WO2008111829A1

WO2008111829A1 - Offshore oil production platform

Info

Publication number: WO2008111829A1
Application number: PCT/MY2007/000049
Authority: WO
Inventors: Nagendran C. Nadarajah; Renata Anita De Raj
Original assignee: Nadarajah Nagendran C; Renata Anita De Raj
Priority date: 2007-03-12
Filing date: 2007-07-17
Publication date: 2008-09-18
Also published as: US20100150660A1

Abstract

The present invention relates to an offshore oil production platform. The platform includes a deck (12) and a sub-structure (10) comprising plurality of ballast chambers (20) and at least one of connecting leg (16) connected from the ballast chambers (20) to the deck (12). The ballast chambers (20) include at least one oil storage compartment (22), at least one ballast compartment (24) and at least one air pressure compartment (26). The oil and gas storage compartment (22) is for storing processed oil and gas. During installation of the platform, the ballast chambers (20) are ballasted with sea water (46) which allows lowering of the connecting legs (16) towards the sea bed (34). After the ballast chambers (20) reach the sea bed (34), locking means is actuated to a locked position to prevent movement of the sub-structure (10) of the platform. The deck (12) is moved up to a predetermined height from sea level by jacking means. After the oil is extracted, it is then processed and separated to processed oil and gas. The processed oil and gas are then stored in the oil and gas storage compartment (22). The oil and gas are then transferred to a buoy and then loaded to tanker vessels by connecting conduits. During the de-installation of the oil production platform, the ballast chambers (20) are de-ballasted whereby the sea water (46) in the ballast compartment (24) is flushed out. Thus, the sub-structure (10) of the platform moves upwards to reach the deck (12). When the base (14) touches the deck (12), the locking means is actuated thereby locking the sub-structure (10) together with the deck (12). Finally, the oil production platform is towed to its new destination for further extraction of oil.

Description

OFFSHORE OIL PRODUCTION PLATFORM

FIELD OF INVENTION

The present invention relates to an oil production platform. More particularly, the invention relates to an offshore oil production platform which includes a deck extending above the level of sea and connected to a lower base with connecting legs extending substantially vertically. The present invention also relates to a method of installing and de-installing the oil production platform.

BACKGROUND ART

Offshore oil production platforms generally include a deck carrying production equipments necessary for drilling, technical buildings and crew quarters, storage for storing petroleum products extracted from offshore oil fields and other requirements for production of oil and gas. Currently, there is a great interest in operating offshore oil fields at great depths, from several hundred meters to thousand meters or more. Therefore, it is not possible at this depth to use gravity platforms resting on sea bed. At great depths, semi-submersible platforms can be used which will allow the platforms to float on the surface of the water and moored by taut anchor lines.

The semi-submersible platform comprises of a deck and a sub-structure of a platform. After the deck and sub-structure of the platform are constructed, the deck is mounted on the sub-structure and the resulting combination is launched and towed to its final installation site. The sub-structure includes a base, and four columns upstanding from the base and the deck being fixed to the top of the top end of the columns. When the platform reaches the destination, the sub-structure is lowered into the water. It is lowered by using rack and pinion mechanism. This system is also combined with ballasting of the sub-structure. The lowering of the base of the substructure is stopped at a predetermined depth. Depending on buoyancy of the substructure, the deck is pushed up to the top of the column using the same rack and pinion mechanism to a height that provides convenient freeboard between the deck and the surface of the water. This mechanism has disadvantages as it needs to ensure exact lateral guidance of the deck as it is raised to a height above the water level, the reason that it needs to withstand high vertical loads due to the weight of the deck. Besides that, this mechanism also leads to an increase of cost and reliability of the platform.

Commonly, offshore oil production platforms include deck carrying drilling equipment and crews quarters. The deck is usually welded to connecting legs which is also known as jacket or columns driven into the sea bed. Steel pilings are driven through hollow corners of the jacket into the sea bed to depths that may exceed 100ft. These pilings secures the platform to the sea bed and ensures that the deck withstand forces of winds and waves. The platform also has well conductors that extend down to drill holes. Oil and gas are extracted through the well conductors and transported to the deck for separation process.

There are various methods to install this kind of platform at the production site. One method of prior art (US 6,293,734) on installing the platform includes the steps of floating the platform and towing it to the production site, lowering the legs or columns until it reaches the sea bed, and finally raising the deck to a height above the water. This is to avoid high tide waves. Second prior art (US6,293,734) method of installing the platform includes the steps lowering the connecting legs on sea bed, transporting deck of the platform on a barge from a construction site and transferring the deck from the barge to the upper ends of the legs. The deck is generally very heavy, which cannot be easily transferred from one place to another. The transferring process is done by placing the barge between the legs of the platform and the deck is moved from the barge to the legs by ballasting the barge or by using equipment to lift the deck. Ballasting is a heavy duty process. Other than ballasting, the deck can be raised or transferred by means of jacks but jacks are sensitive to lateral forces.

Generally, the offshore oil production platform is removed by means of explosive removal. Torches are used to cut the deck from the legs (jackets) or columns. Then the deck is lifted and placed on barge. Sediment or mud is usually found in the lower section of the pilings below the sea bed. Therefore, the interior of the pilings needs to be cleared to allow placement of the explosives charges. Water jets are used to clear out the sediment or mud. Then the explosives are lowered down to a minimum depth of 15ft below the sea bed through the hollow pilings. After that, the deck placed on a barge is moved to a certain distance before the explosives are detonated. Upon detonation, firstly the pilings and well conductors are raised using a large crane and then the legs (jackets) are lifted out of the water. Thereafter, the platform components are later scrapped at the shore or refurbished for reuse or returned to the sea as an artificial reef site.

All the above mentioned platforms have a disadvantage when the oil in the well is in a depletion stage. Most of the platforms are not moveable and re-useable at a new oil production site. Another disadvantage is that the platforms are used for transporting the extracted oil from the deck through long and expensive pipelines up to a carrier vessel where the oil is kept in a storage tank before being loaded onto the carrier vessel. Another disadvantage of the above mentioned platforms is the method of installation. Most of the methods mentioned above encounters problems on lowering the legs and raising the deck up and above the water. The present invention has an objective of solving possibilities of having a moveable and reusable oil production platform at a new production site. The present invention also has an object of having a method that eliminates the problems faced during the installation of the oil production platforms. Therefore, there is a need for an off-shore oil production platform that solves the above mentioned disadvantages.

Besides that, using the above mentioned platforms at marginal oil fields is not economical. Construction, installation and de-installation of the said platforms at marginal oil fields will be very expensive compared to the amount of oil and gas extracted at the marginal fields. Therefore, it is not economically viable. In addition, construction, installation and de-installation of the said platforms are considered a heavy duty job. At the locations where oil and gas reserves are substantial, the oil extracted and processed is transported through pipelines to the shore for processing and storage purposes. Thus, this system incurs further cost on the pipelines too. Therefore, there is a need for an off-shore oil production platform that operates at marginal oil fields which also solves high cost problem, installation, de-installation and also the transportation of the oil to the storage tanks on shore.

SUMMARY OF THE INVENTION

The present invention relates to a first preferred embodiment of an offshore oil production platform being installed on sea bed comprising a deck, a base connected to at least one connecting leg substantially vertical upstanding from the base above the deck wherein the base includes at least one ballast chamber which is secured by connecting means to terminal end region of the at least one connecting leg wherein the ballast chamber includes at least one compartment for storing processed oil and gas, at least one ballast compartment to be filled with sea. water or air or gas and at least one compartment for compressed air or gas. The ballast compartment is connected to the air pressure compartment by at least one first valve and at least one second valve which actuate ballasting and de-ballasting processes respectively. Distal end of the at least one connecting leg is attached to metallic frame. The ballast chamber is adapted to be anchored to sea bed by anchoring means. The ballast chamber further includes a base to support the ballast chamber at the sea bed. The oil platform also consists of plurality of ballast chambers and any one of the ballast chamber is detachable and is replaceable with another ballast chamber.

The present invention relates to second preferred embodiment of an offshore oil production platform being installed on sea bed comprising deck, a base connected to at least one connecting leg substantially vertical upstanding from the base to above the deck wherein the base includes at least one ballast chamber which is secured by connecting means to terminal end region of the at least one connecting leg wherein the at least one ballast chamber has a plurality of chambers connected in a circular ring and each said chamber consists of at least one oil and gas storage compartment for storing processed oil and gas, at least one ballast compartment to be filled with sea water or air or gas and at least one air pressure compartment for compressed air or gas. The chamber is detachable from the circular ring and replaceable with a corresponding chamber. The ballast compartment is connected to the air pressure compartment by at least one first valve and at least one second valve which actuate ballasting and de- ballasting processes respectively. The ballast chambers are adapted to be anchored to sea bed by anchoring means. Operation and other components of the second embodiment are as same as the first embodiment.

A method for installing an offshore oil production platform (first preferred embodiment) towed to an oil extraction destination site wherein the platform includes a deck with at least one connecting leg upstanding from a base to above the deck and the base includes at least one ballast chamber connected to terminal end region of the at least one connecting leg and wherein the at least one ballast chamber includes at least one compartment for storing processed oil, at least one ballast compartment to be filled with sea water or air or gas and at least one compartment for compressed air or gas and the method further includes unlocking the connecting legs from locked to unlocked position, ballasting the ballast chambers with sea water, lowering the at least one connecting leg towards sea bed, locking the connecting legs to a locked position when it reaches the sea bed, jacking up the deck to a predetermined length above sea level and anchoring the ballast chambers to the seabed by anchoring means. The ballasting of the ballast chambers is continued until the ballast chambers reaches the sea bed. The method for installing the second preferred embodiment of an offshore oil production platform is as same as the method for the first embodiment.

A method for removing and re-using an offshore oil production platform (first embodiment) after extraction of oil at an oil field destination to a next oil field destination and wherein the platform includes a deck with at least one connecting leg upstanding from a base to the deck and the base includes at least one ballast chamber connected to terminal end region of the at least one connecting leg and the ballast chamber is anchored to the sea bed by anchoring means and wherein the ballast chamber includes at least one compartment for storing processed oil, at least one ballast compartment to be filled with sea water or air or gas and at least one compartment for compressed air or gas. The method further includes actuating locking means at the deck from locked position to unlocked position, jacking down the deck from a height above sea to reach to sea level, releasing anchoring means from the ballast chambers, de- ballasting the ballast chambers in order to move the at least one connecting leg back up to the deck, actuating locking means to a locked position when the at least one connecting leg and ballast chambers reach to a locked position at the deck and towing the oil production platform to the next oil field destination. The processed oil and gas stored in the oil storage compartment is independently transferable to carrier vessels by means of connecting conduits. The method for de-installing the second preferred embodiment of an offshore oil production platform is as same as the method for the first embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be fully understood from the detailed description given herein below and the accompanying preferred drawings which are given by way of illustration only, and thus are not limitative of the present invention, wherein:

Figure 1 shows a perspective view of the first preferred embodiment of an offshore oil production platform before being towed to an oil extraction destination.

Figure 1 (a) shows a perspective view of the first preferred embodiment of an offshore oil production platform installed at sea bed.

Figure 2 shows a diagrammatic view of the first preferred embodiment of an offshore oil production platform towed to the oil extraction destination.

Figure 2 (a) shows a diagrammatic view of the sea water entering the ballast compartment in the ballast chambers and lowering of the sub-structure of the first embodiment of the offshore oil production platform during the ballasting process.

Figure 2 (b) shows a diagrammatic view of the first embodiment of the offshore oil production platform being installed at the sea bed. Figure 2 (c) shows a diagrammatic view of the sea water being flushed out from the ballast compartment in the ballast chambers of the first embodiment of the offshore oil production platform during the de-ballasting process.

Figure 2 (d) shows a diagrammatic view of the sub-structure of the first embodiment of the offshore oil production platform moving up to the sea level during de-ballasting process be towed to a new destination.

Figure 3 shows a perspective view of a second preferred embodiment of an offshore oil production platform with one connecting leg before being towed to an oil extraction destination.

Figure 3(a) shows a diagrammatic view of a second preferred embodiment of an offshore oil production platform with one connecting leg being towed to an oil extraction destination.

Figure 3(b) shows a diagrammatic view of a second preferred embodiment of an offshore oil production platform with one connecting leg being installed on^' the sea bed.

Figure 3(c) shows a perspective view of a second preferred embodiment of an offshore oil production platform with one connecting leg being installed on the sea bed.

Figure 4 shows a perspective view of a second preferred embodiment of an offshore oil production platform with at least one connecting leg before being towed to an oil extraction destination.

Figure 4(a) shows a diagrammatic view of a second preferred embodiment of an offshore oil production platform with at least one connecting leg being towed to an oil extraction destination. Figure 4(b) shows a diagrammatic view of a second preferred embodiment of offshore oil production platform with at least one connecting leg being installed on the sea bed.

Figure 4(c) shows a perspective view of a second preferred embodiment of an offshore oil production platform with at least one connecting leg being installed on the sea bed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A detailed description of preferred embodiments of the invention is disclosed herein. It should be understood, however, that the disclosed preferred embodiments are merely exemplary of the invention, which may be embodied in various forms.

Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and for teaching one skilled in the art of the invention.

Figure 1 is a diagrammatic view illustrating a first preferred embodiment of an offshore oil production platform before being towed to an oil extraction destination. The oil production platform includes a sub-structure (10) and a deck (12). The substructure (10) comprises a base (14) comprising with four ballast chambers (20i), (2O₂), (2O₃), (2O₄) connected to one terminal end region of four connecting legs (columns or jackets) (16i), (16₂), (I6₃), (I6₄) respectively upstanding from the ballast chambers (20) to above the deck (12). The ballast chambers (20) connected to the terminal end region of the connecting legs (16) are placed and secured at bottom of the deck (12) before being installed at sea bed. Each connecting legs (16) has a mat (18) attached to its distal ends. The mat (18) comprises of a steel frame. The mat (18) supports the connecting legs (16) and prevents the connecting legs (16) and ballast chambers (20) from sinking below sea bed (34). The ballast chambers (20) are connected by connecting means to the terminal end region of each connecting legs (16). The present invention is not restricted to four ballast chambers (20) and four connecting legs (16) but to a plurality of ballast chambers (20) plurality of connecting legs (16). Any one of the ballast chamber (20) is detachable and replaceable with another ballast chamber (20). Buoyancy of the platform is not affected because buoyancy of the other ballast chambers will stabilized the platform. The connecting means used are known in prior art and will not be described herein. Generally, the deck (12) includes facilities for drilling oil purposes, technical buildings, drilling well, wellheads processing facilities, accommodation quarters and other facilities.

The ballast chambers (2O₁), (2O₂), (2O₃), (2O₄) include at least one oil/gas storage compartment (22), at least one air pressure compartment (24) and at least one ballast compartment (26). The oil/gas storage compartment (22) is for storing processed extracted oil/gas. Extracted oil from the oil wells is transported to the deck (12) for separation process. After that, the oil is transported to the ballast chambers (20) and stored in the oil/gas storage compartment (22). The ballast compartment (26) is in between the air pressure compartment (24) and oil/gas storage compartment (22). There are at least one first valve (28) placed at the ballast compartment (26) to control sea water (46) to enter the ballast compartment (26) during ballasting of the ballast chambers (20). There are also at least one second valve (30) placed at the ballast compartment (26) to control compressed air from the air pressure compartment (24) to fill in the ballast compartment (26) during de-ballasting of the ballast chambers (20). The air pressure compartment (24) is connected to compressors at the deck (12) through pipes. The compressed air monitored through sensors at the ballast chambers (20) and control room at the deck (12). When there is a need for de-ballasting process, compressed air will be produced and channeled through the pipes by the compressors to the air pressure compartment (24). Besides that, the ballast chambers (20) also have appropriate sensors to monitor during the ballasting and de-ballasting process. The ballast chambers (20) also have a base (32) respectively to support the ballast chambers (20) at the sea bed (34). The ballast chambers (2Oj), (2O₂), (2O₃), (2O₄) are connected to the four connecting legs (16i), (I62), (I63), (I64) respectively by connecting means. The connecting legs (1O₁), (I6₂), (I6₃), (I6₄) can be made of reinforced concrete or metal. Their function is to support the deck (12). The connecting legs (16) have square cross sections, but they may just as easily have circular or triangular cross sections. The connecting legs (16) can also accommodate various utilities such as pipes, sensors and cables. Method of installing the first preferred embodiment (100) of an offshore oil production platform described above from its construction site, i.e. dry dock to its final site in a deep water oil field will now be described. Firstly, the oil production platform is constructed at the dry dock wherein the platform includes a deck (12) with at least one connecting leg (16) and a base comprising with at least one ballast chamber (20) is connected to the terminal end region of the at least one connecting leg (16) upstanding from the at least one ballast chamber (20) to above the deck (12). The at least one ballast chamber (20) is placed and secured at bottom of the deck before being installed at the sea bed (34). The deck (12) and the connecting legs (16) are then locked in a position by using locking means. The locking means used are made known in the prior art and will not be described herein. When the platform is ready to be towed to its destination, the dry dock is flooded with water. The ballast chambers (2O₁), (2O₂), (2O₃), (2O₄) are then de-ballasted to allow the platform to float wherein compressed air from the air pressure compartment (24) is pumped into the ballast compartment (26) thus allowing the platform to float. The platform is now ready to be towed in deep water to the oil field. Upon reaching the oil field, the connecting legs (16) are then released from the locked position and the ballast chambers (20) is ballasted with sea water (46) wherein valves (30) in the ballast compartment (26) opens and allowing the sea water (46) to enter into the ballast compartment (26). The connecting legs (16) are then lowered towards the sea bed (34) as the sea water (46) enters the ballast compartment (26). Ballasting herein means that the ballast compartment (26) in the ballast chambers (20) are filled with sea water (46) which ensures lowering of the connecting legs (16). When the base (32) of the ballast chambers (20) reach the sea bed (34), the ballasting of the ballast chambers (20) is then stopped. The locking means are actuated to prevent further movement of the sub-structure relative the deck. Later, the deck is raised to a height above the sea level by using jacking means and the platform is ready for oil extraction. Finally the ballast chambers (20) are then anchored to the sea bed (34) by anchoring means. The anchoring means used are made known in the prior art and will not be described herein. The extracted oil is then transported to the deck for further processing and separation of the extracted oil. The extracted oil can be separated to processed oil and gas. After the oil is processed, it is transported back to the oil/gas storage compartment (22). Then the oil is transferred to a buoy above the sea by connecting means. Later, the oil from the buoy can be transferred to tanker vessels. The method of installing the offshore oil production platform is illustrated in Figure 2, 2(a) and 2(b).

In the present invention, the first preferred embodiment (100) of an offshore oil production platform is moveable and reusable. The method of de-installing the first preferred embodiment of an offshore oil production platform is described herein. Firstly, the locking means at the deck (12) is unlocked. Then, water jets are used to clear out the sediment or mud at the distal end of the connecting legs (16). The connecting legs (16) are then released from the locked position. Then the deck (12) is jacked down from the height above the sea to sea level. Then the anchoring means are released from the ballast chambers (20). The ballast chambers (2O]), (2O₂), (2O₃), (2O₄) is de-ballasted wherein the sea water (46) in the ballast compartment (26) in the ballast chambers (20) is flushed out by means of compressed air from the air pressure compartment (24) and allow the connecting legs (16) to move towards the deck (12) to a locked position. When the base (14) touches the deck (12), the locking means is actuated therefore locking the ballast chambers (20) and the connecting legs (16) together with the deck (12). Finally, the oil production platform is towed to its new destination for further extraction of oil. The method of de-installing of the offshore oil production platform is illustrated in Figure 2(c) and 2(d).

Another second preferred embodiment (200) of an offshore oil production platform is described herein. The platform includes a sub-structure (36) and a deck (38). The sub-structure (36) comprises a base (40) comprising at least one ballast chamber (42), wherein the at least one ballast chamber (42) has a plurality of chambers (48) connected in a circular ring with large surface area connected to one terminal end region of one connecting leg (columns or jackets) (44) upstanding from the at least one ballast chamber (42) to above the deck (38). The ballast chambers (42) can be arranged in a deck depending on size and buoyancy requirement. The at least one ballast chamber (42) are placed and secured at bottom of the deck (38) before being installed at the sea bed (34). Each chamber (48) includes at least one oil/gas storage compartment, at least one air pressure compartment and at least one ballast compartment. Figure 3, 3(a), 3(b) and 3(c) shows the construction until installation of the second preferred embodiment (200) of the offshore oil production platform. Operation, function and other components of the second preferred embodiment of an offshore oil production platform is the same as the first preferred embodiment (100) as mentioned above. The chambers (48) are attachable and detachable for maintenance and new replacement of chambers and compartments reasons. While detaching the chambers (48) from the circular ring or attaching a chamber (48) to the circular ring, buoyancy of the circular ring of the at least one ballast chamber (42) is not affected. This is due to other chambers which still have the sea water (46) in their ballast compartments and large surface area that allows the platform to still maintain its position at the sea bed (34). The second embodiment (200) is not restricted to one connecting leg only but can be varied to more than one connecting leg. Figure 4, 4(a), 4(b), 4(c) shows the construction until installation of the second preferred embodiment (200) with at least one connecting leg of the offshore oil production platform. Method of installing and de-installing of the second preferred embodiment (200) is similar to the method of installing and de-installing of the first embodiment (100).

Another third preferred embodiment of an offshore oil production platform is described herein. The third embodiment includes a sub-structure and a deck. The substructure comprises a base comprising at least one ballast chamber connected to one terminal end region of one connecting leg (columns or jackets) upstanding from the ballast chambers to above the decki The ballast chambers are placed and secured at bottom of the deck before being installed at the sea bed (34). Each of the ballast chambers includes at least one oil storage compartment, at least one air pressure compartment and at least one ballast compartment. Operation, function and other components of the third preferred embodiment of an offshore oil production platform is same as the first preferred embodiment (100) as mentioned above. Method of installing and de-installing of the third preferred embodiment is similar to the method of installing and de-installing of the first embodiment (100). The objective of this present invention is the use of the oil production platforms (100) and (200) described above at marginal oil fields. In addition, the ballast compartments of the oil production platform are not only used as to support and balance the platform but use as an oil and gas storage compartment for the processed oil. The processed oil is thereafter transferred to a buoy through pipes and then loaded to the tanker vessels. Thus, the present invention also reduces cost for installing and deinstalling oil production platforms at marginal oil fields. The present invention is not only restricted to marginal oil fields but also can be extended to deep sea oil extraction.

Claims

1. An offshore oil production platform, before being installed on sea bed (34), comprising a deck (12), a base (14) connected to at least one connecting leg (16) substantially vertical upstanding from the base (14) to above the deck (12) characterized wherein the base (14) includes: at least one ballast chamber (20) which is secured by connecting means to one terminal end region of the at least one connecting leg (16) wherein the ballast chamber (20) includes at least one oil and gas storage compartment (22) for storing processed oil and gas, at least one ballast compartment (24) to be filled with sea water (46) or air or gas and at least one air pressure compartment (26) for compressed air or gas.

2. An offshore oil production platform as claimed in claim 1 wherein the ballast compartment (24) is connected to the air pressure compartment (26) by at least one first valve (28) and at least one second valve (30) which actuate ballasting and de- ballasting processes respectively.

3. An offshore oil production platform as claimed in claim 1 wherein the ballast chamber further includes a base (32) to support the ballast chamber (20) at the sea bed (34).

4. An offshore oil production platform as claimed in claim 1 wherein distal end of the connecting legs (16) is attached to a metallic frame (18).

5. An offshore oil production platform as claimed in claim 1 wherein the ballast chamber (20) are adapted to be anchored to sea bed by anchoring means.

6. An offshore oil production platform as claimed in claim 1 wherein the oil platform consists of plurality of ballast chambers (20) and any one of the ballast chamber

(20) is detachable and is replaceable with another ballast chamber (20). ?. An offshore oil production platform before being installed on sea bed (34) comprising a deck (38), a base (40) connected to at least one connecting leg (44) substantially vertical upstanding from the base (40) to above the deck (38) ^; characterized wherein the base (40) includes: a) at least one ballast chamber (42) which are secured by connecting means to terminal end region of the at least one connecting leg (44) wherein the at least one ballast chamber (42) has a plurality chambers (48) connected in a circular ring and och said chamber (48) consists of at least one oil and gas storage compartment for storing processed oil and gas, at least one ballast compartment to be filled with sea water (46) or air ør gas and at least one air pressure compartment for compressed air or gas.

". Λn offshore oil production platform as claimed in claim 7 wherein the ballast compartment is connected to the air pressure compartment by at least one first valve and at least one second valve which actuates ballasting and de-ballasting PiOcesses respectively.

^D. An offshore oil production platform as claimed in claim 7 wherein the chamber (48) is detachable from the circular ring and replaceable with a corresponding chamber

(48).

10. *\n offshore oil production platform as claimed in claim 7 wherein the ballast chamber (42) are adapted to be anchored to sea bed (34) by anchoring means.

11. A method for installing an offshore oil production platform towed to an oil c? traction destination site wherein the platform includes a deck (12) with at least '. lie connecting leg (16) upstanding from a base to above the deck and the base includes at least one ballast chamber (20) connected to terminal end region of the at least one connecting leg (16) and wherein the at least one ballast chamber includes at least one compartment (22) for storing processed oil, at least one compartment (24) to be filled with sea water or air or gas (46) and at least one compartment (26) for compressed air or gas characterized in that the method further includes: a) unlocking the connecting legs from locked to unlocked position; b) ballasting the ballast chamber (20) with sea water (46); c) lowering the at least one connecting leg (16) towards sea bed (34); d) locking the connecting legs (16) to a locked position when it reaches the sea bed (34); e) jacking up the deck (12) to a predetermined length above sea level; f) anchoring the ballast chamber (20) to the seabed by anchoring means. wherein the ballasting of the ballast chamber is continued after step (b) until the ballast chambers reaches the sea bed (34).

12. A method for removing and re-using an offshore oil production platform after extraction of oil at an oil field destination to a next oil field destination and wherein the platform includes a deck (12) with at least one connecting leg (16) upstanding from a base to the deck and the base includes at least one ballast chamber (20) connected to terminal end region of the at least one connecting leg (Ib) and the at least one ballast chamber (20) is anchored to the sea bed by anchoring means and wherein the at least one ballast chamber includes at least one compartment (22) for storing processed oil, at least one ballast compartment (24) to be filled with sea water (46) or air or gas and at least one compartment (26) for compressed air or gas characterized in that the method further includes: a) actuating locking means at the deck (12) from locked position to unlocked position; b) jacking down the deck (12) from a height above sea to reach to sea level; c) releasing anchoring means from the ballast chamber (20); d) de-ballasting the ballast chamber (20) in order to move the at least one connecting leg (16) back up to the deck (12); e) actuating locking means to a locked position when the at least one connecting leg (16) and ballast chamber (20) reach to a locked position at the deck (12); f) towing the oil production platform to the next oil field destination.

13. The use of an offshore oil production platform as claimed in claim 1 wherein the processed oil and gas stored in the oil and gas storage compartment (22) is independently transferable to carrier vessels by means of connecting conduits.

14. The use of an offshore oil production platform as claimed in claim 7 wherein the processed oil and gas stored in the oil and gas storage compartment is independently transferable to carrier vessels by means of connecting conduits.