KR20140012434A - Offshore structure having an ubd system - Google Patents

Abstract

Disclosed is an offshore structure having an underbalanced drilling (UBD) system. The offshore structure having a UBD system includes: a deck; and a UBD system which is prepared on the deck, and which tests and separates well cuttings of a well, drilled by a drilling fluid designed to have a lower pressure than the targeted sea bottom pressure.

Description

Offshore Structure with WD System {OFFSHORE STRUCTURE HAVING AN UBD SYSTEM}

The present invention relates to an offshore structure equipped with a UBD system, and more particularly, to an offshore structure equipped with a UBD system using a drilling fluid designed at a pressure lower than a pressure of a subsea bed to be drilled.

The depth of the oil field currently under development is gradually shifting to deep sea. In order to develop oilfields, drilling operations should be preceded by confirmation of the oil stores, and the depth of drilling is also shifting to deep sea due to the trend of oil field development.

Representative offshore structures for drilling operations include drillships, drilling-rigs, jack-ups and drilling-barge. Drilling ships and drilling rigs are available for drilling in the deep sea.

Drillship is a ship-type drilling ship that has a large loading space and can be operated for a long time without the help of supply vessel. However, due to the disadvantage of poor performance due to the ship type, the input is limited in the sea area where the sea environmental load due to waves and the like is high.

Drilling rigs are also called semi-submersible. Semi-submersible is composed of column and pontoon, and it has good merit because of small repair area. Therefore, it is possible to input even in the sea area where the marine environmental load is relatively high, and it is put into a great deal to develop the deep sea oil field.

On the other hand, the above-described offshore structure with drilling equipment uses a drilling fluid having a higher pressure than the sea bed when forming wells in the sea bed. In this case, since the pressure in the hole is higher than the pressure in the sea bed, oil or gas flows from the hole into the sea bed and loss of oil or gas occurs.

In addition, damage may occur near the hole in the process of introducing the oil or gas into the seabed due to the pressure difference described above. In particular, the pressure of the hole is higher than that of the sea bed, which causes the pressure of the hole to push the drill pipe into the sea bed and to stick to the sea bed. In this case, it is almost impossible to separate the drill pipe from the sea bed.

Further, the pressure difference between the seabed and the drilling fluid causes loss of drilling fluid. That is, the expensive mud, which is a drilling fluid, is sucked into the seabed by the pressure difference to form a mud cake, which causes the mud to be wasted.

Korean Patent Registration Publication No. 10-0231802 (Daewoo Co., Ltd.) 1999. 09. 01

Therefore, the present invention is to provide an offshore structure equipped with a UBD system having an efficient space arrangement and efficient drilling work by adjusting the pressure difference between the seabed and the drilling fluid.

According to an aspect of the invention, the deck (deck); And a UBD system provided on the deck to test and separate well cuts of the drilled wells using a drilling fluid designed at a pressure lower than the pressure of the sea bed to be drilled. Can be.

The UBD system may include a well test separation unit provided on the deck of the stern area of the hull to separate the well cuttings supplied during the test of the well cuttings.

The UBD system may include a nitrogen generating unit provided in the deck of the stern region of the hull and generating nitrogen supplied to the drilling fluid such that the drilling fluid has a pressure lower than the pressure of the seabed.

The nitrogen generating unit may be separately provided on the deck and installed in a platform having at least one rail provided to a ceiling.

The UBD system may include a separation unit provided in the deck area between the bow portion and the stern portion of the hull to separate the cutting and the separation including the drilling fluid from the well cuttings.

The UBD system may include a hammer mill unit provided in the deck of the stern region of the hull to crush the solid contained in the well cuttings, and then separate the oil into a separator including oil and liquid.

The UBD system may comprise a triple cabin and tool house provided in the deck area between the bow and stern of the hull and having an access path.

The UBD system may include a cementing unit for supplying cement for cementing the drilled well provided in the cementing room of the bow portion of the hull.

The offshore structure may comprise a drillship, a drilling rig, a jackup rig or a drilling pant.

Embodiments of the present invention can adjust the pressure difference between the seabed and the drilling fluid to enable efficient drilling operations and space arrangements.

1 is a view schematically showing an underbalanced drilling (UDB) and a conventional drilling to which the present embodiment is applied.
2 is a side view schematically showing a marine structure equipped with a UBD system according to the present embodiment.
FIG. 3 is a view schematically illustrating a state in which a well test separation unit, a nitrogen generation unit, some separation units, and a hammer mill unit are provided at a stern at an offshore structure equipped with the UBD system shown in FIG. 2.
FIG. 4 is an enlarged layout view of the nitrogen generating unit shown in FIG. 3.
5 and 6 are enlarged layout views of the separation unit.
FIG. 7 is an enlarged layout view of the hammer mill unit shown in FIG. 3.
FIG. 8 is an enlarged plan view of a cement unit in an offshore structure equipped with the UBD system shown in FIG. 2.
FIG. 9 is an enlarged layout view of a triple cabin and a full house in an offshore structure equipped with the UBD system shown in FIG. 2.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

1 is a view schematically showing an underbalanced drilling (UDB) and a conventional drilling to which the present embodiment is applied.

In this embodiment, as shown in (a) of Figure 1, UBD drilling using a drilling fluid (P ₂ ) designed to a pressure lower than the pressure (P ₁ ) of the sea bed to be drilled in the sea Use

In conventional drilling, the pressure of the mud, the drilling fluid, is designed to have a hydraulic pressure that is 200 to 1000 psi higher than the pressure of the sea bed. Therefore, as shown in FIG. 1B, the pressure P1 of the sea bed is lower than the pressure P _{2 of the} drilling fluid so that the drilling fluid flows into the sea bed and loss of the drilling fluid occurs. Problems arise.

However, the present embodiment uses a UBD for drilling by drilling the pressure of the drilling fluid to 100 ~ 200psi lower than the pressure of the bottom seabed, so that solid or drilling fluid does not flow into the bottom of the well formed bottom seabed damage is reduced.

In addition, as soon as the drill bit drills the well, fluid such as crude oil is immediately raised by the pressure difference, thereby enabling early production of the fluid stored in the well. In addition, during UBD, no pressure is applied to the substratum to prevent differential sticking of the drill pipe to the substratum during drilling.

In particular, no pressure is applied towards the seabed strata, reducing the loss of expensive mud, increasing the penetration rate, increasing the penetration rate and removing the effective cutting from the drill bit face, increasing the life of the drill bit and using the drill bit. The number of can also be significantly reduced.

Meanwhile, the mud supplies nitrogen and natural gas to design the pressure of the drilling fluid below the pressure of the seabed. Hereinafter, the drilling fluid includes nitrogen in the mud, and the well cuttings include crude oil, gas, drilling fluid, and solid cutting materials, and the offshore structure is based on a drillship for convenience of description. Explain.

2 is a side view schematically showing a marine structure equipped with a UBD system according to the present embodiment.

As shown in this figure, the offshore structure 1 according to the present embodiment is provided with a deck (D, deck), the drilling is provided at a pressure lower than the pressure of the seabed strata provided on the deck (D) and the object of drilling A UBD system is provided for testing and isolating well cuttings in a well that has been drilled using a fluid.

As shown in FIG. 2, the UBD system includes a well test separation unit 100 provided in the deck D of the stern region of the hull to separate the well cuttings supplied during the test of the well, and the stern of the hull. The nitrogen generating unit 200 provided in the deck D of the region and generating nitrogen supplied to the drilling fluid such that the drilling fluid has a pressure lower than the pressure of the sea bed, and the deck D between the bow and the stern of the hull. Separation unit 300 is provided in the area to separate the cutting, the separation including the drilling fluid from the well cuttings, and the deck (D) of the stern area of the hull crushed the solid contained in the well cuttings After the hammer mill unit 400 for separating the oil and the liquid containing a liquid, the cementing unit 500 for supplying cement for cementing the drilled wells provided in the cementing room of the hull part area of the hull, Players and It provided on the deck (D) the area between the tail and includes a triple cabin 600 and the tool house 700 having an access path (800).

The well test separation unit 100 separates the well cuttings supplied during the well test process, and as shown in FIGS. 2 and 3, various equipments including drilling equipment are installed, and thus, space-limited drillships are provided. In the deck (D) of the stern area of the hull for effective space clearance.

In the present exemplary embodiment, the well test separation unit 100 may include a well test separator 110 for separating the well cuttings transferred from the well into cuttings of oil, gas, water, and solids. An oil separator 120 for separating oil from the water supplied from the well test separator 110 and separated from the well test separator 110 is provided in a line through which well cuts are supplied, and the temperature of the well cuts is increased to form hydrates. Steam heat exchanger 130 to prevent the reduction of the like, the surge tank 140 for storing the separated liquid hydrocarbons, and the transfer pump 150 for pumping the liquid hydrocarbons stored in the surge tank 140 with a burner, etc. And a first control cabin 160.

As shown in FIG. 3, the well test separator 110 of the well test separation unit 100 is disposed to be in rapid contact with a crane C provided at a horizontal edge of the deck D, and the well cuttings are firstly cut. The horizontal well test separator 111 and the vertical well test separator 112 for separating the well cuts separated in the horizontal well test separator 111 into secondary, and by the vertical well test separator 112 Installation area can be reduced.

Although not shown, the well test separator 110 may include a first separator, a second separator for separating well cuttings by gravity, a mist extractor for removing small liquid particles from gas, and oil. It may include a liquid separator for removing gas or vapor.

The nitrogen generating unit 200 is provided at the stern of the hull in which the drill pipe is loaded, as shown in FIG. 2, to generate nitrogen supplied to the drilling fluid such that the drilling fluid has a pressure lower than that of the seabed.

In this embodiment, the nitrogen generating unit 200, as shown in Figure 4, the nitrogen generator 210 for generating nitrogen, the booster for raising the pressure of the nitrogen generated in the nitrogen generator 210 to the required pressure A compressor 220, an air compressor 230 for supplying compressed air to the booster compressor, a nitrogen generator 210, a booster compressor 220, and an air compressor 230 are provided inside the upper part. It includes a first platform 240 that provides a space for loading a spider (S, spider), gimbal (G, gimbal) and the like.

In the present embodiment, as shown in FIG. 4, the first platform 240 includes a plurality of first vertical members 241 and a plurality of first vertical members 241 provided at an upper side of the deck D. At least one of the first ceiling plate 242 coupled to the upper end of the first ceiling plate 242 and provided to the inside of the first ceiling plate 242 to tow the hoist trolley HT so as to conveniently move and install the nitrogen generator 210. The first rail 243 of the.

In this embodiment, even when the nitrogen generator 210 or the like is exposed to the outside environment by the first platform 240 without being exposed to the external environment, the nitrogen generator 210 is towed to the rail and moved on the rail. There is an advantage that can be conveniently moved and installed by the trolley (HT).

In addition, since the spider (S), the gym ball (G), etc. can be loaded on the upper side of the first ceiling plate 242, space efficiency can be improved.

The separation unit 300 separates the well cuts supplied in the drilling operation after the well test is completed, and as shown in FIG. 2, the bow portion of the hull, which is a proximal region of the well cuts supplied during the drilling operation, is illustrated. It is provided in the deck area | region D between a and stern part.

In the present embodiment, as shown in FIG. 2, the separation unit 300 is disposed in a stern direction of the hull and separates the samples of the cuttings from the well cuttings supplied. And a second separation unit 320 disposed in a central region between the bow portion and the stern portion of the hull to separate the cuttings from the well cuttings supplied.

As shown in FIGS. 3 and 5, the first separation unit 310 of the separation unit 300 includes a choke manifold 311, which is an inflow conduit for drilling fluid, and a choke manifold 311. Measuring the flow rate of the well cuts provided in the sample catcher (312, which separates the cutting target sample from the incoming well cuttings, and the pipe connecting the choke manifold 311 and the sample catcher 312) The Coriolis flow meter 313, the second control cabin 314, the choke manifold 311, the sample catcher 312, the Coriolis flow meter 313, and the second control cabin 314 are provided inside the upper portion. Between the Coriolis flow meter 313 and the second control cabin 314, providing a space for loading telescopic joints (TJ), pub joints (PJ), and the like. It includes a DAPC pump (DP) disposed in.

In this embodiment, as shown in FIG. 5, the second platform 315 may include a plurality of second vertical members 315a and a plurality of second vertical members 315a provided at an upper side of the deck D. At least one provided inside the second ceiling plate 315b coupled to the upper end and the second ceiling plate 315b to pull the hoist trolley HT so as to conveniently move and install the choke manifold 311. Of the second rail 315c.

According to the present embodiment, the choke manifold 311 or the like is exposed to the second rail 315c even when the choke manifold 311 or the like is exposed to rain or heavy snow by the second platform 315. There is an advantage that it can be conveniently moved and installed by the hoist trolley HT supported and moved on the second rail 315c.

In addition, since the telescopic joint (TJ), the pub joint (PJ), etc. may be loaded on the upper side of the second ceiling plate 315b, space efficiency may be improved.

As shown in FIG. 6, the second separation unit 320 of the separation unit 300 separates the well cuts supplied through the choke manifold 311 without passing through the sample catcher 312. A centrifuge 321 for separating most of the solid cuttings from the well cuttings supplied by centrifugal force, a cutting dryer 322 for drying the solid cuttings separated from the centrifuge 321, and a centrifugal separator. A cutting blower 323 for transferring the cuts separated by the separator 321 to an ISO pump 324 which will be described later, and an ISO pump for transferring the cuttings supplied from the cutting blower 323 to a supply source using compressed air ( 324).

In this embodiment, the cutting blower 323 includes a pressure vessel body having an inlet valve and an outlet valve, and a feed hopper provided at an upper side of the pressure vessel body and into which cutting flows are introduced, and the cutting flows introduced through the feed hopper. Is discharged by compressed air.

As shown in FIGS. 2 and 3, the hammer mill unit 400 is provided in the deck D of the stern region of the hull to pulverize the solid contained in the well cuttings, and then contain oil, gas, and the like. It separates into water.

In the present embodiment, the well cuttings supplied to the hammer mill unit 400 may be supplied via the separation unit 300 or the well test separation unit 100, or the separation unit through the choke manifold 311. It may be supplied directly without passing through the 300 and the well test separation unit 100.

In this embodiment, the hammer mill unit 400, as shown in Figure 7, the hopper 410 is stored in the well cuttings supplied through the choke manifold, and the well cuttings supplied from the hopper 410 The hammer mill 420 is driven by the drive motor 430 to crush the fine particles into fine particles, and the solid grains mixed into the fluid by centrifugal force in the well cuttings supplied except the fine particles from the hammer mill 420. Cyclones (440, cyclone) to be separated into, and the oil condenser 450, which absorbs heat from the well cuttings supplied from the cyclone 440 and uses oil as a coolant, and is cooled and supplied from the oil condenser 450 A steam condenser 460 for cooling the well cuts with steam, and a separator 470 for separating the well cuts supplied from the steam condenser 460 into oil and water.

The hammer mill 420 of the hammer mill unit 400 has a rotor that is rotated by the drive motor 430 therein, and the well cuttings supplied to the hammer mill 420 are fine particles by collision with the rotor. The oil and water contained in the well cuttings are evaporated by the heat generated by friction in the process.

Hammer mill unit 400 in the present embodiment, as shown in Figure 7, the oil scrubber 480 provided between the cyclone 440 and the oil condenser 450 to remove volatile compounds from the well cuttings, A demister 490 is disposed between the oil condenser 450 and the steam condenser 460 to remove mist, and a storage tank T in which fine particles pulverized in the hammer mill 420 are stored. Unexplained reference numeral P is a pump.

As shown in FIG. 2, the cementing unit 500 supplies cement for cementing the drilled wells provided in the cementing room of the bow portion of the hull, and as shown in FIG. A cement mixer 510, a cement unit 520 for pumping the mixed cement in the cement mixer 510, and a slurry remover 530 for removing the slurry present in the mixed cement pumped in the cement unit 520. It includes.

The cement unit 520 is, as shown in FIG. 8, a cement pump 521 for pumping the mixed cement supplied from the cement mixer 510, and a cementer motor for providing a pumping force to the cement pump 521. It includes.

In this embodiment, the cementing unit 500, as shown in Figure 8, the pressure fluctuations in the pipe when the pressure is rapidly changed in the pipe to which the mixed cement supplied by removing the slurry from the slurry removal unit 530 is transferred It further includes a cement surge tank 540 to relax the piping and the cement pump 521.

In addition, in the present embodiment, for the convenience of movement and installation of the cement pump 521 and the cement motor 522 in the ceiling of the cement room R in which the cementing unit 500 is disposed, as shown in FIG. 8, At least one third rail 550 is provided.

The hoist trolley HT may be supported by the third rail 550, and the hoist trolley HT is moved back and forth along the third rail 550 to tow the cement pump 521 and the cement motor 522. You can move it.

Furthermore, the cementing unit 500 further includes a dust collector 560 provided at one side of the cement room R to collect dust contained in the mixed cement, as shown in FIG. 8. do.

Meanwhile, in this embodiment, the cementing unit 500 is provided in a separate cement room R at a predetermined height from the deck D, as shown in FIG. 2, unlike the other components described above. This is to minimize the influence of the external environment when working in the external environment in the cement operation, and to prevent delay in cementing work.

Triple cabin 600 and tool house 700 are located at the highest position from deck D, as shown in FIG. 2, and have a small space compared to other areas. Therefore, in the present embodiment, as shown in FIG. 9, a separate access path 800 is secured in an area where the triple cabin 600 and the tool house 700 are provided to secure convenience of movement and worker safety. There is an advantage to this.

As described above, since the present embodiment uses UBD for drilling by drilling the pressure of the drilling fluid lower than the pressure of the seabed layer by 100 to 200 psi, solid or drilling fluid does not flow into the well formed seabed so that damage of the seabed layer is prevented. Is reduced.

In addition, as soon as the drill bit drills the well, fluid such as crude oil is immediately raised by the pressure difference, thereby enabling early production of the fluid stored in the well. In addition, during UBD, no pressure is applied to the substratum to prevent differential sticking of the drill pipe to the substratum during drilling.

In particular, no pressure is applied towards the seabed strata, reducing the loss of expensive mud, increasing the penetration rate, increasing the penetration rate and removing the effective cutting from the drill bit face, increasing the life of the drill bit and using the drill bit. The number of can also be significantly reduced.

Furthermore, there is an advantage in that the arrangement for separating or cementing the well cuttings supplied from the well during the well testing process or the drilling operation can be efficiently arranged to maximize the space within the limited space.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

1: Offshore Structure with UBD System
100: well test separation unit 110: well test separator
120: oil separator 130: steam heat exchanger
140: surge tank 150: transfer pump
160: first control cabin 200: nitrogen generating unit
210: nitrogen generator 220: air compressor
230: booster compressor 240: first platform
300: Separation unit 310: First separation unit
320: second separation unit 400: hammer mill unit
410: Hopper 420: hammer mill
430: drive motor 440: cyclone
450: oil condenser 460: steam condenser
470: separator 480: oil scrubber
490: Demister 500: cementing unit
510: cement mixer 520: cement unit
530: slurry removal unit 540: surge tank
550: 3rd rail 560: dust collector
600: Triple Cabin 700: Tool House
800: approach path C: crane
D: Deck HT: Hoist Trolley
P: Pump R: Cement Room
T: Storage tank

Claims (9)

Deck; And
And a UBD system provided in the deck for testing and separating well cuttings of the wells drilled using a drilling fluid designed to be lower than the pressure of the sea bed to be drilled. The method according to claim 1,
The UBD system,
And a well test separation unit provided on the deck of the stern region of the hull to separate the well cuttings supplied during the test of the well cuttings. The method according to claim 1,
The UBD system,
And a nitrogen generating unit provided in the deck in the stern region of the hull and generating nitrogen supplied to the drilling fluid such that the drilling fluid has a pressure lower than the pressure of the seabed. The method according to claim 3,
The nitrogen generating unit is provided separately on the deck and offshore structure, characterized in that installed on the inside of the platform having at least one rail on the ceiling. The method according to claim 1,
The UBD system,
And a separation unit provided in the deck area between the bow portion and the stern portion of the hull to separate the cut and the separation including the drilling fluid from the well cuttings. The method according to claim 1,
The UBD system,
And a hammer mill unit disposed on the deck of the stern region of the hull to crush the solid contained in the well cuttings and then separate the solid into a separator including oil and gas. The method according to claim 1,
The UBD system,
Offshore structure comprising a triple cabin and a tool house provided in the deck area between the fore and aft parts of the hull and having an access path. The method according to claim 1,
The UBD system,
And a cementing unit provided in the cementing room of the bow region of the hull to supply cement for cementing the drilled well. The method according to claim 1,
The offshore structure includes a drillship, a drilling rig, a jackup rig or a drilling pant.

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