Abstract

In many parts of the world, the redevelopment of older fields presents unique problems that will require innovative solutions. With the rising costs of finding and developing new oil fields, oil companies are turning more attention to revitalizing existing fields. Because of historical practices, these fields often have significant potential for enhanced recovery. These older fields have many different problems to deal with than the more modern fields that traditionally drive petroleum technology.

Advances in computer hardware and software technology have made it possible to analyze reservoirs at a level of detail unimagined only a few years ago. With all of this power on our desktops, it is easy to lose sight of a major problem in dealing with older fields - the historical data.

In many cases, there may be a large amount of historical data, but much of it is either inaccurate or critical types of data have not been gathered. Several field examples are discussed in this paper. Each field has redevelopment potential using modern techniques, but each project has great uncertainty due to data constraints. The conclusions and recommendations of the paper include suggestions for ways to solve these problems. Since we cannot go back in time to gather critical missing data (e.g., early production and injection data, initial fluid properties, produced compositions, etc.), special techniques will be needed to determine the value of these projects.

Introduction

We will soon mark the 150th anniversary of the discovery of commercial quantities of oil in Pennsylvania and the start of the modern petroleum industry. Since that time, oil has truly been the driver of industrialization around the world. The twentieth century was rightly called the Oil Century. The real oil production history of the planet actually dates back to 3000 B.C., but nobody then cared much about accurately measuring the volumes as it seeped out of the ground in various parts of the Middle East, Europe and elsewhere 1.

More than 100 billion metric tons (800 billion stock tank barrels) have been produced in the last 150 years 2. According to recent estimates 3 (see Table 1), this represents less than half of the estimated total world recoverable oil reserves. There are also estimates that another 40 to 140 billion tons are yet to be discovered 4. In any case, with a steadily increasing demand projected, it is now expected that worldwide oil production will start to decline in the next 5–20 years, depending on how optimistic the forecast is.

Oil field technology has changed dramatically in recent time. Since the 1970's, modern computer technology has helped to improve our understanding of reservoir geology and fluid flow. Field measurement techniques have also greatly improved. Much of this coincided with the needs of the harsher operating environments of the North Sea and Alaskan North Slope, which started development at that time.

Today, technology enables us to develop, operate and understand difficult fields and produce them more economically than would have been possible in the past. Modern measuring and analysis tools reduce the uncertainties in field development and allow operators to control costs effectively.

Old Fields

- Of the remaining already discovered oil (148 billion tons), 80% of it is contained in the Middle East, the Former Soviet Union (FSU), and South America where many fields can be classified as "old" fields. For example, the supergiant Ghawar field in Saudi Arabia and the Burgan field in Kuwait were found in the late 1930's. Major fields in Iran and Iraq were found even earlier. The Siberian oilfields in Russia were found in the 1950's. The Maricaibo basin fields in Venezuela started in the 1920's.

Old Fields

- Of the remaining already discovered oil (148 billion tons), 80% of it is contained in the Middle East, the Former Soviet Union (FSU), and South America where many fields can be classified as "old" fields. For example, the supergiant Ghawar field in Saudi Arabia and the Burgan field in Kuwait were found in the late 1930's. Major fields in Iran and Iraq were found even earlier. The Siberian oilfields in Russia were found in the 1950's. The Maricaibo basin fields in Venezuela started in the 1920's.

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