Handbook of Multiphase Flow Assurance

Taras Y. Makogon

• Publisher: Gulf Professional Publishing
• Year: 2019
• ISBN:
  9780128130636
• Topic: Technology & Engineering
• Subtopic: Renewable Power Resources
• Index: Technology & Engineering

Handbook of Multiphase Flow Assurance allows readers to progress in their understanding of basic phenomena and complex operating challenges. The book starts with the fundamentals, but then goes on to discuss phase behavior, fluid sampling, fluid flow properties and fluid characterization. It also covers flow assurance impedance, deliverability, stability and integrity issues, as well as hydraulic, thermal and risk analysis. The inclusion of case studies and references helps provide an industrial focus and practical application that makes the book a novel resource for flow assurance management and an introductory reference for engineers just entering the field of flow assurance.

• Starts with flow assurance fundamentals, but also includes more complex operating challenges
• Brings together cross-disciplinary discussions and solutions of flow assurance in a single text
• Offers case studies and reference guidelines for practical applications

Chapter 1

Introduction

Abstract

Flow assurance aims to make sure oil and gas keep flowing. To achieve that goal, flow assurance relies on the analysis of multiphase flow and on the selection and use of production chemicals. Flow assurance engineers commonly analyze the flow of oil and gas in wells, production flowlines, process facilities and export pipelines. Complex networks of gathering lines feeding into trunk flowlines exist in onshore and offshore fields, and the analysis to optimize flow routing through such networks is equally complex.

Keywords

Multiphase; Flow assurance; Risk analysis; Process safety; Product value; Production

Outline

• Multiphase production problems: Blockages and restrictions
• Savings from using flow assurance
• Examples of flow assurance problems
• How flow assurance and production chemistry work together
• When is flow assurance applied
• Knowledge required in flow assurance
• Why flow assurance failures happen
• Flow assurance background
• Flow assurance requirements
  • Basis of design
  • Units for fluid characterization
• Introduction to flow assurance risk analysis
  • Threats to flow are normally attributed to flow assurance
  • Threats to product value or process safety (asset integrity)
• Hardware cost
  • Cost of subsea hardware related to flow assurance
• Monitoring and data mining
• Flow assurance in operations
  • Onshore production
  • Offshore production
  • Deepwater production
• Systematic approach to solving flow assurance problems
• Process safety
• System of measures for flow assurance
• Outlook for flow assurance
• References

Flow assurance aims to make sure oil and gas keep flowing. To achieve that goal, flow assurance relies on the analysis of multiphase flow and on the selection and use of production chemicals. Flow assurance engineers commonly analyze the flow of oil and gas in wells, production flowlines, process facilities and export pipelines. Complex networks of gathering lines feeding into trunk flowlines exist in onshore and offshore fields, and the analysis to optimize flow routing through such networks is equally complex.

Definitions of flow assurance are numerous, including this one: Flow Assurance is the analysis of thermal, hydraulic and fluid-related threats to flow and product quality and their mitigation using equipment, chemicals and procedure.

Multiphase production problems: Blockages and restrictions

Oil and gas are currently produced through wells and pipelines. The lack of flow in wells and pipelines may be due to low reservoir pressure or productivity, due to complete blockages or due to partial restrictions.

Flow restrictions may happen in a reservoir, in a well production tubing or a tree, in a jumper between a well and a flowline, in a flowline, in a riser or in an export pipeline. In some cases, restrictions may happen in several locations simultaneously. The largest number I have seen is five blockages in the same production flowline at the same time. Restrictions may also occur in water and gas injection systems as in wells, flowlines or reservoirs.

Restrictions may be hydraulic, such as liquid accumulation also known as a holdup in flowlines and risers, liquid loading in wells, or mechanical such as a partly closed valve or a scraper. Restrictions or blockages may also be solid, including organic (e.g., paraffin wax), inorganic (scale) or particulate (sand). The hydraulic, mechanical or solid restrictions may be stationary such as the liquid holdup or moving such as the slugging. A flow assurance practitioner should be able to recognize the signs of and potential for any type of restriction and either economically design it out of a new system or mitigate it in an existing system.

In some cases, restrictions may lead to other restrictions. There is an early 2000s example from West Africa offshore production where a wax deposit in a flowline got scraped by a formed hydrate plug into a solid paraffin wax blockage. Similarly, combined hydrate-paraffin restrictions have also formed in the North Sea in the early 1990s and asphaltene-hydrate in the Gulf of Mexico in the 2010s. Paraffin-asphaltene-sand restrictions have been common in Siberian pipelines through the decades.

Modeling of multiphase flow can be done to find optimal conditions for a stable production of gas and hydrocarbon liquids with water. When the gas flow rate is not high enough to sweep the liquid hydrocarbons and liquid water from a well or a pipeline, these liquids accumulate in low spots because of gravity.

The liquids can accumulate either downhole in a vertical well or at a heel or a toe, whichever is lower, in a horizontal well which is known as liquid loading. Both deepwater and shale horizontal wells are susceptible to liquid loading.

Severe slugging is one of the issues in multiphase flow also related to gravity. Liquids can accumulate at a subsea riser base and then get periodically produced to a topsides separator after a sufficient gas pressure has built up behind the accumulated liquids as a large sudden gush of liquid preceded by a period of no or limited flow, which is known as severe slugging. Wells keep producing during severe slugging at a steady rate, but backpressure on wells may change noticeably between slug accumulation and displacement. Severe slugs keep repeating, and slug size and momentum are substantial as to cause vibration at pipe bends in flow geometry, overfill the process vessel or both.

Liquids also can accumulate in the low spots of a near-horizontal pipeline and get periodically displaced by a steady flow of gas, which leads to terrain slugging. Terrain slugs keep repeating and are usually smaller in size and don't overfill the process vessel but may cause vibration at pipe bends. Hydrodynamic slugging occurs as liquids holdup is displaced by an increasing flow of gas from a flowline in form of a liquid surge. If the surge volume is significant, the hydrodynamic slugs can be as detri...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Preface
• Chapter 1: Introduction
• Chapter 2: Initial diagnosis and solution of flow assurance production problems in operations
• Chapter 3: PVT and rheology investigation
• Chapter 4: Hydraulic and thermal analysis
• Chapter 5: Flow restrictions and blockages in operations
• Chapter 6: Production chemistry and fluid quality
• Chapter 7: Flow assurance deliverability issues
• Chapter 8: Flow assurance stability issues
• Chapter 9: Flow assurance integrity issues
• Chapter 10: Research methods in flow assurance
• Chapter 11: Toolkit
• Chapter 12: Flow assurance modeling
• Chapter 13: Risk analysis
• Chapter 14: Case studies/reference material
• Index