I. Introduction

A. The fundamental question in petroleum geology:

Where are there economically recoverable reserves of hydrocarbons?

To answer this question requires understanding geologic processses in a regional context. This means that Petroleum Geology doesn't ask fundamental science questions. Instead, it uses all of the fundamental geologic (and chemical and physical concepts) and applies them to finding oil reserves.

Some of the geologic processes include :

(1) Historical geology (timing of maturation, migration, and trap formation),


(2) Structural and stratigraphic geology- the origin and physical properties of reservoir and source rocks,


(3) Geochemistry- what are hydrocarbons? where do they come from? What are their properties?,


(4) Geophysics- seismics and well logs- subsurface exploration techniques.

Although each of these are fundamental geologic disciplines, the technology that allows them to be applied to petroleum geology have changed:

• Originally, field mapping- frontier areas, surface geology, was important. This mapping in the field eventually evolved into geophysical (subsurface) mapping, using both seismic techniques and well logging.
  
• Now much mapping now done in the office. Data is collected remotely and brought to the central office. Mapping done by computers, so the geologist must have skills in many areas:
  

(1) the basic geologic sciences

(2) Ancillary sciences, particularly chemistry and physics, as well as math

(2) computer science

(3) interpersonal skills

B. Oil exploration as a business:

The basic objective of petroleum geologist is to make money. This requires finding sufficient hydrocarbon reserves to be worth extracting and extracting them in the most cost-efficient way possible.

Requires expertise of many different disciplines:

(1) Exploration geologist: A geologist who looks at areas not previously found to bear hydrocarbons. Could be small region within an established hydrocarbon province, or a completely new sedientary basin that has never been drilled.


(2) Development geologist: A geologist who takes a "discovery well"- i.e. a well that produces hydrocarbons, and figures out the most economic way of developing the newly-discovered oil field.


(3) Geophysicist- a person largely responsible for the collection, processing and interpretation of seismic data. Often works closely with exploration geologists to combine geologic and geophysical information


(4) Engineer- There are a variety of engineering disciplines, for example:


(a) Drilling engineers, who are responsible for economically and successfully drilling wells. Drilling is a complex business, particularly now that hydrocarbons are being produced from deeper in the crust (>30,000 ft) and at greater water depths (> 1000 ft) than before.

(b) Reservoir engineers- responsible for the proper maintance and production of hydrocarbons from the reservoir. These engineers decide how much hydrocarbons to produce and at what rate, how secondary and tertiary recovery may be accomplished, and make estimates of the amounts of hydrocarbons that are present and how much can be produced.


(5) Land men- responsible for the legal aspects of extracting hydrocarbons. For example, they determine who owns the surface land, who owns the minerals rights, and make sure all the contracts are in order. Boring, but very important job.

Commonly all of these different people work together as a team. It requires that people with many different backgrounds be able to communicate efficiently and effectively. Thus, a large part of the course will be presentations.

e.g. Figs. 1.4 and 1.5 in Seeley

II. What is the course about?

A. Three main objectives:

(1) Introduction to the "science" of petroleum geology. That is how hydrocarbons form, what they are, where they go, how they are trapped.


(2) Introduction of exploration techniques- how are hydrocarbons found? Drilling methods, seismics and well logs.


(3) To give you experience at developing "plays" and "prospects", evaluating plays and prospects, and presenting your work to others.

B. Course outline and work expectations.

(1) Begining of course: lectures for approximately the first half of the course (first 6 to 7 weeks). Exam material will come primarily from lectures, but also from problems and presentation by students (see numbers 2 and 3).


(2) Middle of the course: Work on two problems. You will work in groups of 2 to 3.


• Group work objectives- learn to arrange and budget time of groups, learn how to communicate within the group, learn how to divide work equitably. Result should be a product that is better (not worse) than individual work.
  
• Problem one- seismic interpretation- we should have copies of seismic lines from Exxon- actual producing field off the Gulf Coast. Objective- interprete lines, draw maps (structure, isopach) that will identify a location to drill
  
• Problem two- log interpretation- Hopefully you will interprete a suite of logs from the same field as the seismic problem (if I can get the data from Exxon). If not, I will try to get logs from another area for you to work one. The problem will be identical to problem #1- draw maps of region based on interpretation of log data. Identify area where good location for "wildcat" well.
  
• After developing prospect for each of the problems, the group will present the prospect to the class. The class will act as "board of directors" and evaluate the technical merits of the prospect (i.e. "grade it")
  
  

(3) Middle and end of the course: Presentation of papers (written individually) called "The Petroleum Geology of BLANK" A 10 to 20 page paper, including figures, excluding references that will describe the petroleum geology of a particularly region of the world, and its prospects for economic hydrocarbons.


• Look at the course information sheet to see a possible outline for the paper.
  
• Note on the syllabus that there will be a preliminary presentation on February 18 of the work that you have done up to that point. There will be no procrastination.
  
• Choose a region that has some information, but not too much information.
  
• For example, the Middle east is too large an area, but Kazakstan would be OK. The United States is too large (California is also probably to large), but smaller regions might be OK, such as the Williston Basin, the Gulf Coast, or the Monterey Formation.
  
• You need to decide within the next two weeks where you will work and let me know. There will be no duplication.
  
  

III. A brief history of the "Oil Bidness"

(1) Initially, hydrocarbons collected from oil seeps- "springs" discharging liquid hydrocarbons.

Usage of the hydrocarbon included warfare, medication (externally on wounds and rheumatism, internally as laxitive), waterproofing.

(2) In 1847- James Young began retorting ( a method of distallation by heat) oil from oil shales in Scotland.

Products and their uses included parafin, used for candles, and kerosene (coal oil), used for lamps.


Kerosene became cheaper than whale oil (which previously had been used in lamps)- this greatly expoanded the demand for oil products- The first oil boom.

(3) In 1859, "Colonel" Drake drilled a well to 59 feet and produced oil at Oil Creek PA. This well marked the beginning of the modern oil "bidness" where large volumes of hydrocarbons were extracted from the subsurface.

As a result of this discovery, so much oil was discovered and produced that the price of kerosene dropped to nearly nothing. The first oil bust


The oil bust continued until the mass production of the internal combustion engine, and the development of mass produced automobiles. The auto created another large demand for lhydrocarbon products, and caused a second oil boom.

(4) With the second oil boom, and first world war, large large multinational oil companies developed. The seven Sisters: BP, Shell, Exxon, Fulf, TExaco, Mobil, Socal, among other "minor" companies, and thousands of "independent" oil companies.

The major and some of the minor oil companies are vertically integrated- that is they explore, produce, refine, and market the products. Thus when crude oil prices are low, they make money in the refining business, when crude oil prices are high, they make money in the exploration/production business.

(5) 1960, Organization of Petroleum Exproting Countries (OPEC) was founded. Consist of countries whoseeconomy is based on oil exports. Countries include Iraq, Iran, Kuwait, Saudi Arabia, Venezuela, Algeria, Dubai, Ecuador, Gabon, Indonesia, Libya, Nigeria, Qatar, and United Arab Emirates.

By the 1970's, OPEC countries produced 2/3 of the worlds oil. Thus controled the price of crude oil. By limiting production, the price increased rapidly through the 1970's.


The result was conservation, a world wide recession, and drop in consumption of oil.


About the same time, major oil deposits were discovered in the North Sea. The combined drop in consumption and the increase in production from the North Sea (largely from Norway), caused a major slump in oil prices in the early 1980's. Another Bust

(6) Since that time, prices of gasoline have remained more or less constant, and as a result consumption has risen again. Americans are driving big cars, the world's economy is booming.

The result- Oil companies are hiring, I'm teaching, and you are taking, a course in petroleum geology.

IV. A brief introduction to petroleum exploration

(1) Originally, oil exploration done by wandering aound the country side- look for seeps.

East Texas Oil field (7 billion barrels of oil) was "discovered" by drilling at the intersection of all the major structures in North America. The field is trapped stratigraphically.

(2) An early exploration technique, used by Howard Hunt, was called "creekology". He would drill following creek beds.

The reasoning was that oil flowed in "streams" just as surface water did.


Creekology was relatively successful (Hunts sons were nearly able to purchase all of the silver in the world), but not because oil flows in streams. Surface streams often flow along the crest of eroded anticlines, and since oil is lighter than water it gets trapped in the crest of the anticlines.

(3) Exploration largely evolved into surface mapping of anticlines- e.g. Teapot Dome in Wyoming. In the right places, most anticlines contain oil. Through much drilling, it because clear that oil could be trapped stratigraphically as well- through facies changes within porous and permeable rocks.

Stratigraphic mapping using subsurface information became important.

(4) With improved geophysical technology in the 1920's and 30's. Two catagories- regional mapping tools, and logging tools.

a)These were largely seismic refraction, and gravity studies. Refraction could be used to study subsurface structures, and gravity could be used to look for salt domes. (Problem 1)


b) Well logs were invented in 1927 by the Schlumberger brothers. These tools are lowered into well bores, and provide information about the rocks that were drilled. Initially they included electric logs (many types), also sonic, radioactive, caliper etc. (Problem 2).

(5) In the 1950's and 1960's, geologist realized that the distribution of rocks in the past and in the subsurface could be compared with modern environments "uniformatarianism". Many oil companies at the time support research at modern depositional environments- Galveston Island, Mississippi delta, Bahamas, etc.

(6) Now, the latest in exploration include computers, which allow rapid integration of large amounts of data.