Introduction to Enhanced Recovery Methods for Heavy Oil and Tar Sands

James G. Speight

• Publisher: Gulf Professional Publishing
• Year: 2016
• ISBN:
  9780128018750
• Edition: 2
• Topic: Tecnologia e ingegneria
• Subtopic: Combustibili fossili

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

Part I

Reservoirs and Reservoir Fluids

Outline

Chapter 1 Heavy Oil and Tar Sand Bitumen

Chapter 2 Occurrence and Reservoir Evaluation

Chapter 3 Sediments, Reservoirs, and Deposits

Chapter 4 Reservoir Fluids

Chapter 5 Evaluation of Reservoir Fluids

Chapter 1

Heavy Oil and Tar Sand Bitumen

Abstract

Petroleum (crude oil; conventional petroleum) is found in the microscopic pores of sedimentary rocks such as sandstone and limestone. Not all of the pores in a rock contain petroleum and some pores will be filled with water or brine that is saturated with minerals. However, not all of the oilfields that are discovered can be exploited since the reservoir may be (1) too deep for economic recovery under the prevalent economic conditions, (2) contain crude oil of insufficient volume, (3) so remote that transportation costs would be high, or (4) in a tight formation where additional techniques such as hydraulic fracturing are required to recover the crude oil. In very general terms, conventional petroleum is a free-flowing liquid while, on the other hand, heavy oil is a viscous type of petroleum that contains higher levels of sulfur and nonvolatile constituents than conventional petroleum but occurs in similar locations to petroleum. The viscous nature of heavy oil is a problem for recovery operations and for refining—the viscosity of the oil may be too high thereby rendering recovery expensive and/or difficult and the sulfur content may be high, which increases the expense of refining the oil.

It is the purpose of this chapter to introduce the reader to the terminology and definitions related to petroleum, heavy oil, and tar sand bitumen and to describe briefly, as an introduction to, the associated recovery technologies. This chapter will alleviate much of the confusion that exists, but it must be remembered that the terminology of petroleum is still open to personal choice and historical usage.

Keywords

History; definitions; conventional petroleum; tight oil; opportunity crudes; high acid crudes; foamy oil; heavy oil; tar sand bitumen

1.1 Introduction

Petroleum (crude oil; conventional petroleum) is found in the microscopic pores of sedimentary rocks such as sandstone and limestone. Not all of the pores in a rock contain petroleum and some pores will be filled with water or brine that is saturated with minerals. However, not all of the oilfields that are discovered are exploited since the reservoir may be (1) too deep for economic recovery under the prevalent economic conditions, (2) contain crude oil of insufficient volume, (3) so remote that transportation costs would be high, or (4) in a tight formation where additional techniques such as hydraulic fracturing are required to recover the crude oil (see chapter: General Methods of Oil Recovery) (Speight, 2014a, 2015a).

In the typical porous rock reservoir, conventional petroleum is a free-flowing liquid while, on the other hand, heavy oil is a viscous type of petroleum that contains higher levels of sulfur and nonvolatile constituents than conventional petroleum but occurs in similar locations to petroleum (IEA, 2005; Ancheyta and Speight, 2007; Speight, 2014a). The viscous nature of heavy oil is a problem for recovery operations and for refining—the viscosity of the oil may be too high thereby rendering recovery expensive and/or difficult and the sulfur content may be high, which increases the expense of refining the oil.

In any text related to the properties and behavior (recovery or refining) of a natural resource (ie, heavy oil), it is necessary to understand the resource first through the name or terminology or definition. Terminology is the means by which various subjects are named so that reference can be made in conversations and in writings and so that the meaning is passed on. Definitions are the means by which scientists and engineers communicate the nature of a material to each other and to the world, through either the spoken or the written word. Thus the definition of a material can be extremely important and have a profound influence on how the technical community and the public perceive that material.

Because of the need for a thorough understanding of petroleum and the associated technologies, it is essential that the definitions and the terminology of petroleum science and technology be given prime consideration. This will aid in a better understanding of petroleum, its constituents, and its various fractions. Of the many forms of terminology that have been used not all have survived, but the more commonly used are illustrated here. Particularly troublesome, and more confusing, are those terms that are applied to the more viscous materials, for example, the use of the terms bitumen and asphalt. This part of the text attempts to alleviate much of the confusion that exists, but it must be remembered that the terminology of petroleum is still open to personal choice and historical usage.

The name heavy oil can often be misleading as it has also been used in reference to (1) fuel oil that contains residuum left over from distillation, that is, residual fuel oil, (2) coal tar creosote, or (3) viscous crude oil. For the purposes of this text the term is used to mean viscous crude oil.

Heavy oil typically has relatively low proportions of volatile compounds with low molecular weights and quite high proportions of high molecular weight compounds of lower volatility. The high molecular weight fraction of heavy oils are comprised of a complex assortment of different molecular and chemical compounds (not necessarily just paraffins or asphaltenes) with high melting points and high pour points that greatly contribute to the poor fluid properties of the heavy oil, thereby contributing to low mobility (compared to conventional crude oil).

More generally, heavy oil typically has low levels (if any at all) of paraffins (straight-chain alkanes) with moderate-to-high levels of asphaltene constituents. The asphaltene constituents are not necessarily the primary cause for the high specific gravity (low API gravity) of the oil nor are they always the prime cause for production problems. It is essential to consider the content of the resin constituents and the aromatic constituents, both of which are capable of hindering the asphaltene constituents from separation during recovery. It is only when the asphaltene constituents separate from the oil as separate phase that they deposit in the formation or in the production train.

1.2 History

Petroleum, in various forms, is not a recent discovery (Abraham, 1945; Forbes, 1958a, 1958b, 1959, 1964; Speight, 2014a). More than four thousand years ago, bitumen from natural seepages was employed in the construction of the walls and towers of Babylon. Ancient writings indicate the medicinal and lighting uses of petroleum in various societies. In terms of petroleum recovery, the earliest known wells were drilled in China in 347 BC to depths of 800 feet (240 m) and were drilled using bits attached to bamboo poles. The oil was burned to evaporate brine and produce salt. By the tenth century, extensive bamboo pipelines connected oil wells with salt springs.

The use of petroleum in the Middle East was established by the eighth century, when the streets of the newly constructed Baghdad were paved with the nonvolatile residue derived from accessible petroleum and seepages (particularly Hit) in the region. In the ninth century, petroleum was distilled at Baku, Azerbaijan, to produce naphtha which formed the basis of the incendiary Greek fire (Cobb and Goldwhite, 1995). These Baku experiences were reported by the geographer Masudi in the tenth century, and by Marco Polo in the thirteenth century, who described the output of those wells as hundreds of shiploads.

The earliest mention of American petroleum occurs in Sir Walter Raleigh’s documentation of the Trinidad Asphalt Lake (also called the Trinidad Pitch Lake) in 1595. In 1632, the journal of a Franciscan, Joseph de la Roche d’Allion, describing his visit to the oil springs of New York was published in Sagard’s Histoire du Canada. A Russian traveler, Peter Kalm, in his work on America published in 1748 showed on a map the oil springs of Pennsylvania. In 1854, Benjamin Silliman, a science professor at Yale University in New Haven, Connecticut followed the work by Arabic alchemists and fractionated petroleum by distillation. These discoveries rapidly spread around the world, and Meerzoeff built the first Russian refinery in the then-mature oil fields at Baku in 1861, where at that time about 90% of the world’s oil was produced.

The first commercial oil well drilled in North America was in Oil Springs, Ontario, Canada in 1858 by James Miller Williams. The US petroleum industry began with Edwin Drake’s drilling of a 69-foot (21 m) oil well in 1859 at Oil Creek near Titusville, Pennsylvania for the Seneca Oil Company. The well originally yielded 25 barrels per day and by the end of the year output was at the rate of 15 barrels per day. The industry grew through the 1800s, driven by the demand for kerosene and for oil lamps. Petroleum refining became even more popular, perhaps essential, in the early part of the twentieth c...