Petroleum System

         

Oil is a hydrocarbon liquid substance that is greasy to the touch and is formed by natural resources or the breakdown of fats. Oil comes in many forms as diverse as crude oil and vegetable oil, which serve very different purposes. Products consisting of oil are insoluble when added to water, but will dissolve in organic substances such as those acquired from living organisms.

          In search of oil and gas needed an exploration. Exploration is an activity search and find hydrocarbon resources and estimate the hydrocarbon potential in a basin. But to make an exploration of the need for a system. This system is called the Basic Petroleum System is the process of finding hydrocarbon content below the surface. In Basic Petroleum System are critical components that must be present. The components are:

          1. Source Rock

          2. Reservoir Rock

          3. Migration

          4. Trap

          5. Seal/Cap Rock

1   1.Source Rock

Are sediments containing organic materials sufficient to produce oil and gas when the sediment is buried and heated, and can produce the oil and natural gas in economic quantities. Organic materials contained called karogen. Karogen has 4 types namely:

• Type 1

   Algae from Lacustrine deposition environment and lagoon. This type can    

   produce oil with good quality and able to produce gas.

• Type 2

   A mixture of plants and marine microorganisms. This type is the main

   ingredient of oil and gas.

• Type 3

   Land plants in sediments containing coal. This type generally produces gas and   

   a small amount of oil.

• Type 4

   Materials plant material is oxidized. This type is not able to produce oil and

   gas.

2. Reservoir Rock

Rocks that are capable of storing and capable of flowing hydrocarbons. Reservoir rock is where hydrocarbons accumulate. Where the rock must have porosity as a hydrocarbon storage and permeability as where the flow of hydrocarbons. Types of Reservoir are:

• Siliclastic rock

• Carbonate Rock

• Igneous Rock (Rock Frozen)

• Metamorphic Rock

3. Migration

The process of oil and gas transportation from the source rock to the reservoir. Transportation of hydrocarbons occur in some processes, namely:

- Primer Migration             = Migration in sequence of Source Rock

- Ekspulsion                     = From sequence to the carrier bed Source Rock

- Secondary Migration       = Transport carrier bed leading to the trap

4. Trap

The shape of a geometry or facies are able to hold oil and gas to gather and not move again. A trap should consist of rock hydrocarbon reservoir as a storage place and a set of seals as a cover to prevent the migration again.

The process of migration and trap formation are not interconnected and occur at different times. Trap formation time is very important because if the hydrocarbon trap formed before migrating it would likely ditemukanya hydrocarbon accumulation in the trap. And otherwise the possibility of hydrocarbons have been passed through the trap. The type of trap that is:

• Structural Traps

  Entrapment is affected by the occurrence of deformation to the bedding with the       

  formation of folds and faults structures is a response to tectonic events and the most   

  original trap and trap the most important.

• Entrapment Stratigraphy

  Trap is affected by variations perlapisan vertically and laterally, rock facies changes and 

  disharmony and lateral variations in reservoir lithology on a layer in the transfer of oil.

• Trap Combination

  The combination of structural and stratigraphic. Where in the trap of this type is a factor 

  in limiting the movement along or trapping petroleum.

5. Seal Rock

Seal rock is rock baffle system that is not permeable like claystone / mudstone, anhydrite and salt.