(一)Drilling underwater main purpose equipment, classification and composition
1. The main purpose of Drilling underwater equipment
Drilling underwater equipment is floating ocean oil drilling (including floating drilling vessels, semi-submersible drilling rigs and other floating oil drilling equipment) device key equipment, has the following main purposes:
(1) so that the floating oil rigs at anchor or dynamic positioning conditions, the displacement of the ship deviated from the center of the mouth does not exceed 5% of the working depth (maximum 10%) of the range, adapt heave, swing, comprehensive translational motion state By drilling for oil.
(2) the formation of channels separated by sea between the wellhead and subsea vessel floating drilling unit to facilitate the circulation of mud, drilling rotary drilling, lifting and return to the well bore.
(3) Remote blowout section exile or kill spray.
(4) supporting each seabed type casing, and remain sealed.
(5) the tension in the heave motion state ropes into the water and riser.
(6) into the oil drilling technology to meet the needs of the job and removing appliances.
(7) connection and disconnection subsea wellhead and subsea prepare the conditions for the next step.
(8) In the case of an emergency (such as severe sea conditions, the ship's position can not be maintained or blowout can not control), you can cut the hole drilling, pipe line connection across disconnected systems and plugging, the boat safely evacuated.
2．Drilling underwater equipment classification and composition
Drilling underwater equipment can be divided into general guide rope without the rope guide underwater equipment and two subsea equipment, the former is commonly used in the depth of 300m (1000in) range, which is used more than 300 ~ 500m depth.
(1) Drilling underwater equipment having a guide rope
Guide rope Drilling underwater equipment generally consists of the following components:
1) wellhead system: including wellhead catheter, GM series of casing head group, wellhead disk, permanent guide racks. Mainly used for: identifying and fixing the wellhead; according to process requirements and remain sealed casing layers servant; permanent installation guide rope or undersea acoustic beacon system; provide import subsea connection interface for the next step.
2) plugging system (ie, the BOP stack): including hydraulic connectors, hydraulic ram blowout preventer (including both shear ram BOP drill Xuan), hydraulic universal BOP, killing the pilot orifice valves, fittings and the BOP stack BOP stack guide frame, etc., is the heart and the key to the underwater equipment, primarily for connection or disengagement line wells. When the drill or not drill wells there, plugging blowout prevention, killing or put spray job.
3) Riser System: Includes guide arm with a riser system, hydraulic connectors, hydraulic balanced ball joints or flexible connectors and flexible hydraulic universal blowout preventers and kill blowout pipeline group consisting of lower riser, press Working depth with different lengths of riser or riser buoyancy, pneumatic or hydraulic control seal telescopic riser, ball joints and hydraulic control deflector slurry outlet pipe and other groups. Mainly used for separating water, circulating mud; import layers casing or drill; by the upper and lower ball (or flexible) joints and telescopic riser to accommodate floating drilling heave, swing, translation and other integrated campaign; in shallow stratigraphic drilling triage BOP and when natural gas drilling; temporary control blowout (with universal BOP) and in bad sea conditions across the connection pipe lines disconnected and plugging system.
4) Control system: control system is divided into liquid, liquid control systems, electrical and hydraulic control system and acoustic control system for three kinds. The acoustic control is used for liquid, liquid or electricity, liquid control auxiliary emergency control. They include the boat (water) accumulator hydraulic pump group, driller control cabinet (driller control cabinet), living area remote cabinets, cable winches tubing, pipes, cables, pulleys; surface to seabed oil pipeline bundles or cables ; seabed valve connector set (liquid, liquid or electricity, liquid, acoustic) and other components. Mainly used for remote subsea hydraulic actuators each of the opening and closing action.
(2) no rope-oriented Drilling underwater equipment
No ropes oriented Drilling underwater equipment, mainly applied to work deeper than dynamic positioning floating oil rigs 300m of the package.
No rope guide Drilling underwater equipment essential part of having a guide rope and Drilling underwater equipment is basically the same, but the shape structure and import in different ways. Oriented approach takes advantage of its undersea acoustic beacons instrument on board the ship's position, underwater television combined dynamic positioning system to adjust their positions to import it.
1) wellhead system: With acoustic beacon transmitting device and reverse horn, spring contact pin type shock wellhead system has. Its casing head lock assembly is suspended at the wellhead, and to provide a hydraulic connector that matches the shape of the structure.
2) plugging system: In addition to having the upper inverted cone speakers, spring pin type shock contacts with a large angle secure the release of the lower outer joins hydraulic connector, and the rest of the hydraulic ram BOP, BOP hydraulic universal, etc., and a guide rope style is basically the same.
3) Riser System: In addition to having a voice on the flexible coupling hydraulic emergency move off the lower marine riser connecting devices and secure the release of a large angle hydraulic connector, the other components: such as BOP hydraulic universal, flexible joints are with a guide rope style riser system is basically the same (but using riser buoyancy type).
4) Control system: electrical, hydraulic remote control (or electrical, hydraulic multiplexed remote) and acoustic control system combined with the emergency.
5) tensioning system: Because no permanent guide rope, it does not require a permanent guide rope tensioner, but must be equipped with tension (or a greater number, usually six or more) riser tensioner.
(二)Drilling underwater equipment abroad and level overview of recent developments
1. With increasing water depth and drilling depth. Plugging work pressure has increased to 105MPa (fairly 15000 psi) up to 140MPa (quite 20000psi), a minimum of 70MPa (quite 10000psi).
2. Dual BOP systems. By a single set of BOP system replaced; BOP path has been standardized, usually 476.3mm (ie 18 3 / 4in); and the diameter of 406.4mm (although p 16in) BOP is mainly used in deep-sea oil drilling.
3. Wellhead system
(1) For the exploration wells and development wells combined have been developed in the seabed removable modular seabed substrate; for the realization of the early development of offshore oil fields, the development of a new jacket can import pre-drilling the chassis; wellhead center of cluster distance and guide ropes for drilling center. Has been standardized and has adjustable level devices.
(2) subsea casing head and casing program group has standardized and unified: 762mm (30in), 508mm (20in), 340mm (13 3 / 8in), 244.5ram (9 5 / sin), 178mm (7in ) and 140ram (5 1 / 2in) 6 species.
(3) the structure of the seabed casing head group has been designed to accommodate both 10.5MPa pressure and suspended over deep underwater casing can adapt completion operations. Extruded seal from developing self-styled or metal seals; to adapt to deepwater drilling, casing head group into tools from the general left-hand thread tool, developed for hydraulic or other tools easy to remove.
4. BOP stack
(1) upper and lower hydraulic coupler has been developed as an annular cylinder easy to open, and the abolition of emergency backup hydraulic cylinder, and can be manually opened rope.
(2) With increasing depth, the BOP hydraulic control pressure is relatively lower. And balanced development of the hydraulic ram BOP, when a substantial increase in water depth, no need to increase the BOP hydraulic control.
(3) In order to meet the need for additional work after the combination drill depth and drilling depth, has successfully used the adjustable gate. Reducing the scope of its closure of the drill pipe, usually 89 ~ 127mm (3 1/2 ~ 5in); shear ram full closure after use of aerospace materials. Its hardness increased significantly, and to prevent hydrogen embrittlement caused by hydrogen sulfide; between the shutter and the supporting shell with a corrosion-resistant hardfacing materials to increase its service life.
(4) BOP housing design, using the finite element method, photoelastic method, fracture mechanics, acoustic emission testing and CAD and other modern design. To reduce the effective height of the space BOP. Also uses a ram blowout preventer with the ring (Universal) BOP whole casting process; BOP stack configuration, generally use two sets of double plate (one of the most full closure on one shear ram) and on the Circular (Universal) BOP, water pipes across the next group also installed a set of annular BOP.
(5) To improve the choke and kill blowout valve working pressure. Streamline its manufacturing process and reduce the dimensions, mostly parallel gate type and style of forged steel manifold housing.
5. Riser System
(1) developed a long-life special rubber-like plate combined with a spherical laminated flexible joints, without any maintenance, the service life of up to 20 years.
(2) development of a deepwater riser buoyancy buoyancy microsphere material, pressure 20MPa, suitable buoyancy 2000m water depth within the riser use.
(3) in the inner telescopic riser expansion stroke range of 15m, by using a surface-treated steel and wear regulator seal, in use, replaceable sealing element, and upper and lower sealing (under seal in the drill When used in conjunction with the case of shallow gas deflector, and use as an emergency item when the seal is damaged).
(4) the development of a continuous throttle, killing a flexible high-pressure hose, saving the riser choke, kill line pressure test plug decentralization time, and to overcome the high pressure (> 10.5MPa) under mechanical plug-in pipeline section due to the presence of the docking ring tremendous thrust up and down.
(5) the widespread adoption of the deflector and the development of a more secure, full closure of the spherical plastic core deflectors.
One reason for the occurrence of a major offshore oil drilling in the shipwreck, when shallow gas drilling. Since there is no installation deflector caused. Shallow gas blowout preventer can not be used (closed BOP) approach. Because in the shallow, large diameter casing (low bearing strength) can not ensure its cementing shallow gas seal for the shallow casing does not destroy, but to use diversion approach will lead to natural gas left (or right) side of the ship burned. So now all drilling rigs are equipped with deflector, than follow the cylinder seal cystic deflector removed. Also recently developed a similar spherical rubber core universal BOP deflector, West 546mm × 14MPa (West 21in × 2000psi) combined diversion BOP Hydril Company adopted the program control, you can close any size drill tools, but also full closure and diversion when no drill holes.
(三)Overview of Development Drilling underwater equipment, the level of the gap
1.1974, the Ministry of Geology and Mineral Resources Bureau of Shanghai Marine Geological Survey for the first time to design and manufacture a full range of I-Drilling underwater equipment, used in oil rigs catamaran "exploration No. 1" on, and in the South Yellow Sea survey completed nine oil drilling This type Drilling underwater equipment mainly consists of the following components:
(1) BOP stack: from the casing head hydraulic connector set, two double plate BOP on BOP connector, four groups of hydraulic control fluid balance control valve and BOP BOP stack guide frame components.
(2) Under the riser groups: mechanical connectors, ball joints, high-pressure flexible hose spray discharge pipeline and riser under the group consisting of the guide arm.
(3) Control system: hydraulic hose from electrical, hydraulic control, and a separate multi-core cables, ship control cabinet, hydraulic console, motors, pumps, tanks, fluid pipe, dual winch and hydraulic backup control group hose winch components.
Type I Drilling underwater equipment main technical parameters are:
Vertical hole diameter 324mm (12 1 / 2in)
Working pressure plugging 1 5MPa
BOP stack weight 80t (including two submarine cables, hydraulic valve connector group)
Retractable telescopic riser stroke l 0m
Control voltage 24V (DC)
Hydraulic control system 1 6MPa
Drilling underwater equipment package weight of about l 80t (including all into the tool)
I type Drilling underwater equipment, compared with foreign products whose main difference is: the low working pressure blowout preventer. Only 15MPa (currently abroad up 105 ~ 140MPa); diameter is too small and does not work standards, the current foreign Chase has used 476.3mm diameter (18 3 / 4in) standard; the underwater part of the manufacturing quality electrical and hydraulic systems are not high, the solenoid valve seal links, unreliable; the whole system is imperfect. While I type underwater equipment at sea survey completed nine oil drilling. But none of drilling oil, gas reservoir, it has not been a major plugging control performance test. The I-Drilling underwater equipment abroad only quite late 1960s, early 1970s levels.
2. In type I summarize Drilling underwater equipment development, on the basis of experience. The mine Shanghai Marine Geological Survey Bureau has designed a type Ⅱ Drilling underwater equipment, in 1981 in Shanghai to complete the fabrication and assembly and test land, type Ⅱ Drilling underwater equipment package includes the following parts:
(1) BOP stack: the hydraulic connector (with spare emergency cylinders), two double plate BOP, BOP universal sphere, joint group on BOP, BOP stack guide frame, 8 groups parallel gate style killing the pilot put the spray valve.
(2) riser system: by the hydraulic riser connector (with the BOP hydraulic connector GM), hydraulic balanced spherical flexible couplings, hydraulic control oily Road Jack, fast riser card connector block throttle manifold and flexible combination of male plug, next riser group guide frame, telescopic riser group (double sealed pressurized split seal structure), with a mud ball joint outlet pipe and other components.
(3) underwater equipment control system: electrical, hydraulic control of electro-hydraulic hoses and modular cabinet for board control, mini remote control cabinets, energy storage group (motors, hydraulic pumps), modular power liquid hose winch and other components.
The main technical parameters of type Ⅱ Drilling underwater equipment is:
Vertical through-hole diameter: 346mm (13 5 / 8in)
Plugging working pressure: 35MPa (5000 psi)
Casing program: 508,340,244.5,178,140mm
(20,13 3 / 8,9 5 / 8,7,5 1 / 2in)
BOP stack Weight: 48.2t
Riser diameter: 370mm
Choke line and kill line (diameter × pressure): 68mm × 35MPa
Retractable telescopic riser group itinerary: l0m
Control system voltage: 24V (DC wet solenoid)
Hydraulic control system: 20MPa
Drilling underwater equipment package weight: about 200t (including all into the tool)
Type Ⅱ Drilling underwater equipment compared with foreign products, the main difference is:
Plugging the pressure is still low, the maximum foreign pressure 105 ~ 140MPa, type Ⅱ underwater equipment only 35MPa; small diameter work abroad for 476.3mm (18 3 / 4in) diameter standard, Ⅱ type only 346mm (13 5 / 8in); foreign electro stretch a liquid-liquid system, the control system is reliable. Ⅱ type underwater tank seal electro-hydraulic system, although larger than type I, but with power stretch a liquid-liquid system (underwater only liquid-liquid system) ratio, its reliability is poor (due to domestic manufacturing unconditionally long hose bundle liquid-liquid system). Later, discover the East China Sea drilling wellhead pressure is higher than 50MPa, type Ⅱ dare not put into use at sea. The device is quite foreign late 1970s level.
Currently, Drilling used on "Exploration No. 3" semi-submersible platform underwater equipment, by the US Department of Vetco company assembly, in addition to the BOP control system used by the US N · L · Shaffer company's products, guide selection of Hughes offshore Company (Hughcs Offshore) products, the rest are Vetco products; "the South China Sea on the 2nd 'Cameron all its partners the company's products; more than two semi-submersible platform in the BOP stack are 476mm diameter (18 3 / 4in), plugging pressure (10000 lbf / in2) "Nanhai No. 5" and the "South China Sea No. 6" 70MPa work BOP stack diameter are also 476.3ram (18 3 / 4in), plugging pressure of 105MPa (15000] bf / in2), United States Hadley ear (Hydril Co.) company and other products, in line with international technical level of the late 1980s.
(四)Proposals for Development of Drilling underwater equipment
As previously described. China has successively developed the I, type Ⅱ Drilling underwater equipment. In addition, the Shanghai Dalong machine factory was the mid-1980s, the company introduced the United States Hughes offshore manufacturing technology, and the establishment of a special assembly of the pilot plant Drilling underwater equipment; Shanghai Petroleum Machinery Factory has introduced the first American Koomey's underwater equipment control systems manufacturing technology and has complete supply land with oil drilling anti Suo group and control systems; Shanghai second petroleum Machinery Factory has introduced the United States McVoy company About casing head group, parallel gate high pressure throttling, killing gate technology. Description of Drilling underwater equipment design, manufacturing technology and capability greatly improved, recommendations for future floating drilling unit needed to be developed in our country.