Drilling platform is an offshore structure mainly used for drilling exploration wells.Installed on the platformwell drillingPower, communication, navigation and other equipment, as well as safety and life-saving and personnel living facilities, are indispensable means for offshore oil and gas exploration and development.[1]
Chinese name
drilling platform
Foreign name
drilling platform
Causes
Deepening of human development and utilization of oil and gas resources
(1) Mobile platform: bottom supported platform, jack up platform, drilling vesselSemi submersibleTension leg platform, guyed tower platform
(2) Fixed platform: jacket platform, concrete gravity platform, deepwater compliant tower platformFixed drilling platformMost of them are built in shallow water. They are devices that are fixed on the seabed with the help of jackets and no longer move above the sea surface. Deck is laid on the platform to place drilling equipment.The pile legs supporting the fixed platform are directly driven into the seabed, so the stability of the drilling platform is good, but because the platform cannot move, the cost of drilling is high.
Bottom supported drilling platformAlso called drill barge or pile inserted drill barge, it is applicable to shallow waters below 30m, such as rivers and bays.The bottom supported platform has two hulls, the upper hull is also called the working deck, which is used to place living cabins and equipment, and drill through the tail county opening with the help of cantilever structure;The lower part is a cushion, which is mainly used for ballast and seafloor support, and is used as the foundation for drilling.The two hulls are connected by supporting structures.This kind of drilling device injects water into the cushion after arriving at the operation site to make it touch the bottom.Therefore, in terms of stability and structure, the operating water depth is not only limited, but also restricted by the seabed foundation (flatness and solidity).Therefore, the development of this platform is slow.However, along the Bohai Sea coast of ChinaShengli Oilfield、Dagang OilfieldandLiaohe OilfieldIn the shallow sea area extending in the isotropic sea, the tidal range is large and the seabed slope is small. For the development of oil resources in this kind of shallow sea area, the bottom supported platform still has a great development prospect.In the early 1980s, people began to pay attention to the oil development in the Arctic waters, and the design and construction of polar bottom supported platforms also aroused the interest of the marine engineering community.Several bottom supported platforms have been used in polar regions, which can be pressurized to sit on the seabed, and then filled with sand and gravel in the center of the platform to prevent the platform from sliding. After drilling, the ballast can be discharged to float and moved to another well location.
Jack up drilling platformBy platform, pile leg andLifting mechanismThe platform can rise and fall along the pile legs, and generally has no self navigation ability.When working, the pile legs are lowered into the seabed, and the platform is lifted to a safe working height away from the sea surface, and the pile legs are preloaded to ensure that the pile legs will not sink when the platform encounters a storm.After well completion, the platform is lowered to the sea surface, and the pile legs are pulled out and all lifted. The whole platform floats on the sea surface and is towed by tugboat to a new well location.In 1953, the first jack up platform was built in the United States. This platform has strong adaptability to water depth, good working stability, and rapid development, accounting for about 1/2 of the total number of mobile drilling units.The four pile legs of the self elevating drilling platform "Bohai No.1" made in China are made of round steel pipes. The height of the pile legs is more than 70 meters. The lifting device is pin typehydraulic control Institutions.This type of drilling platform has low cost, good mobilitySubmarine topographyTherefore, jack up rigs are often used for offshore drilling in China.
The height of the leg of the drilling platform is always limited. In order to solve the drilling problem in the deep sea area, there are drilling ships floating on the sea.
offshore drilling rigIt is a floating ship type drilling platform, which usually arranges drilling equipment on motor boats or barges.The platform is anchored orDynamic positioning systemlocation.According to its propulsion capability, it can be divided into self-propelled type and non self-propelled type;According to ship type, there are end drilling, side drilling, midship drilling and catamaran drilling;According to positioning, there are general anchoring type, central rotary table anchoring type anddynamic positioning Formula.The hull of the floating ship type drilling unit is floating on the sea surface and vulnerable to wave impact. However, it can be refitted with existing ships, so it can be put into use at the fastest speed.The displacement of the drilling ship varies from thousands to tens of thousands of tons. It not only has the ship type and self-propelled capacity of ordinary ships, but also can float on the sea for oil drilling.Because the drilling ship is often floating, when encountering the wind, wave and tide at sea, it will inevitably tilt, swing, translate and lift. Therefore, the stability of the drilling ship is a very critical issue.Offshore drilling vesselThe anchoring method is commonly used for positioning, but this method is generally only applicable to the water depth within 200m. When the water is deeper, a new automatic positioning method is required.
Semi submersible drilling platform(SEMI) is developed from the bottom supported platform. The upper part is the working deck, and the lower part is two lower hulls connected by support columns.When working, the lower hull dives into the water, the deck is at a safe height above the water, the waterline area is small, the wave influence is small, the stability is good, the self-supporting force is strong, and the working depth is large. After the newly developed dynamic positioning technology is applied to the semi submersible platform, the working depth can reach 900-1200 meters.Compared with jack up drilling platform, semi submersible drilling platform has the advantages of large working depth and flexible movement;The disadvantages are large investment, high maintenance cost, need a set of complex underwater tools, and the effective utilization rate is lower than that of jack up drilling platform.Semi submersible drilling platform has experienced the first generation to the sixth generation.According to statistics, there are 65 deepwater jack up rigs worldwide, most of which work in the Gulf of Mexico andthe north sea。Its operator is mainly American Petroleum Company.
Guyed tower drilling platformThe structure named after its supporting platform is like a truss tower, which uses symmetrically arranged cables to keep the tower in a positive floating state.Common drilling and production operations can be carried out on the platform.Crude oil is generally transported by pipeline and can be transported by offshore oil loading facilities in deep water.The guyed tower platform is more suitable for deep-water operations than jacket platform and gravity platform, and its application range is 200 meters to 650 meters.
Fixed platforms include jacket platforms, concrete gravity platforms, deepwater compliant tower platforms, etc.The water depth of steel jacket platform is generally less than 300m, which is fixed to the seabed by pilingOffshore oilfieldA widely used platform.Since 1947, when it was first used in the 6 meter water area of the Gulf of Mexico, it has developed rapidly. By 1978, its working water depth had reached 312 meters, which is more than 300 meters in the worldJacket platformThere are 7 seats.
The bottom of the concrete gravity platform is usually a huge concrete foundation (caisson). The deck structure is supported by three or four hollow concrete columns. The huge foundation at the bottom of the platform is divided into many cylindrical oil storage tanks and ballast tanks. The weight of this platform can reach hundreds of thousands of tons. The platform is directly placed on the seabed by its own huge weight.About 20 concrete gravity platforms have been used in the North Sea.However, due to the large dead weight of the concrete platform and the high requirements for the foundation, its use is limited.
The drilling module of a fixed platform can be placed on either a fixed platform or a mobile platform. However, the price of the upper module is relatively expensive, with a set of modules worth more than hundreds of millions of dollars. Therefore, it can generally be transplanted to a mobile platform, which is usually a place to be replaced by a shot.
Tension leg drilling platform(TLP) is a drilling platform or production platform that balances the tension generated by the anchor cable under tension with the residual buoyancy of the platform.
Tension leg drilling platform is also usedAnchor positioningBut different from the general semi submersible platform.The anchor cable is tensioned into a straight line, not a suspension curve, and the lower end of the steel cable is not tangent to the water bottom, but almost vertical.Pile anchors (that is, the piles driven into the water bottom are anchors) or gravity anchors (heavy blocks) are used, which are not generally easy to lift and place.The gravity of the tension leg platform is less than the buoyancy, and the force difference can be compensated by the downward tension of the anchor cable, which should be greater than the force generated by waves, so that there is often downward tension on the anchor cable, which plays the role of tensioning the platform.Tension leg platform has a history of 40 years since it was proposed in 1954.
The forces acting on the TLD are not stable.The gravity will change due to the change of load and ballast water;Buoyancy will increase or decrease due to the change of wave peak and valley;In terms of disturbing force, the disturbance of wind and waves will produce periodic changes in vertical and horizontal directions, so the design of tension legs must carefully consider different loads and sea conditions.The underwater components of the platform, whether vertical or horizontal, will be affected by the action of wave peaks and troughs. Therefore, how to select the shape and size of the underwater components to minimize the effect of wave disturbance and reduce the motion of the platform in waves and the periodic load on the anchor cable is one of the research topics of tension leg platform.Generally, the center of gravity of the tension leg platform is high and the center of buoyancy is low. In the case of non anchoring, the initial stability height is required to be positive. Therefore, the metacentric radius or the moment of inertia of the waterline plane is required to be largeSerious accidentIt can still float on the water surface.To achieve this goal, the column should be designed to be thicker, which will inevitably make the motion response of the platform in waves larger.There is also a way to design the column very carefully. Although the initial stability may be negative, it is stable under the tension of the anchor cable.The motion response of this platform in waves is small, and the cost may be lower, but the safety is poor.
Development History
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The world's modern oil industry was first born in Titusville Village, Pennsylvania, USA.A man named George Beers invitedYale UniversitySillimanThe professor made a chemical analysis of the oil and found that the oil can be separated into several parts by heating and distillation. Each part contains carbon and hydrogen, one of which is high-quality oil for lighting.In 1858, Bierce asked Colonel Drake to lead a man to dig a well. On August 27, 1859, when he reached 69 feet, he finally got oil.Since then, the technology of obtaining oil by drilling and refining kerosene by distillation has truly realized industrialization, and the modern petroleum industry was born.With the continuous deepening of human research on oil, in the 20th century, oil has not only become the most importantEnergy materialsMoreover, its various products have penetrated into every corner of people's lives, known as "black gold" and "the blood of modern industry", which has greatly promoted the process of human modern civilization.High oil profits have greatly promoted oil exploration and exploitation activities. In addition to onshore oil exploration, the development of offshore oil resources is also increasingly in-depth.The exploration and development of offshore oil has a history of more than 100 years.In 1897, in the United StatesCaliforniaA 76.2m long wooden frame was first erected on the tidal zone of Summer land beach, and the drilling rig was put on it to drill a well, which was the first offshore drilling in the world.1920VenezuelaA wooden platform was built for drilling.In 1936, the United States successfully drilled the first offshore oil well and built a wooden structure production platform in order to develop the continuation of the onshore oil field in the Gulf of Mexico. Two years later, the United States successfully developed the world's first offshore oil field in 1938.the Second World WarLater, the wooden structure platform was changed into a steel pipe frame platform.In 1964-1966, Britain and Norway successfully developed theBeihai Oilfield。It indicates that the technology for people to develop offshore oil fields has reached maturity.More than 80 countries have carried out oil commercial activities offshore, and crude oil production accounts for about 30% of the world's total oil production.In 1897, beside the world's first offshore drilling, American Williams built a trestle perpendicular to the coast at the same place, on which drilling rigs, derricks, etc. were placed for drilling.Since the trestle is connected to the land, the material supply is much more convenient.In addition, the drilling rig can float freely on the trestle, so that many wells can be drilled on one trestle.Erecting shelves and trestles at the seaside is basically an extension of land, which is no different from drilling on land.Can we drill in deeper sea far away from the shore?In 1932, the United StatesTexasThe company built a drilling barge "Mcbride", on which several anchors were placedLouisianaWell drilling in the "Garden" island bay in Plaquemines area.This is the first time for human beings to "drill by floating boat", that is, the barge floats on the calm sea and is anchored for drilling.However, since the ship was loaded with many equipment and materials, the barge sat on the seabed when drilling.Since then, drilling has been carried out in this way.This is the first bottom supported drilling platform.In the same year, the company built a bottom mounted drilling barge "Gilliasso" according to the design intent.In 1933, the barge drilled "Well 10" in Pelto Lake, Louisiana, with a drilling footage of 5700 feet.In the following years, many bottom supported drilling barges of different models were designed and manufactured. For example, in 1947, John Hayward designed a "No. 20 Buller Road". The platform support was more than 20 meters higher than the barge, and the platform was equipped with power equipment, pumps, etc.Its use marks the birth of modern offshore drilling industry.
Due to economic reasons, jack up rigs began to emerge, and coastal drilling contractors realized that the cost of lifting systems is much lower than that of bottom supported vessels when working in 40 feet or more of water.The legs of the jack up drilling platform can be raised and lowered. When drilling is not in progress, raise the legs, sit the platform on the water surface, drag the platform to the work area by tugboat, then lower the legs to the seabed, pressurize them, and raise the platform to a certain height, free from the influence of tide, wave, and surge, so as to drill.In 1954, the first jack up drilling ship "Dilong No.1" was launched, with 12 cylindrical pile legs.The following jack up drilling platforms are all multi legged.The "Scopi" platform, built in 1956, is the first three legged jack up platform. The motor driven pinion is used to lift the hull along the rack on the pile leg, and the pile leg is × rack type.Cass II, manufactured in 1957, is a platform with cushions and four cylindrical pile legs.With the improvement of drilling technology, many wells can be drilled on one drilling platform without moving the drilling platform, especially offshore development wells.In this way, fixed platforms have also developed.Fixed platform is to build a permanent drilling platform, mostly steel structure, piling, and then rising out of the sea;Some are cement structural members.The fixed platform with the deepest working depth is "Cognac", which can work in 318 meters of water off the coast of Louisiana.
In 1953, the "Submarex" drilling ship created by the Cuss consortium was the first drilling floating ship in the world. It was refitted and built by a patrol ship of the Navy, and a coring well was drilled in 3000 feet of water off the coast of California.In 1957, the "Cass I" drilling ship was refitted, 78 meters long, 12.5 meters wide, 4.5 meters deep, 3 meters draft, and 3000 tons gross tonnage. Six windlasses and six steel cables were used to tie the ship to the buoy.The use of floating boat drilling will bring a series of problems. Since waves and tides bring at least three kinds of motions to the ship, namely, drifting, shaking and heave, the bit may leave the bottom of the well at any time, mud returns and leaks, and the pipe with large diameter of high-pressure oil and gas can not withstand high pressure due to telescopic motion when drilling.In this way, the blowout preventer will be placed on the seabed.The ship first used simple underwater equipment, thus advancing the floating ship drilling technology a step forward.The floating ship drilling is characterized by its flexibility, fast displacement, ability to drill in deep water and economy.However, its disadvantage is that it is greatly affected by wind, wave and sea conditions, and its stability is relatively poor, which brings difficulties to drilling.
In 1962, Shell Petroleum Company used the world's first "Bishui No.1"Semi submersible drilling vesselSuccessful drilling."Bishui No. 1" was originally a bottom supported platform with a working water depth of 23 meters.At that time, in order to reduce the displacement time, the company towed in a semi submersible with a draft of 12 meters.During the towing process, it was found that the platform was stable and could drill well at this time, which was enlightening. Later, the platform was converted into a semi submersible drilling platform.In July 1964, a specially designed semi submersible platform "Bishui II" was drilled in California.The first triangular semi submersible platform was the "Marine Driller" completed in 1963, and the second was the "Sideco 135" completed in 1965.
With the continuous development of offshore drilling, human eyes are moving to deeper waters.The semi submersible drilling platform has fully demonstrated its advantages. In the Beihai Sea, where the sea conditions are bad, it is even more dominant. The matching underwater drilling equipment has also developed, gradually becoming perfect from the original simple type.Semi submersible drilling platform is generally positioned byAnchor positioningThe deep sea must use dynamic positioning.The first dynamic positioning ship is "Cussl", which can work in 12000 feet of water depth and obtain 600 feet of rock core.Then came the dynamic positioning ship "Gloma Challenger", which was put into operation in 1968 and has been used for ocean coring drilling.The first dynamic positioning ship truly used for offshore oil exploration in the world is the "SECCO 445" drilling ship built in 1971, and the working water depth can reach more than 600 meters during dynamic positioning.Semi submersibles are self-propelled and non self-propelled.The underwater equipment of the dynamic positioning ship is the underwater drilling equipment without guide rope.Later, a new type of drilling platform appeared.asTension leg platformAnd "Spar".With the progress of science, the development of the times, and the rapid development of offshore drilling technology, people have entered deeper waters, and new world records have emerged in terms of drilling depth, drilling depth, and drilling efficiency.
Development overview
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China's petroleum industry started relatively late. At the end of the 1950s, the leaders of the Ministry of Petroleum put forward the development strategy of offshore oil, which is "going up the mountain and down the sea, pushing the sea by land".In 1963, on theHainan IslandOn the basis of detailed analysis of geological data of GuangxiSouth China SeaBuild offshore oil platforms.In the following two years, GuangdongMaomingExperts from oil companies made China's first pontoon drilling platform by indigenous methods, drilled three exploratory wells 4 kilometers from the coast outside the Yinggehai Fishing Village Waterway mouth, and drilled 15 liters of crude oil at the 400m deep seabed.On December 31, 1966, China's first official offshore platform was drilled in the Bohai Sea, and on June 14, 1967, industrial oil flow was obtained, which openedCNOOCThe prelude to exploration and development.
In 1981, in order to carry out offshore oil exploration, the Ministry of Geology and Mineral Resources decided to build a semi submersible offshore drilling ship called "Exploration No.3".In June 1984, Shanghai 708 Research InstituteShanghai Shipyard Exploration 3, China's first semi submersible drilling platform jointly designed by the Marine Geological Survey and built by Shanghai Shipyard, was completed.Later, he moved to the north and south and drilled 15 subsea oil and gas wells.To discover the East China SeaPinghu Oil and Gas FieldCanxue structure has made important contributions.
"Exploration 3" is a semi submersible drilling platform composed of a box deck (also called platform deck), 6 large columns, a tall derrick and two submarine style mattresses.The height from the bottom of the mat to the upper deck of the platform is 35.2 meters, which is equivalent to a 12 storey building. If the total height of the derrick top is 100 meters, the total length is 91 meters, the total width is 71 meters, the working displacement is 219910 tons, the working draft is 20 meters, and the platform is equipped with 900 items and more than 8600 unitselectromechanical equipment。The platform deck is held aloft by six main pillars with a diameter of 9 meters, which looks like an island from a distance.In addition to a full set of drilling equipment including drilling, mud, cementing and blowout prevention systems, it is also equipped with four sets (eight sets) of 150 ton electric windlass, five sets of 660 kWDiesel generator set。At the same time, the ship is also equipped with 200m saturated diving system consisting of diving bell and deck decompression chamber, and modern equipment such as fire prevention, explosion prevention and combustible gas automatic alarm system.The "Exploration 3" platform is equipped with modern living facilities such as geological building, radio room, emergency generator room, hydrometeorology room, central control room and living room. Water, electricity and communication should be complete, and the deck top has a parking apron for helicopters to take off and land.
Semi submersible drilling platform has excellent anti wind wave performance and large variable load, and can carry out drilling operations in deeper sea areas.At that time, only a few countries in the world could build it, and the cost was expensive.In order to design a semi submersible drilling platform that can adapt to the actual situation of the Chinese continental shelf, the designers of three units collected a large number of hydrometeorological data, and through in-depth practical investigation and research, strictly screened five plans, and finally formally determined the plan to use a rectangular semi submersible drilling platform.Its main performance parameters are:;The working water depth is 35~200 meters, and the maximum drilling depth is 6000 meters.
On the morning of June 25, 1984, "Exploration 3" was towed by China's largest tugboat "Deda" and leftShanghai PortConduct various performance tests in the sea area outside Wenzhou Bay in the East China Sea.The test shows that the arrangement of the "Exploration 3" radial mooring system is reasonable, and it is very suitable for the precise positioning and operation of the platform.During this period, "Exploration 3" was under testStrong wind and wavesChina has accepted the classification visa issued by the China Shipbuilding Inspection Bureau and the American Bureau of Shipping (ABS), and the Japanese surveyor of the American Bureau of Shipping (ABS), Bomin Musha, calls "Exploration 3" as the symbol of China's modern offshore engineering.When general overseas offshore drilling companies learned that China has such high-quality drilling platforms, they came to inquire about the possibility of renting or jointly operating "Exploration 3" drilling contract operations.
The exploration and development of the world's offshore oil are mainly concentrated in the part near the land called the continental margin.The continental margin is divided into continental shelfContinental slopeAnd continental uplift.The Chinese continental shelf is one of the widest in the world, with a total area of 4.73 million square kilometers.According to relevant experts, only the continental shelf has about 25 billion tons of geological oil reserves and 800 billion cubic meters of natural gas.If we consider the whole continental margin, its development prospects are even more unlimited.According to the data in 1994, China collected 570000 kilometers of seismic lines offshore, drilled 363 exploration wells, found 88 oil and gas structures, obtained 1.188 billion tons of geological oil reserves, 180 billion cubic meters of geological natural gas reserves, and reached 6.47 million tons of annual production.The annual oil output is 25 million tons and the annual gas output is about 5 billion cubic meters.
On June 6, 2008, China National Petroleum Corporation announced that the world's largest underfloor drilling platform, CNOOC 3 underfloor drilling platform, had arrived safelyNanpu Oilfield, Jidong。After the platform is put into use, it will greatly improve the exploration and development capacity of PetroChina beach area.CNOOC No.3 is jointly developed by CNOOC and Shanghai 708 InstituteShanhaiguanShipyard manufacturing.The platform is 78.4m long, 41m wide, 20.9m high upper deck, 5888t empty ship weight, suitable for offshore operations in water depths less than 10m, and is the world's largest pedestal drilling platform.CNOOC was established in November 2004 and 2006Bohai Bay17 offshore wells were drilled and completed in three oilfields, 112000 tons of oil were tested and produced, 8 self owned ships and 19 outsourced ships were used, and 19 towing and shifting of offshore platforms were completed safely.CNOOC has seven mobile platforms of various types, including five jack up drilling platforms and two living platforms, and is building three jack up drilling platforms in Singapore, which is expected to be completed in succession from 2008 to 2009.
The ultra deepwater drilling platforms (ships) being designed and built in China mainly include:
1、 Between 708 Institute andShanghai Waigaoqiao ShipyardDesign and build a semi submersible drilling platform with a working water depth of 3000 meters.
3、 The semi submersible platform "Sevan Driller", built by Jiangsu Hantong Shipbuilding Heavy Industry Co., Ltd., a joint venture between China and South Korea, and owned by Sevan Drilling, has a working water depth of 12500 feet (3810 meters), which is currently a world record;A 40000 foot (12200 meter) ultra deep well drilling rig with double derrick in the middle and its drilling capacity reaching the current world record;It is the world's first SSP (Sevan stability (anti rolling) drilling platform).
4、 Signed by Shanghai Shipyard and American Fronter on March 3, 2007End of quarterLater, the construction of 40000 to 50000 ton dynamic positioning deepwater drilling vessels began.
All of the above are important signs of China's collapse in the construction of ultra deepwater drilling platforms. China ranks second only to South Korea in terms of the total tonnage of platforms and hulls, but there is almost no domestic marine equipment enterprises to design and build their own main engines for platforms and ships, especially the special floating drilling equipment. This requires the continued efforts of domestic marine equipment enterprises to aim at the world's top level.V“Offshore Oil 981”It is the sixth generation 3000m deepwater semi submersible drilling platform independently designed and built by China for the first time, representing the highest level of offshore oil drilling platform technology in the world today, and can be called "aircraft carrier" in marine engineering equipment
