CN104563947A - An oil well downhole blowout prevention pipe string - Google Patents

Abstract

The invention relates to the field of oil well construction, in particular to a tubular column for preventing blowout of a shaft of an oil well in the process of tripping the oil well. The rotary plate switch of the underground blowout prevention pipe column of the oil well is connected to the lower end of a suspension type packer, the lower end of the production pipe column is lowered to a preset position for setting, then a single-flow sealing insertion pipe is connected to the lower end of the production pipe column and lowered into the underground, the single-flow sealing insertion pipe is inserted into the rotary plate switch, the rotary plate switch is jacked open, and the oil well normally produces; when the underground operation is carried out, the production pipe column is lifted out, the uniflow sealing insertion pipe is lifted, the rotary plate switch is closed, the blowout prevention effect of the oil well shaft is realized, the shaft on the upper portion of the suspension packer is separated from the oil-gas layer, and the well blowout is effectively prevented.

Description

An oil well downhole blowout prevention pipe string

technical field

The invention relates to the field of oil well construction, in particular to a pipe string used for preventing the blowout of the wellbore of the oil well during the tripping of the oil well.

Background technique

At present, in some oilfields, Triassic oil reservoir blocks have relatively high oil and gas levels. At present, the tubing cannot prevent blowout when pulling out the drill, and the operation can only be carried out after the blowout is released, which affects the timeliness of oil well operation and oil well production, and there are certain safety and environmental protection risks. At present, a kind of anti-blowout oil drainer is generally used, which is connected to the upper end of the fixed valve of the conventional pipe pump. During the process of lowering the oil pipe, the oil drainer is in a closed state, which can prevent formation oil and gas from ejecting from the oil pipe. After it is lowered in place, use the plunger to press down the oil drainer so that it is in a connected state in the oil pipe, that is, it can start pumping normally. When the oil pipe needs to be lifted again, pull out the sucker rod and the pump plunger, put the sucker rod into the oil pipe to short-circuit, and through the impact, break the internal and external communication valve of the oil drainer to realize the internal and external communication of the oil drainer (the oil pipe is connected to the oil pipe). When the oil pipe is lifted, the oil can be drained. The use of this type of blowout preventer can effectively solve the blowout prevention problem during the running of the tubing string. However, during the pulling out of the tubing, because the oil drain has been opened, it is connected with the inside and outside of the tubing, and with the inside and outside of the tubing. It cannot play the role of blowout prevention. However, during the construction of high gas-oil ratio wells, as the pipe string is pulled out, the wellbore liquid column will drop, which will lead to degassing of crude oil and short-term oil and gas ejection, posing hidden dangers to construction safety.

Contents of the invention

The purpose of the present invention is aimed at the oil wells with high oil-gas ratio in the Triassic block. At present, the tubing cannot prevent blowout when pulling out the drill, and the operation can only be carried out after the blowout is released, which affects the timeliness of oil well operation and oil well production, and there are certain hidden dangers of safety and environmental protection. , The present invention provides a downhole blowout prevention pipe string for an oil well, which prevents the problem of liquid injection in the wellbore of an oil well with a high oil-gas ratio during tripping and tripping in, so as to ensure safety and timeliness for oil well operations.

The technical solution adopted by the present invention to solve the technical problem is: an oil well downhole blowout prevention pipe string, which is composed of two pipe strings: a hand-off pipe string and a production pipe string. Switch, the bottom of the production string is a single-flow sealed intubation, and the single-flow sealed intubation is inserted into the rotary plate switch.

The dropout string also includes a dropout joint, a suspended packer, a connecting valve and a female plug, wherein the upper end of the dropout string is a dropout joint, and the lower part of the dropout joint is connected to the rotary plate through a suspension packer Switch, the bottom of the rotary plate switch is connected to the female plug through the communication valve.

The drop-off joint is a ball-type safety drop-off joint.

The production string also includes an oil well pump and a screen pipe, the oil well pump is connected to the screen pipe through the oil pipe, and the lower end of the screen pipe is connected to a single-flow sealing intubation pipe.

The top of the single-flow sealing insertion tube is an upper joint used to connect with the bottom of the screen pipe, the bottom of the single-flow sealing insertion tube is a diversion ejector pin for pushing up the rotary plate switch, and the lower parts of the upper joints are respectively arranged in sequence There is a one-way valve and a well-washing protection cup, and a diversion hole is opened on the wall of the single-flow sealing intubation tube from the bottom of the well-washing protection cup to the top of the diversion ejector rod to connect the outside of the pipe wall to the central channel in the pipe.

The single-flow valve includes a single-flow valve cover, a valve ball, and a valve seat. A valve seat is arranged at the top of the central passage in the pipe of the single-flow sealing intubation tube, and a single-flow valve cover is fixed on the valve seat. The single-flow valve cover is built with a valve. ball.

The well cleaning protection cup includes a cup rubber tube, a cup center tube and a cup support seat, the cup center tube is sleeved on the outer wall of the single-flow sealing intubation tube, and the cup center tube fixes the cup through the cup support seat Rubber cartridge.

The rotary plate switch is mainly composed of a rotary plate switch mechanism and a forced reset mechanism,

The rotary plate switch mechanism includes an upper joint, a fixed pin seat, a rotating shaft, and a rotary plate. The fixed pin seat is fixed at the bottom of the upper joint, and the rotary plate is pinned to the bottom of the fixed pin seat through the rotating shaft. The size of the rotary plate is larger than the port at the bottom of the upper joint. ;

The forced return mechanism includes a push rod, a jacket, a forced return spring, and a lower joint. One end of the push rod is hinged to the rotary plate through a pin, the other end of the push rod is fixed on the upper part of the forced return spring, and the lower part of the forced return spring is fixed on the lower joint. A coat is also connected between the upper joints.

The beneficial effect of the present invention is that the rotary plate switch of the downhole blowout prevention pipe string of the oil well is connected to the lower end of the suspension packer, and the production pipe string is lowered to a predetermined position for setting, and then the single-flow sealing intubation pipe is connected to the lower end of the production pipe string Going into the downhole, the single-flow sealing cannula is inserted into the rotary plate switch, and the rotary plate switch is pushed up, and the oil well is in normal production; when the downhole operation is performed, the production string is pulled out, the single-flow sealing cannula is lifted up, and the rotary plate switch is closed , to achieve the blowout prevention effect of the wellbore of the oil well, and the upper wellbore of the suspension packer is separated from the oil and gas layer, effectively preventing blowout.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings of the embodiments.

Figure 1 is a schematic diagram of a downhole blowout preventer string;

Figure 2 is a structural diagram of a single-flow sealed intubation;

Fig. 3 is a structural diagram of a rotary plate switch;

In the figure: 1. Oil well pump; 2. Screen pipe; 3. Single-flow sealing intubation; 4. Drop-in joint; 5. Hanging packer; 6. Rotary plate switch; 7. Connecting valve; 8. Female plug ;

3-1, upper joint; 3-2, single-flow valve cover; 3-3, valve ball; 3-4, valve seat; 3-5, leather bowl rubber tube; 3-6, leather bowl center tube; 3- 7. Leather bowl support seat; 3-8, diversion hole; 3-9, diversion ejector rod;

6-1, upper joint; 6-2, fixed pin seat; 6-3, rotating shaft; 6-4, rotary plate; 6-5, push rod; 6-6, jacket; 6-7, forced return spring; 6-8. Lower connector.

Detailed ways

Example 1

As shown in the structural diagram of the downhole blowout prevention pipe string of the oil well of the present invention shown in Fig. 1, the blowout prevention pipe string is composed of two trip pipe strings, the discard pipe string and the production pipe string, and the top of the discard pipe string is a rotary plate switch 6 for production Below the column is a single-flow sealing intubation tube 3 , and the single-flow sealing intubation tube 3 is plugged into the rotary plate switch 6 .

The drop-out string also includes a drop-out joint 4, a suspension packer 5, a communication valve 7 and a female plug 8, wherein the upper end of the drop-out string is a drop-out joint 4, and the drop-out joint 4 is a ball-type safety drop-out joint. The lower part of the drop-off joint 4 is connected to the rotary plate switch 6 through the hanging packer 5, and the lower part of the rotary plate switch 6 is connected to the female plug 8 through the communication valve 7.

The production string also includes an oil well pump 1 and a screen pipe 2. The oil well pump 1 is connected to the screen pipe 2 through the oil pipe, and the lower end of the screen pipe 2 is connected to a single-flow sealing intubation pipe 3.

In this blowout prevention pipe column, except for the structure of the single-flow sealing intubation tube 3 and the rotary plate switch 6, other structures are existing mature technologies or mature products, such as the screen pipe 2, the ball-throwing safety drop joint 4, and the hanging seal Device 5, communication valve 7, female plug 8, the structure of which will not be described in detail here.

The working process of the oil well blowout prevention string is as follows: the rotary plate switch 6 is connected to the lower end of the suspension packer 5, and the production string is lowered to the predetermined position for setting, and then the single-flow sealing cannula 3 is connected to the lower end of the production string and run into Downhole, the single-flow sealing cannula 3 is plugged into the rotary plate switch 6, and the rotary plate switch 6 is pushed up, and the oil well is in normal production; when performing downhole operations, the production string is pulled out, the single-flow sealing cannula 3 is lifted up, and the rotary plate The switch 6 is closed to realize the blowout prevention effect of the wellbore of the oil well, and the upper wellbore of the suspension packer 5 is separated from the oil and gas layer, effectively preventing blowout.

Specific construction site examples:

The test well XX-XX well drilled a long X layer, completed drilling depth of 1406.0m, artificial well bottom of 1397.5m, daily fluid production before operation of 4.62m3 ^, daily oil production of 4.11t, water cut of 11.0%, gas-oil ratio of ^86.5m3 /t.

1. The lower packer is set and dropped:

Connect the oil well blowout preventer string to the production string and go down to the predetermined position (1213.5m), pressurize from the tubing according to the steps of 5-10-15 MPa, stabilize the pressure for 5 minutes each time during the period, pressurize and set the tubing through the tubing, and after the tool setting is completed, Slowly lower the oil pipe, the depth of the oil pipe remains the same, the self-weight is reduced by 1-2t, and the tool setting is completed; then put the sucker rod from the oil pipe into the short circuit, knock off the throwing safety joint, and the throwing is completed, and the throwing safety is released. Discard the fitting above the string.

2. Run into the production string and seal the intubation:

Connect the single-flow sealing cannula to the tail of the oil well pump, and the pipe string is combined from top to bottom: φ73mm oil pipe + tubular pump + φ73mm oil pipe + screen tube 2 + single-flow sealing cannula 3. According to the planned depth, the tool is lowered to the predetermined position (1213.5m), and the oil pipe is slowly lowered. The depth of the oil pipe remains unchanged, and the dead weight decreases by 10-30kN. Then the load of the pipe string returns to normal. Downward, the single-flow sealed intubation tube 3 is put in place, and the rotary switch 6 is opened.

3. Verify the reliability of the rotary switch

The production string was raised 0.3m, pumping was started after completion of the well, and the oil well did not produce fluid for 12 hours. The rotary plate switch successfully sealed the upper wellbore and oil and gas layers of the packer, achieving the expected effect.

4. Completion

Run the sucker rod and plunger according to the predetermined design, complete the well, and produce fluid from the oil well 2 hours after the well is opened.

Example 2

As shown in the schematic diagram of the single-flow sealing intubation in Figure 2, the top of the single-flow sealing intubation 3 is the upper joint 3-1 for connecting with the bottom of the screen pipe 2, and the bottom of the single-flow sealing intubation 3 is for the top joint 3-1. The diversion ejector pin 3-9 of the swing plate switch 6 and the lower part of the upper joint 3-1 are respectively arranged with a check valve and a well cleaning protection cup in sequence, and the bottom of the well flushing protection cup reaches the top of the diversion ejector rod 3-9 The tube wall of the single-flow sealed intubation tube 3 is provided with a diversion hole 3-8 connecting the outside of the tube wall to the central passage in the tube.

The working principle of the single-flow sealing cannula: the single-flow sealing cannula 3 is connected to the lowermost section of the production string, the diversion ejector pin 3-9 at the bottom of the single-flow sealing cannula 3 is inserted into the rotary plate switch 6, and the rotary plate The rotary plate 6-4 in the switch is pushed back, so that the single-flow sealing cannula 3 communicates with the oil layer, and at the same time, the liquid in the wellbore passes through the diversion holes 3-8 on the single-flow sealing cannula and passes through the central channel of the single-flow sealing cannula 3 It enters the annular space of the upper oil jacket of the hanging packer through the check valve.

The single-flow valve includes a single-flow valve cover 3-2, a valve ball 3-3, and a valve seat 3-4. A valve seat 3-4 is arranged on the top of the central passage in the pipe of the single-flow sealing intubation tube 3, and the valve seat 3-4 is fixed There is a single-flow valve cover 3-2, and the single-flow valve cover 3-2 has a built-in valve ball 3-3, and the liquid in the central channel of the single-flow sealing cannula 3 pushes the valve ball 3-3 on the valve seat 3-4 to enter upper space.

The well-washing protective leather bowl includes a leather bowl rubber tube 3-5, a leather bowl center tube 3-6, and a leather bowl support seat 3-7. The central tube 3-6 fixes the rubber cup 3-5 through the cup support seat 3-7, and after the single-flow sealing intubation tube 3 is plugged into the rotary switch 6, the rubber cup 3-5 and the rotary switch 6 The central channel part plays a sealing role through interference fit. When washing the well, the well washing fluid cannot pass through the gap between the single-flow sealing intubation tube 3 and the rotary plate switch 6 in the tubing to pollute the formation. The combination of the two can effectively prevent the flushing fluid from pouring into the formation.

Example 3

As shown in the structural diagram of the rotary switch 6 in FIG. 3 , the rotary switch 6 is mainly composed of a rotary switch mechanism and a forced reset mechanism.

Wherein the rotary plate switch mechanism includes an upper joint 6-1, a fixed pin seat 6-2, a rotating shaft 6-3, and a rotary plate 6-4, and the bottom of the upper joint 6-1 is fixed with a fixed pin seat 6-2, and the rotary plate 6-2 4. The rotating shaft 6-3 is pinned to the bottom of the fixed pin seat 6-2, so that the rotating plate 6-4 can rotate downward with the rotating shaft 6-3 as the rotating shaft. The size of the rotating plate 6-4 is larger than that of the upper joint 6-2. 1 bottom port, so that the bottom port of the upper joint 6-1 can be blocked when the rotary plate 6-4 rotates to the upper end.

The forced reset mechanism includes a push rod 6-5, an overcoat 6-6, a forced reset spring 6-7, and a lower joint 6-8. The other end is fixed on the upper part of the forced return spring 6-7, and the lower part of the forced return spring 6-7 is fixed on the lower joint 6-8, and an overcoat 6-6 is also connected between the lower joint 6-8 and the upper joint 6-1 for forced reset The spring 6-7 can be compressed in the cavity surrounded by the jacket 6-6.

The working principle of the rotary plate switch 6: the rotary plate switch 6 is connected to the lower end of the suspension packer 5 through the upper joint 6-1, and the diversion ejector pin 3-9 at the bottom of the single-flow sealing cannula 3 is inserted into the rotary plate switch 6, and the In the rotary plate switch, the rotary plate 6-4 is pushed open, and the rotary plate 6-4 is pushed by the diversion ejector rod 3-9, and the rotary plate 6-4 moves downward with the rotating shaft 6-3 as the axis center, and pushes the push rod 6-5 is compressed and the forced return spring 6-7 contracts, and the oil layer is connected through the diversion hole 3-8 on the single-flow sealing cannula 3; when the single-flow sealing cannula 3 is lifted out, the forced return spring 6-7 leans against the spring The elastic force of the push rod 6-5 resets the rotary plate 6-4 in the rotary plate switch 6, so that the rotary plate switch 6 is in the closed state.

Claims (8)

1. An oil well downhole blowout prevention pipe string, which is composed of two pipe strings: the abandon pipe string and the production pipe string. The single-flow sealing intubation tube (3), the single-flow sealing intubation tube (3) is plugged into the rotary plate switch (6). 2. A downhole blowout preventive string for an oil well according to claim 1, characterized in that: the dropout string also includes a dropout joint (4), a hanging packer (5), a communication valve ( 7) and the female plug (8), wherein the upper end of the drop-out string is a drop-out joint (4), and the lower part of the drop-out joint (4) is connected to the rotary plate switch (6) through the hanging packer (5), and the rotary plate The lower part of the switch (6) is connected to the female plug (8) through the communication valve (7). 3. A downhole blowout preventive pipe string for an oil well according to claim 1, characterized in that: said hands-off joint (4) is a throwing ball type safety hands-off joint. 4. A downhole blowout prevention pipe string for an oil well according to claim 1, characterized in that: the production pipe string also includes an oil well pump (1) and a screen pipe (2), and the oil well pump (1) is connected through the oil pipe A screen tube (2), the lower end of the screen tube (2) is connected with a single-flow sealing intubation tube (3). 5. A downhole blowout prevention pipe string for an oil well according to claim 1, characterized in that: the top of the single-flow sealing insert (3) is an upper joint ( 3-1), the bottom of the single-flow sealed intubation tube (3) is the diversion ejector rod (3-9) for opening the rotary plate switch (6), and the bottom of the upper joint (3-1) is respectively arranged in sequence The single-flow valve and the well-washing protection cup, the single-flow sealing intubation tube (3) from the bottom of the well-washing protection cup to the top of the diversion ejector rod (3-9) has a channel connecting the outside of the pipe wall to the center of the pipe. Diversion holes (3-8). 6. A downhole blowout prevention pipe string for an oil well according to claim 5, characterized in that: the check valve includes a check valve cover (3-2), a valve ball (3-3), a valve seat ( 3-4), a valve seat (3-4) is arranged on the top of the central passage in the tube of the single-flow sealed intubation tube (3), and a single-flow valve cover (3-2) is fixed on the valve seat (3-4). The valve cover (3-2) is built with a valve ball (3-3). 7. A downhole blowout prevention pipe string for an oil well according to claim 5, characterized in that: the well washing protection cup includes a rubber cup (3-5), a cup central tube (3-6) And the cup support seat (3-7), the cup center tube (3-6) is sleeved on the outer wall of the single-flow sealing intubation tube (3), and the cup center tube (3-6) passes through the cup support seat (3-6) 7) Fix the rubber cup (3-5). 8. A downhole blowout prevention pipe string for an oil well according to claim 1, characterized in that: the rotary plate switch (6) is mainly composed of a rotary plate switch mechanism and a forced reset mechanism, The rotary plate switch mechanism includes an upper joint (6-1), a fixed pin seat (6-2), a rotating shaft (6-3), and a rotary plate (6-4). The bottom of the upper joint (6-1) is fixed with a fixed The pin seat (6-2), the rotating plate (6-4) is pinned to the bottom of the fixed pin seat (6-2) through the rotating shaft (6-3), and the size of the rotating plate (6-4) is larger than that of the upper joint (6-4). -1) Bottom ports; The forced return mechanism includes a push rod (6-5), a jacket (6-6), a forced return spring (6-7), a lower joint (6-8), one end of the push rod (6-5) and the rotary plate (6- 4) Hinged by the pin shaft, the other end of the push rod (6-5) is fixed on the upper part of the forced return spring (6-7), the lower part of the forced return spring (6-7) is fixed on the lower joint (6-8), and the lower joint ( 6-8) is also connected with an overcoat (6-6) between the upper connector (6-1).