Geologia de Sistemas petrolíferos / Petroleum Systems Geology Exercise 1

Evaluation: 50% exercises + 50% case study

Subject: Introductory concepts and Petroleum Systems Genetic Classification (Demaison & Huizinga, 1994). Answers in English or Portuguese language.

A. Petroleum Systems Elements and processes

This cross section shows the elements of a Petroleum System. Potential reservoir sandstones (yellow), deposited at the basin margin, intertongue to the left with organic-rich source rocks. Owing to the increasing temperature with depth, the source rocks are mature for gas in the deep basin. Below the oil window, the source rocks are generating oil. Hydrocarbons migrate up the flank of the basin and accumulate in a trap (structural). The layer overlying the reservoir is a low-permeability seal. In order to have a commercial field/ prospect, the trap must form prior to hydrocarbon migration, and the trap must have maintained its integrity.

1. Define Petroleum System.

2. How many systems are represented in the figure?

3. Explain the localization/creation of the 3 petroleum reservoirs?

4. Indicate the importance of geographic and stratigraphic extends of the systems to the exploration programs.

5. How do we know that a particular source rock is mature?

Geologia de Sistemas petrolíferos / Petroleum Systems Geology Exercise 1

B. Petroleum Systems Elements and processes (cont.)

1. Chose the appropriate legend box to the figure

2. Discuss these 3 situations (what differences relative to the previous case?): a. Monoclinal structure

b. A porous and permeable rock with cementation

c. Slow deposition of overburden, or none at all

Geologia de Sistemas petrolíferos / Petroleum Systems Geology Exercise 1

C. Source rock properties and maturation

The organic fragments in sedimentary rocks are called kerogen. There are different types of kerogen, depending on the source of organic material. If sedimentary rocks have sufficient organic content to supply economic hydrocarbon deposits, they are called source rocks. Most source rocks are shale or carbonates rocks that were deposited under anaerobic conditions.

1. How many kerogen types could be defined in the oil source rocks? (web search)

2. What are the vitrinite reference values to evaluate the rock maturation?

Geologia de Sistemas petrolíferos / Petroleum Systems Geology Exercise 1

D. Genetic Classification of Petroleum Systems

Flow diagram for the genetic classification of a petroleum system

1. What is the purpose of this classification?

2. Define charge, charge volume, regional charge?

3. Distinguish between SPI, “source potential rating index” and TOC parameters.

4. Chose and describe ONE of the nine cases presented in the class room (Chapter 4 – Genetic Classification of Petroleum Systems Using Three Factors: Charge, Migration, and Entrapment). Include the geographic localization, sedimentary basin typology, different petroleum systems present and respective elements, justification to the reservoirs localization and typology, and characterization of the charge, migration and entrapment. (web search).