Kerogen origin, evolution and structure

Coal as a source rock for oil: a review

The aim of the present paper is to review the conceptual and analytical developments in the period 1970-1990 which have led, through kerogen isolation and analysis on one hand, and case studies of petroleum systems on the other hand, to the concept of kerogen types, evolution paths, and statistical chemical models. Kerogen is defined as the sedimentary organic matter generating petroleum, an insoluble product as opposed to its counterpart soluble in usual organic solvents, such as petroleum. As kerogen is a complex organic material intimately mixed with minerals in sediments, the first task was to set up a robust procedure for its isolation, enabling then its study by various physicochemical analyses. The parallel development of oil exploration, resulting in geological sample availability, made the geochemical comparison of various petroleum systems possible. Comparisons concerned not only oils, source rock extracts and kerogen compositions, but also the timing of petroleum generation. The notion of kinetic cracking of kerogen into petroleum stemming from these case studies, associated with the observation of time and temperature compensation, resulted in the use of pyrolysis to evaluate the oil potential still to be generated by the kerogen, and in the construction of the Rock-Eval. In the mid 70s, all main parameters on kerogens from reference series of source rocks were available to define the notions of types and evolution paths of kerogens upon geological maturation. A further important step for improving the knowledge of kerogen composition was achieved in the 80s using new techniques of analytical and preparative pyrolysis and their coupling with different detectors. The pyrolysis products, small building blocks issued from the kerogen thermal cracking, could thus be analyzed and quantified at the molecular level, without the problems of representativity associated with natural extract analyses, such as loss of volatile fractions or product migration out of source rocks. ;Contemporaneous developments in solid state 13C NMR allowed quantification of the various forms of carbon and their molecular environment in the kerogen, whereas quantification was not possible with IR or UV spectroscopy. The quantification of molecular building blocks and their bonding functional groups in kerogens allowed conceptual averaged molecular models of kerogens to be proposed in order to visualize their atomic and molecular composition, and the changes occurring in this composition according to types and maturity. Although it will never be possible to represent a true kerogen structure, simply because it is a mixture of various nonpolymeric macromolecules, an hypothetical average structure of kerogen, representing a large amount of information from various analyses, can provide a synthetic view of the main resemblances and differences among sedimentary organic matters.

/pdf/kerogen-from-types-to-models-of-chemical-structure-3k7n1dmwhg.pdf

Kerogen: from Types to Models of Chemical Structure

The generally accepted geochemical-stratigraphic model for the Mahakam-Makassar area downgrades the potential for commercial deep-water hydrocarbon accumulations on the outer shelf, yet fails to explain recent discoveries in this area. According to this model, effective middle Miocene coaly source rocks are restricted to updip shelfal areas, whereas age-equivalent rocks on the outer shelf are thermally postmature for generating oil and buried too deeply to preserve good reservoir quality. Our revised geochemical-stratigraphic model upgrades the potential of the outer shelf and directly influenced recent oil and gas condensate discoveries in this area. The middle Miocene source rock interval is not buried as deeply as was previously believed and is now within the oil window based on our regional seismic reinterpretation and source-specific kerogen kinetics. Genetically distinct petroleum accumulations are charged from local kitchens between anticlinal structural trends aligned parallel to the coastline. High-resolution geochemistry confirms that crude oil samples from these different trends (e.g., Handil-Nilam-Badak, Bekapai-Tunu-Attaka, Perintis-Sisi-Ragat) are genetically distinct. Two major (1, 2) and two minor (3, 4) petroleum systems dominated by terrigenous type III organic matter are recognized. The highstand, lowstand 1, lowstand 2, and transgressive systems tract oils account for about 46, 31, 15, and 8%, respectively, of the 61 oil samples and about 45, 32, 11, and 12%, respectively, of the estimated ultimate recoverable reserves from the fields represented by these samples. These fields account for about 13 of the 16 BBOE (billion bbl of oil equivalent) estimated ultimate recoverable reserves in the entire Kutei basin. (1) Waxy highstand oils (e.g., Handil, Nilam) occur mainly onshore in middle Miocene-Pliocene reservoirs. These oils originated from middle-upper Miocene coal and shale source rocks deposited in coastal-plain highstand kitchens now near the peak of the oil window. (2) Less waxy lowstand 1 oils (e.g., Perintis, Sisi, Ragat) occur offshore in middle-upper Miocene reservoirs. These oils originated from middle-upper Miocene coaly source rocks deposited in deep-water lowstand kitchens now mostly in the early oil window. (3) Lowstand 2 oils (e.g., Semberah 037) are similar to the lowstand 1 oils but occur mainly onshore in lower-middle Miocene reservoirs. These oils generally are more mature than lowstand 1 oils and originated from lower-middle Miocene coaly source rocks. (4) Nonwaxy transgressive oils (e.g., Badak) occur mainly onshore in middle-upper Miocene reservoirs. These oils were generated at low thermal maturity from middle Miocene suboxic marine shales deposited near maximum flooding surfaces. Our three-dimensional geochemical-stratigraphic models for highstand and lowstand source rocks indicate that less fractional conversion of the kerogen occurred than had been predicted by the generally accepted stratigraphic model and classic type III kerogen kinetics; furthermore, two-dimensional fluid flow modeling supports independent geochemical evidence for commingling of oils in the Tunu field from highstand and lowstand kitchens to west and east, respectively. Finally, our model successfully predicted that oil and gas, rather than gas only, End page 12---------------- would be discovered at the recently drilled deep-water Merah Besar and West Seno fields. Geochemical analyses of oils from the Merah Besar field confirm that they belong in the lowstand 1 oil group.

A New Geochemical-Sequence Stratigraphic Model for the Mahakam Delta and Makassar Slope, Kalimantan, Indonesia

https://hal-bioemco.ccsd.cnrs.fr/bioemco-00156951/document

Predicting generation and expulsion of paraffinic oil from vitrinite-rich coals

Oil-generating coals of the San Juan Basin, New Mexico and Colorado, U.S.A.

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

D.D. Rice

Author Tools

Chat about Author

Papers

Oil-generating coals of the San Juan Basin, New Mexico and Colorado, U.S.A.