CN111535766A - Drilling fluid circulation system - Google Patents

Abstract

The invention relates to a drilling fluid circulating system.A first valve and a third valve of a valve group of a drill floor are connected in series in a low vertical pipe and the first valve is arranged above, a second valve and a fourth valve are connected in series in a high vertical pipe and the second valve is arranged above, and the first valve and the third valve are connected with each other through a fifth valve and a second valve and a fourth valve; the ground valve group comprises a valve six to a valve twelve, an outlet pipe of the first pump is connected with a right ground pipe sequentially through the valve six and the valve twelve, and an outlet of the right ground pipe is connected with the lower end of the low vertical pipe; an outlet pipe of the third pump is connected with a left pipe sequentially through a valve eight and a valve nine, and an outlet of the left pipe is connected with the lower end of the high vertical pipe; the outlet pipe of the second pump is connected with a seventh valve, the outlet of the seventh valve is respectively connected with a tenth valve and a eleventh valve through a tee joint, the other end of the tenth valve is connected with a bypass port of the nine-inlet four-way valve, and the other end of the eleventh valve is connected with a bypass port of the twelve-inlet four-way valve. The system can convey mud through the vertical pipes with different heights, and can reasonably switch the mud pumps to ensure normal discharge capacity and pumping pressure.

Description

Drilling fluid circulation system

Technical Field

The invention relates to a valve for an oil drilling machine, in particular to a drilling fluid circulating system, and belongs to the technical field of valves for oil drilling machines.

Background

In the drilling process, one or more slurry pumps spray high-pressure fluid to the bottom of the well through a manifold, a gate group, a hose, a drilling tool and a drill bit water hole, so that the high-pressure fluid is flushed on the bottom of the well, and solid-phase particles in the well are carried out. The fluid drilling fluid participating in circulation has the following functions: firstly, cleaning the bottom of a well, suspending and carrying rock debris, and keeping a well clean; the formation pressure is balanced, the well wall is stabilized, and well collapse, blowout and well leakage are prevented; thirdly, water power is transmitted to help the drill bit to break the rock; fourthly, power is transmitted to the underground power drilling tool; fifthly, cooling the drill bit and the drilling tool; and sixthly, the drilling fluid is used for geological and gas logging.

According to different construction capacities of the drilling machines, the number of the matched slurry pumps is different from one to four, the drilling machines of 2000 meters and below are matched with one pump at present, the drilling machines of 3000 plus 5000 meters are matched with two pumps, the drilling machines of 7000 plus 9000 meters are matched with three pumps, and the drilling machines of 12000 meters and above are matched with four pumps. The deeper a drilling machine is used for constructing a borehole, the more the mud pump platforms are, the more control gates of a drilling fluid circulating system are, and the more complex the gate groups are, so as to ensure normal discharge capacity and pumping pressure.

The conventional drilling fluid valve group is manually operated, the opening and closing purposes are achieved by lifting a screw rod, a hand wheel needs to be rotated for 12-14 circles when a single valve is opened, the operation process is 30-60 seconds long, any one slurry pump is switched to be used, at least two valves on the valve group are operated, and the consumed time is about 3 minutes.

The ground valve group is located on the ground behind the right side of the drill floor and is far away from a driller room, when the valve needs to be switched, the driller needs to communicate with an operator (generally a secondary driller) of the valve group through telephone, signal and gesture actions, and special operation environments such as high field noise, poor light at night and the like easily cause communication errors, so that equipment is damaged, and construction time is delayed.

The drilling fluid valve group is positioned in a high-pressure area, so that sand setting at the well bottom is avoided, construction safety is ensured, pump stopping time needs to be reduced as much as possible, and operation under pressure is needed. If the auxiliary driller enters the high-pressure area switch valve in the pressure-holding state, the personal safety of the auxiliary driller is threatened by the puncture of the valve, and potential safety hazards exist. And the valve is opened under the pressure build-up state, so that the valve is difficult to open and has low opening speed, and the flashboard is easy to erode.

For preventing the lead screw of bad valve is pounded to the heavy object, the lead screw is equipped with the valve rod guard shield outward, and the valve rod guard shield also leads to the valve to open and the closed state is distinguished unclear when protecting the lead screw. If the valve is in a half-open state, the slurry flow is easily influenced, and even erosion is generated on the gate. If the gap between the screw rod and the valve rod protective cover is seriously rusted or enters dust, the screw rod is not easy to rotate.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a drilling fluid circulating system which can convey mud to a drilling tool through vertical pipes with different heights according to the condition of one opening or two openings and can reasonably switch mud pumps according to the drilling of a well depth so as to ensure normal discharge capacity and pumping pressure.

In order to solve the technical problems, the drilling fluid circulating system comprises a drill floor valve group and a ground valve group, wherein the drill floor valve group comprises a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth; the ground valve group comprises a valve six to a valve twelve, an outlet pipe of the first pump is connected with a right ground pipe sequentially through the valve six and the valve twelve, and an outlet of the right ground pipe is connected with the lower end of the low vertical pipe; an outlet pipe of the third pump is connected with a left pipe sequentially through a valve eight and a valve nine, and an outlet of the left pipe is connected with the lower end of the high vertical pipe; the outlet pipe of the second pump is connected with a seventh valve, the outlet of the seventh valve is respectively connected with a tenth valve and a eleventh valve through a tee joint, the other end of the tenth valve is connected with a bypass port of the nine-inlet four-way valve, and the other end of the eleventh valve is connected with a bypass port of the twelve-inlet four-way valve.

Compared with the prior art, the invention has the following beneficial effects: the drilling of one well from the zero well depth is the first drilling, which is called as first drilling for short; drilling after cementing the surface casing, which is called as second drilling for short; and (4) drilling after the technical casing cementing is finished, and three-opening is called for short. When the drilling tool is opened, the vibration of the drilling tool is large, in order to avoid the top driving device from being damaged, the top of the drilling tool is usually connected with the top of the low vertical pipe through a lower faucet gooseneck, the top of the low vertical pipe is about two meters lower than the top of the high vertical pipe, and at the moment, the valve I is opened, and the valve II is closed. And when the second valve is opened, the vibration of the drilling tool is smaller, the top of the drilling tool is connected with the top of the high stand pipe through a top drive gooseneck, and the second valve is opened and the first valve is closed. Drilling fluid from the right pipe can enter the high riser through valve three and valve five, and drilling fluid from the left pipe can enter the low riser through valve four and valve five. Valve six controls the output of pump one, valve seven controls the output of pump two, valve eight controls the output of pump three, valve nine controls the output of left pipe, and valve twelve controls the output of right pipe. Opening the valve ten and closing the valve eleven, and allowing the drilling fluid of the second pump to enter a left pipe; the valve eleven is opened and the valve eleven is closed, and the drilling fluid of the second pump can enter the right pipe; opening a valve ten and a valve eleven, closing a valve nine, and allowing the drilling fluid of the third pump to enter a right pipe; valve ten is opened, valve eleven is closed, valve twelve is closed, and drilling fluid from pump one can enter the left pipe.

As the improvement of the invention, another by-pass port of the valve twelve inlet four-way is connected with a valve thirteen, and the outlet of the valve thirteen is connected with a slurry-mixing water return pipeline; and the other bypass port of the four-way valve nine inlet is connected with a valve fourteen, and the outlet of the valve fourteen is connected with a reverse circulation pipeline. And opening a valve thirteen, enabling an outlet of the slurry pump to enter the ground tank through a slurry-distributing water-returning pipeline, and enabling a manifold to release pressure, prepare slurry and return water. When blowout occurs, after the blowout preventer at the wellhead is closed, the fourteen valves are opened, and mud enters the annular space of the casing through the reverse circulation pipeline and the main four-way at the wellhead to kill the well.

As a further improvement of the invention, the first valve to the fourteenth valve are special high-pressure valves for drilling, each of the first valve to the fourteenth valves comprises a valve body, a valve cover is arranged at the top of the valve body, a left-right through fluid channel is arranged in the valve body, a valve seat is arranged at the middle section of the fluid channel, a flashboard is inserted in the valve seat, the top of the flashboard is connected with a valve rod, the valve rod penetrates upwards from a central hole of the valve cover and is sealed with the valve cover, a cylinder body is arranged above the valve cover, a hydraulic cylinder base is arranged at the lower port of the cylinder body, a base internal thread section extending downwards is arranged on the lower end surface of the hydraulic cylinder base and is screwed on the periphery of a central boss of the valve cover, a cylinder cover is arranged at the top; one side of cylinder body is connected with the cylinder body connecting block, and the upper portion of cylinder body connecting block is equipped with the hydraulic fluid port on the connecting block that link up mutually with cylinder body epicoele hydraulic fluid port, and the outer port of hydraulic fluid port has connect soon to go up the hydraulic fluid port on the connecting block, and the lower part of cylinder body connecting block is equipped with the hydraulic fluid port under the connecting block that link up mutually with cylinder body cavity hydraulic fluid port, and the outer port of hydraulic fluid port has connect soon to have.

When the valve is opened hydraulically, high-pressure oil enters the lower cavity of the cylinder body through the lower cavity oil port connector, oil in the upper cavity of the cylinder body flows out through the upper cavity oil port connector, the piston drives the valve rod to move upwards, the lower end of the valve rod drives the flashboard to move upwards to open the fluid channel, and the valve rod nut leaves the nut sleeve and moves upwards along with the valve rod. When the valve is hydraulically closed, high-pressure oil enters an upper cavity of the cylinder body through an upper cavity oil port connector, oil in a lower cavity of the cylinder body flows out through a lower cavity oil port connector, the piston drives the valve rod to move downwards, the lower end of the valve rod drives the flashboard to move downwards to close the fluid passage, and the valve rod nut follows the valve rod to move downwards and falls on the nut sleeve. The hydraulic power opening and closing valve is adopted, so that the opening or closing action time is only 1 second, any one slurry pump is switched, or a slurry flow channel is replaced, and the operation can be finished within 3-5 seconds. The valve is not influenced by the operation under pressure in the construction link, can be quickly opened or closed to prevent the erosion of high-pressure fluid to the flashboard, and prolongs the service life of the valve. The hydraulic oil in the cylinder body can form the auto-lock, prevents to take place to lead to the valve to close unusually because of vibrations. The driller can realize remote control by switching the hydraulic oil circuit in the driller room, and does not need to enter a high-pressure area switch valve by an auxiliary driller, thereby avoiding potential safety hazards caused by high-pressure leaked slurry.

As a further improvement of the invention, the upper oil port of the connecting block is communicated with the inner port of the lower oil port of the connecting block through a connecting block throttling oil duct, and the middle section of the connecting block throttling oil duct is provided with a throttling valve core which can cut off or run through the throttling valve core. When the hydraulic operation is carried out, the throttle valve core cuts off the throttle oil duct of the connecting block. When the manual operation is performed, the throttle valve core is adjusted to enable the throttle oil duct of the connecting block to be communicated, at the moment, the upper cavity of the cylinder body is communicated with the lower cavity, the piston is in a floating state, and the interference of the hydraulic cavity on the manual operation is avoided.

As a further improvement of the invention, the throttle valve core comprises a throttle valve core sealing section positioned at the inner end and a throttle valve core thread section positioned at the outer end, wherein a plurality of throttle valve core radial holes which are communicated in a shape like a Chinese character 'mi' are arranged on the throttle valve core sealing section, the throttle valve core thread section is screwed in a throttle valve core nut, and the throttle valve core nut is screwed in a counter bore of the cylinder body connecting block. And when the radial hole of the throttle valve core and the throttle oil duct of the connecting block are positioned on the same cross section and the holes are aligned, the throttle oil duct of the connecting block is communicated, and the throttle valve core enters a manual operation state at the moment. When the radial hole of the throttle valve core and the throttle oil duct of the connecting block are not on the same cross section, the throttle oil duct of the connecting block is cut off, and then the hydraulic operation state is entered.

As a further improvement of the invention, a top dead center proximity switch for detecting the top dead center of the piston is screwed on the cylinder cover, and a bottom dead center proximity switch for detecting the bottom dead center of the piston is screwed on the base of the hydraulic cylinder. When the piston reaches the top dead center, the fluid channel is completely opened, the top dead center proximity switch sends a signal to the control system, and the valve is displayed to be in an open state on the operation panel; when the piston reaches bottom dead center, the fluid passage is completely closed and the bottom dead center proximity switch signals the control system that the valve is closed on the operating panel. The driller can conveniently and accurately master the state of the valve, and the control system can close the hydraulic oil channels of the upper cavity and the lower cavity of the cylinder body to realize self-locking.

As a further improvement of the invention, a valve rod thread section is arranged at the upper part of the valve rod, the valve rod thread section is screwed in the valve rod nut, the lower part of the valve rod nut is connected with a nut sleeve through an I-shaped key, the nut sleeve is rotatably fixed in a valve rod nut seat, and the lower end of the valve rod nut seat is screwed on a central boss of the cylinder cover. When the hydraulic operation is carried out, the I-shaped key is not placed in the key groove, and the valve rod nut and the nut sleeve are in a separated state. When the manual operation is carried out, the I-shaped key is embedded into the key groove, so that the valve rod nut is combined with the nut sleeve; the nut sleeve is rotationally limited in the valve rod nut seat by the nut sleeve lock nut and the bearing, the valve rod pulls the flashboard to lift by rotating the valve rod nut by a tool, at the moment, the connecting block throttling oil duct is cut off by the throttling valve core, and the piston is in a floating state.

As a further improvement of the invention, the lower circumference of the nut sleeve is provided with a nut sleeve convex ring, the periphery of the nut sleeve convex ring is in clearance fit with the inner hole wall of the valve rod nut seat, the upper part of the nut sleeve convex ring is supported on the inner step of the valve rod nut seat through a nut sleeve upper bearing, the lower part of the nut sleeve convex ring is supported on a nut sleeve lock nut through a nut sleeve lower bearing, and the external thread of the nut sleeve lock nut is screwed in the internal thread of the valve rod nut seat. The nut sleeve locking nut, the nut sleeve upper bearing, the nut sleeve lower bearing and the inner step of the valve rod nut seat realize the axial positioning of the nut sleeve convex ring, and the nut sleeve upper bearing and the nut sleeve lower bearing enable the nut sleeve to rotate more flexibly and enable the nut sleeve to be lighter and lighter during manual operation.

As a further improvement of the invention, the reverse circulation pipeline is connected to the left side of the main four-way of the wellhead, the right side of the main four-way of the wellhead is connected with a blowout manifold, and a blowout flat valve is arranged at an outlet of the blowout manifold; a semi-sealed large valve core flashboard, a semi-sealed small valve core flashboard, a semi-sealed blowout preventer, a fully-sealed single flashboard and an annular blowout preventer are sequentially arranged above the main four-way of the wellhead; the blowout plate valve is controlled by a blowout liquid rotary valve Y1, and an operating handle of the blowout liquid rotary valve is connected with a piston rod of a blowout cylinder T1; the annular blowout preventer is controlled by an annular hydraulic rotary valve Y2, and an operating handle of the annular hydraulic rotary valve is connected with a piston rod of an annular cylinder T2; the full-sealed single gate plate is controlled by a full-sealed hydraulic rotary valve Y4, an operating handle of the full-sealed hydraulic rotary valve is connected with a piston rod of a full-sealed cylinder T4, the half-sealed big valve core gate plate 21a is controlled by a half-sealed big valve core hydraulic rotary valve Y3, and an operating handle of the half-sealed big valve core hydraulic rotary valve Y3 is connected with a piston rod of a half-sealed big valve core cylinder T3; the semi-closed small valve element flashboard 21b is controlled by a semi-closed small valve element hydraulic rotary valve Y5, and an operating handle of the semi-closed small valve element hydraulic rotary valve Y5 is connected with a piston rod of a semi-closed small valve element cylinder T5; the air source pipe Z1 is connected with a P port of an air source control valve Q0, a port A of the air source control valve Q0 is connected with a compressed air main pipe Z2, and the compressed air main pipe Z2 is respectively connected with P ports of a first blow-off air control valve Q1, an annular air control valve Q2, a half-sealed big valve core air control valve Q3, a full-sealed air control valve Q4, a second blow-off air control valve Q5 and a half-sealed small valve core air control valve Q6; the A port of the first blowout shuttle valve Q1 is connected with the right inlet of the second blowout shuttle valve S5, the middle outlet of the second blowout shuttle valve S5 is connected with the left inlet of the first blowout shuttle valve S1, and the middle outlet of the first blowout shuttle valve S1 is connected with the upper cavity air port of the blowout cylinder T1; the port A of the first blowout pneumatic control valve Q1 is also connected with the left inlet of a first dual-pressure valve A1, the port A of the annular pneumatic control valve Q2 is connected with the right inlet of a first dual-pressure valve A1, the middle outlet of the first dual-pressure valve A1 is connected with the port P of a first quick release valve F1, the port A of the first quick release valve F1 is connected with the left inlet of an annular shuttle valve S2, and the middle outlet of the annular shuttle valve S2 is connected with the upper cavity air port of an annular air cylinder T2; the port A of the half-sealed big valve core pneumatic control valve Q3 is connected with the left inlet of a half-sealed big valve core shuttle valve S3, and the middle outlet of the half-sealed big valve core shuttle valve S3 is connected with the upper cavity air port of a half-sealed big valve core cylinder T3; the A port of the semi-sealed small valve core pneumatic control valve Q6 is connected with the left inlet of the semi-sealed small valve core shuttle valve S6, and the middle outlet of the semi-sealed small valve core shuttle valve S6 is connected with the upper cavity air port of the semi-sealed small valve core air cylinder T5.

When a drilling tool is used for soft well closing in a well, an air source control valve Q0 is opened firstly, compressed air in an air source pipe Z1 enters a compressed air main pipe Z2, then a first blowout pneumatic control valve Q1 and an annular pneumatic control valve Q2 are opened simultaneously, the compressed air enters an upper cavity of a blowout cylinder T1 through the first blowout pneumatic control valve Q1 and a first blowout shuttle valve S1, the blowout cylinder T1 drives a blowout rotary valve Y1 to switch stations, and a blowout flat valve V15 is opened; meanwhile, compressed air enters the left side of the first double-pressure valve A1, compressed air flowing out of the opening A of the annular pneumatic control valve Q2 enters the right side of the first double-pressure valve A1, the opening A of the first double-pressure valve A1 is communicated, the compressed air enters the opening A from the opening P of the first quick air release valve F1 and then enters the upper cavity of the annular air cylinder T2 through the annular shuttle valve S2, and the annular air cylinder T2 drives the annular hydraulic rotary valve Y2 to switch work positions so that the annular blowout preventer 23 is closed. After the control is finished, the air in the loop of the annular cylinder T2 can be exhausted from the P port to the O port of the quick air relief valve F1, and the return of the loop is ensured. When a wellhead is a large-diameter drilling tool, after the annular pneumatic control valve Q2 is opened, the half-sealed large valve core pneumatic control valve Q3 is opened after being delayed for 10-25 seconds, compressed air enters the upper cavity of the half-sealed large valve core air cylinder T3 through the half-sealed large valve core shuttle valve S3, the half-sealed large valve core air cylinder T3 drives the half-sealed large valve core hydraulic rotary valve Y3 to switch work positions, the half-sealed large valve core flashboard is closed later than the annular blowout preventer 23, the half-sealed small valve core flashboard is kept still, soft well closing is strictly realized, wellhead blowout preventers are protected, and well site safety is ensured. When a wellhead is a small-diameter drilling tool, after the annular pneumatic control valve Q2 is opened, the semi-sealed small valve core pneumatic control valve Q6 is opened after 10-25 seconds of delay, compressed air enters the upper cavity of the semi-sealed small valve core air cylinder T5 through the semi-sealed small valve core shuttle valve S6, the semi-sealed small valve core air cylinder T5 drives the semi-sealed small valve core hydraulic valve Y5 to switch work positions, the semi-sealed small valve core flashboard is closed later than the annular blowout preventer 23, and the semi-sealed large valve core flashboard is kept still. The driller can complete wellhead control without leaving an operation table of a driller room, the control time is short, and the control is easy to master before operation. And after the well mouth is closed, injecting a well killing fluid through a reverse circulation pipeline to perform reverse circulation well killing.

As a further improvement of the invention, the A port of the full-sealing pneumatic control valve Q4 is connected with the left inlet of the dual-pressure valve II A2, the A port of the blowout pneumatic control valve II Q5 is connected with the right inlet of the dual-pressure valve II A2 and the left inlet of the blowout shuttle valve II S5, the middle outlet of the dual-pressure valve II A2 is connected with the P port of the quick release valve II F2, the A port of the quick release valve II F2 is connected with the left inlet of the full-sealing shuttle valve S4, and the middle outlet of the full-sealing shuttle valve S4 is connected with the upper chamber air port of the full-sealing air cylinder T4.

This system ensures that when the annular blowout preventer 23 is closed, the blow-out plate valve V15 is in an open state; if the blowout plate valve V15 is not opened, the annular blowout preventer 23 cannot be opened, and misoperation is not easy to occur. When no drilling tool is used underground, if overflow occurs, the full-sealing pneumatic control valve Q4 can be opened, compressed air enters the upper cavity of the full-sealing air cylinder T4 from the left side of the full-sealing shuttle valve S4 to the port A, and the full-sealing air cylinder T4 drives the full-sealing hydraulic rotary valve Y4 to switch work positions, so that the full-sealing single gate plate 22 is closed. Or the blowout flat valve V15 can be opened first, and then the fully-closed single gate plate 22 is closed, so that the well can be closed softly.

The fully-sealed pneumatic control valve Q4, the first open-jet pneumatic control valve Q1 and the second open-jet pneumatic control valve Q5 are opened at the same time, compressed air enters an upper cavity of the open-jet air cylinder T1 through the first open-jet pneumatic control valve Q1, the second open-jet shuttle valve S5 and the first open-jet shuttle valve S1 in sequence, and the open-jet air cylinder T1 drives the open-jet liquid rotary valve Y1 to switch work positions, so that the open-jet flat valve V15 is opened. Meanwhile, compressed air enters the left side of the double-pressure valve II A2 through the full-sealing pneumatic control valve Q4, enters the right side of the double-pressure valve II A2 through the blowout pneumatic control valve II Q5, the double-pressure valve II A2 is opened, the port A of the double-pressure valve II A2 is conducted, the compressed air enters the port A from the port P of the quick air release valve II F2 and then enters the upper cavity of the full-sealing cylinder T4 through the full-sealing shuttle valve S4, and the full-sealing cylinder T4 drives the full-sealing hydraulic rotary valve Y4 to switch work positions, so that the full-sealing single gate plate 22 is closed. Thus, when the fully-sealed single gate plate 22 is closed, the blowout flat valve V15 is in an open state; if the blowout plate valve V15 is not opened, the fully enclosed single gate plate 22 cannot be opened. After the control is finished, compressed air in the loop of the full-closed air cylinder T4 can be exhausted from the P port to the O port of the second quick release valve F2, and the return of the loop is ensured.

Drawings

The invention will be described in further detail with reference to the following drawings and detailed description, which are provided for reference and illustration purposes only and are not intended to limit the invention.

FIG. 1 is a flow diagram of a drilling fluid circulation system of the present invention.

FIG. 2 is an enlarged view of the location of the drill floor valve block and surface valve block of FIG. 1.

Fig. 3 is a schematic diagram of the special high-pressure valve for drilling in the invention when the valve is opened hydraulically.

Fig. 4 is a schematic diagram of the special high-pressure valve for drilling in the invention when the valve is hydraulically closed.

Fig. 5 is a schematic diagram of the high-pressure valve special for drilling in the invention when being manually operated.

Fig. 6 is a state view showing the valve stem nut and the nut bushing of fig. 5 coupled by an i-key.

Fig. 7 is an enlarged view of the extension bar of fig. 5 with the extension bar removed.

Fig. 8 is an enlarged view of a wellhead in accordance with the present invention.

Fig. 9 is a schematic diagram of a first embodiment of a wellhead hydraulic control system of the present invention.

Fig. 10 is a schematic diagram of a second embodiment of a wellhead hydraulic control system of the present invention.

Fig. 11 is a schematic diagram of a third embodiment of a wellhead hydraulic control system of the present invention.

In the figure: 1. a valve body; 1a. a fluid channel; 2. a valve cover; 2a, filling; 2b, a packing gland; 3. a valve seat; 4. a shutter plate; 5. a valve stem; 5a, a lower tenon of the valve rod; 6. a valve stem nut; an I-shaped key; 6b, a nut sleeve; 6b1, sleeving a convex ring on the nut; 6c, sleeving a bearing on the nut sleeve; 6d, sleeving a lower bearing with a nut; 7. the nut sleeve is locked; 8. a valve stem nut seat; 9. a cylinder body; 9a, an upper cavity oil port of the cylinder body; 9b, a lower cavity oil port of the cylinder body; 9c, a piston; 10. a cylinder cover; 11. a hydraulic cylinder base; 12. a cylinder body connecting block; 12a, an oil feeding port of the connecting block; 12b, a connecting block lower oil port; 12c, an upper cavity oil port connector; 12d, a lower cavity oil port joint; 12e, connecting block throttling oil duct; 12f. throttling spool nut; 13. a throttle valve cartridge; 13a, throttling valve core radial holes; 14. a valve stem shroud; 15. a nut lug; 16. lengthening a rod; 17. a casing head; 18. lifting the short section; 19. a secondary four-way joint; 20. a wellhead main four-way; 21a, a semi-closed large valve core flashboard; a semi-closed small valve element flashboard; 22. a fully enclosed single gate plate; 23. an annular blowout preventer; 24. an anti-overflow pipe; jk1. top dead center proximity switch; jk2. bottom dead center proximity switch. G1. A pump outlet line; G2. a second pump outlet pipe; G3. a pump outlet pipe III; G4. a right ground pipe; G5. left ground management; G6. a lower riser; G7. a high riser; G8. a hose; G9. a slurry-mixing water return pipeline; G10. a reverse circulation pipeline; G11. blowing out a manifold; G12. a return pipe; v1, valve I; v2, valve II; v3., valve III; v4. valve four; v5. valve five; v6., valve six; v7. valve seven; v8. valve eight; v9. valve nine; v10, valve ten; v11, valve eleven; v12, valve twelve; v13. valve thirteen; v14. valve fourteen; discharging the flat plate valve; ZJ. drilling tool. Z1. a gas source tube; z2. compressed air manifold; q0. air supply control valves; q1. air-release control valve I; q2, an annular pneumatic control valve; q3. semi-sealed big valve core air control valve; q4, fully sealing the pneumatic control valve; q5. air-release control valve II; q6, a semi-sealed small valve core pneumatic control valve; A1. a first double-pressure valve; A2. a second double-pressure valve; F1. a first quick air release valve; F2. a second quick air release valve; s1, a blowout shuttle valve I; s2, an annular shuttle valve; s3, semi-sealing a shuttle valve with a large valve core; s4, fully sealing the shuttle valve; s5, a blowout shuttle valve II; s6, semi-sealing a small valve core shuttle valve; t1, open-flow cylinder; t1a, opening a blowout cylinder to a proper position to form a normally open contact; t1b, closing the blowout cylinder to the right and normally opening a contact; t2, an annular cylinder; t2a, closing the annular cylinder to a proper position and normally opening a contact; t2b, opening the annular cylinder to the right and normally opening the contact; t3, a half-sealed large valve core cylinder; t3a, closing a half-sealed large valve core cylinder to a proper position to form a normally open contact; a half-sealed large valve core cylinder is opened to an in-place normally open contact; t4, fully sealing the cylinder; TG11. closing the full-sealed cylinder to the normal open contact; TG10. opening the full-sealed cylinder to the right place normally open contact; t5, semi-sealing a small valve core cylinder; t5a, closing a semi-closed small valve core cylinder to a proper position by using a normally open contact; t5b, opening a semi-sealed small valve core cylinder to a proper position to form a normally open contact; y1. discharging the liquid rotary valve; y2. annular liquid rotary valve; y3. semi-sealed big valve core hydraulic rotary valve; y4. full-sealing liquid rotary valve; y5. A semi-closed small valve core hydraulic rotary valve.

Detailed Description

As shown in fig. 1 and 2, the drilling fluid circulation system of the present invention includes a drill floor valve group and a ground valve group, the drill floor valve group includes a first valve V1 to a fifth valve V5, the first valve V1 and a third valve V3 are connected in series in a low riser G6 with a first valve V1 above, the second valve V2 and a fourth valve V4 are connected in series in a high riser G7 with a second valve V2 above, a low riser bypass port is provided between the first valve V1 and the third valve V3, a high riser bypass port is provided between the second valve V2 and the fourth valve V4, and the low riser bypass port is connected to the high riser bypass port through the fifth valve V5; the ground valve group comprises valves six V6 to twelve V12, a first pump outlet pipe G1 is connected with a right pipe G4 through a valve six V6 and a valve twelve V12 in sequence, and the outlet of the right pipe G4 is connected with the lower end of a low vertical pipe G6; the third pump outlet pipe G3 is connected with a left pipe G5 through a valve eight V8 and a valve nine V9 in sequence, and the outlet of the left pipe G5 is connected with the lower end of a high riser G7; the outlet pipe G2 of the second pump is connected with a valve seven V7, the outlet of the valve seven V7 is respectively connected with a valve ten V10 and a valve eleven V11 through a tee joint, the other end of the valve ten V10 is connected with a bypass port of a valve nine-inlet four-way joint, and the other end of the valve eleven V11 is connected with a bypass port of a valve twelve V12 inlet four-way joint.

The drilling of one well from the zero well depth is the first drilling, which is called as first drilling for short; drilling after cementing the surface casing, which is called as second drilling for short; and (4) drilling after the technical casing cementing is finished, and three-opening is called for short. When the drill ZJ is opened, the vibration of the drill ZJ is larger, and in order to avoid the top drive from being damaged, the top of the drill ZJ is usually connected with a water hose G8 through a lower-position water faucet gooseneck, the water hose G8 is connected with the top of a low riser G6, the top of the low riser G6 is about two meters lower than the top of the high riser G7, and at the moment, a valve I V1 is opened, and a valve II V2 is closed. Second, the drill ZJ has less vibration, and the top of the drill ZJ is connected to the top of the high riser G7 through the top drive gooseneck and hose, at which time valve II V2 is opened and valve II V1 is closed.

Drilling fluid from right leg G4 may enter high riser G7 through valve three V3 and valve five V5, and drilling fluid from left leg G5 may enter low riser G6 through valve four V4 and valve five V5. Valve six V6 controls the output of pump one, valve seven V7 controls the output of pump two, valve eight V8 controls the output of pump three, valve nine V9 controls the output of left pipe G5, and valve twelve V12 controls the output of right pipe G4.

Opening valve ten V10 and closing valve eleven V11, drilling fluid from pump two can enter left pipe G5; opening valve eleven V11 and closing valve ten V10, drilling fluid from pump two can enter right pipe G4; the valves ten V10 and eleven V11 are opened, the valve nine V9 is closed, and the drilling fluid of the third pump can enter the right pipe G4; valve ten V10, valve eleven V11, and valve twelve V12 are closed and drilling fluid from pump one can enter left pipe G5.

The other bypass port of the twelve-inlet four-way valve is connected with a valve thirteen V13, and the outlet of the valve thirteen V13 is connected with a slurry-blending water return pipeline G9. The valve is opened to thirteen V13, the outlet of the slurry pump enters the ground tank through a slurry preparation water return pipeline G9, and the manifold can be decompressed, prepared with slurry and returned with water.

The other bypass port of the nine-inlet four-way valve is connected with a valve fourteen V14, and the outlet of the valve fourteen V14 is connected with a reverse circulation pipeline G10. When blowout occurs, after the blowout preventer at the wellhead is closed, the fourteen V14 valves are opened, and mud enters the annular space of the casing through the reverse circulation pipeline G10 and the main four-way at the wellhead to kill the well.

As shown in fig. 3, each of the first valve V1 to the fourteenth valve V14 is a high-pressure valve special for drilling, the high-pressure valve special for drilling comprises a valve body 1, a valve cover 2 is arranged at the top of the valve body 1, a left-right through fluid channel 1a is arranged in the valve body 1, a valve seat 3 is arranged at the middle section of the fluid channel 1a, a gate plate 4 is inserted in the valve seat 3, a valve rod 5 is connected to the top of the gate plate 4, the valve rod 5 penetrates upwards from a central hole of the valve cover and is sealed with the valve cover 2, a cylinder body 9 is arranged above the valve cover 2, a hydraulic cylinder base 11 is arranged at a lower port of the cylinder body 9, a base internal thread section extending downwards is arranged at the lower end surface of the hydraulic cylinder base 11, the base internal thread section is screwed on the periphery of a central boss of the valve cover 2, a cylinder cover 10 is arranged; one side of the cylinder 9 is connected with a cylinder connecting block 12, the upper part of the cylinder connecting block 12 is provided with a connecting block upper oil port 12a communicated with the cylinder upper oil port 9a, the outer end port of the connecting block upper oil port 12a is screwed with an upper oil port connector 12c, the lower part of the cylinder connecting block 12 is provided with a connecting block lower oil port 12b communicated with the cylinder lower oil port 9b, and the outer end port of the connecting block lower oil port 12b is screwed with a lower oil port connector 12d.

When the valve is opened hydraulically, high-pressure oil enters the lower cavity of the cylinder body 9 through the lower cavity oil port connector 12d, the oil in the upper cavity of the cylinder body flows out through the upper cavity oil port connector 12c, the piston 9c drives the valve rod 5 to move upwards, the lower end of the valve rod 5 drives the gate plate 4 to move upwards to open the fluid channel 1a, and the valve rod nut 6 leaves the nut sleeve 6b and moves upwards along with the valve rod 5.

As shown in fig. 4, when the valve is closed hydraulically, high-pressure oil enters the upper chamber of the cylinder 9 through the upper chamber oil port connector 12c, oil in the lower chamber of the cylinder flows out through the lower chamber oil port connector 12d, the piston 9c drives the valve rod 5 to move downwards, the lower end of the valve rod 5 drives the gate plate 4 to move downwards to close the fluid passage 1a, and the valve rod nut 6 follows the valve rod 5 to move downwards and falls on the nut sleeve 6b. The hydraulic power opening and closing valve is adopted, so that the opening or closing action time is only 1 second, any one slurry pump is switched, or a slurry flow channel is replaced, and the operation can be finished within 3-5 seconds.

The upper oil port 12a of the connecting block is communicated with the inner port of the lower oil port 12b of the connecting block through a connecting block throttling oil duct 12e, and a throttling valve core 13 capable of cutting off or penetrating the connecting block throttling oil duct 12e is arranged in the middle section of the connecting block throttling oil duct 12e. When hydraulically operated, the throttle valve core 13 cuts off the connector block throttle passage 12e. During manual operation, the throttle valve core 13 is adjusted to enable the connecting block throttle oil duct 12e to be communicated, at the moment, the upper cavity and the lower cavity of the cylinder body 9 are communicated, the piston 9c is in a floating state, and interference of a hydraulic cavity on manual operation is avoided.

The throttle valve core 13 comprises a throttle valve core sealing section positioned at the inner end and a throttle valve core thread section positioned at the outer end, the throttle valve core sealing section is provided with a plurality of throttle valve core radial holes 13a which are communicated in a meter shape, the throttle valve core thread section is screwed in a throttle valve core nut 12f, and the throttle valve core nut 12f is screwed in a counter bore of the cylinder body connecting block 12. And (3) rotating the throttle valve core 13 to enable the sealing section of the throttle valve core to generate axial displacement relative to the connecting block throttling oil duct 12e, and when the radial hole 13a of the throttle valve core and the connecting block throttling oil duct 12e are positioned on the same cross section and the holes are aligned, conducting the connecting block throttling oil duct 12e, and then entering a manual operation state. When the throttle valve core radial hole 13a and the connecting block throttling oil channel 12e are not on the same cross section, the connecting block throttling oil channel 12e is cut off, and at the moment, the hydraulic operation state is entered.

A top dead center proximity switch JK1 for detecting the top dead center of the piston is screwed on the cylinder cover 10, and a bottom dead center proximity switch JK2 for detecting the bottom dead center of the piston is screwed on the hydraulic cylinder base 11. When the piston 9c reaches the top dead center, the fluid passage 1a is fully opened, and the top dead center proximity switch JK1 signals the control system that the valve is in the open state on the operation panel; when the piston 9c reaches the bottom dead center, the fluid passage 1a is completely closed, and the bottom dead center proximity switch JK2 signals the control system that the valve is in the closed state on the operation panel. The driller can conveniently and accurately master the state of the valve, and the control system can close the hydraulic oil channels of the upper cavity and the lower cavity of the cylinder body to realize self-locking.

As shown in fig. 5 to 7, a stem thread section is provided on the upper portion of the stem 5, the stem thread section is screwed into the stem nut 6, the lower portion of the stem nut 6 is connected to a nut sleeve 6b by an i-key 6a, the nut sleeve 6b is rotatably fixed in the stem nut seat 8, and the lower end of the stem nut seat 8 is screwed onto a central boss of the cylinder head 10. During hydraulic operation, the I-shaped key 6a is not placed in the key groove, and the valve rod nut 6 and the nut sleeve 6b are in a separated state. When the manual operation is carried out, the I-shaped key 6a is embedded into the key groove, so that the valve rod nut 6 is combined with the nut sleeve 6 b; since the nut sleeve 6b is rotatably limited in the valve rod nut seat 8 by the nut sleeve lock nut 7 and the bearing, the valve rod 5 pulls the gate plate 4 to ascend and descend by rotating the valve rod nut 6 by a tool, at the moment, the connecting block throttling oil passage 12e is cut off by the throttling valve core 13, and the piston 9c is in a floating state.

The circumference of the lower part of the nut sleeve 6b is provided with a nut sleeve convex ring 6b1, the periphery of the nut sleeve convex ring 6b1 is in clearance fit with the inner hole wall of the valve rod nut seat 8, the upper part of the nut sleeve convex ring 6b1 is supported on the inner step of the valve rod nut seat 8 through a nut sleeve upper bearing 6c, the lower part of the nut sleeve convex ring 6b1 is supported on the nut sleeve lock nut 7 through a nut sleeve lower bearing 6d, and the external thread of the nut sleeve lock nut 7 is screwed in the internal thread of the valve rod nut seat 8. The nut sleeve locking nut 7, the nut sleeve upper bearing 6c, the nut sleeve lower bearing 6d and the inner steps of the valve rod nut seat 8 realize the axial positioning of the nut sleeve convex ring 6b1, and the nut sleeve upper bearing 6c and the nut sleeve lower bearing 6d enable the nut sleeve 6b to rotate more flexibly and enable the manual operation to be more portable.

The valve rod nut seat 8 and the periphery of the upper end of the valve rod 5 are covered with a valve rod protective cover 14, and the lower end of the valve rod protective cover 14 is screwed on the periphery of the lower end of the valve rod nut seat 8. The valve stem guard 14 prevents the valve stem 5 from being contaminated with dust or being damaged by heavy objects.

The upper portion of valve gap centre bore is equipped with the packing box, and the bottom of packing box is equipped with the packing 2a of sealing in valve rod 5 periphery, and the last port of packing box has connect gland 2b soon, and the lower terminal surface of hydraulic cylinder base 11 is pressed in gland 2b top. The packing gland 2b compresses the packing 2a in the packing box to realize reliable sealing between the valve rod 5 and the valve cover central hole, and the hydraulic cylinder base 11 is pressed on the packing gland 2b to prevent the loosening caused by vibration.

The upper part of the valve rod nut 6 is provided with a square tenon or is symmetrically provided with nut lugs 15 which extend outwards along the radial direction. After the valve rod protective cover 14 is removed, the valve rod nut 6 can be clamped on the square tenon through a spanner or a hand wheel to rotate; an extension bar 16 can also be sleeved on the nut ear rod 15 so as to rotate the valve rod nut 6 more easily to realize the opening and closing of the valve.

The lower end of the valve rod 5 is provided with a valve rod lower tenon 5a with an I-shaped cross section, and the upper end of the flashboard 4 is embedded in a groove of the valve rod lower tenon 5a. The cooperation of tenon 5a and flashboard 4 under the valve rod that is I shape cross-section makes and realizes axial positioning between valve rod 5 and the flashboard 4, and if valve rod 5 produced when rotating, flashboard 4 can not bear torsion, makes the lift of flashboard more nimble and the life of extension valve.

As shown in fig. 1 and 8, the wellhead device comprises a semi-closed blowout preventer, a fully-closed single ram 22 and an annular blowout preventer 23 which are arranged above a wellhead main four-way 20 from bottom to top, the top of the annular blowout preventer 23 is connected with an overflow preventing pipe 24 which extends upwards, and the upper end of the overflow preventing pipe 24 is connected with a return pipe G12. The right side of the wellhead main four-way 20 is connected with a blowout manifold G11, the outlet of the blowout manifold G11 is connected with a throttle manifold, and the inlet of the throttle manifold is provided with a blowout flat valve V15; the left side of the wellhead main four-way joint 20 is connected with a reverse circulation pipeline G10. An auxiliary four-way joint 19 below the wellhead main four-way joint 20 is positioned below the ground, and a lifting short joint 18 below the auxiliary four-way joint 19 is connected to the casing head 17. The drilling tool ZJ extends downhole along the axis of each blowout preventer and wellhead main spool 20.

As shown in fig. 9, the blowout plate valve V15 is controlled by a blowout liquid rotary valve Y1, and an operating handle of the blowout liquid rotary valve is connected with a piston rod of a blowout cylinder T1; the annular blowout preventer 23 is controlled by an annular hydraulic rotary valve Y2, and an operating handle of the annular hydraulic rotary valve is connected with a piston rod of an annular cylinder T2; the semi-closed blowout preventer is a double-ram blowout preventer consisting of a semi-closed large valve core ram 21a and a semi-closed small valve core ram 21b, the semi-closed large valve core ram 21a is controlled by a semi-closed large valve core hydraulic transfer valve Y3, and an operating handle of a semi-closed large valve core hydraulic transfer valve Y3 is connected with a piston rod of a semi-closed large valve core cylinder T3; the semi-closed small valve element flashboard 21b is controlled by a semi-closed small valve element hydraulic rotating valve Y5, and an operating handle of the semi-closed small valve element hydraulic rotating valve Y5 is connected with a piston rod of a semi-closed small valve element air cylinder T5. The full-sealing single gate plate 22 is controlled by a full-sealing hydraulic rotary valve Y4, and an operating handle of the full-sealing hydraulic rotary valve is connected with a piston rod of a full-sealing air cylinder T4.

The air source pipe Z1 is connected with a P port of an air source control valve Q0, a port A of the air source control valve Q0 is connected with a compressed air main pipe Z2, and the compressed air main pipe Z2 is respectively connected with P ports of a blow-off air control valve I Q1, an annular air control valve Q2, a semi-sealed big valve core air control valve Q3 and a semi-sealed small valve core air control valve Q6; the A port of the first blowout shuttle valve Q1 is connected with the left inlet of the first blowout shuttle valve S1, and the middle outlet of the first blowout shuttle valve S1 is connected with the upper cavity air port of the blowout cylinder T1; the A port of the annular pneumatic control valve Q2 is connected with the P port of the first quick release valve F1, the A port of the first quick release valve F1 is connected with the left inlet of the annular shuttle valve S2, and the middle outlet of the annular shuttle valve S2 is connected with the upper cavity air port of the annular air cylinder T2; the port A of the half-sealed big valve core pneumatic control valve Q3 is connected with the left inlet of a half-sealed big valve core shuttle valve S3, and the middle outlet of the half-sealed big valve core shuttle valve S3 is connected with the upper cavity air port of a half-sealed big valve core cylinder T3; the A port of the semi-sealed small valve core pneumatic control valve Q6 is connected with the left inlet of the semi-sealed small valve core shuttle valve S6, and the middle outlet of the semi-sealed small valve core shuttle valve S6 is connected with the upper cavity air port of the semi-sealed small valve core air cylinder T5.

When a drilling tool is used for soft well closing in a well, an air source control valve Q0 is opened firstly, compressed air in an air source pipe Z1 enters a compressed air main pipe Z2, then a first blowout pneumatic control valve Q1 and an annular pneumatic control valve Q2 are opened simultaneously, the compressed air enters an upper cavity of a blowout cylinder T1 through the first blowout pneumatic control valve Q1 and a first blowout shuttle valve S1, the blowout cylinder T1 drives a blowout rotary valve Y1 to switch stations, and a blowout flat valve V15 is opened; meanwhile, compressed air enters the left side of the first double-pressure valve A1, compressed air flowing out of the opening A of the annular pneumatic control valve Q2 enters the right side of the first double-pressure valve A1, the opening A of the first double-pressure valve A1 is communicated, the compressed air enters the opening A from the opening P of the first quick air release valve F1 and then enters the upper cavity of the annular air cylinder T2 through the annular shuttle valve S2, and the annular air cylinder T2 drives the annular hydraulic rotary valve Y2 to switch work positions so that the annular blowout preventer 23 is closed. After the control is finished, the air in the loop of the annular cylinder T2 can be exhausted from the P port to the O port of the quick air relief valve F1, and the return of the loop is ensured.

When a wellhead is a large-diameter drilling tool, after the annular pneumatic control valve Q2 is opened, the half-sealed large valve core pneumatic control valve Q3 is opened after being delayed for 10-25 seconds, compressed air enters the upper cavity of the half-sealed large valve core air cylinder T3 through the half-sealed large valve core shuttle valve S3, the half-sealed large valve core air cylinder T3 drives the half-sealed large valve core hydraulic rotary valve Y3 to switch work positions, the half-sealed large valve core flashboard 21a is closed later than the annular blowout preventer 23, the half-sealed small valve core flashboard 21b is kept still, soft well closing is strictly achieved, wellhead blowout preventers are protected, and well site safety is guaranteed.

When the wellhead is a small-diameter drilling tool, after the annular pneumatic control valve Q2 is opened, the semi-sealed small valve core pneumatic control valve Q6 is opened after delaying for 10-25 seconds, compressed air enters the upper cavity of the semi-sealed small valve core air cylinder T5 through the semi-sealed small valve core shuttle valve S6, the semi-sealed small valve core air cylinder T5 drives the semi-sealed small valve core hydraulic valve Y5 to switch work positions, the semi-sealed small valve core flashboard 21b is closed later than the annular blowout preventer 23, and the semi-sealed large valve core flashboard 21a is kept still. The driller can complete wellhead control without leaving an operation table of a driller room, the control time is short, and the control is easy to master before operation. After the well head is closed, the well killing fluid is injected through a reverse circulation pipeline G10 to perform reverse circulation well killing.

As shown in fig. 10, the port a of the first bleed air control valve Q1 is connected with the left inlet of the first dual-pressure valve a1, the port a of the annular air control valve Q2 is connected with the right inlet of the first dual-pressure valve a1, and the middle outlet of the first dual-pressure valve a1 is connected with the port P of the first quick release valve F1. This system ensures that when the annular blowout preventer 23 is closed, the blow-out plate valve V15 is in an open state; if the blowout plate valve V15 is not opened, the annular blowout preventer 23 cannot be opened, and misoperation is not easy to occur.

The compressed air manifold Z2 is also connected with the P port of a full-seal pneumatic control valve Q4, the A port of a full-seal pneumatic control valve Q4 is connected with the left inlet of a full-seal shuttle valve S4, and the middle outlet of the full-seal shuttle valve S4 is connected with the upper cavity air port of a full-seal air cylinder T4. When no drilling tool is used underground, if overflow occurs, the full-sealing pneumatic control valve Q4 can be opened, compressed air enters the upper cavity of the full-sealing air cylinder T4 from the left side of the full-sealing shuttle valve S4 to the port A, and the full-sealing air cylinder T4 drives the full-sealing hydraulic rotary valve Y4 to switch work positions, so that the full-sealing single gate plate 22 is closed. Or the blowout flat valve V15 can be opened first, and then the fully-closed single gate plate 22 is closed, so that the well can be closed softly.

As shown in fig. 11, the compressed air manifold Z2 is further connected with a P port of a second bleed air control valve Q5, an a port of a second bleed air control valve Q5 is connected with a right inlet of a second dual-pressure valve a2, a left inlet of the second dual-pressure valve a2 is connected with an a port of a fully-closed pneumatic control valve Q4, an intermediate outlet of the second dual-pressure valve a2 is connected with a P port of a second quick-release valve F2, and an a port of the second quick-release valve F2 is connected with a left inlet of a fully-closed shuttle valve S4.

The fully-sealed pneumatic control valve Q4, the first open-jet pneumatic control valve Q1 and the second open-jet pneumatic control valve Q5 are opened at the same time, compressed air enters an upper cavity of the open-jet air cylinder T1 through the first open-jet pneumatic control valve Q1, the second open-jet shuttle valve S5 and the first open-jet shuttle valve S1 in sequence, and the open-jet air cylinder T1 drives the open-jet liquid rotary valve Y1 to switch work positions, so that the open-jet flat valve V15 is opened. Meanwhile, compressed air enters the left side of the double-pressure valve II A2 through the full-sealing pneumatic control valve Q4, enters the right side of the double-pressure valve II A2 through the blowout pneumatic control valve II Q5, the double-pressure valve II A2 is opened, the port A of the double-pressure valve II A2 is conducted, the compressed air enters the port A from the port P of the quick air release valve II F2 and then enters the upper cavity of the full-sealing cylinder T4 through the full-sealing shuttle valve S4, and the full-sealing cylinder T4 drives the full-sealing hydraulic rotary valve Y4 to switch work positions, so that the full-sealing single gate plate 22 is closed. Thus, when the fully-sealed single gate plate 22 is closed, the blowout flat valve V15 is in an open state; if the blowout plate valve V15 is not opened, the fully enclosed single gate plate 22 cannot be opened. After the control is finished, compressed air in the loop of the full-closed air cylinder T4 can be exhausted from the P port to the O port of the second quick release valve F2, and the return of the loop is ensured.

The liquid discharging rotary valve Y1, the annular liquid rotary valve Y2, the semi-sealed big valve core liquid rotary valve Y3, the full-sealed liquid rotary valve Y4 and the semi-sealed small valve core liquid rotary valve Y5 are all three-position four-way liquid rotary valves, and the air source control valve Q0, the air discharging pneumatic control valve I Q1, the semi-sealed big valve core pneumatic control valve Q3, the full-sealed pneumatic control valve Q4, the air discharging pneumatic control valve II Q5 and the semi-sealed small valve core pneumatic control valve Q6 are all two-position three-way valves.

Claims (10)

1. The utility model provides a drilling fluid circulation system, includes drill floor valve group and ground valve group, its characterized in that: the drill floor valve group comprises a first valve, a second valve, a third valve, a fourth valve; the ground valve group comprises a valve six to a valve twelve, an outlet pipe of the first pump is connected with a right ground pipe sequentially through the valve six and the valve twelve, and an outlet of the right ground pipe is connected with the lower end of the low vertical pipe; an outlet pipe of the third pump is connected with a left pipe sequentially through a valve eight and a valve nine, and an outlet of the left pipe is connected with the lower end of the high vertical pipe; the outlet pipe of the second pump is connected with a seventh valve, the outlet of the seventh valve is respectively connected with a tenth valve and a eleventh valve through a tee joint, the other end of the tenth valve is connected with a bypass port of the nine-inlet four-way valve, and the other end of the eleventh valve is connected with a bypass port of the twelve-inlet four-way valve.

2. The drilling fluid circulation system of claim 1, wherein: the other bypass port of the valve twelve inlet four-way is connected with a valve thirteen, and the outlet of the valve thirteen is connected with a slurry preparation water return pipeline; and the other bypass port of the four-way valve nine inlet is connected with a valve fourteen, and the outlet of the valve fourteen is connected with a reverse circulation pipeline.

3. The drilling fluid circulation system of claim 2, wherein: the first valve, the second valve, the fourth valve and the sixth valve are special high-pressure valves for drilling, each special high-pressure valve for drilling comprises a valve body, a valve cover is arranged at the top of the valve body, a fluid passage which is communicated from left to right is arranged in the valve body, a valve seat is arranged in the middle section of the fluid passage, a flashboard is inserted in the valve seat, a valve rod is connected to the top of the flashboard, the valve rod penetrates out of a central hole of the valve cover upwards and is sealed with the valve cover, a cylinder body is arranged above the valve cover, a hydraulic cylinder base is arranged at a lower port of the cylinder body, a base internal thread section which extends downwards is arranged on the lower end face of the hydraulic cylinder base, the base internal thread section is screwed on the periphery; one side of cylinder body is connected with the cylinder body connecting block, and the upper portion of cylinder body connecting block is equipped with the hydraulic fluid port on the connecting block that link up mutually with cylinder body epicoele hydraulic fluid port, and the outer port of hydraulic fluid port has connect soon to go up the hydraulic fluid port on the connecting block, and the lower part of cylinder body connecting block is equipped with the hydraulic fluid port under the connecting block that link up mutually with cylinder body cavity hydraulic fluid port, and the outer port of hydraulic fluid port has connect soon to have.

4. The drilling fluid circulation system of claim 3, wherein: the oil port on the connecting block is communicated with the inner port of the oil port under the connecting block through a connecting block throttling oil duct, and the middle section of the connecting block throttling oil duct is provided with a throttling valve core which can cut off or run through the connecting block throttling oil duct.

5. The drilling fluid circulation system of claim 4, wherein: the throttling valve core comprises a throttling valve core sealing section positioned at the inner end and a throttling valve core thread section positioned at the outer end, the throttling valve core sealing section is provided with a plurality of throttling valve core radial holes which are communicated in a meter shape, the throttling valve core thread section is screwed in a throttling valve core nut, and the throttling valve core nut is screwed in a counter bore of the cylinder body connecting block.

6. The drilling fluid circulation system of claim 3, wherein: the cylinder cover is rotatably connected with an upper dead center proximity switch for detecting the upper dead center of the piston, and the hydraulic cylinder base is rotatably connected with a lower dead center proximity switch for detecting the lower dead center of the piston.

7. The drilling fluid circulation system of claim 3, wherein: the upper portion of the valve rod is provided with a valve rod thread section, the valve rod thread section is screwed in a valve rod nut, the lower portion of the valve rod nut is connected with a nut sleeve through an I-shaped key, the nut sleeve is rotatably fixed in a valve rod nut seat, and the lower end of the valve rod nut seat is screwed on a central boss of the cylinder cover.

8. The drilling fluid circulation system of claim 7, wherein: the valve rod nut is characterized in that a nut sleeve convex ring is arranged on the circumference of the lower portion of the nut sleeve, the periphery of the nut sleeve convex ring is in clearance fit with the inner hole wall of the valve rod nut seat, the upper portion of the nut sleeve convex ring is supported on an inner step of the valve rod nut seat through a nut sleeve upper bearing, the lower portion of the nut sleeve convex ring is supported on a nut sleeve lock nut through a nut sleeve lower bearing, and the external thread of the nut sleeve lock nut is screwed in the internal thread of the valve rod nut seat.

9. The drilling fluid circulation system of any one of claims 2 to 8, wherein: the reverse circulation pipeline is connected to the left side of the main four-way of the wellhead, the right side of the main four-way of the wellhead is connected with a blowout manifold, and a blowout flat valve is arranged at an outlet of the blowout manifold; a semi-sealed large valve core flashboard, a semi-sealed small valve core flashboard, a semi-sealed blowout preventer, a fully-sealed single flashboard and an annular blowout preventer are sequentially arranged above the main four-way of the wellhead; the blowout plate valve is controlled by a blowout liquid rotary valve (Y1), and an operating handle of the blowout liquid rotary valve is connected with a piston rod of a blowout cylinder (T1); the annular blowout preventer is controlled by an annular hydraulic rotary valve (Y2), and an operating handle of the annular hydraulic rotary valve is connected with a piston rod of an annular cylinder (T2); the full-sealed single gate plate is controlled by a full-sealed hydraulic rotary valve (Y4), an operating handle of the full-sealed hydraulic rotary valve is connected with a piston rod of a full-sealed cylinder (T4), the half-sealed big valve core gate plate (21a) is controlled by a half-sealed big valve core hydraulic rotary valve (Y3), and an operating handle of the half-sealed big valve core hydraulic rotary valve (Y3) is connected with a piston rod of a half-sealed big valve core cylinder (T3); the semi-closed small valve element flashboard (21b) is controlled by a semi-closed small valve element hydraulic rotary valve (Y5), and an operating handle of the semi-closed small valve element hydraulic rotary valve (Y5) is connected with a piston rod of a semi-closed small valve element cylinder (T5); the air source pipe (Z1) is connected with a P port of an air source control valve (Q0), an A port of the air source control valve (Q0) is connected with a compressed air main pipe (Z2), and the compressed air main pipe (Z2) is respectively connected with P ports of a first blow-off air control valve (Q1), an annular air control valve (Q2), a semi-sealed big valve core air control valve (Q3), a fully-sealed air control valve (Q4), a second blow-off air control valve (Q5) and a semi-sealed small valve core air control valve (Q6); an A port of the first blowout shuttle valve (Q1) is connected with a right inlet of a second blowout shuttle valve (S5), a middle outlet of the second blowout shuttle valve (S5) is connected with a left inlet of the first blowout shuttle valve (S1), and a middle outlet of the first blowout shuttle valve (S1) is connected with an upper cavity air port of a blowout cylinder (T1); the port A of the first blowout pneumatic control valve (Q1) is also connected with the left inlet of a first double-pressure valve (A1), the port A of the annular pneumatic control valve (Q2) is connected with the right inlet of the first double-pressure valve (A1), the middle outlet of the first double-pressure valve (A1) is connected with the port P of a first quick release valve (F1), the port A of the first quick release valve (F1) is connected with the left inlet of an annular shuttle valve (S2), and the middle outlet of the annular shuttle valve (S2) is connected with the upper cavity air port of an annular air cylinder (T2); the A port of the half-sealed big valve core pneumatic control valve (Q3) is connected with the left inlet of the half-sealed big valve core shuttle valve (S3), and the middle outlet of the half-sealed big valve core shuttle valve (S3) is connected with the upper cavity air port of the half-sealed big valve core cylinder (T3); the A port of the semi-sealed small valve core pneumatic control valve (Q6) is connected with the left inlet of the semi-sealed small valve core shuttle valve (S6), and the middle outlet of the semi-sealed small valve core shuttle valve (S6) is connected with the upper cavity air port of the semi-sealed small valve core air cylinder (T5).

10. The drilling fluid circulation system of claim 9, wherein: an A port of the full-sealing pneumatic control valve (Q4) is connected with a left inlet of a double-pressure valve II (A2), an A port of a blowout pneumatic control valve II (Q5) is connected with a right inlet of the double-pressure valve II (A2) and a left inlet of a blowout shuttle valve II (S5), a middle outlet of the double-pressure valve II (A2) is connected with a P port of a quick deflation valve II (F2), an A port of the quick deflation valve II (F2) is connected with a left inlet of the full-sealing shuttle valve (S4), and a middle outlet of the full-sealing shuttle valve (S4) is connected with an upper cavity air port of a full-sealing air cylinder (T4).

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