Internal Course: Petroleum System and Basic Log Interpretation

Date                                       : 16th March 2018

Time                                     : 18.00 a.m – 20.00 p.m

Venue                                    : Laboratory of Paleontology, Departemen of Geologcal Engineering, UGM

Speakers                             : Mr. Ichsan Ramadhan (AAPG UGM – SC Vice President)




This internal course was the first course from Course and Workshop division of AAPG UGM – SC, and it was held for all member. This course took Basic Petroleum as a theme, with Mr.Ichsan Ramadhan, as a speaker. There were two sessions of this course, presentation and discussion session in a small group.

Petroleum System

Base on the data, petroleum is the biggest primary energy source in earth now, and still dominant until 2040. This flammable natural liquid is made up of Carbon and Hydrogen atoms. To know how the materials turn into oil, we must know about petroleum system, include all the elements and the processes.

The first element is source rock, the rock that can generated and expelled hydrocarbons. Fine grains sediment rock with organic matter, is the most common type of source rock. Then the hydrocarbons is transported to porous and permeable rock, which is called reservoir, as the second element in petroleum system. Pore in this rock is able to filled by water and hydrocarbons. Next, in a petroleum system, there must be a rock that can isolate and retain the fluid, and it is called cap rock. The example type of cap rock are marl, gypsum, and anhidrite. Then, also there must be a trap, a geologic features in which petroleum can accumulate, involve geologic structure and stratigraphy. And the last, all of those elements must be formed in a perfect time, to make sure the oil migrate properly.

Before the processes on petroleum system, we must know about where the organic matter in source rock come from. Dead organism that burried beneath the earth surface, classificate into three types that produced different form of hydrocarbon. Type 1 is algae, type 2 are spora, fitoplankton, leaf, and type 3 is log. Type 1 is familiar to oil, type 3 to gas, and type 2 is the transition. After the oil and gas is formed, then it is migrating. The migration also divide into three types, primary, secondary, and tertiary migration. Primary migration is the process of the hydrocarbon leaves the source rock, then move to reservoir as the secondary migration. And we will never expect for the tertiary migration, which is the seepage of hydrocarbon on earth surface. After the migration, hydrocarbon must be sealed by the cap rock, and accumulated with perfect timing in the trap. Then, the accumulated hydrocarbon have to be preservated to avoid the degradation.

Basic Log Interpretation

In a petroleum exploration, there is a metode to interpretate beneath earth surface with log data. Three main data that can be identified by this metode is the litology, especially about the grain size, resistivity, and porosity. This data can be used to know condition of sedimentary rock in every depth, is that rock layer contain fluid or not, and what kind of the fluid, is it oil, gas or only ordinary groundwater.


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