Chemistry for Enhancing the Production of Oil and Gas Wayne W. Frenier Murtaza Ziauddin Chemistry for Enhancing the Production of Oil and Gas Chemistry for Enhancing the Production of Oil and Gas Wayne W. Frenier Frenier Chemistry Consultants Murtaza Ziauddin Schlumberger Society of Petroleum Engineers © Copyright 2013 Society of Petroleum Engineers All rights reserved. No portion of this book may be reproduced in any form or by any means, including electronic storage and retrieval systems, except by explicit, prior written permission of the publisher except for brief passages excerpted for review and critical purposes. Society of Petroleum Engineers 222 Palisades Creek Drive Richardson, TX 75080-2040 USA http://www.spe.org/store [email protected] 1.972.952.9393 Preface In approximately 1983, Al Look* (at that time the President of the Dowell Division of the Dow Chemi- cal Company) noted that each day, hundreds (possibly thousands) of small chemical plants are set up in the world’s oil/gas fields, and hundreds of thousands of pounds of chemicals are pumped into the Earth to enhance and maintain the flow of oil and gas. Frequently at the end of the treatment, these “mini-plants” [see Fig. P.1 in API (2008) for drawing of a hydraulic fracturing set up] are broken down and transported to a new site. The chemistry applied is the same as might happen in a refinery or a chemical plant, but here, most of the reactions take place out of sight and control of the process engineers. Thus, the design of the chemistry is of particular importance because usually it cannot be changed once it is pumped. This book will describe how these underground reactions work to keep the world’s hydrocarbon life lines flowing. This document has been written to provide an improved understanding of the role of chemical reactions for enhancing and maintaining the production of oil and gas. There are several books that describe the thousands of production chemicals in use and include those by Fink (2003), Fink (2011), and Kelland (2009). These documents are useful references and have been cited frequently by the authors of this book. In addition, the reviews in Economides and Nolte (2000) have several excellent chapters (Constein et al. 2000; Hill and Schechter 2001) on some aspects of production chemistry and their applications in acid and hydraulic prop stimulation. This current book will also review many new aspects of the application of chemistry for enhancement oil and gas production that have reached the market since 2000 and will provide new mechanistic information. *Al Look. 1983. Private communication. v vi Preface This publication will provide an overview of the science and technology of the use of many production chemicals to a general technically trained audience, with emphasis placed on the basic chemical and physical principles by which the chemicals can enhance or maintain oil and gas production. The introductory chapter describes the production environment, problems that require chemical intervention, and thus, the need for the thousands of different chemicals that are in use. This chapter also reviews the important chemical and physical principles that are common to most if not all of the enhancement treatments. This also places the technical aspects of production management in the perspective of the upstream oil and gas business. Subsequent chapters discuss aspects of the use and mechanisms of the complex chemistries that take place with the application of flow assurance chemi- cals, during stimulation (reactive chemistry and prop fracturing) and chemically improved oil recov- ery, including the use of chemical tracers. A separate chapter (Chapter 6) emphasizes the importance of health, safety, and environmental compliance in all aspects of oilfield treatments. Most of the chapters of the book end with a section where successful chemical enhancement or control methods have been used to solve specific production problems. An outline for analysis is • Is there a problem that requires an intervention? • If there is a problem, how bad will it be? • Can the problem be managed through engineering, and/or chemical means? • Evaluate the results of an intervention or control strategy. Each major section and most subsections will include reviews of current literature as well as sum- maries of the consensus understandings from the literature cited. Chapter 1—Introduction This section describes the reasons producing formations require intervention to enhance or maintain production, and the various types of chemical intervention in use. This chapter also reviews basic chemical and engineering processes that occur in production operations. It emphasizes the common- ality of many of the chemical and engineering processes across the various production enhancement processes. Chapter 2—Chemistry of Production Impairment This chapter describes processes that impair the production of oil and gas such as formation damage and formation (and then mitigation) of emulsions in the production stream. It also updates techniques for mitigating and inhibiting deposition of inorganic and organic materials using references from ear- lier sources (Frenier and Ziauddin 2008; Frenier et al. 2010). Chapter 3—Formation Stimulation With Reactive Chemicals This chapter reviews the chemicals and mechanisms of reactive fluids (including acids) stimulation of oil and gas formations. Chapter 4—Propped Fracturing Chemistry and Applications This chapter discusses techniques and chemicals for formation stimulation using hydraulic fracturing using essentially nonreactive fluids. Chapter 5—Improved Oil Recovery Chemical Applications This chapter provides details of the chemicals and formation interactions that allow chemical sweep methods and conformance control processes to enhance hydrocarbon recovery. This chapter also gives a short review of the use of chemical tracers. Preface vii Chapter 6—Health, Ecology, and Safe Handling of Treating Chemicals and Produced Fluids This chapter reviews general guidelines for planning and use of potentially toxic or hazardous chemi- cals that are frequently part of a treatment. Included is a discussion of the hazards associated with flowing back fluids. This chapter also reviews the use of chemicals to remediate spills of crude oil or production chemicals. Chapters 1 through 5 each conclude with a “Things to Think About” section that summarizes the major findings revealed by the review of the technologies that were discussed and how this knowledge can be applied to chemical production management projects. Chapters 2 through 5 also have a section titled Histories and Best Practices (based on the technologies in that chapter). Here, the science and engineering principles described in the earlier sections are illustrated through practical demonstrations of chemical intervention and remediation. Definition of the Upstream Oilfield Environment The scope of this document is limited to chemical intervention and enhancement in the production (“upstream”) oilfield environment. This includes the entire production field including injection wells, the producing formation, and especially the near wellbore area as well as flowlines and gathering lines. This includes the natural or artificial tubulars, subsurface devices, gathering lines, and wellsite surface equipment. The book will not describe chemicals in use to drill, complete, or cement the well field. See the books by Growcock (2005) and Nelson and Guillot (2005). The discussion will also not include problems in transmission pipelines or refineries. However, many of the techniques and technologies needed are very similar to those described in this book and could be applied with appropriate modifica- tions. See Frenier (2001b) for a review of cleaning of industrial equipment, including the downstream oil and gas equipment. Acknowledgment The authors acknowledge the help and encouragement of Schlumberger Technology Company. In particular, we thank Schlumberger for releasing significant portions of text and illustrations from com- pany files for use in the document. Olga Kresse, Bruno Lecerf, Philippe Enkababian, Eric Clum, and Greg Kubala, (all of Schlumberger) reviewed some of the portions of the text and provided very use- ful suggestions for improvements.We also acknowledge the help and encouragement of Prof. Mojdeh Delshad, University of Texas at Austin. SPE would like to thank Mojdeh Delshad for his generous contributions to the oversight of this book project on behalf of the Books Development Committee. We appreciate his contributions in working with the author and ensuring that timelines and quality standards were upheld throughout the process. This book is dedicated to my wife, Dolores, and our children, Andrew Frenier and Kathleen Turner, as well as our grandchildren. They inspire me to continue to work, learn, and become a better person. –Wayne W. Frenier I humbly dedicate this modest endeavor to the 52nd Dai al Mutlaq, His Holiness, Dr. Syedna Moham- med Burhanuddin (TUS), on the occasion of his 102nd birthday and 50 years as Dai al Mutlaq. I pray that Allah may grant him a long and healthy life. –Murtaza Ziauddin Contents Preface 1. Introduction .....................................................................................................................1 1.1 Chemical Applications in the Reservoir Life Cycle ...................................................1 1.2 Need for Chemical or Engineering Practices to Enhance Production .....................4 1.3 Production Chemistry Economics .........................................................................11 1.4 Basics of Fluid Chemistries ...................................................................................12 1.5 Key Production Chemistry Concepts .....................................................................23 1.6 Injecting Fluids Into the Earth .................................................................................39 1.7 Treating Equipment on the Wellsite .......................................................................49 1.8 Electronic Sources of Oilfield Chemistry Information .............................................53 2. Chemistry of Production Impairment .........................................................................55 2.1 Introduction to Production Impairment Processes .................................................55 2.2 Organic and Inorganic Deposits .............................................................................57 2.3 Formation Damage ................................................................................................87 2.4 Formation and Control of Emulsions in Production Operations .............................99 2.5 Flow Enhancers ...................................................................................................116 2.6 Case Histories and Best Practices for Use of Production Chemicals ..................118 2.7 Things to Think About ...........................................................................................120 3. Formation Stimulation With Reactive Chemicals ....................................................121 3.1 Introduction to Stimulation Using Reactive Chemicals .........................................121 3.2 Laboratory Test Methods for Matrix Reactive Fluid Treatments ...........................126 3.3 Matrix Stimulation of Carbonate Formations .......................................................132 3.4 Chemical Formulations for Stimulation of Carbonate Reservoirs.........................142 3.5 Sandstone Matrix Stimulation ..............................................................................163 3.6 Additives—What Is in the Reactive Fluid? ...........................................................184 3.7 Placement of Matrix Fluids ..................................................................................206 3.8 Fracture Stimulation of Carbonates and Sandstone Using Reactive Fluids .............................................................................................231 3.9 Best Practices and Case Histories of Use of Reactive Chemicals for Stimulation ....................................................................................253 3.10 Things to Think About ..........................................................................................257 4. Propped Fracturing Chemistry and Applications ....................................................259 4.1 Introduction to Propped Fracturing Processes .....................................................259 4.2 Characteristics of Fracturing Fluids, Additives, and Proppants ...........................271 4.3 Introduction to Fracture Fluid/Proppant Chemistry Using HPG as an Example .....................................................................................................284 4.4 Water-Based Fluids ..............................................................................................291 4.5 Nonwater-Based Fluids ........................................................................................312 4.6 Fluid Loss Agents and Breakers ..........................................................................313 4.7 Additional Frac Additives ......................................................................................322 4.8 Reactions of Fracturing Fluids With Formations and Well Fluids .........................331 4.9 Proppants and Proppant Aids ..............................................................................333 ix x Contents 4.10 Fluid Selection/Proppant Selection ......................................................................345 4.11 Fracture Planning and Models: Combining Chemistry and Engineering ..............353 4.12 Case Histories and Best Practices for Proppant Fracturing .................................366 4.13 Things to Think About ..........................................................................................369 5. Improved Oil Recovery Chemical Applications .......................................................371 5.1 Basic Principles of IOR .......................................................................................373 5.2 Selection Criteria for IOR Treatments ..................................................................384 5.3 Testing Methods for IOR Processes .....................................................................389 5.4 Immiscible Displacement Processes ....................................................................395 5.5 Miscible Displacement Processes ........................................................................414 5.6 Chemical Methods for Improving Sweep Efficiency (Mobility Control) .................445 5.7 Use of Chemical Tracers ......................................................................................456 5.8 Case Histories and Best Practices for Chemical EOR .........................................460 5.9 Things to Think About ...........................................................................................462 6. Health, Ecology, and Safe Handling of Treating Chemicals and Produced Fluids ..........................................................................................................463 6.1 Safety Considerations During Production Enhancement Operations...................463 6.2 Health, Safety, and Environmental (HSE) Management ......................................467 6.3 Handling, Reuse, and Disposal of Flowback Fluids .............................................476 6.4 Control and Remediation of Spills in Water Bodies and on Land ........................489 6.5 Continual Quality Improvements With Oilfield Chemistry .....................................505 Nomenclature ...................................................................................................................509 References .......................................................................................................................513 Author Index ....................................................................................................................577 Subject Index ...................................................................................................................593