Book Three of the Vocational Training Series Third Edition, October 1995 American Petroleum Institute and al artment American Petroleum Institute SPECIAL NOTES 1. API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED. API IS NOT UNDERTAKING TO MEET THE DUTIESOF EMPLOYERS, MANU- FACTURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY RISKSA N D PRECAUTIONS, NOR UNDERTAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS.
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All rights reserved. No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or other- wise, without prior writtenpermission from the publisher. Contact API Publications Manager,1220 L Street, N. Copyright 0 1995 American Petroleum Institute API TITLE*VT-3 95 0 7 3 2 2 9 0 0 5 4 9 3 7533 2 FOREWORD The underground injection of water, whether into waterfloods or disposal systems, is an integral portion of the cost of producing oil.
The magnitude ofthis cost has increased because more water is being produced as: m More reservoirs are nearing completion. m Wells are being produced to higher water-cut due to the demand foroil. m Many older waterfloods are being expanded and new ones started in order to recover once marginal reserves. The expense of injecting larger volumes of produced wateris further compounded by the rapid rise in the cost of energy neededto inject this water andthe increasingly higher costs of measures needed to protect the environment.
The objective of this manual is to provide information for field operating personnel on the systems, methods and practices to most economically operate an underground injection program while maintaining the schedules and volumes required. The manual is written to help the overseer of the system solve many of the problems associated with underground water injection. Its intent is to provide the readerwith information regarding the following: a. Suitable design of the injection system including wells,lines and surface facilities.
Regulations and other restrictions related to subsurface water injection. Measures to be taken to protect life, property and the public interest. Factors which affect injection cost. The material in this manualis of a basic, cursory, and introductory nature.
The reader should consult-technicalexperts for more detailed information on specific items of interest. iii CONTENTS Page SECTION 1-INTRODUCTION TO SALTWAER INJECTION 1.3 Disposal Versus Enhanced Recovery .4 Components of an Injection System.2 Water Treatment Facilities .1 Underground Injection Control (UIC).2 Air Pollution Concerns .3 Waste Management-Hazardous Materials .5 Hazardous Chemicals Inventory .6 Naturally Occurring Radioactive Material (NORM) .7 Other Environmental Concerns .6 Health and Safety Concerns .2 Chemicals at Injection Facilities .5 Naturally Occurring Radioactive Material (NORM) .10 Fires and Explosions. 7 CHAPTER 2-THE GATHERING SYSTEM 2.2 Initial OiliWater Separation .2 Gravity Flow and Pumping Techniques .5 Types of Pipe Used in Gathering Systems.9 Inspection and Sampling .4 Installation of Pipelines .5 Pipeline Inspection and Maintenance. 12 CHAPTER 3-WATER TREATMENT FACILITIES 3.1 Gravity Segregation Vessel .2 Heater Treater and Electrical Chemical Treater.3 Skim Tanks and Coalescers .1 Coagulation and Sedimentation .4 Scales and Other Precipitates .2 Preventing or Removing Scales and Other Deposits .3 Sampling Water-Formed Deposits .4 Field Sample Collection .3 Anaerobic Sulfate-Reducing Bacteria.
20 CHAPTER +INJECTION FACILITIES 4.2 Prediction of Volume and Rateof Water Production For Disposal.1 Active Water Drive .2 Limited Water Drive .3 Maximum Future Water Production Rate.4 Future Water Production Curve .1 Permeability and Thickness .5 Selection of Wells For Injection.1 The Newly Drilled Hole .2 Conversion of an Existing Well .6 Drilling and Completion.1 Methods of Completion .2 Access to the Objective Formation .4 Adequate Hole Diameter .5 Containment of Injected Fluids to Target Formation.7 The Long String.8 Protection Against Corrosion .7 Equipping The Well For Injection.2 Designing the Tubing String .3 Hook-up Considerations .9 Putting The Well Into Service .1 Rate Testing Disposal Wells .2 Rate Selection for Enhanced Recovery. 33 CHAPTER 5-ECONOMIC CONSIDERATIONS OF SALTWATER INJECTION OPERATIONS 5.2 Disposal Costs For Salt Water .3 Value of Salt Water .2 Effect ofDisposal on Economic Limit.4 Organizational Procedures For Handling Salt Water Disposal .1 Disposal by Others for a Fee .2 Disposal into an Operator's Own System.3 Association Disposal System .4 Joint Interest Disposal System.1 Disposal Volumes and Pressures .2 Remedial Well Work .3 Repairs to Injection System. 45 Figures 1-Fiberglass Saltwater Handling Tank. 8 2-Transfer Pump and Back-up Pump.
8 3-Fiberglass Tank and Transfer Pump. 9 &Friction-loss Chad. 10 5-Bundle of 8-inch PlasticPipe With Bell End Joint Connectors. 11 6"Orifice Meter Type Metering Installation.
12 7"Chemical Injection System. 13 8-Trap for Inserting a Pipeline Scraper Intoa Line. 14 9-Typical Skim Tank. 16 IO-Typical BaffleType Coalescer.
16 1I-Common Methods of Completion. 24 12-Typical Injection Wellhead Assembly and Meter Run. 27 13-Installation Utilizing Vertical Centrifugal Pumps. 28 14"large Water Injection Station.
28 15-Electric Motor-Driven Positive Displacement Pump. 29 16"Centralized Injection Pump Station. 30 ~~ ~ A P I TITLEsVT-3 95 m 0732290 0549375 Lb8 m Subsurface Saltwater Injection andDisposal SECTION 1-INTRODUCTION TO SALTWATER INJECTION 1.1 Introduction OSHA' 29 Code ofFederal Regulations Part 1910:1200 Deep beneath the surface of the earth lie layers of soil containing the oil and gas used to fuel our world. Unfortu- NACE2 nately for oil andgas producers, water isalso found in those TMO194-94 Field Monitoring of Bacteria Growth in very same formations.
Since technology has developed no Oiljîeld Systems (1994) effective methodto date for selectively producing hydrocar- bons only, this water, knownas produced water or brine, is 1.3DisposalVersusEnhancedRecovery produced with theoil or gas, and separated at the surface. The primary difference between injection wells used for Sometimes the water is fresh. In those cases, many disposal and those usedfor enhanced recovery is the purpose options are availablefor its management whenit reaches the each serves. surface and is separated from the oil.
However, in other cases, the water is verysaline. B The disposal well is used for the subsurface disposal of With rare exceptions, only four acceptable methods exist unwanted salt water. In many cases, only one disposal well for saltwater management: serves a field or system. Suitable formations for disposal may include depleted oil reservoirs and portions of oil- a.
Injection into underground saltwater-bearing formations. producing reservoirs' down dip from the water-oil contact. Injection into oil-bearing underground reservoirs. B The enhanced recovery well is used for the subsurface c.
Disposal of carefully treated water into the ocean in the injection of water into an oil-bearing formation to displace case of offshore production platforms. movable oil toward producing wells. The enhanced recovery d. well is usually part of a pattern of several injection wells This manualdiscusses options (a) and (b)-injection into serving an enhanced recoveryproject.
deep wellsfor disposal or for enhanced product recovery.It Unless otherwise noted,in this manual the terminjection presents minimum guidelines covering well construction, well will be used to refer to either type. The more specific operation and monitoring. terms disposal well or enhanced recovery well will be used when discussing issues particular to one or the other.2ReferencedPublications types of wells have a common objective-to ~~ furnish an The following bulletins, recommended practices, andavenue, or wellbore, for the subsurface managementof salt codes are cited this in publication. Because common this of objective, most completion and operational practices fit both.
API BullE2 Bulletin on Management of Naturally The salt water is injected through a cased and cemented Occurring Radioactive Materials (NORM) well to protect other underground reservoirs, especially those in Oil and Gas Production containing potable ground water. If the project is to be installed and operated at minimum Bull E3 Well AbandonmentandInactive Well be selected. cost, the best materials for distribution lines must Practices f o r US. Exploration and Planning of an injection system may include a water Production Operations treatment program that will control corrosion of the piping Bull D16D Suggested Procedurefor Development of system and prevent pluggingof the injection formation.
Spill Prevention Control and Counter- Careful selection of plant equipment and treating facilities is measure Plans important. RP 55 Recommended Practices for Conducting Injection well permits are required from the U. Envi- Oil and Gas Producing and Gas ronmental Protection Agency (EPA) or the applicable state Processing Plant Operations Involving regulatory agency. The wells must designed, be constructed, Hydrogen Sulfide and operated in accordance with regulatory requirements.
Environmental Guidance Document: Onshore Solid Waste IOSHA, The Code of Federal Regulations is avilable from the U. Govem- Management in ExPLoration and produc- mentPrinting Office,Washington, D. tion Operations ZNACE, P. Box 218340, Texas Houston, 77218.
1 ~ ~ A P IT I T L E S V T - 3 95 m 0732290 0549376 O T 4 m 2 Book Three of fhe Vocational Training Series However, some differencesexist. Collection center equipment. D There are more injection wells in an enhanced recovery e. Inspection and maintenance of the system.
project than in a disposal project. The volume of waterto be used for enhanced recovery is Additionalinformation on thegathering system is selected for each well; with disposal, however, whatever provided in Section2. water is produced must be managed. Injection volume in a disposal well is limited onlyby permit condition or the injec- 1.2 WATERTREATMENTFACILITIES tivity of the well.
Although preliminary separationof salt water from other In enhanced recovery projects, the formation and its prop- components (oil, solids, and the like)begins at the tank erties are already known from production history. For battery, additional treatmentis often requiredprior to injec- disposal, this is not always true. It may be necessary to select tion to protect the surface facilities, the well, and/or the the best formation from information that must be gathered. Additionally, further product recovery can occur.
Enhanced recovery systemsgenerallyrequire much Various types of treatment may be necessary, depending longer surface lines to distribute the water to the injection upon the types of contaminantsto be removed.Some of the wells than those fora disposal system. most common includethe following: Installation and operation of a saltwater system are expen- a. Skimmers or coalescers to remove oil. Careful planningis mandatory before beginning b.
Filters to remove solids. construction to allow time for the following: c. Chemical treatment to remove or control scales and a. Designing the system.
sludges, or kill bacteria. Notifying the offset operator. Stripping to remove oxygen. Planning safety, environmental and health considerations.
It is necessary to determine which types of treatment d. Selecting materials and equipment. might be requiredso that proper facilities can be planned and e. Securing required environmental and operational permits.
This may require sampling the wateror deposits. Scheduling possible hearingsbefore state and federal The saltwater contaminants and the treatment methods are regulatory bodies. discussed further in Section3.4 Components of an Injection System 1.3 INJECTIONFACILITIES Whether for enhanced recovery or disposal, the basic Once thesalt water has been moved to the central facility components of the injection system are the same. These and treated, itis ready for injection.
Pumpsare used to move include the following: the salt water down the well and into the injection formation.