From Elements of Petroleum Geology, Second Edition


The preceding chapters discussed the physical and chemical properties of crude oil and natural gas and the behavior of fluids in the subsurface. The object of this chapter is to discuss the genesis, migration, and maturation of petroleum. We now have a good understanding of what oil and gas are made of and plenty of empirically derived data that show how they occur. Thus we know how to find and use oil and gas. However, the precise details of petroleum generation and migration are still debatable. Recent advances in geochemistry, especially in analytical techniques, have resulted in rapid progress on this front, but many problems remain to be solved. Any theory of petroleum generation must explain two sets of observations: geological and chemical.

A theory of petroleum genesis must explain the following geological facts:

  1. Major accumulations of hydrocarbons characteristically occur in sedimentary rocks (Table 5.1). In the words of Pratt (1942): I believe that oil in the earth is far more abundant and far more widely distributed than is generally realized. Oil is characteristic of unmetamorphosed marine rocks of shallow water origin. In its native habitat in the veneer of marine sediments that came with time to be incorporated into the earth s crust, oil is a normal constituent of that crust; a creature of the direct reaction of common earth forces on common earth materials. Half a century later few geologists would disagree with this statement, except perhaps to note in passing that continental and deep marine sediments...

Products & Services
Geotechnical Services
Geotechnical engineering services includes soil, rock and subsurface testing and analysis for site feasibility, foundations, embankments, pavements, retention structures, and other earthworks projects.
Geophysical Instruments
Geophysical instruments are used for geological study, including rock and soil mechanics, core analysis and surveys of the earth.
Marine Services
Marine services provide repair, maintenance, logistics, testing, storage, and transportation services for boats, ships, oil tankers, and other watercraft.
Energy Production and Exploration Services
Energy production and exploration services specialize in electrical power generation, oil and gas exploration and extraction, fuel refining, and other utility-related services.
Gas Compressors and Gas Compressor Systems
Gas compressors and gas compressor systems circulate gas through a process, enhance conditions for chemical reactions, provide inert gas for safety or control systems, recover and recompress process gas, and maintain correct pressure levels by either adding and removing gas or vapors from a process system.

Topics of Interest

Chapter 1 showed that one of the five essential prerequisites for a commercial accumulation of hydrocarbons is the existence of a reservoir. Theoretically, any rock may act as a reservoir for oil or...

8.1 BASIC CONCEPTS AND TERMS A sedimentary basin is an area of the earth s crust that is underlain by a thick sequence of sedimentary rocks. Hydrocarbons commonly occur in sedimentary basins and are...

OVERVIEW Petroleum exploration is largely concerned with the search for oil and gas, two of the chemically and physically diverse group of compounds termed the hydrocarbons. Physically, hydrocarbons...

6.7 GEOPHYSICAL APPLICATIONS Magnetotellurics Magnetotellurics employ naturally occurring electromagnetic fields to investigate the earth's internal resistivity distribution. The interaction of...

INTRODUCTION Fractures are displacement discontinuities in rocks, which appear as local breaks in the natural sequence of the rock's properties. Most geological formations in the upper part of the...