the numerical simulation of compositional models in porous media, including a description of the possible applications of nanotechnology acting as a booster of traditional chemical EOR processes. A large part of the world economy depends nowadays on non-renewable energy sources, most of them of fossil origin. Though the search for and the development of newer, greener, and more sustainable sources have been going on for the last decades, humanity is still fossil-fuel dependent. Primary and secondary oil recovery techniques merely produce up to a half of the Original Oil In Place. Enhanced Oil Recovery (EOR) processes are aimed at further increasing this value. Among these, chemical EOR techniques (including polymer flooding) present a great potential in low- and medium-viscosity oilfields. • Describes recent advances in chemical enhanced oil recovery. • Contains detailed description of polymer flooding and nanotechnology as promising boosting tools for EOR. • Includes both experimental and theoretical studies. About the Authors Patrizio Raffa is Assistant Professor at the University of Groningen. He focuses on design and synthesis of new polymeric materials optimized for industrial applications such as EOR, coatings and smart materials. He (co)authored about 40 articles in peer reviewed journals. Pablo Druetta works as lecturer at the University of Groningen (RUG) and as engineering consultant. He received his Ph.D. from RUG in 2018 and has been teaching at a graduate level for 15 years. His research focus lies on computational fluid dynamics (CFD).

Chemical Enhanced Oil Recovery cEOR

Chemical Enhanced Oil Recovery  cEOR  Book
Author : Laura Romero-Zerón
Publisher : BoD – Books on Demand
Release : 2016-10-19
ISBN : 9535127004
Language : En, Es, Fr & De

GET BOOK

Book Description :

Commercial application of chemical enhanced oil recovery (cEOR) processes is expected to grow significantly over the next decade. Thus, Chemical Enhanced Oil Recovery (cEOR): A Practical Overview offers key knowledge and understanding of cEOR processes using an evidence-based approach intended for a broad audience ranging from field operators, researchers, to reservoir engineers dealing with the development and planning of cEOR field applications. This book is structured into three sections; the first section surveys overall EOR processes. The second section focuses on cEOR processes, while the final section describes the electrorheology technology. These sections are presented using a practical and realistic approach tailored for readers looking to improve their knowledge and understanding of cEOR processes in a nutshell.

Applied Enhanced Oil Recovery

Applied Enhanced Oil Recovery Book
Author : Aurel Cârcoană
Publisher : Unknown
Release : 1992
ISBN : 0987650XXX
Language : En, Es, Fr & De

GET BOOK

Book Description :

Presents in a step-by-step progression the complex problems of oil displacement in porous media using EOR methods.

Chemical Nanofluids in Enhanced Oil Recovery

Chemical Nanofluids in Enhanced Oil Recovery Book
Author : Rahul Saha,Pankaj Tiwari,Ramgopal V.S. Uppaluri
Publisher : CRC Press
Release : 2021-09-22
ISBN : 1000433617
Language : En, Es, Fr & De

GET BOOK

Book Description :

Sustainable world economy requires a steady supply of crude oil without any production constraints. Thus, the ever-increasing energy demand of the entire world can be mostly met through the enhanced production from crude oil from existing reservoirs. With the fact that newer reservoirs with large quantities of crude oil could not be explored at a faster pace, it will be inevitable to produce the crude oil from matured reservoirs at an affordable cost. Among alternate technologies, the chemical enhanced oil recovery (EOR) technique has promising potential to recover residual oil from matured reservoirs being subjected to primary and secondary water flooding operations. Due to pertinent complex phenomena that often have a combinatorial role and influence, the implementation of chemical EOR schemes such as alkali/surfactant/polymer flooding and their combinations necessitates upon a fundamental understanding of the potential mechanisms and their influences upon one another and desired response variables. Addressing these issues, the book attempts to provide useful screening criteria, guidelines, and rules of thumb for the identification of process parametric sets (including reservoir characteristics) and response characteristics (such as IFT, adsorption etc.,) that favor alternate chemical EOR systems. Finally, the book highlights the relevance of nanofluid/nanoparticle for conventional and unconventional reservoirs and serves as a needful resource to understand the emerging oil recovery technology. Overall, the volume will be of greater relevance for practicing engineers and consultants that wish to accelerate on field applications of chemical and nano-fluid EOR systems. Further, to those budding engineers that wish to improvise upon their technical know-how, the book will serve as a much-needed repository.

Hybrid Enhanced Oil Recovery Using Smart Waterflooding

Hybrid Enhanced Oil Recovery Using Smart Waterflooding Book
Author : Kun Sang Lee,Ji Ho Lee
Publisher : Gulf Professional Publishing
Release : 2019-04-03
ISBN : 0128172983
Language : En, Es, Fr & De

GET BOOK

Book Description :

Hybrid Enhanced Oil Recovery Using Smart Waterflooding explains the latest technologies used in the integration of low-salinity and smart waterflooding in other EOR processes to reduce risks attributed to numerous difficulties in existing technologies, also introducing the synergetic effects. Covering both lab and field work and the challenges ahead, the book delivers a cutting-edge product for today’s reservoir engineers. Explains how smart waterflooding is beneficial to each EOR process, such as miscible, chemical and thermal technologies Discusses the mechanics and modeling involved using geochemistry Provides extensive tools, such as reservoir simulations through experiments and field tests, establishing a bridge between theory and practice

Surfactants for Enhanced Oil Recovery Applications

Surfactants for Enhanced Oil Recovery Applications Book
Author : Muhammad Sagir,Muhammad Mushtaq,M. Suleman Tahir,Muhammad Bilal Tahir,Abdul Ravoof Shaik
Publisher : Springer Nature
Release : 2020-01-29
ISBN : 3030187853
Language : En, Es, Fr & De

GET BOOK

Book Description :

This book provides a concise treatise on the use of surfactants in enhanced oil recovery (EOR), including information on key types of surfactants and their respective applications in the wider petroleum industry. The authors discuss carbon dioxide EOR, alkaline-surfactant-polymer flooding strategies, and the use of surfactants as a means of reducing interfacial tension, while also paying special attention to the challenges involved in using surfactants for enhanced oil recovery, such as the difficult issue of surfactant adsorption on reservoir rock. All chapters highlight and are based on the authors’ own laboratory-scale case studies. Given its content, the book offers a valuable asset for graduate students of petroleum and chemical engineering, as well as researchers in the field of chemical enhanced oil recovery. It will also be of interest to professionals involved in enhanced industrial oil recovery.

Enhanced Oil Recovery Field Case Studies

Enhanced Oil Recovery Field Case Studies Book
Author : James Sheng
Publisher : Gulf Professional Publishing
Release : 2013-04-10
ISBN : 0123865468
Language : En, Es, Fr & De

GET BOOK

Book Description :

Enhanced Oil Recovery Field Case Studies bridges the gap between theory and practice in a range of real-world EOR settings. Areas covered include steam and polymer flooding, use of foam, in situ combustion, microorganisms, "smart water"-based EOR in carbonates and sandstones, and many more. Oil industry professionals know that the key to a successful enhanced oil recovery project lies in anticipating the differences between plans and the realities found in the field. This book aids that effort, providing valuable case studies from more than 250 EOR pilot and field applications in a variety of oil fields. The case studies cover practical problems, underlying theoretical and modeling methods, operational parameters, solutions and sensitivity studies, and performance optimization strategies, benefitting academicians and oil company practitioners alike. Strikes an ideal balance between theory and practice Focuses on practical problems, underlying theoretical and modeling methods, and operational parameters Designed for technical professionals, covering the fundamental as well as the advanced aspects of EOR

Chemical Methods

Chemical Methods Book
Author : Abdolhossein Hemmati Sarapardeh,Mahin Schaffie,Mohammad Ranjbar,Mingzhe Dong,Zhaomin Li
Publisher : Gulf Professional Publishing
Release : 2021-11-30
ISBN : 0128219327
Language : En, Es, Fr & De

GET BOOK

Book Description :

Chemical Methods, a new release in the Enhanced Oil Recovery series, helps engineers focus on the latest developments in one fast-growing area. Different techniques are described in addition to the latest technologies in data mining and hybrid processes. Beginning with an introduction to chemical concepts and polymer flooding, the book then focuses on more complex content, guiding readers into newer topics involving smart water injection and ionic liquids for EOR. Supported field case studies illustrate a bridge between research and practical application, thus making the book useful for academics and practicing engineers. This series delivers a multi-volume approach that addresses the latest research on various types of EOR. Supported by a full spectrum of contributors, this book gives petroleum engineers and researchers the latest developments and field applications to drive innovation for the future of energy. Presents the latest research and practical applications specific to chemical enhanced oil recovery methods Helps users understand new research on available technology, including chemical flooding specific to unconventional reservoirs and hybrid chemical options Includes additional methods, such as data mining applications and economic and environmental considerations

Enhanced Oil Recovery in Shale and Tight Reservoirs

Enhanced Oil Recovery in Shale and Tight Reservoirs Book
Author : James J.Sheng
Publisher : Gulf Professional Publishing
Release : 2019-11-07
ISBN : 0128162716
Language : En, Es, Fr & De

GET BOOK

Book Description :

Oil Recovery in Shale and Tight Reservoirs delivers a current, state-of-the-art resource for engineers trying to manage unconventional hydrocarbon resources. Going beyond the traditional EOR methods, this book helps readers solve key challenges on the proper methods, technologies and options available. Engineers and researchers will find a systematic list of methods and applications, including gas and water injection, methods to improve liquid recovery, as well as spontaneous and forced imbibition. Rounding out with additional methods, such as air foam drive and energized fluids, this book gives engineers the knowledge they need to tackle the most complex oil and gas assets. Helps readers understand the methods and mechanisms for enhanced oil recovery technology, specifically for shale and tight oil reservoirs Includes available EOR methods, along with recent practical case studies that cover topics like fracturing fluid flow back Teaches additional methods, such as soaking after fracturing, thermal recovery and microbial EOR

Introduction to Enhanced Oil Recovery EOR Processes and Bioremediation of Oil Contaminated Sites

Introduction to Enhanced Oil Recovery  EOR  Processes and Bioremediation of Oil Contaminated Sites Book
Author : Laura Romero-Zerón
Publisher : BoD – Books on Demand
Release : 2012-05-23
ISBN : 9535106295
Language : En, Es, Fr & De

GET BOOK

Book Description :

This book offers practical concepts of EOR processes and summarizes the fundamentals of bioremediation of oil-contaminated sites. The first section presents a simplified description of EOR processes to boost the recovery of oil or to displace and produce the significant amounts of oil left behind in the reservoir during or after the course of any primary and secondary recovery process; it highlights the emerging EOR technological trends and the areas that need research and development; while the second section focuses on the use of biotechnology to remediate the inevitable environmental footprint of crude oil production; such is the case of accidental oil spills in marine, river, and land environments. The readers will gain useful and practical insights in these fields.

Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs

Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs Book
Author : Alireza Bahadori
Publisher : Gulf Professional Publishing
Release : 2018-08-18
ISBN : 0128130288
Language : En, Es, Fr & De

GET BOOK

Book Description :

Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs delivers the proper foundation on all types of currently utilized and upcoming enhanced oil recovery, including methods used in emerging unconventional reservoirs. Going beyond traditional secondary methods, this reference includes advanced water-based EOR methods which are becoming more popular due to CO2 injection methods used in EOR and methods specific to target shale oil and gas activity. Rounding out with a chapter devoted to optimizing the application and economy of EOR methods, the book brings reservoir and petroleum engineers up-to-speed on the latest studies to apply. Enhanced oil recovery continues to grow in technology, and with ongoing unconventional reservoir activity underway, enhanced oil recovery methods of many kinds will continue to gain in studies and scientific advancements. Reservoir engineers currently have multiple outlets to gain knowledge and are in need of one product go-to reference. Explains enhanced oil recovery methods, focusing specifically on those used for unconventional reservoirs Includes real-world case studies and examples to further illustrate points Creates a practical and theoretical foundation with multiple contributors from various backgrounds Includes a full range of the latest and future methods for enhanced oil recovery, including chemical, waterflooding, CO2 injection and thermal

Formation Damage during Improved Oil Recovery

Formation Damage during Improved Oil Recovery Book
Author : Bin Yuan,David A. Wood
Publisher : Gulf Professional Publishing
Release : 2018-05-31
ISBN : 0128137835
Language : En, Es, Fr & De

GET BOOK

Book Description :

Formation Damage during Improved Oil Recovery: Fundamentals and Applications bridges the gap between theoretical knowledge and field practice by presenting information on formation damage issues that arise during enhanced oil recovery. Multi-contributed technical chapters include sections on modeling and simulation, lab experiments, field case studies, and newly proposed technologies and methods that are related to formation damage during secondary and tertiary recovery processes in both conventional and unconventional reservoirs. Focusing on both the fundamental theories related to EOR and formation damage, this reference helps engineers formulate integrated and systematic designs for applying EOR processes while also considering formation damage issues. Presents the first complete reference addressing formation damage as a result of enhanced oil recovery Provides the mechanisms for formation damage issues that are coupled with EOR Suggests appropriate preventative actions or responses Delivers a structured approach on how to understand the fundamental theories, practical challenges and solutions

Theory and Practice in Microbial Enhanced Oil Recovery

Theory and Practice in Microbial Enhanced Oil Recovery Book
Author : Kun Sang Lee,Tae-Hyuk Kwon,Taehyung Park,Moon Sik Jeong
Publisher : Gulf Professional Publishing
Release : 2020-07-18
ISBN : 0128204257
Language : En, Es, Fr & De

GET BOOK

Book Description :

Selection of the optimal recovery method is significantly influenced by economic issues in today’s oil and gas markets. Consequently, the development of cost-effective technologies, which bring maximum oil recovery, is the main interest in today’s petroleum research communities. Theory and Practice in Microbial Enhanced Oil Recovery provides the fundamentals, latest research and creditable field applications. Microbial Enhanced Oil Recovery (MEOR) is potentially a low-priced and eco-friendly technique in which different microorganisms and their metabolic products are implemented to recover the remaining oil in the reservoir. Despite drastic advantages of MEOR technology, it is still not fully supported in the industry due to lack of knowledge on microbial activities and their complexity of the process. While some selected strategies have demonstrated the feasibility to be used on a mass scale through both lab and field trials, more research remains to implement MEOR into more oil industry practices. This reference delivers comprehensive descriptions on the fundamentals including basic theories on geomicrobiology, experiments and modeling, as well as current tested field applications. Theory and Practice in Microbial Enhanced Oil Recovery gives engineers and researchers the tool needed to stay up to date on this evolving and more sustainable technology. Covers fundamental screening criteria and theories selective plugging and mobility control mechanisms Describes the basic effects on environmental parameters and the mechanics of simulation, including microbial growth kinetics Applies up to date practical applications proven in both the lab and the field

Surfactants in Upstream E P

Surfactants in Upstream E P Book
Author : Theis Solling,Muhammad Shahzad Kamal,Syed M. Shakil Hussain
Publisher : Springer Nature
Release : 2021-06-19
ISBN : 3030700267
Language : En, Es, Fr & De

GET BOOK

Book Description :

This edited book explores the use of surfactants in upstream exploration and production (E&P). It provides a molecular, mechanistic and application-based approach to the topic, utilising contributions from the leading researchers in the field of organic surfactant chemistry and surfactant chemistry for upstream E&P. The book covers a wide range of problems in enhanced oil recovery and surfactant chemistry which have a large importance in drilling, fracking, hydrate inhibition and conformance. It begins by discussing the fundamentals of surfactants and their synthesis. It then moves on to present their applicability to a variety of situations such as gas injections, shale swelling inhibition, and acid stimulation. This book presents research in an evolving field, making it interesting to academics, postgraduate students, and experts within the field of oil and gas.

Enhanced Oil Recovery Processes

Enhanced Oil Recovery Processes Book
Author : Ariffin Samsuri
Publisher : BoD – Books on Demand
Release : 2019-12-18
ISBN : 1789851076
Language : En, Es, Fr & De

GET BOOK

Book Description :

Concerned with production decline, shortages of new oil reserves, and increasing world energy demand, the oil sector continues to search for economic and efficient techniques to enhance their oil recovery from the existing oil field using several enhanced oil recovery techniques (EOR)methods. Despite its highefficiency, widely acclaimed potentials, and limitations, the Low Salinity Water Flooding (LSWF), hybrid, and nanotechnology applications have gained vast interest with promising future to increase ultimate oil recovery, tackle operational challenges, reduce environmental damage, and allow the highest feasible recoveries with lower production costs. This synergistic combination has opened new routes for novel materials with fascinating properties. This book aims to provide an overview of EOR technology such as LSWF, hybrid, and nanotechnology applications in EOR processes.

Nanofluids and Their Engineering Applications

Nanofluids and Their Engineering Applications Book
Author : K.R.V. Subramanian,Tubati Nageswara Rao,Avinash Balakrishnan
Publisher : CRC Press
Release : 2019-06-18
ISBN : 0429886993
Language : En, Es, Fr & De

GET BOOK

Book Description :

Nanofluids are solid-liquid composite material consisting of solid nanoparticles suspended in liquid with enhanced thermal properties. This book introduces basic fluid mechanics, conduction and convection in fluids, along with nanomaterials for nanofluids, property characterization, and outline applications of nanofluids in solar technology, machining and other special applications. Recent experiments on nanofluids have indicated significant increase in thermal conductivity compared with liquids without nanoparticles or larger particles, strong temperature dependence of thermal conductivity, and significant increase in critical heat flux in boiling heat transfer, all of which are covered in the book. Key Features Exclusive title focusing on niche engineering applications of nanofluids Contains high technical content especially in the areas of magnetic nanofluids and dilute oxide based nanofluids Feature examples from research applications such as solar technology and heat pipes Addresses heat transfer and thermodynamic features such as efficiency and work with mathematical rigor Focused in content with precise technical definitions and treatment

Essentials of Polymer Flooding Technique

Essentials of Polymer Flooding Technique Book
Author : Antoine Thomas
Publisher : Wiley
Release : 2019-05-06
ISBN : 1119537584
Language : En, Es, Fr & De

GET BOOK

Book Description :

Provides an easy-to-read introduction to the area of polymer flooding to improve oil production The production and utilization of oil has transformed our world. However, dwindling reserves are forcing industry to manage resources more efficiently, while searching for alternative fuel sources that are sustainable and environmentally friendly. Polymer flooding is an enhanced oil recovery technique that improves sweep, reduces water production, and improves recovery in geological reservoirs. This book summarizes the key factors associated with polymers and polymer flooding—from the selection of the type of polymer through characterization techniques, to field design and implementation—and discusses the main issues to consider when deploying this technology to improve oil recovery from mature reservoirs. Essentials of Polymer Flooding Technique introduces the area of polymer flooding at a basic level for those new to petroleum production. It describes how polymers are used to improve efficiency of “chemical” floods (involving surfactants and alkaline solutions). The book also offers a concise view of several key polymer-flooding topics that can’t be found elsewhere. These are in the areas of pilot project design, field project engineering (water quality, oxygen removal, polymer dissolution equipment, filtration, pumps and other equipment), produced water treatment, economics, and some of the important field case histories that appear in the last section. Provides an easy to read introduction to polymer flooding to improve oil production whilst presenting the underlying mechanisms Employs “In A Nutshell” key point summaries at the end of each chapter Includes important field case studies to aid researchers in addressing time- and financial-consumption in dealing with this issue Discusses field engineering strategies appropriate for professionals working in field operation projects Essentials of Polymer Flooding Technique is an enlightening book that will be of great interest to petroleum engineers, reservoir engineers, geoscientists, managers in petroleum industry, students in the petroleum industry, and researchers in chemical enhanced oil recovery methods.

Advanced Modeling with the MATLAB Reservoir Simulation Toolbox

Advanced Modeling with the MATLAB Reservoir Simulation Toolbox Book
Author : Knut-Andreas Lie,Olav Møyner
Publisher : Cambridge University Press
Release : 2021-10-31
ISBN : 1009022490
Language : En, Es, Fr & De

GET BOOK

Book Description :

Many leading experts contribute to this follow-up to An Introduction to Reservoir Simulation using MATLAB/GNU Octave: User Guide for the MATLAB Reservoir Simulation Toolbox (MRST). It introduces more advanced functionality that has been recently added to the open-source MRST software. It is however a self-contained introduction to a variety of modern numerical methods for simulating multiphase flow in porous media, with applications to geothermal energy, chemical enhanced oil recovery (EOR), flow in fractured and unconventional reservoirs, and in the unsaturated zone. The reader will learn how to implement new models and algorithms in a robust, efficient manner. A large number of numerical examples are included, all fully equipped with code and data so that the reader can reproduce the results and use them as a starting point for their own work. Like the original textbook, this book will prove invaluable for researchers, professionals and advanced students using reservoir simulation methods.

Introduction to Enhanced Recovery Methods for Heavy Oil and Tar Sands

Introduction to Enhanced Recovery Methods for Heavy Oil and Tar Sands Book
Author : James G. Speight
Publisher : Gulf Professional Publishing
Release : 2016-02-24
ISBN : 0128018755
Language : En, Es, Fr & De

GET BOOK

Book Description :

Introduction to Enhanced Recovery Methods for Heavy Oil and Tar Sands, Second Edition, explores the importance of enhanced oil recovery (EOR) and how it has grown in recent years thanks to the increased need to locate unconventional resources such as heavy oil and shale. Unfortunately, petroleum engineers and managers aren't always well-versed in the enhancement methods that are available when needed or the most economically viable solution to maximize their reservoir’s productivity. This revised new edition presents all the current methods of recovery available, including the pros and cons of each. Expanded and updated as a great preliminary text for the newcomer to the industry or subject matter, this must-have EOR guide teaches all the basics needed, including all thermal and non-thermal methods, along with discussions of viscosity, sampling, and the technologies surrounding offshore applications. Enables users to quickly learn how to choose the most efficient recovery method for their reservoir while evaluating economic conditions Presents the differences between each method of recovery with newly added real-world case studies from around the world Helps readers stay competitive with the growing need of extracting unconventional resources with new content on how these complex reservoirs interact with injected reservoir fluids