Oil and Gas Sector
1- Introduction
1- Upstream
2- Midstream
3- Downstream
1- Introduction
Currently, oil is considered one of the most important primary sources of energy.
There are three important stages involved in the extraction of oil, starting from the oil reservoir or well within the earth until it reaches the consumer, whether for industrial use such as plastics or as an energy source such as fuel.
The stages are:
1- Upstream .
2- Midstream .
3- Downstream .
1- Upstream
The stage of Exploration and Production (E&P) is related to the phases of oil extraction, encompassing all activities surrounding an oil field and divided into five temporal stages that an oil field goes through from beginning to end:
1- Exploration Stage.
2- Appraisal Stage.
3- Development Stage.
4- Production Stage.
5- Decommissioning Stage.
1- Exploration Stage.
This involves studying and researching the locations of oil presence, often underground, either onshore or offshore. It includes:
Geological studies by geologists to understand the composition of the potential oil-bearing area.
Utilization of satellite photography.
Aerial photography surveys.
Gravity surveys.
Magnetic surveys.
Geochemical surveys.
Seismic surveys.
Wildcat drilling for exploration.
2- Appraisal Stage.
Once the presence of oil or gas in the area is confirmed, a study is conducted on the properties of the oil and the volume and composition of the oil reservoir. Further drilling is undertaken in this stage to assess the production potential and the economic viability of production.
3- Development Stage.
After confirming the economic viability of drilling, the decision to invest is made. The development phase involves:
Formulating a timeline for oil extraction.
Engineering studies to determine the best production methods.
Planning how to extract from the oil reservoir.
Installing all necessary equipment around the oil field.
4- Production Stage.
Drilling is conducted, this time for production purposes, to extract the oil from its reservoir for sale or transport. The production stage also includes operating and maintaining the equipment.
The drilling steps for production typically include:
Setting up the drilling rig and controlling it from the tower.
Rotating the drilling column to penetrate the earth layers to reach the oil.
Casing the well.
Cementing to secure the casing.
Redrilling to deeper layers and repeating the previous steps until reaching the oil.
Inserting tubing for oil extraction, controlled by a Christmas tree.
Post-extraction operations such as perforation to increase production efficiency.
Separating oil from water and gas, with gas being exported and water either disposed of or reused.
There are three methods of extraction:
1- Primary extraction: When the oil is initially pressurized in its reservoir and flows out of the well due to natural pressure.
2- Secondary extraction: After the natural pressure from the reservoir diminishes, the reservoir is injected with water from another area to push the oil out.
3- Enhanced Oil Recovery (EOR): After the weakening of secondary extraction, thermal, chemical, or gas methods are used for extraction.
5- Decommissioning Stage.
After fully exploiting the oil field, either by extracting oil from its reservoirs or if drilling is no longer financially viable, the final stage is reached, which involves abandoning the field. This includes dismantling the equipment and leaving the site.
2- Midstream
The stage of Transportation and Storage is considered less complex than the upstream and downstream stages. In this stage, there are two processes that occur and are not necessarily sequential:
1- Transportation:
Transporting oil and gas from the field to storage locations or from storage locations can be done through several methods:
Pipeline Transportation: Pipes are used either underwater, underground, or on the surface.
Truck Transportation: Oil is transported via trucks.
Maritime Oil Tankers: There are specialized tankers for oil transportation of various sizes, such as VLCC (Very Large Crude Carrier) and ULCC (Ultra Large Crude Carrier).
2- Storage:
Storage can be either onshore or offshore:
Onshore storage usually occurs alongside oil refinery facilities.
Offshore storage is typically near offshore drilling platforms.
These processes are not necessarily sequential; storage may precede transportation or vice versa, or there may be an interchange between the two processes as needed.
3- Downstream
The stage of oil refining, known as Refining, is the final stage in the oil sector and involves the processes that occur within an oil refinery to deliver oil derivatives to the end consumer.
It consists of six stages. However, this doesn’t mean that all refineries contain the same units or stages. Each refinery contains stages according to its needs:
1- Refining Stage
In this stage, three basic processes occur with the aim of analyzing the oil into smaller compounds as much as possible, primarily through distillation. These processes are:
A. Atmospheric Distillation
B. Vacuum Distillation
C. Other distillation processes
A. Atmospheric Distillation
Crude oil, upon arrival, is exposed to high temperatures, around 400 degrees Celsius. It then enters a distillation column (fractional distillation). Inside the distillation column are plates containing funnels aimed at separating gas from liquid. Lighter materials rise to the top, while heavier ones settle at the bottom.This stage separates the basic elements or derivatives of oil but in a rudimentary manner. They are divided based on carbon atoms:
Gas and gasoline
Kerosene
Light oil gas or naphtha
Heavy oil gas or heavy naphtha
Residue from atmospheric distillation (unanalyzable at atmospheric pressure)
B. Vacuum Distillation
This process occurs to analyze the derivatives not analyzed in the previous process, the residue from atmospheric distillation. It takes place under lower atmospheric pressure.Derivatives of vacuum distillation include:
Light vacuum gas oil
Heavy vacuum gas oil
Residue from vacuum distillation
C. Other distillation processesFollowing this, gas and gasoline are separated from each other through several fractional distillation processes, each carried out separately.
2-Treatment Stage
There are several operations that occur in the treatment stage, but the most important one is Hydrotreating. It’s a process that happens in the presence of compressed hydrogen, high temperatures, and a catalyst to chemically react and separate impurities. In this stage, derivatives are purified from impurities like sulfur and oxygen, starting from gasoline to vacuum gas oil outside the vacuum distillation.
3-Conversion Stage
Several basic operations occur in the conversion stage for various purposes, such as increasing fuel quality or breaking down into smaller components to increase compound production. These include:A. Isomerization
B. Alkylation
C. Catalytic Reforming
D. Fluid Catalytic Cracking (FCC)
E. Hydrocracking
F. Delayed Coking
Each process has specific objectives and outcomes aimed at enhancing fuel properties or increasing production.
Storage StageAfter conversion, numerous compounds are formed as a result of the conversion process. The storage process follows for each compound after treatment separately, followed by appropriate mixing as needed. Storage occurs after mixing to obtain the final products.
4-Mixing and Product Stage
In this stage, the previous elements are blended to obtain the final product. These include:
Fuel gas (methane and ethane)
Propane and butane
Automotive fuel
Jet A1 aviation fuel
Diesel
Heavy fuel used in ships
Lubricants and wax
Asphalt for road construction
Coke for steel and steel industries
5-Distribution Stage
The final stage involves distributing the products to consumers for consumption. There are several distribution methods, including transport trucks, ships, and trains.