Sample Research Paper On Offshore Facilities At The Persian Gulf

Introduction:

The Persian gulf is part of the Arabian sea situated in between Iran and the Arabian peninsula. It is around 90,000 sq miles that links to the Gulf of Oman extending around 600 miles from the delta of Shatt al Arab to the Hormuz Strait. It is popularly known as the Arabian Gulf. Basically, the Persian Gulf contains many islands and the waters are relatively shallow. The Gulf is rich with oil, producing approximately 28% of the global oil supply and exporting more than 18 million bbl/d. The countries Iran, Bahrain, Kuwait, Saudi Arabia, Qatar, Iraq, and United Arab Emirates combined in 2006 and exported 18.2 million bbl/day plus the 17 million bbl/day from the Hormuz Straight that covered one fifth of the total oil supply of the world. The group exports the oil through pipelines passing through Turkey, going to the Mediterranean and the Saudi Arabia, finally to the Red sea, as seen in the Figure 1. Oil reserves in the Persian Gulf are relatively rich, large, and abundant (Marcon International, 2015). Due to the rich resources for natural gases and petroleum, the Persian Gulf is home to many oil fields and offshore facilities. The largest oil field found in the Persian Gulf is the Al Safaniya, which is also the largest oil producing field in the world.
Figure 1. Oil and Gas Pipeline at the Persian Gulf and Middle East (Marcon International, 2015).
Offshore Facilities at the Persian Gulf
The offshore oil drilling activities at the Persian Gulf are supplying most of the global oil resource. The offshore drilling is the process of drilling through the seabed for exploration and extraction of petroleum that is found in the rock formations in the seabed. There are many different types of offshore facilities for the offshore drilling operations. The construction of the offshore and marine structures for petroleum platforms have been a hot topic of debate due to its environmental impact. Thus, the facilities that are developed must be functioning with utmost safety imposing minimum impact to the marine environment. These offshore structures are installed along the Gulf many kilometers away from the shorelines. The structures are made up of steel with various grades from mild steels to steels of high strength. The platforms for these structures are very heavy and they are mostly the tallest structures made by man.
The offshore facilities that are installed in the ocean are established for oil and gas exploration. They are located in water with depths from the shallow to the deep part of the ocean. The structural arrangements are built depending on the depth of the water and the various environmental conditions of the location. There are many types of offshore facilities that are employed in the Persian Gulf. Various companies use various techniques and technologies in the drilling and exploration of oil along the gulf.

Moveable Platforms

The installation of drilling structures on the offshore requires either rigs that are either bottom supported or floating. These rigs have drilling equipment that functions similarly with the drilling rigs on the land. Drilling rigs at the offshore are categorized into floating or mobile bottom supported rigs, and stationary production structures. The moveable offshore drilling rigs are the types of rigs that can be moved from place to place.

Jackup Rigs

One of the types of this rigs that is employed in the Persian Gulf is the Jackup rigs. These rigs function similarly with the drilling barges with around three to four legs being lowered until they reach the sea bed at the drilling sites. These are mostly suitable for the shallow waters that are compatible with the shallow waters of the Persian Gulf. Most of these rigs operate with a depth reaching to 500 feet. The working platform for this rig is above the water level which made it safer as compared with the drilling barges operations (Sadeghi, 2007). The jack-up rigs are dominating in the Persian Gulf considering the waters with average of 160 feet deep to 300 feet deep. In the current tally, there are around 73 jackups that are located along the Gulf, where 68 of which are performing drilling operations. The number of jackups in the Gulf continues to grow as evident in the Figure 2. This fact made the Middle East as the largest employer for the jackup rigs in the world (Rigzone, 2009).
Figure 2. Number of Jackup Rigs in the Persian Gulf (Rigzone, 2009).
The Jackup rigs provide stable and safe drilling environment. These rigs are only employed with in the given water depth. It employs the use of the legs to make a firm and stable drilling point. One of the legs incorporated are the open-truss legs. These legs resemble the common electrical towers and made of steels that are tubular and arranged in crisscross for its rigidity but lightweight structure. The other legs are composed of the columnar legs also made up of big steel tubes (CPEG, 2015).
The offshore drilling activities in the Persian Gulf dominated by Jackup Rigs would prosper in the near future. The contracts for the operations using this type of drilling operation offer efficiency and there are already in place contractors that would continue with their operations for the next coming years. According to the RigOutlook, there is a forecasted demand of around 80 t 82 number of jackup rigs that will be employed in the next three years (Rigzone, 2009).

Semi-submersible Rigs

The semi-submersible rigs are commonly employed rigs in the Persian Gulf. In 2010, there are around 15 semi-submersibles that are operating with 80% of which are under contract (Rigzone, 2010). Semi-submersible rigs have floating units with pontoons and columns. The pontoons tend to submerge when flooded with water, to a certain predetermined depth. It is the common type of rigs that combines the benefits of submersible rigs in its drilling capacity in deep water. Its working principle is based on the inflating and deflating mechanisms at the lower hull. The rig is floating above the water level but partially submerged. In the process of drilling, the water filled lower hull provides the rig with stability. These rigs are held by strong anchors weighing up to ten tons. They can also be used even in the dynamic positioning drilling operations. These rigs can be used in the drilling operations with depth reaching to 6,000 feet. They can drill holes on the seabed and quickly move to other new locations (Sadeghi, 2007).
One of the future employments of semi-submersible rigs is done by BP through the installation of the Crazy Horse Field that would be the biggest structure so far with around 40,000 tons. It can be used in water depths of 6,500 ft that would be able to drill around 250,000 bbl/d and 250 MMcf/d of natural gas. This four-column supported semi-submersible rig will stand over a ring pontoon. It would have an “integrated buoyant deck box’ that will add to the safety feature of the rig (Offshore, 2001).

Drilling Ships

The drilling ships are continuously employed along the waters of the Persian Gulf. In 2010, there were about 13 drillships operating in the Persian Gulf with 77% of which are under contract (Rigzone, 2010). Drilling ships are especially designed for drilling operations to the deep sea locations and can drill in very deep waters. Drill ships contain the materials and equipment that are needed for the drilling operation that includes the moon pool found at the center of the ship, the drilling assembly, wellhead equipment, riser pipe, and others. They are also equipped with storage tanks and other test facilities. These ships are said to be able to drill oils with water depth of around 3,000 meters or around 9,842 feet. Modern technological features of the drilling ships have dual-activity rigs where there are two sets of equipment used for drilling that includes draw works, mud pumps, mud treatment system, and top drives. It is used for making up tubing casing strings after the hole has been drilled by the first drilling system. This dual activity system is cost efficient and saves time for the drilling operations (Tanaka et al, 2005).

Fixed Platforms

Fixed platforms are also built along the Persian Gulf. Fixed platforms are done mostly in shallow waters where they are physically attached and connected to the sea floors. They have legs that are made up of steels, extending from the platform, and fixed to the seafloor. These establishments are advantageous due to the stability of the structures since they are standing firmly on the sea beds. There are also lesser exposure to various external factors such as the forces of the current, waves, and the wind. These structures are limited to certain depths since it is no longer economical to build longer legs in the deep part of the water.

Jacket Platforms

The jacket platforms are commonly installed offshore facility along the Persia Gulf. It is composed of the deck, piles, and jackets. There are around 145 template platforms that belong to Iran and around 130 templates by the Arabian countries (Sadeghi, 2007). This bottom supported platform supports it deck load through a jacket that is fixed by means of piles to the sea bottom. The deck side contains all the equipment for drilling. The jacket is made up of tubular steels that are prefabricated, transported, and installed at the sea bottom. The deck has several modules that are also prefabricated and installed at the sea after the jacket has been built. As the depth of the water increases, the template platforms must be able to maintain the rigidity and stiffness that can overcome the overturning moments (Tanaka et al, 2005).
One of the established jacket platforms at the Persian Gulf is the Hengam oil field. It lies around 70 km from the Iranian sores and 30 km away from the Hengam Island. This oil field started operation in 2010 and continues to expand over time. It contains around 700 million bbls of oil and around 2 tcf of gas. There are two jacket platforms installed at the Hengam. The oil produced from the drilling operation is sent through pipeline that goes into the Qeshm Island where a separation and refinery plant process the oil. It has a capacity of 100,000 bbl/d. The oil is further processed into the Bandar Abbas refinery plant (Offshore Technology, 2015).

Compliant Tower Platforms

Compliant Tower is a type of fixed platforms consists of towers that are narrow and are attached to the seafloor foundations extending towards the platforms. The towers for this structure are flexible to enable them to operate in deep waters. They are able to absorb pressures that are exerted by the waves and the wind. They are not as rigid as the fixed platforms but they are still strong structures that can withstand hurricane conditions (Sadeghi, 2007). These are alternative structures for fixed platforms that have longer sway periods that enable them to avoid the resonance of the high energy storm waves. These platforms are applicable in water depths that are higher than 500 meters.

Subsea Manifolds

The subsea manifolds are drilling manifolds employed along the Persian Gulf. It consists of valves and piping, along with equipment, associated controls, and the structure that supports these components. The number of injection lines and flow lines in between platforms and wells are reduced significantly resulting to a substantial amount of savings in the investment. The process of extraction of oil allows for the produced fluid to be diverted or comingled and the injections of fluids are distributed along desire flow paths. Some of the disadvantages involved are the complex and hard to access subsea environment along with the high maintenance cost (Tanaka, 2005).
The subsea manifold is one of the booming offshore facilities employed in the Persian Gulf. Its technology is producing great contributions for the environmentally sound and safe operations. One example is the SPM technology, or the “Single Point Mooring”. It consists of a loading buoy that is anchored offshore that serves as the mooring point. It is interconnected with tankers for the offloading gas and other fluid products. This technology is capable of handling various sizes of ships even the large crude carriers. The SPMs are associated with vessels that are moored at fixed locations. They consist of floating production, tower yokes, storage and offloading, FSOs, single and catenary anchor legs mooring systems (Canty, 2009).

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