Surface Production Operations: Volume IV: Pumps and Compressors

Maurice Stewart

• Publisher: Gulf Professional Publishing
• Year: 2018
• ISBN:
  9780128099223
• Topic: Technology & Engineering
• Subtopic: Industrial Engineering
• Index: Technology & Engineering

For over thirty years, the Surface Production Operations Series has taken the guess work out of the design, selection, installation, operation, testing, and troubleshooting of surface production equipment. The fourth volume in this series, Pumps and Compressors is directed to both entry-level personnel and practicing professionals looking for an up-to-date reference book on managing, evaluating, sizing, selecting, installing, operating and maintaining pump and compressor systems. Packed with examples drawn from years of design and field experience, this reference features many charts, tables, equations, diagrams, and photographs to illustrate the basic applications including pump hydraulics, centrifugal and reciprocating compressor applications, compressor performance maps, pump performance curves, pump and compressor testing and installation, and many more critical topics. Packed with practical solutions Surface Production Operations: Pumps and Compressors delivers an essential design and specification reference for today's engineers.

• Covers application and performance considerations for all types of pumps and compressors
• Delivers hands-on manual for applying mechanical and physical principles to select and design pump and compressor systems, supported by many tables and diagrams
• Gives expert advice on how to apply design codes and standards such as API 610, API 674, ANSI B78.1, API 617, API 11P, API RP 14C and the Hydraulic Institute

1

Overview of pumps, compressors, and drivers

Abstract

This chapter builds upon the information presented in Volumes 1 through 3 of the Surface Production Operations series. It begins by presenting an overview of the purposes of pumps, compressors, and drivers used in production facilities. The chapter closes by providing the scope and organization of each chapter in the text.

Keywords

Pumps; Compressors; Drivers; Scope; Application; Criteria for equipment selection; Hydraulic system design; Thermodynamic system design; Troubleshooting; Installation

1.1 Overview

After wells are successfully drilled and completed, the fluid produced must be transported to a facility where it is separated into oil, water, and gas; conditioned to meet process input requirements; treated to remove impurities such as H₂S, CO₂, H₂O, and solids; and refined or stored for eventual sales. Fig. 1.1 is a simplified block diagram that illustrates the basic “wellhead to sales” concept. The diagram begins with the wellhead choke which is used to control the rate of flow from each well. The fluid from the well travels through a flowline to the production facility where the fluid is separated, conditioned, treated, processed, measured, refined, or stored.

Fig. 1.1 Block diagram of “wellhead to sales” concept. (⁎Interconnection piping between production equipment-separators: treaters, heaters, and tankage.)

Volume 1: Design of Oil-Handling Systems and Facilities and Volume 2: Design of Gas-Handling Systems and Facilities of the Surface Production Operations series present the basic concepts and techniques necessary to select, specify, size, operate, and troubleshoot oil, water and gas handling, conditioning, and processing facilities. Volume 3: Facility Piping and Pipeline Systems; Volume 4: Pumps, Compressors, and Drivers; Volume 5: Process Equipment-Pressure Vessels, Heat Exchangers and Storage Tanks; and Volume 6: Instrumentation, Process Control, and Safety Systems of the Surface Production Operations series build upon the information that is presented in Volumes 1 and 2.

1.1.1 Pumps

Pumps serve many purposes in production facilities. The largest pumps are usually shipping or sales pumps which increase the pressure of oil or condensate so that it can flow into a sales pipeline or be loaded into tankers, barges, railroad cars, or trucks. Other large pumps are used with water injection systems for disposing of produced water or for waterflooding. Smaller pumps are used to pump liquids from low to higher pressure vessels, to pump liquids from tanks at a low elevation to tanks at a higher elevation, or to transfer liquids for further processing.

A facility's utility system often has many pumps, which may be used for firewater wash down and utility water, heat medium, fuel oil or diesel, and hydraulic systems.

The project/facility engineer must be able to select the proper pump for each application, determine horsepower requirements, design the piping system associated with the pump, and specify materials and details of construction for bearings, seals, and so on. On standard applications the project/facility engineer may allow the vendor to specify materials and construction details for the specified service conditions. Even then, the project/facility engineer should be familiar with different alternatives so that he or she can better evaluate proposals and alternate proposals of vendors.

1.1.2 Compressors

Compressors are used whenever it is necessary to flow gas from a low-pressure system to a high-pressure system. Flash gas from low-pressure vessels used for multistage stabilization of liquids, oil treating, water treating, and so on, often exists at too low a pressure to flow into the gas sales pipeline. Sometimes this gas is used as fuel and the remainder is flared or vented. In many instances, it is economically attractive to compress this gas to a high-pressure system so it can be sold.

Compression may also be required due to environmental reasons. Flash gas, which might otherwise be flared, may be compressed for sales, or gas produced with oil (associated gas) may be compressed for reinjection to avoid flaring or to help maintain reservoir pressure.

In some marginal gas fields and in many larger gas fields that experience a decline in flowing pressure with time, it may be economical to allow the wells to flow at surface pressures below that required for gas sales. In such cases, a booster compressor (one in which the ratio of discharge to suction pressure is low) may be installed. Booster compressors are also used on long pipelines to restore pressure lost to friction.

The use of large compressors is probably more prevalent in oil field facilities than in gas field facilities. Oil wells often require low flowing surface pressures, and the gas that flashes off the oil in the separator must be compressed. Often, natural gas is injected into the tubing of the well to lighten the column of liquid and reduce hydrostatic backpressure. This “gas lift” gas is produced with the well fluids at low pressure. Compressors are used so the gas lift gas can be recirculated and injected back into the well at high pressure. Gas lift compressors are characterized by both high overall ratios of discharge to suction pressure (“pressure ratios”) and relatively high throughputs.

As with pumps, the project/facility engineer must select the type of compressor to use for each application, determine power requirements, design the piping system associated with the compressor, and specify materials and details of construction for bearings, cylinders, and so on. On standard applications, the project/facility engineer may allow the vendor to specify materials and construction details for the specified service conditions. However, even in these instances the project/facility engineer should be familiar with different alternatives so that he can better evaluate vendors' proposals and alternative proposals.

1.1.3 Drivers

Drivers must be capable of developing the required horsepower and torque to drive mechanical equipment such as pumps, compressors, and fans used throughout the production facility. The most common drivers used are electric motors, internal combustion engines, combustion gas turbines, and steam turbines.

Three-phase alternating-current (AC) induction and synchronous motors are used primarily with reciprocating and centrifugal pumps. Motor types, performance characteristics, enclosures, and maintenance considerations should be reviewed when selecting an electric motor.

Two- and four-stroke internal combustion engines are typically used with reciprocating pumps and compressors. Several factors such as support systems, emissions control, arrangements, natural aspiration, supercharging, and turbocharging should be reviewed when selecting an internal combustion engine.

Combustion gas turbines (CGTs) are almost always used with centrifugal compressors. Types of turbines as well as their performance characteristics, emissions, and auxiliary systems should be reviewed when selecting a CGT.

1.2 Scope and application

Volume 4 of the Surface Production Operations series is directed both to entry-level personnel and experienced personnel who are looking for a reference on pumps, compressors, and drivers.

It covers approximately 90% of the most commonly used pumps, compressors, and drivers, focusing on four areas: fundamentals, specifying and purchasing, troubleshooting, and modifying. It gives little attention to large, complex or to specialty pumps, compressors, and drivers, although such machines are important in their individual applications. This text should not be used as a substitute for sound engineering judgment.

This text contains guidelines that can be used as is or modified for local or geographical preferences, priorities, or experiences.

The intent of this text is to provide practical, useful information based on standard industry practice and the author's personal experience.

1.3 Organization

Volume 4 is divided into three parts:

• • Part 1: Pumps (Chapters 2–6)
• • Part 2: Compressors (Chapters 7–11)
• • Part 3: Drivers (Chapter 12)

Each of these parts is i...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Acknowledgments
• Disclaimer
• 1: Overview of pumps, compressors, and drivers
• 2: Pump fundamentals
• 3: Centrifugal pumps
• 4: Reciprocating pumps
• 5: Rotary pumps
• 6: Special purpose pumps
• 7: Compressor fundamentals
• 8: Dynamic compressors
• 9: Reciprocating compressors
• 10: Application of compression theory and practical solutions
• 11: Rotary compressors
• 12: Overview of commonly used drivers
• Index