EA010222B1 - Self-elevating platform for offshore driiling operation and oil production - Google Patents

Abstract

A self-elevating platform is embodied as two orthogonally positioned self-elevating barges, wherein a recess is made in the end part of the first barge and a derrick with a cantilever derrick substructure. The second barge is provided with equipment for preparing drilling fluid, a recess is made in its side part of the barge similar to that in the first barge by its dimensions enabling to form a hole for drilling column when connecting both barges. Each barge is provided with retractable supports, shelves for storing supports and mechanisms for raising the barge above water surface. The mechanism for raising the barge above the water surface is embodied as a block of pulleys, each of them comprises a rack jack rigidly fixed on the barge body and kinematically connected to a shaft of a reversible engine. The retractable supports are made variable round or rectangular cross-section over their length. Each self-elevating barge is a flat-bottomed barge adaptable for motion separately in shallow water.

Description

The invention relates to drilling platforms on lifting supports for the exploration and production of oil in coastal waters.

According to Forest Gray (Oil Production / English Trans. - Moscow: Olimp-Business CJSC, 2003, pp. 32-34, 83-85), currently there is a problem of exploration and production of oil in the shallow waters of coastal waters. This is due to the fact that modern environmental laws of a number of countries have banned the creation for drilling and exploration of oil-bearing layers of the Earth artificial stationary structures (bulk dams, reinforced concrete piers, islands and platforms with constant reliance on the bottom of reservoirs), changing the ecology, biological habitat of animal and vegetable world, the natural landscape of water bodies, as well as impeding fishing and navigation. In addition, the exploration of the oil-bearing layers is associated with the risk and necessity of conducting many drilling operations due to the uncertainty of the presence of oil in the search area, the location and shape of the oil-bearing layers. The latter leads to unjustified material costs for the construction in stationary reservoirs of reconnaissance platforms and the deterioration of the environmental situation in them.

The solution of these environmental problems in the exploration of oil in coastal waters is provided by the creation of mobile (waterborne) platforms for drilling rigs. Depending on the depth of the coastal waters, drilling ships are used as mobile platforms; semi-submersible installations; installations on a fixed platform; self-lifting installations and barges (Forest Gray. Oil production / transl. from English. - Moscow: Olimp-Business CJSC, 2003, p. 85-103). Below are specific examples of known solutions that are similar in design and element base to the claimed invention.

Famous platforms for exploration and production of oil in coastal waters (GK. 2774967, cl. В63В35 / 44; В63В35 / 44, 1999; ОВ 849588, cl. В63В21 / 50; В63В21 / 00, 1960), including a semi-submersible floating platform with derrick ( mast tower) and anchor system for fixing the platform to the bottom of the sea.

A disadvantage of the known platform is the lack of resistance to disturbances of the aquatic environment.

Known self-elevating platforms for exploration and production of oil in coastal waters (OB763864, CL. EV02 / 02; EV21B35 / 00; EV02B17 / 00, 1956; I8 4103503, Cl. EV02B17 / 02; E02B17 / 00, 1978; I85833396, CL Е02В17 / 00; Е02В17 / 02; Е02В17 / 08, 1998; ГК2604413, CL ВВВВ35 / 00; Е02В17 / 00, 1998), including a cantilever self-lifting base with a derrick, self-retracting supports and a device for lifting the base above the surface of the water. On each of the supports mounted portal lift, including rack jack connected to an electric motor or hydraulic motor. To protect the platform from the waves of the length of the sliding supports of the platform are made with the possibility of lifting the latter above the surface of the water to a height of at least 8 m. For drilling on soft soils, the supports (sliding legs of the platforms) are equipped with a common horizontal plate (bottom cushion). Pontoon vehicles (to keep the platform afloat) and powerful towing vessels were used to move platforms to the drilling site. Due to weight and size limitations and limited leg length (Forest Gray. Oil production / translation from English - Moscow: Olimp-Business, 2003, p. 102), such platforms can be used at depths from 15.3 to 100 m

A disadvantage of the known platforms is a deep sediment and the difficulty of its movement in shallow water, a depth of less than 15 m.

A platform for exploration and production of oil in coastal waters (OB756826, CL EV15 / 02; EV21B15 / 00, 1956) is known as a floating catamaran-type floating barge with a drilling rig, the casing of which is at the same time the anchor of the barge.

A disadvantage of the known platform is the low resistance to disturbances of the aquatic environment, associated with a large area of interaction between the bottom of the barge and the aquatic environment.

A self-climbing platform is known for the exploration and production of oil in coastal waters (I8 6305881, cl. Е02В17 / 00; Ε02Ό27 / 14; Ε02Ό27 / 52, 2001), which includes a self-heated barge with vertical struts installed on its deck, a platform for installing drilling equipment and lifting a mechanism for lifting the platform on racks above the barge and the surface of the water.

A disadvantage of the known platform is the lack of resistance to disturbances of the aquatic environment and the impossibility of its use at depths of less than 25 feet (7.5 m) due to the large draft of the self-flooded barge.

Considering that the shallow waters of coastal waters, such as the Caspian and Azov Seas, Lake Sivash, do not exceed 6 meters at distances of hundreds of meters-units of kilometers from the coast, there remains the problem of exploration and development of gas and oil fields in the shallow waters of coastal waters.

The objective of the invention is to solve this problem, namely the provision of opportunities for exploration and development of gas and oil fields in the shallow waters of coastal waters while maintaining the ecology of the environment.

The technical result that provides a solution to this problem is to reduce the draft of the self-lifting platform barge in the transport position (when moving in shallow water) and increase its resistance to storm loads in the working position.

The solution of the task and the achievement of the stated technical result is ensured by the fact that the self-lifting platform for exploration and production of oil in coastal waters according to the invention is made in the form of two orthogonal self-lifting barges, in the end part

- 1 010222 of the hull of the first barge is made a notch and derrick is placed horizontally with a cantilever self-lifting base, and the second barge is equipped with equipment for preparing drilling mud, in its side part there is a notch similar in size to the notch of the first barge, and barge interconnection, in addition, each of the barges is equipped with retractable supports, racks for storing supports and lifting mechanisms of the barge above the surface of the water. In this case, the mechanism for lifting the barge above the surface of the water is made in the form of a block of lifts, each of which contains a rack jack fixed on the body of the barge and kinematically connected to the shaft of the reversing engine. The extendable supports of the barge are made with a circular or rectangular cross-section of variable length. Each self-lifting barge is flat-bottomed with the possibility of separate movement in shallow water.

The implementation of the self-lifting platform not solid design, but in the form of two self-lifting barges (with reduced weight and size characteristics) allows reducing the draft of the latter and transporting them through shallow water in the form of separate transport barges. Supplying each section with retractable supports and lifting mechanisms for barges, as well as making recesses in barges that form an opening under the drill string during orthogonal connection, allow the barges to be raised above the water surface to a height that protects the self-lifting drilling platform from storm waves, and also facilitates the lifting of the barges and their docking at one level above the surface of the water. The orthogonal arrangement of barges in the assembled platform allows increasing the stability of the structure to storm loads. Placing on one barge a derrick with a cantilever base, and on other equipment for preparing drilling mud, allows to evenly distribute the load between the barges and, thus, to ensure a uniform draft of the latter when moving them over shallow water. In general, these technical advantages make it possible to achieve the claimed technical result and solve the problem of exploration and development of gas and oil fields in the shallow waters of coastal waters while simultaneously preserving the ecology of the environment.

FIG. 1 is a side view of a self-climbing platform assembly; FIG. 2 is a top view thereof, in FIG. 3 - view of barges in the transport position.

The self-elevating platform for exploration and production of oil in coastal waters is designed as two orthogonal self-elevating barges 1 and 2 located. Barges 1 and 2 are installed on retractable tubular supports 3 above the water surface at a height that excludes the possibility of the platform being washed away by storm waves at the exploration site. In protected shallow waters, for example, in lagoons or river channels, the elevation of the platform above the water should be at least 2 m, and in the open shallow waters of the seas - at least 8 m. To ensure buoyancy in shallow water, when changing the location of the platform, each barge 1 and 2 is made with a flat bottom and dimensions, providing its small draft. Considering the depth of the above shallow waters, the draft (height of the waterline) of barges 1 and 2 at full load should not exceed 2 m. Each barge 1 and 2 is equipped with retractable tubular supports 3 and lifting mechanisms of the barge above the water surface, made in the form of blocks of lifts 4. Each lift 4 contains rigidly mounted on the hull of the barge 1 and 2 rack jack, kinematically connected at the entrance to the shaft of the reversing engine, and at the exit with supports 3, when installed in guide tubes 5. To ensure reliable engagement of the river jack 4 with a lift outrigger supports 3, the latter are made variable over the length of a circular or rectangular cross section. The length of the supports 3 for the worst environmental conditions (taking into account the maximum depth of shallow waters of 6 m and the required height of lifting barges 1 and 2 above the water surface is 8 m) must be at least 14 m. Considering the waterlogging and silting of shoals in the mouths of the rivers flowing into the seas and lakes, the required length of each support 3 can be increased not less than 2 times. To ensure the possibility of transportation and vertical installation of retractable tubular supports 3 last made composite. The length of the components of the supports 3 is selected from the condition of the possibility of their placement on the racks 6 in the transport position of barges 1 and 2. The guide tubes 5 are welded vertically from the sides of the hulls of barges 1, 2 or passed through the hold of the latter. In the latter case, in order to prevent water from entering the bilge, pipes 6 are welded circumferentially, respectively, in the lower part to the bottom of the barge 1, 2, and in the upper part - to its deck. In the end, for example in the aft, part of the barge 1, a notch 7 is made, and in the orthogonally mounted to it the barge 2, in its side part, a similarly sized notch 8 is made. To increase the stability of the assembled platform to wind loads, a notch is from one or all sides 8 is made in the side of the barge 2, respectively, closer to its stern or in the middle of the side. The notches 7 and 8 form when connecting the barges 1 and 2 a hole for placing the drill string 9 in it and a seat for the derrick 10 with a cantilever self-lifting base 11. For uniform distribution of the load between the barges 1 and 2 in the transport position of the last derrick 10 with a cantilever self-lifting base 11 is placed horizontally on the barge 1, and on the barge 2 is placed the equipment 12 for the preparation of drilling mud.

Self-lifting platform works as follows.

A jack-up platform, including barge 1 and barge 2, is towed to a geological survey site separately from each other. Upon arrival at the place of reconnaissance, barge 1 installed

- 2 010222 waving perpendicular to the barge 2 so that the notch 7 in the barge 1 is located opposite the notch 8 of the barge 2, forming an opening under the drill string 9. At the junction of the barge 1 and 2 are fastened together. Then, through the guide tubes 5, barges 1 and 2 are vertically lowered by means of a crane (not shown in the figure) to the bottom of the reservoir the constituent elements of the supports 3, sequentially connecting them together. When reaching the bottom of the reservoir supports 3 include lifts 4. In this case, the shafts of the reversing engines of lifts 4 begin to rotate. The rotation of the shafts of the engines of the lifts 4 using their rack jacks is converted into translational motion of the supports 3. In this case, the barge 1 and barge 2 are detached from the surface of the water and rise to the required height of the platform installation. Then the decks of barges 1 and 2 are aligned with each other by successively turning on the respective lifts 4. After horizontal alignment of barges 1 and 2 above the hole 13 formed by the recesses 7 and 8, the cantilever base 11 with the derrick 10 is mounted using a floating crane (not shown) and is fixed using a bolt joint at the same time to the decks of barges 1 and 2. This forms a rigid base for a drilling rig with a hole 13. After the derrick 10 is installed in a vertical position, the drill is hung on its winch 14 column 9 delivered by a separate barge. At the same time, a drilling solution is prepared on the barge 2 by the equipment 12, for example, a slurry of clay with water. Winch 14 down the drill string 9 to the bottom of the reservoir. When the bottom is reached, the drillstring 9 is actuated with simultaneous feed of drilling mud inside the string. At the same time, the drilling fluid passes down the column and returns to the surface outside the pipe, providing cooling of the drill bit, removal of cuttings from the drilling zone and the formation of a solid mudcake on the borehole walls. After drilling and exploration, the drill string 9 is excavated, the well exit is cemented, the drilling equipment is removed, the self-lifting platform is disassembled in the reverse order of assembly, and brought into transport position (Fig. 3). Next, barges 1 and 2 are towed to a new geological survey site, and the platform assembly process and geological survey is repeated.

The invention was developed at the level of technical proposals and physical modeling. Testing the model showed the possibility of solving the task and achieving the stated technical result.

Claims (4)

CLAIM 1. Self-elevating platform for exploration and production of oil in coastal waters, characterized in that it is made in the form of two orthogonally located self-elevating barges, a notch is made in the front part of the hull of the first barge and a derrick with a cantilever self-elevating base is horizontally placed, and the second barge is equipped with equipment preparation of drilling fluid, in the side of which a recess is made, similar in size to the recess of the first barge, and with the possibility of forming a hole for the drill string when connecting the ba w interconnected, in addition, each of the barge is provided with sliding bearings, racks for storing supports and lifting mechanisms barge above the water surface. 2. The self-lifting platform according to claim 1, characterized in that the barge lifting mechanism above the water surface is made in the form of a block of lifts, each of which contains a rack jack rigidly fixed to the barge body, kinematically connected to the shaft of the reversing engine. 3. The self-lifting platform according to claim 1, characterized in that the retractable supports are made with a variable in length round or rectangular cross-section. 4. The self-lifting platform according to claim 1, characterized in that each self-lifting barge is flat-bottomed with the possibility of separate movement in shallow water.