Download IGR2012 Exercise 1

Introdução à Geologia de Reservatórios/ Introduction to Reservoir 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 lowpermeability 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?
Introdução à Geologia de Reservatórios/ Introduction to Reservoir Geology
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
Exercise 1
Introdução à Geologia de Reservatórios/ Introduction to Reservoir Geology
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?
Exercise 1
Introdução à Geologia de Reservatórios/ Introduction to Reservoir Geology
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).
Exercise 1