The use of modern technologies in the production of oils and gas, the quality of machinery and equipment in oil extraction plants, petroleum refining plants in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
An industrial worker wearing a helmet and protective vest performs petroleum extraction operations, petrochemical industries and projects, engineering and industrial equipment, oil and gas refining plant in the middle of the sea, Dukhan refinery laboratories, factories and laboratories in the Kingdom of Saudi Arabia
Petrochemical industries and projects, factories and laboratories of the Kingdom of Saudi Arabia, a shadow image of an oil and gas refining factory at sunset time, huge and large warehouses, industrial engineering and equipment
Pipelines and steel equipment, factory and laboratory engineering in the industrial zone in the Kingdom of Saudi Arabia, petrochemical industries and projects, huge and large warehouses,
The quality of machinery and equipment in industrial oil extraction plants, modern technologies in oil and gas production, oil refining plants at sunset in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
The concept of work in the industrial engineering sector, the quality of machines and equipment in oil extraction laboratories, modern technologies in oil and gas production, petroleum refining plants in the Kingdom of Saudi Arabia.
Engineering, equipment and large industrial warehouses, a close-up of an oil and gas refining plant, petrochemical industrial projects, economic growth and progress, oil and petroleum production in the Kingdom of Saudi Arabia, a view of factory smoke in the air
View of factory smoke spreading in the air at sunset, oil and gas refining plant, petrochemical industrial projects, economic growth and progress, oil production in the Kingdom of Saudi Arabia
The quality of machinery and equipment in oil extraction plants, the use of modern technologies in the production of oils and gas, petroleum refining plants in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
Modern technologies in oil and gas production, petroleum refining plants at sunset in the Kingdom of Saudi Arabia, the quality of machinery and equipment in oil extraction plants, the concept of work in the industrial engineering sector
Modern technologies in the production of oils and gas, the quality of machinery and equipment in oil extraction plants, petroleum refining plants in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
The quality of machinery and equipment in industrial oil extraction plants, modern technologies in oil and gas production, oil refining plants at sunset in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
Abu Dhabi National Oil Company, ADNOC Oasis Services in Al Ain City in the Emirate of Abu Dhabi, providing and securing basic services and gas stations for cars in the United Arab Emirates
Industrial engineering and equipment, oil and gas refining plant in the middle of the sea, Dukhan refinery, factories and laboratories in the Kingdom of Saudi Arabia, two industrial workers wearing helmets and protective vests carrying out petroleum extraction operations, petrochemical industries and projects.
Factories and laboratories of the Kingdom of Saudi Arabia, oil and gas refining plant at night, Dukhan refinery laboratories, petrochemical industries and projects, huge and large warehouses, industrial engineering and equipment.
Petrochemical industries and projects, pipelines and steel cables, oil and gas refining plant in the industrial zone, factories and laboratories in the Kingdom of Saudi Arabia, huge and large warehouses, industrial engineering and equipment.
Engineering, equipment and large industrial warehouses, a close-up of an oil and gas refining plant, petrochemical industrial projects, economic growth and progress, oil and petroleum production in the Kingdom of Saudi Arabia, a view of factory smoke in the air
The quality of machinery and equipment in oil extraction plants, modern technologies in oil and gas production, petroleum refining plants in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
Factories and laboratories of the Kingdom of Saudi Arabia, oil and gas refining plant at night, Dukhan refinery laboratories, petrochemical industries and projects, huge and large warehouses, industrial engineering and equipment.
Factories and laboratories in the Kingdom of Saudi Arabia, Nahar oil and gas refining plant, Dukhan refinery laboratories, petrochemical industries and projects, huge and large warehouses, engineering and industrial equipment.
Quality of oil production plants and equipment, adoption of modern techniques and technology in gas production in the Kingdom of Saudi Arabia, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, following up on the progress of factory work, engineering professions and jobs, petrochemical industrial projects
Factories and laboratories in the Kingdom of Saudi Arabia, Nahar oil and gas refining plant, Dukhan refinery laboratories, petrochemical industries and projects, huge and large warehouses, engineering and industrial equipment.
Petrochemical industrial projects, engineering professions and jobs, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a safety helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment.
Saudi professions and jobs, following up on the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, background of an oil refining plant
Following up on the progress of the factory’s work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, engineering professions and jobs, petrochemical industrial projects
Following up on the progress of the factory’s work, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a side photo of a Saudi Gulf Arab engineer wearing a protective jacket and helmet working on the oil refinery at sunset, the quality of oil production laboratories and equipment, Saudi professions and jobs
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
The concept of gas production in the Kingdom of Saudi Arabia, Saudi jobs and professions, following up on the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, background of an oil refining plant
Cartoon drawings of a Saudi-Gulf Arab engineer wearing a protective jacket and helmet, monitoring the progress of factory work, the quality of oil production laboratories and equipment, Saudi professions and jobs, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, background of the oil refinery
Following up on the progress of work in factories, Saudi professions and jobs, a picture from the back of two Saudi Gulf Arab engineers wearing helmets and protection vests walking in an oil refining plant, the concept of gas productivity in the Kingdom of Saudi Arabia
Oil and gas refining plant, view of factory smoke spreading in the air at sunset, petrochemical industrial projects, economic growth and progress, oil production in the Kingdom of Saudi Arabia
The concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, following up on the progress of work in factories, a picture from the back of two Saudi Arab Gulf engineers wearing helmets and protective vests standing between pipelines at sunset, background of the oil refining plant
Following the progress of work in factories, a picture from the back of two Saudi Gulf Arab engineers wearing helmets and protection vests standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, background of the oil refining plant
Quality of oil production laboratories and equipment, adoption of modern techniques and technology in gas production in the Kingdom of Saudi Arabia, cartoon drawings of a Saudi-Gulf Arab engineer wearing a protective helmet working on an oil refinery, following up on the progress of factory work, Saudi professions and jobs
The quality of machinery and equipment in oil extraction plants, the concept of work in the industrial engineering sector, modern technologies in oil and gas production, petroleum refining plants at sunset in the Kingdom of Saudi Arabia.
Adopting modern technologies in gas production in Saudi Arabia, monitoring the progress of work in factories, Saudi professions and jobs, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and protective vest standing between pipelines at sunset, background of an oil refining plant
Following the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, background of an oil refining factory
Petrochemical industries and projects, huge and large warehouses, engineering and industrial equipment, factories and laboratories in the Kingdom of Saudi Arabia, oil and gas refining plant in the middle of the sea, Dukhan refinery laboratories.
Saudi professions and jobs, following up on the progress of the factory, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a picture from the side of a Saudi Gulf Arab engineer wearing a protective jacket and helmet working on the oil refinery at sunset, the quality of oil production laboratories and equipment
Saudi jobs and professions, following up on the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas productivity in the Kingdom of Saudi Arabia, background of an oil refining plant
Huge and large warehouses, petrochemical industries and projects, engineering and industrial equipment, factories and laboratories in the Kingdom of Saudi Arabia, oil and gas refining plant in the middle of the sea, Dukhan refinery laboratories.
Following up on the progress of work in factories, the concept of gas production in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Factories and laboratory engineering in the industrial zone in the Kingdom of Saudi Arabia, petrochemical industries and projects, huge and large warehouses, pipelines and cables, steel equipment.
The concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, following up on the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, background of an oil refining plant
Pursuing work in the industrial engineering sector, youth engineering professions and works, standing confidently and looking at the camera, Saudi laboratories and factories, close-up portrait of a Saudi Gulf Arab engineer wearing a helmet and safety glasses, standing with crossed hands, black background
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi professions and jobs, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Working in the industrial engineering sector, a close-up photo of a Saudi Gulf Arab engineer wearing a jacket and a protective helmet standing with crossed hands at his workplace, Saudi laboratories and factories, youth engineering professions and works, standing confidently and looking at the camera
Engineering professions and jobs, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, petrochemical industrial projects
The quality of machinery and equipment in industrial oil extraction plants, modern technologies in oil and gas production, oil refining plants at sunset in the Kingdom of Saudi Arabia, the concept of work in the industrial engineering sector.
Following up on the progress of the factory’s work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, engineering professions and jobs, petrochemical industrial projects
Oil and gas refining plant, view of factory smoke spreading in the air at sunset, petrochemical industrial projects, economic growth and progress, oil production in the Kingdom of Saudi Arabia
Economic growth and progress, petrochemical industrial projects, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a safety helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment.
Following up on the progress of the factory’s work, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a side photo of a Saudi Gulf Arab engineer wearing a protective jacket and helmet working on the oil refinery at sunset, the quality of oil production laboratories and equipment, Saudi professions and jobs
Factories and laboratories in the Kingdom of Saudi Arabia, oil and gas refining plant in the industrial zone, pipelines and steel cables, petrochemical industries and projects, huge and large warehouses, industrial engineering and equipment.
Following up on the progress of the factory’s work, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a side photo of a Saudi Gulf Arab engineer wearing a protective jacket and helmet working on the oil refinery at sunset, the quality of oil production laboratories and equipment, Saudi professions and jobs
Engineering professions and jobs, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, petrochemical industrial projects
The quality of oil production plants and equipment, Saudi professions and jobs, following up on the progress of the factory, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a Saudi Gulf Arab engineer wearing a protective jacket and helmet working on the oil refinery
Petrochemical industrial projects, engineering professions and jobs, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a safety helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment.
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Following up on the progress of the factory’s work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, engineering professions and jobs, petrochemical industrial projects
Saudi jobs and professions, following up on the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas productivity in the Kingdom of Saudi Arabia, background of an oil refining plant
Adoption of modern techniques and technology in oil and gas production in the Kingdom of Saudi Arabia, quality of oil production laboratories and equipment, picture from behind of a Saudi-Gulf Arab businessman wearing the traditional Saudi thobe, following the progress of the factory’s work, Saudi professions and jobs, background of the oil refinery
A view of factory smoke in the air, engineering, equipment and huge industrial warehouses, a close-up of an oil and gas refining plant in the sunset, petrochemical industrial projects, economic growth and progress, oil production in the Kingdom of Saudi Arabia
Saudi jobs and professions, following up on the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas productivity in the Kingdom of Saudi Arabia, background of an oil refining plant
Adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a picture from the side of a Saudi Gulf Arab engineer wearing a protective jacket and helmet, monitoring the progress of the factory’s work, the quality of oil production plants and equipment, Saudi professions and jobs, oil refinery background
Engineering professions and jobs, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, petrochemical industrial projects
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Huge and large temporary storage warehouses, petrochemical industries and projects, industrial engineering and equipment, petroleum processing in Saudi Arabia’s factories, oil and gas extraction platform in the middle of the sea, sunset view in the sky full of clouds
Engineering professions and jobs, monitoring the progress of factory work, cartoon drawings of a Saudi Gulf Arab engineer wearing a protective helmet, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, quality of oil production plants and equipment, petrochemical industrial projects
The concept of gas production in the Kingdom of Saudi Arabia, following up on the progress of work in factories, a close-up photo of two Saudi Gulf Arab engineers wearing helmets and a protective vest and standing between pipelines, Saudi engineering professions and jobs, oil refining factory background
Achieving the industrial revolution, adopting modern techniques and technology in engineering, a close-up image of a Saudi-Gulf Arab engineer wearing glasses and a safety helmet inspecting oil and gas equipment in the factory, Saudi professions and jobs, quality of production and manufacturing
Youth engineering professions and works, standing confidently and looking at the camera, achieving the industrial revolution, Saudi laboratories and factories, working in the industrial engineering sector, a close-up photo of a Saudi Gulf Arab engineer wearing a jacket and a protective helmet standing with crossed hands at his workplace
The concept of gas production in the Kingdom of Saudi Arabia, following up on the progress of work in factories, Saudi professions and jobs, two Saudi Gulf Arab engineers wearing helmets and protection vests standing in an oil refining factory
Petrochemical industries and projects, huge and large warehouses, engineering and industrial equipment, factories and laboratories in the Kingdom of Saudi Arabia in Al-Shorouk, oil and gas refining plant at sea, Dukhan refinery laboratories.
Supervising work in the industrial engineering sector, youth engineering professions and works, standing confidently and looking at the camera, Saudi laboratories and factories, close-up portrait of a smiling Saudi Arabian Gulf engineer wearing a protection helmet standing with crossed hands, black background
Following up on the progress of work in factories, the concept of gas production in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Saudi professions and jobs, adopting modern techniques and technology in oil and gas production in the Kingdom of Saudi Arabia, quality of oil production laboratories and equipment, photo from behind of a Saudi Arabian Gulf businessman wearing the traditional Saudi thobe following the progress of factory work, background of the oil refinery
Saudi professions and jobs, following up on the progress of the factory, adopting modern techniques and technology in gas production in the Kingdom of Saudi Arabia, a picture from the side of a Saudi Gulf Arab engineer wearing a protective jacket and helmet working on the oil refinery, the quality of oil production laboratories and equipment
Factories and laboratories engineering in the industrial zone in the Kingdom of Saudi Arabia, petrochemical industries and projects, huge and large warehouses, pipelines and steel equipment.
Pipelines and steel equipment, factory and laboratory engineering in the industrial zone in the Kingdom of Saudi Arabia, petrochemical industries and projects, huge and large warehouses,
Pursuing work in the industrial engineering sector, youth engineering professions and works, standing confidently and looking at the camera, Saudi laboratories and factories, close-up portrait of a Saudi Gulf Arab engineer wearing a helmet and safety glasses, standing with crossed hands, black background
Pipelines and steel cables, oil and gas refining plant in the industrial zone at sunset, factories and laboratories in the Kingdom of Saudi Arabia, petrochemical industries and projects, huge and large warehouses, industrial engineering and equipment.
Following the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, background of an oil refining factory
Following up on the progress of work in factories, a picture from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest working in the petroleum industry, the interior of a large industrial building equipped with pipelines for gas production in Saudi Arabia, heavy equipment and tools, the concept of engineering and industry
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi professions and jobs, a picture from the back of engineers, a picture from the back of a Saudi-Gulf Arab businessman wearing the traditional Saudi dress standing in a desert area at sunset, the background of an oil refinery factory
Following up on the progress of work in factories, the interior of a large industrial building equipped with a crane and pipes, adopting modern technologies in gas production in Saudi Arabia, heavy equipment and tools, the concept of engineering and industry
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Saudi laboratories and factories, work in the industrial engineering sector, a close-up photo of a Saudi Gulf Arab engineer wearing a jacket and a protective helmet standing with crossed hands at his workplace, youth engineering professions and works, standing confidently and looking at the camera
Adopting modern technologies in gas production in Saudi Arabia, following up on the progress of work in factories, a picture from the back of two Saudi Gulf Arab engineers wearing helmets and a protective vest and standing between pipelines, Saudi professions and jobs, background of the oil refining factory.
Saudi youth jobs and professions, following up on the progress of work in factories, a picture from the back of two Saudi Gulf Arab engineers wearing helmets and a protective vest standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, background of the oil refining plant
Production and extraction of gas in the Kingdom of Saudi Arabia, supervising the progress of work in factories, Saudi professions and jobs, a picture from the back of engineers, a picture from the back of a Saudi-Gulf Arab businessman wearing the traditional Saudi thobe, standing in a desert area at sunset, background of the oil refinery factory
Oil and gas refining plant in the industrial zone, factories and laboratories in the Kingdom of Saudi Arabia, pipelines and steel cables, petrochemical industries and projects, huge and large warehouses, industrial engineering and equipment.
Following up on the progress of work in factories, the concept of gas production in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Engineering and industry concept, pipelines and steel equipment, factory and laboratory engineering in the Kingdom of Saudi Arabia, water industries and projects, industrial water treatment plant
Introducing women into the field of industrial engineering, a close-up photo of a Saudi Arabian Gulf woman wearing a hijab, a yellow safety vest and wearing a safety helmet looking at the camera with a smile, Saudi national development projects, supervising and following up on the workflow mechanism of equipment and machines inside the factory
Working in factories and laboratories in the Kingdom of Saudi Arabia, following up and monitoring production processes and the workflow of machines, youth engineering jobs and professions, a close-up photo of a smiling Saudi Gulf Arab industrial engineer wearing a white jacket and a protective helmet standing with crossed hands inside the factory
Monitoring the progress of work in factories and laboratories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi professions and jobs, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining plant
Two Saudi Arabian Gulf industrial engineers inside the iron factory, supervising the working mechanism of the iron production machine and how to develop it, follow-up to the manufacturing and production process, the concept of engineering and manufacturin
Monitoring the progress of work in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi jobs and professions, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the background of an oil refining factory
Following the progress of work in factories, a close-up photo from the back of a Saudi Gulf Arab engineer wearing a helmet and a protective vest standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, background of an oil refining factory
Following the progress of work in factories, a close-up photo of a Saudi Gulf Arab man wearing traditional clothing and medical glasses and looking at something, adopting modern techniques and technology in oil and gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, background of the oil refinery.
Following the progress of work in factories, a close-up photo from the back of two Saudi Gulf Arab engineers wearing helmets and protection vests and standing between pipelines at sunset, the concept of gas production in the Kingdom of Saudi Arabia, Saudi professions and jobs, background of the oil refining plant.
Monitoring and troubleshooting the workflow in factories, the concept of gas productivity in the Kingdom of Saudi Arabia, Saudi engineering professions and jobs, a picture from the back of Saudi Gulf Arab engineers wearing helmets and protection vests walking in an oil refinery factory
The quality of oil production plants and equipment, the adoption of modern techniques and technology in oil and gas production in the Kingdom of Saudi Arabia, a picture from the back of a Saudi-Gulf Arab businessman wearing the traditional Saudi thobe, following the progress of the factory’s work, Saudi professions and jobs, oil refinery background