Petroleum Geochemistry:  Concepts, Applications, and Results

Abstract

Petroleum geochemistry has played an important role in many areas of exploration and production for fossil fuels. Many of the more recent developments can be seen to have developed in parallel with developments in analytical chemistry such as gas chromatography and gas chromatography-mass spectrometry. For the past two decades such analytical techniques have been used to search for trace amounts of compounds known as biomarkers present in oils and source rock extracts which can be used to provide valuable information on the origin and history of the oil. In the past two or three years much more effort has been placed on the development and utilization of such techniques as an aid to solving reservoir and production problems. In this paper it is proposed to provide an overview of major developments that have occurred in a number of areas of geochemistry in recent years. This will include developments in reservoir geochemistry such as the use of high-resolution gas chromatography for reservoir continuity studies and high-temperature gas chromatography for characterization of wax deposits. A brief overview of recent developments in biomarker geochemistry will be provided in the section on exploration geochemistry along wth a discussion on the use of various pyrolysis techniques for the purposes of artificial maturation or characterization of the insoluble organic matter in source rocks or asphaltenes in oils. While this paper is not intended for the specialist in geochemistry, it is designed to provide the interested reader with a broad overview of the areas of geochemistry where the significant developments have occurred and continue to occur. As our analytical capabilities increase so do our abilities to obtain a far more detailed and comprehensive picture on the origin of fossil fuels than could ever have been imagined a mere two decades ago.

Stratigraphic distribution of macerals and biomarkers in the Donets Basin: Implications for paleoecology, paleoclimatology and eustacy

“…The abundance of hopanes above C 31 decreases progressively with increasing carbon number. This pattern is characteristic for the presence of bacteria in the swamp (Ourisson et al, 1979) and for an oxic-type environment (Philp and Mansuy, 1997). The hopanes / steranes ratio allows estimation of the relative abundance of bacteria versus algae and terrestrial higher plants (Boreham et al, 1994;Bechtel et al, 2001).…”

Organic matter provenance and depositional environment of marine-to-continental mudstones and coals in eastern Ordos Basin, China—Evidence from molecular geochemistry and petrology

“…According to previous studies, most bitumen extracts show a clear predominance of C 30 hopanes, while the predominance of C 29 hopanes is common for organic matter deposited in anoxic carbonate settings (Philp and Mansuy, 1997). Besides, hopanoids can also be derived from ferns, lichens or mosses, as well as degradation of bacteriohopantetrol (Chaffee et al, 1986;Böcker et al, 2013).…”

Maturity of Potential Cretaceous Source Rocks at the Isis Field, Offshore Eastern Tunisia: Influence of Hydrothermal Fluids

“…In combination with T max , values of the Hydrogen Index (HI) can be used to determine the kerogen type (Tissot and Welte, 1984). These indexes are commonly used as indicators of source rock quality in terms of oil-versus gas-generation potential (Peters and Cassa, 1994;Philp and Mansuy, 1997). T max <430°C in general indicates immature kerogen, whereas T max > 465°C indicates the end of the oil window and the beginning of the wet gas zone (Espitalié et al, 1977).…”