CN114075933A

CN114075933A - Sand washing and filling pipe column system and sand washing and filling process

Info

Publication number: CN114075933A
Application number: CN202010809948.7A
Authority: CN
Inventors: 孔令军; 赵益忠; 杨军; 王钧; 赵小龙; 牛成成; 贾培锋
Original assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Current assignee: China Petroleum and Chemical Corp; Sinopec Research Institute of Petroleum Engineering
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2022-02-22
Anticipated expiration: 2040-08-13

Abstract

The invention provides a sand washing and filling pipe column system, which comprises: the wellhead device comprises a first connecting four-way, a second connecting four-way, a conversion pipe and a connecting pipe, wherein the first connecting four-way and the second connecting four-way are arranged at the wellhead; the sleeve is connected to the lower end of the first connecting cross, and an oil pipe is concentrically arranged in the sleeve; the filling tool comprises a central pipe communicated with the oil pipe, an outer pipe concentrically arranged on the radial outer side of the central pipe, a packer device arranged on the outer peripheral surface of the outer pipe and a backwashing setting device arranged in the central pipe, wherein a hydraulic transmission joint is arranged on the outer wall of the central pipe, corresponding to the packer device; and a filling through hole is formed in the side wall of the central pipe, and the backwashing seat sealing device closes the filling through hole in an initial state. The invention also provides a sand washing and filling process.

Description

Sand washing and filling pipe column system and sand washing and filling process

Technical Field

The invention belongs to the field of oil drilling development, and particularly relates to a sand washing and filling pipe column system. The invention also relates to a sand washing and filling process.

Background

Loose sandstone reservoirs are generally buried to a small depth, so that overlying pressure of the reservoir is small, the diagenesis is poor, the rock cementation is mainly based on substrate cementation, and the cementation is mainly based on oil and mud, so that the cementation degree is very loose. Based on special cementing property, the adoption of an open hole sand screen for well completion easily causes well wall collapse, so that a horizontal well section is often unstable, bent and damaged. Therefore, the stratum is generally put into operation by adopting a well completion mode of casing perforation and sand control in a pipe. However, due to poor formation and no framework support, a sand drift area exists in a near wellbore area, the production horizon is maliciously produced with sand, and the sand control pipe column is still difficult to put in place after repeated sand washing. The existing gravel packing sand control pipe column under the side of flushing of the horizontal well needs to be carried out in two steps in construction, sand flushing is carried out firstly, a sand flushing inner pipe column is taken out, an inner filling pipe column is put in, and then packing is carried out.

At present, the existing anti-leakage sand washing methods or sand washing pipe columns are various, but still have some problems. For example, although the existing anti-leakage sand washing method can prevent the sand from entering an oil layer, the sand washing and sand control operations of the same pipe column cannot be realized, and under the condition of serious sand production, the sand washing and the sand control are completed by two pipe columns, so that a large operation risk exists. The overflow preventing device of the existing sand washing pipe column of the oil-water well is connected between a single pouring oil pipe and the sand washing pipe column below a water hose, and can be opened or closed through an operation wrench, but the sand washing process can not be avoided, wherein flowing sand enters a shaft to cause the difficulty of putting down the sand washing pipe column. In addition, when the speed of the quicksand invading into the shaft is too fast, the sand washing and filling process tubular columns in the prior art cannot realize the same time of the tubular columns for sand washing and sand prevention operation.

Therefore, a one-trip pipe column sand washing and filling process pipe column capable of remarkably improving the sand prevention success rate and the sand prevention effect of the unconsolidated sandstone reservoir is needed.

Disclosure of Invention

In view of the above technical problems, the present invention is directed to a sand washing and filling pipe column system, which has a one-time pipe column sand washing and filling function, and can perform continuous reverse circulation well washing and sand washing, and perform filling construction quickly, thereby greatly improving operation efficiency.

The invention also provides a sand washing and filling process, which has the advantages of simplified sand washing and filling procedures, high safety and capability of greatly improving the operation efficiency.

To this end, according to a first aspect of the present invention, there is provided a sand wash and pack string system comprising: the wellhead device comprises a first connecting four-way arranged at a wellhead, a second connecting four-way communicated with the first connecting four-way, a conversion pipe concentrically arranged in the first connecting four-way and a connecting pipe concentrically arranged in the conversion pipe; the sleeve is connected to the lower end of the first connecting cross, and an oil pipe is concentrically arranged in the sleeve; the filling tool comprises a central pipe communicated with the oil pipe, an outer pipe concentrically arranged on the radial outer side of the central pipe, a packer device arranged on the outer peripheral surface of the outer pipe, and a backwashing setting device arranged inside the central pipe, wherein a hydraulic transmission joint is arranged on the outer wall of the central pipe, corresponding to the packer device; a filling through hole is formed in the side wall of the central pipe, and the backwashing seat sealing device closes the filling through hole in an initial state; wherein in a first state the wellhead and the packing tool are capable of forming a first reverse circulation channel for a first reverse circulation well-flushing to lower the packing tool down to a predetermined depth while flushing cyclically; in a second state, injecting liquid from the oil pipe through the wellhead device, closing the backwashing setting device by the liquid, transmitting the hydraulic pressure through the hydraulic transmission joint to set the packer device, further suppressing the pressure of the backwashing setting device until the filling through hole is opened to form a filling channel, and then performing filling construction through the filling channel; in a third state, the packing tool can be closed by lifting the connecting pipe and the oil pipe, and a second reverse circulation channel can be formed to perform second reverse circulation well washing so as to wash out redundant gravel in the shaft, thereby completing sand prevention construction.

In one embodiment, the oil pipe is fixedly connected to the lower end of the connecting pipe through a switching mechanism, the switching mechanism is communicated with the oil pipe and a first annular space formed between the connecting pipe and the switching pipe, and the first annular space is communicated with the bypass port of the second connecting four-way valve.

In one embodiment, a second annulus is formed radially between the transfer tube and the first connection cross, the second annulus communicating with an annulus space formed between the tubing and the casing and a bypass port of the second connection cross, respectively.

In one embodiment, the two bypass ports of the first connecting four-way are respectively connected with a first inlet control valve and a first outlet control valve, the two bypass ports of the second connecting four-way are respectively connected with a second inlet control valve and a second outlet control valve, the first inlet control valve and the second inlet control valve are communicated and then communicated with the pump truck connecting port,

in the first state, the first inlet control valve and the second outlet control valve are opened, and the second inlet control valve is closed, so that the first reverse circulation channel is formed;

in the second state, the second inlet control valve is opened, the first inlet control valve is closed, and the filling channel is formed after the filling through hole is opened;

and in a third state, after the connecting pipe and the oil pipe are lifted up, the first inlet control valve and the second outlet control valve are opened, and the second inlet control valve is closed, so that the second reverse circulation channel is formed.

In one embodiment, the packer device includes slips, a hydraulic cylinder disposed at a downstream end of the slips, and a packing element disposed between the slips and the hydraulic cylinder, the slips being disposed on an outer wall surface of the outer tube by two slip seating cones axially spaced apart from each other,

the hydraulic cylinder can transmit the pressure of liquid in the central pipe through the hydraulic transmission joint to squeeze the rubber sleeve, so that the rubber sleeve expands radially to realize setting, and the slip setting cone is pushed to move upwards, so that the slips are pushed to extend radially to form axial fixation between the outer pipe and the sleeve.

In one embodiment, the hydraulic transfer joint is uniformly provided with a plurality of radially extending pressure transfer holes and a plurality of axially extending axial through holes in the circumferential direction, the pressure transfer holes and the axial through holes are distributed in a staggered manner in the circumferential direction, and the pressure transfer holes are communicated with the internal channel of the central pipe and the hydraulic cylinder.

In one embodiment, the hydraulic cylinder comprises a hydraulic cylinder lower body fixedly connected with the outer pipe and a hydraulic cylinder upper body arranged between the hydraulic cylinder lower body and the outer pipe, and the hydraulic cylinder upper body is fixedly connected with the hydraulic cylinder lower body through a first shearing pin in an initial state.

In one embodiment, the backwashing seat sealing device is fixedly connected with the central pipe through a second shearing pin in an initial state so as to close the filling through hole, and the shearing force of the second shearing pin is larger than that of the first shearing pin.

In one embodiment, the backwash setting device comprises a backwash and filling ball seat, a setting ball arranged in the backwash and filling ball seat and a backwash baffle arranged at the upper end of the backwash and filling ball seat, and the backwash setting device is constructed to be capable of being positively pressurized to be closed and reversely conducted to be opened.

In one embodiment, a ball seat locking ring for axially limiting the backwash seat is arranged on the inner wall of the lower end of the central tube.

In one embodiment, a sand control screen and a filling outer pipe are sequentially connected to the downstream end of the outer pipe, and an annulus formed among the outer pipe, the sand control screen and the base pipe is communicated through the axial through hole, so that a circulating liquid return passage is formed, and the upper end of the circulating liquid return passage is communicated with the annular space.

In one embodiment, a first compound seal is provided between the connecting tube and the second connecting cross, and a second compound seal is provided between the outer packing tube and the center tube.

In one embodiment, a door closing locking device for closing the filling tool is arranged at the lower end of the second composite sealing device, and the door closing locking device can block the filling outer pipe after the central pipe is lifted.

According to a second aspect of the present invention there is provided a sand wash and pack process using a sand wash and pack string system according to the above, comprising the steps of:

introducing liquid through the wellhead device to carry out first reverse circulation well flushing, and then putting the filling tool into the well while flushing the well;

setting the packer device by passing fluid through the wellhead device to seal off an annulus formed between a packing tool and a horizontal wellbore and opening the packing bore to form the packing passage;

introducing a sand carrying fluid carrying gravel through the wellhead device, and performing filling construction through the filling channel;

lifting the connecting pipe to close the packing tool, and controlling the wellhead device to feed liquid to carry out secondary reverse circulation well washing so as to wash out redundant gravel;

and (5) pulling out the filling tool, thereby completing the sand washing and filling construction.

Compared with the prior art, the method has the advantages that:

the sand washing and filling pipe column system has the functions of washing sand and filling by one-time pipe column, can be matched with a ground continuous sand washing well head to carry out continuous reverse circulation well washing and sand washing, and does not need to stop a pump to connect a single pipe in the middle process, thereby effectively avoiding the risk of pipe column clamping caused by pump stopping and obviously improving the safety and the construction efficiency of construction. The sand washing and filling pipe column system carries out sand washing and filling construction through a pipe column, the construction is continuous, stratum sand return spitting can be avoided, the filling tool can carry out filling construction from the designed depth, the construction process is simplified, the safety is higher, the manual workload is reduced, and the operation efficiency can be further improved. In addition, the sand washing and filling pipe column system is simple to operate, and forward sand washing and reverse sand washing can be rapidly converted, so that the construction efficiency can be further improved, and the sand prevention effect is enhanced. According to the sand washing and filling process, the filling tool of the sand washing and filling pipe column system can be ensured to be lowered to the designed depth, the filling construction is rapidly carried out, the operation efficiency is greatly improved, the mixed filling sand belt caused by the backflow of stratum sand can be reduced, a high-strength sand blocking barrier is established in the near-wellbore area, the sand control validity period is prolonged, and the sand control effect is greatly enhanced.

Drawings

The invention will now be described with reference to the accompanying drawings.

Figure 1 shows the structure of a sand wash and pack string system according to the present invention.

FIG. 2 shows the configuration of a wellhead in the sand wash and packing string system of FIG. 1.

Figure 3 shows the configuration of the packing tool in the sand wash and packing string system of figure 1.

Figure 4 shows a first condition of a sand wash and packing string system according to the present invention running a circulating sand wash into a wellbore.

Fig. 5 shows the process of opening the packing channel of the sand wash and packing string system according to the present invention.

Fig. 6 shows a second state of the sand wash and packing string system according to the present invention in a packing operation.

FIG. 7 shows a third condition of a sand wash and packing string system performing a reverse circulation well wash and performing sand control in accordance with the present invention.

In the present application, the drawings are all schematic and are used only for illustrating the principles of the invention and are not drawn to scale.

Detailed Description

The invention is described below with reference to the accompanying drawings.

In this application, it is noted that the end of the sand wash and pack string system 100 according to the present invention that is lowered into the wellbore near the wellhead is defined as the upper end or similar term and the end that is remote from the wellhead is defined as the lower end or similar term. And, the direction indicated by the arrow in the figure is the liquid flow direction.

FIG. 1 shows the configuration of a sand wash and pack string system 100 according to the present invention. As shown in FIG. 1, the sand wash and fill string system 100 includes a wellhead 10, a fill tool 60, and a casing 40 connected between the wellhead 10 and the fill tool, and a tubing 50 concentrically disposed inside the casing 40. The wellhead assembly 10 is disposed at a wellhead, and the wellhead assembly 10 is configured to provide a liquid or a sand-carrying liquid to the sand-washing and filling pipe string system 100, and is capable of controlling a flow direction of an internal channel of the sand-washing and filling pipe string system 100, thereby performing different construction operations. The filling tool 60 is used to lower down to the horizontal wellbore section for filling operations.

Fig. 2 shows the construction of the wellhead 10. As shown in fig. 2, the wellhead 10 includes a first connecting spool 20 disposed at the wellhead, a second connecting spool 30 communicating with the first connecting spool 20, a shift pipe 11 concentrically disposed within the first connecting spool, and a connecting pipe 12 concentrically disposed inside the shift pipe 11. The first connecting four-way 20 is connected with the wellhead in a sealing way, and the second connecting four-way 30 is arranged at the upper end of the first connecting four-way 20 and is connected with the first connecting four-way 20 in a sealing way.

In this embodiment, the upper end of the switching pipe 11 is fixedly connected to the lower end of the second connecting cross 30, and the lower end of the switching pipe 11 extends to the outside of the lower end of the first connecting cross 20 in the axial direction and partially extends outward. The inner diameter of the main body communication port of the first connecting four-way connection 20 is larger than that of the second connecting four-way connection 30, the inner diameter of the switching tube 11 is equal to that of the second connecting four-way connection 30, and the outer diameter of the switching tube 11 is smaller than that of the second connecting four-way connection 30, so that a second annulus 14 is formed radially between the switching tube 11 and the first connecting four-way connection 20. The connection tube 12 passes through the main body communication ports of the first and second connection four-

ways

20 and 30, and passes through the switching tube 11. The two ends of the connecting pipe 12 extend to the axial outer sides of the first connecting four-way connection 20 and the second connecting four-way connection 30, respectively, and extend outward by a portion. The connecting tube 12 has an outer diameter smaller than an inner diameter of the switching tube 11, so that a first annulus 13 is formed between the connecting tube 12 and an inner wall of the first connecting cross 20 and a radial direction of the switching tube 11.

In order to ensure the sealing performance between the connection pipe 12 and the second connection cross 30, a first composite sealing device 121 is disposed between the connection pipe 12 and the second connection cross 30. The composite sealing device 121 can effectively ensure the sealing performance between the connecting pipe 12 and the second connecting cross 30.

According to the present invention, a casing 40 is fixedly connected to the lower end of the first connection cross 20, and an oil pipe 50 is concentrically arranged inside the casing 40, so that an annular space 41 is formed between the casing 40 and the oil pipe 50 in the radial direction. The annular space 41 communicates with the second annulus 14, and the second annulus 14 communicates with the bypass port of the second connecting cross 30. The oil pipe 50 is fixedly connected to the lower end of the connecting pipe 12 by the switching mechanism 51, the switching mechanism 51 communicates the oil pipe 50 with the first annulus 13 formed between the connecting pipe 12 and the switching pipe 11, and the first annulus 13 communicates with the bypass port of the second connecting cross 30. An oil jacket seal 52 is provided between the shift mechanism 51 and the shift pipe 11 so that the first annular space 13 and the second annular space 14 form separate spaces.

In the present embodiment, the first inlet control valve 21 and the first outlet control valve 22 are connected to two bypass ports of the first connecting four-way valve 20, respectively, and the second inlet control valve 31 and the second outlet control valve 32 are connected to two bypass ports of the second connecting four-way valve 30, respectively. The first inlet control valve 21 and the second inlet control valve 31 are communicated with the pump truck connecting port 23, and the pump truck connecting port 33 is used for supplying liquid or sand-carrying liquid to the sand washing and filling pipe column system 100. The trailing end of the first inlet control valve 21 is sealed by a plug 23. In the actual working process, the sand washing and filling pipe column system 100 is controlled to carry out different construction operations by controlling the opening or closing of the first inlet control valve 21, the second inlet control valve 31, the first outlet control valve 22 and the second outlet control valve 32, the working procedure is simplified, the operation is simple, the safety is improved, the sand washing and filling construction can be carried out by one pipe column, time and labor are saved, and the working efficiency is greatly improved.

Fig. 3 shows the structure of the filling tool 60. The packing tool 60 is lowered into the horizontal wellbore section, which forms an annulus with the horizontal wellbore. As shown in fig. 3, the packing tool 60 includes a central tube 61, an upper joint 612 is fixedly connected to an upper end of the central tube 61, and the central tube 61 is fixedly connected to a lower end of the oil pipe 50 through the upper joint 612. An outer pipe 62 is sleeved on the radial outer side of the central pipe 61, and the outer pipe 62 is arranged at one end close to the upper joint. A sand screen 66 and a packing outer tube 64 are connected in series at the downstream end of the outer tube 62. In one embodiment, the sand screen 66 is connected at both ends to the outer pipe 62 and the filler outer pipe 64 by safety joints 661, respectively. The inner diameters of the outer pipe 62, sand screen 66, and filler outer pipe 64 are all larger than the outer diameter of the base pipe 61. An annular second composite sealing device 67 is provided between the filling outer tube 64 and the center tube 61 in the radial direction, and the second composite sealing device 67 is fixedly connected to the inner wall surface of the filling outer tube 64. Thus, a circulation return channel 65 is formed in the annular region between the outer pipe 62, the sand screen 66 and the base pipe 61, and the upper end of the circulation return channel 65 communicates with the annular space 41 formed between the casing 40 and the tubing 50, and the lower end of the circulation return channel 65 communicates with the annular space formed between the packing tool 60 and the horizontal wellbore through the sand screen 66. In one embodiment, the upper end surface of the outer tube 62 is connected to the lower end surface of the upper joint 612, and the upper end side wall of the outer tube 62 is provided with a groove penetrating through the side wall of the outer tube, so that the circulation return passage 65 is communicated with the annular space 41 through the groove.

As shown in fig. 3, a packer device 70 is provided on the outer peripheral surface of the outer tube 62. The packer assembly 70 includes slips 71, a hydraulic cylinder 74 disposed at a downstream end of the slips 71, and a packing element 73 disposed between the slips 71 and the hydraulic cylinder 74. The slips 71 are set on the outer wall surface of the outer tube 62 by two slip setting cones 72 distributed axially spaced apart from each other. In an initial state, the slips 71 are held against the outer wall surface of the outer tube 62 by radial compression of the slip sleeve 712 and pin 711. A hydraulic cylinder 74 is provided at a downstream end of the slips 71, the hydraulic cylinder 74 including a hydraulic cylinder lower body 742 fixedly connected to the outer tube 62 and a hydraulic cylinder upper body 741 provided between the hydraulic cylinder lower body 742 and the outer tube 62. The hydraulic cylinder upper body 741 is fixedly connected to the hydraulic cylinder lower body 742 by the first shear pin 75 in an initial state, and an upper end of the hydraulic cylinder upper body 741 protrudes axially outward. A rubber cylinder 73 is arranged between the slip seat cone 72 and the hydraulic cylinder 74, and both axial ends of the rubber cylinder 73 are respectively contacted with the upper end surfaces of the slip seat cone 72 and the hydraulic cylinder lower body 742.

In this embodiment, a hydraulic pressure transfer joint 63 is provided on the outer wall of the base pipe 61 corresponding to the packer device 70, and the hydraulic pressure transfer joint 63 is provided with a pressure transfer hole extending radially and penetrating the base pipe 61 and the hydraulic pressure transfer joint 63, and the pressure transfer hole communicates with the internal passage of the base pipe 61 and the hydraulic cylinder 74. The liquid from the inner channel of the central tube 61 can transmit hydraulic pressure through the hydraulic transmission joint to enable the packer device 70 to achieve setting, specifically, the internal liquid pressure of the central tube 61 is transmitted to the hydraulic cylinder 74 through the pressure transmission hole, the liquid pressure acts on the hydraulic cylinder upper body 741 until the first shearing pin 75 is sheared, the hydraulic cylinder upper body 741 is further pushed to move axially upwards, the hydraulic cylinder upper body 741 pushes the rubber sleeve 73, and the rubber sleeve 73 is squeezed to expand radially, so that setting is achieved. The annulus formed between the packing tool 60 and the horizontal wellbore is thereby sealed off by the packing element 73. Meanwhile, the rubber sleeve 73 axially pushes the slip seat cone 72, and the slips 71 enable the pins 711 to be out of work and extend out radially under the action of the conical structure between the slip seat cone 72 and the slips 71, so that the slips 71 and the inner wall surface of the casing 40 are axially fixed. The outer pipe 62, the sand screen 66, and the packing outer pipe 64 outside the base pipe 61 are thereby axially fixed by the slips 71.

According to the present invention, the packer device 70 further includes a lock ring (not shown) provided between the hydraulic cylinder lower body 742 and the axial end surface of the hydraulic cylinder lower body 742. The locking ring can keep the rubber sleeve 71 in a setting state all the time after setting. Thus, after the packer device 70 is set, the setting is maintained by the locking ring.

In the present embodiment, the hydraulic pressure transmission joint 63 is provided with an axial through hole. The annulus formed between the outer tube 62, sand screen 66 and base pipe 61 is communicated through the axial through-holes to form a circulating fluid return passage 65. The hydraulic transfer joint 63 may be provided with a plurality of pressure transfer holes and a plurality of axial through holes, which are circumferentially staggered.

According to the invention, the filling tool 60 further comprises a backwash setting device 80 arranged inside the central tube 61. A filling through hole 611 is provided in the side wall of the central tube 61 near the lower end surface, and the backwash setting device 80 closes the filling through hole 611 in an initial state. As shown in fig. 3, the backwash setting device 80 includes a backwash and filling ball seat 81, a setting ball 82 provided inside the backwash and filling ball seat 81, and a backwash baffle 83 provided at the upper end of the backwash and filling ball seat 81, and the backwash setting device 80 is configured to be closed by being pressurized in the forward direction and opened by being conducted in the reverse direction. In one embodiment, the backwash and filling ball seat 81 has a flow passage and a chamber communicating with the flow passage inside, a backwash baffle 83 is provided at the end of the chamber, and a seat ball 82 is provided in the chamber. The inner diameter of the cavity is larger than the diameter of the seat sealing ball 82, the inner diameter of the flow passage is smaller than the diameter of the seat sealing ball 82, and a conical surface with gradually changed inner diameter is arranged at the joint of the cavity and the flow passage. Thus, the seating ball 82 moves downward to block the flow path and form a pressure build-up, and the seating ball 82 moves upward to open the flow path. Here, it should be noted that the forward direction is directed in the downstream direction and the reverse direction is directed in the upstream direction.

In this embodiment, backwash setting device 80 is fixedly connected to central tube 61 by second shear pin 84 in an initial state and is disposed at filling through hole 611, thereby causing backwash and filling ball seat 81 to fill through hole 611. The shear force of the second shear pin 84 is greater than the shear force of the first shear pin 75. When the filling through hole 611 needs to be opened, the seat sealing ball 82 is moved forward through liquid to block the flow passage, so that pressure is suppressed, and after the second shearing pin 84 is sheared, the backwashing seat sealing device 80 moves downstream, so that the filling through hole 611 is opened.

In one embodiment, a ball seat locking ring 69 is provided on the lower inner wall of the center tube 61 to axially define the backwash seat 80. Thus, the backwash setting device 80 can be prevented from falling into the shaft due to falling off, and the backwash setting device 80 can be lifted out of the shaft along with the pipe column after construction is completed.

According to the invention, the filling tool 60 further comprises a door closing locking device 68, the door closing locking device 68 being used for closing the filling tool 60. As shown in fig. 3, the door closing lock 68 is disposed in the annular region formed by the filling outer tube 64 and the central tube 61, and the door closing lock 68 is fixedly connected to the lower end of the second composite seal 67. After the central tube 61 is lifted up through the door closing locking device 68 and the second composite sealing device 67, the door closing locking device 68 is automatically closed under the action of an internal torsion spring (not shown) thereof, and the bottom of the filling outer tube 64 is blocked by the end surface of the second composite sealing device 67, so that the filling sand is prevented from flowing out.

The sand washing and filling pipe column system 100 according to the present invention is particularly suitable for loose sandstone reservoirs, and by using the sand washing and filling pipe column system 100, the construction process can be significantly simplified, the construction process is simplified, the manual workload is reduced, and the operation efficiency is greatly improved.

According to the present invention, there is also provided a sand wash and fill process using the sand wash and fill string system 100 according to the present invention. First, a first reverse circulation well flushing is performed by controlling the wellhead 10 to inject liquid, thereby lowering the filling tool 60 while flushing the well until the filling tool 60 is lowered to a predetermined depth. The packer device 70 is then set by controlling the wellhead 10 to let in fluid, thereby sealing off the annulus formed between the filling tool 60 and the horizontal wellbore, and the filling channel is formed by backwashing the setting device 80 to build pressure and open the filling through holes 611. Then, the sand carrying fluid carrying sand is introduced through the control wellhead device 10, and filling construction is carried out through the filling channel. After completion of the packing operation, the connecting pipe 12 is lifted to close the packing tool 60 and a second reverse circulation wash is performed by controlling the wellhead 10 to pass fluid to wash out excess gravel. Finally, the filling tool 60 is pulled out, thereby completing the sand washing and filling construction.

The operation of the sand wash and pack string system 100 according to the present invention will now be described in detail with reference to figures 4 to 6. During the well descending process, when the pipe string is blocked due to sand production, the first inlet control valve 21 and the second outlet control valve 32 are opened, the second inlet control valve 31 is closed, and circulating sand washing is carried out. The pump truck connection port 33 provides fluid through the first inlet control valve 21 into the first four-way connection 20 and flows sequentially through the second annulus 14, the annular space 41, the annular space between the packing tool 60 and the horizontal wellbore section, the internal passage of the base pipe 61, the tubing 50, the switching mechanism 51, the first annulus 13, and the second outlet control valve 32, thereby forming a first reverse circulation passage. The liquid carries the sand through the first reverse circulation passage and back to the surface from the second outlet control valve 32, completing the first reverse circulation well wash. Therefore, the pipe column is lowered while the well is circularly washed. At this point, the sand wash and pack string system 100 is in the first state. Figure 4 shows a first condition in which the sand wash and packing string system 100 is running a circulating sand wash into the wellbore. When a single joint needs to be connected, the pump does not need to be stopped, the non-collar oil pipe 50 is directly connected to the connecting pipe 12, the well is circularly washed, and the well is continuously lowered until the designed depth is reached. This makes sand washing and filling tubular column system 100 can carry out the incessant circulation well washing sand washing in succession, and the intermediate process need not to stop the pump and can connect single, has avoided the sand card tubular column risk that the pump that stops leads to, great improvement the security of construction, and simplified the construction process, labour saving and time saving has improved the operating efficiency greatly.

In the filling work, first, the filling tool 60 itself opens the filling through hole 611 to form a filling channel, and the filling work is performed through the filling channel. Fig. 5 shows a process in which the filling channel 611 of the filling tool 60 is opened. When the filling tool 60 is lowered into the shaft to reach a preset depth, the second inlet control valve 21 is opened, the first inlet control valve 31 is closed, the pump truck connecting port 33 provides liquid, the liquid enters the second connecting four-way valve 30 through the second inlet control valve 21, and flows through the first annular space 13, the switching structure 51, the oil pipe 50, the central pipe 61 and the backwashing seat sealing device 80 in sequence, so that the seat sealing ball 82 positively seals the flow passage to close the backwashing seat sealing device 80. At this time, the liquid transmits the liquid pressure to the hydraulic cylinder 74 through the pressure transmission hole in the hydraulic transmission joint 63, so that the liquid pressure acts on the hydraulic cylinder upper body 741 until the first shear pin 75 is sheared, and then the rubber cylinder 73 is pushed through the hydraulic cylinder upper body 741, so that the slip setting cone 72 is pushed, and the slip 71 is radially extended to realize setting. Thereby, the packer device 70 is caused to pack the annulus formed between the packing tool 60 and the horizontal wellbore. After the packer device 70 is set, the backwash setting device 80 continues to build pressure until the second shear pin 84 is sheared and the backwash setting device 80 moves downstream, thereby opening the fill through hole 611. At this time, the backwash setting device 80 is confined inside the end of the center tube 61 by the door closing lock 68. Thereby forming a filling channel.

In the filling operation, first, the upper joint 612 is rotated by the forward rotation of the coupling tube 12 by releasing the back-off, so that the upper joint 612 is disengaged from the main body of the filling tool 60. Whether the back-off is successful or not can be verified by lifting the connecting pipe 12, and the upper joint 612 is pressed back to perform filling construction after the back-off is successful.

During filling, the pump truck connection port 33 provides gravel-laden sand fluid to enter the second four-way connection 30 through the second inlet control valve 21, and sequentially flows through the first annulus 13, the transition structure 51, the tubing 50, the internal channel of the base pipe 61, the filling through hole 611, the annulus between the filling tool 60 and the horizontal wellbore at the downstream sealed position of the packer device 70, the sand control screen 66, the circulation fluid return channel 65, the annular space 41, the second annulus 14 and the first outlet control valve 22, so as to form a filling channel. The sand-carrying fluid carries the gravel into the packing passage, and as it passes through the sand screen 66, the sand screen 66 filters to leave the gravel for packing, while the sand-carrying fluid continues to flow out of the first outlet control valve 22 through the packing passage, thereby completing the packing. At this point, the sand wash and pack string system 100 is in the second state. Fig. 6 shows a second state of the sand wash and packing string system 100 in a packing operation.

And after the filling construction is finished, performing secondary reverse circulation well flushing to finish the sand prevention construction. The central tube 61 is driven to lift by lifting the connecting tube 11, after the central tube 61 lifts the door closing locking device 68 and the second composite sealing device 67, the door closing locking device 68 seals the bottom of the filling outer tube 64 by the end surface of the second composite sealing device 67 under the action of the torsion spring inside the door closing locking device, and therefore filling sand is prevented from flowing out. And opening the first inlet control valve 21 and the second outlet control valve 32, closing the second inlet control valve 31, and performing reverse circulation well washing. The pump truck connection port 33 provides fluid through the first inlet control valve 21 into the first four-way connection 20 and through the annulus 14, the annular space 41, the outer tube 62 and the annulus between the sand screen 66 and the base pipe 61, the backwash setting device 80, the internal passage of the base pipe 61, the oil pipe 50, the switching mechanism 51, the first annulus 13, the second outlet control valve 32 in that order, and then returns to the surface to wash out excess gravel. Thereby, a second reverse circulation passage is formed. And the liquid passes through the second reverse circulation channel to carry out second reverse circulation well washing. At this point, the sand wash and pack string system 100 is in the third state. FIG. 7 shows a third condition in which the sand wash and packing string system 100 is performing a reverse circulation well wash and performing sand control. Finally, the filling tool 60 is pulled out, and the sand washing and filling construction is completed.

The sand washing and filling pipe column system 100 has the functions of washing sand and filling by one-time pipe column, can be matched with a ground continuous sand washing well head to carry out continuous reverse circulation well washing and sand washing, and does not need to stop a pump to connect a single pipe in the middle process, thereby effectively avoiding the risk of pipe column clamping caused by pump stopping and obviously improving the safety and the construction efficiency of construction. The sand washing and filling pipe column system 100 carries out sand washing and filling construction through a pipe column, the construction is continuous, stratum sand return spitting can be avoided, the filling tool 60 can carry out filling construction from the designed depth, the construction process is simplified, the safety is higher, the manual workload is reduced, and the operation efficiency can be further improved. In addition, the sand washing and filling tubular column system 100 is simple to operate, and forward sand washing and reverse sand washing can be rapidly converted, so that the construction efficiency can be further improved, and the sand prevention effect is enhanced. According to the sand washing and filling process, the filling tool 60 of the sand washing and filling pipe column system 100 can be ensured to be lowered to the designed depth, the filling construction is rapidly carried out, the operation efficiency is greatly improved, the sand mixing and filling belt caused by stratum sand backflow can be reduced, a high-strength sand blocking barrier is established in a near-wellbore area, the sand control validity period is prolonged, and the sand control effect is greatly enhanced.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing examples, or that equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sand wash and pack string system comprising:

a wellhead device (10) comprising a first connecting cross (20) disposed at a wellhead, a second connecting cross (30) in communication with the first connecting cross, a transfer tube (11) concentrically disposed within the first connecting cross, and a connecting tube (12) concentrically disposed within the transfer tube;

a sleeve (40) connected to a lower end of the first connecting cross, an oil pipe (50) being concentrically arranged inside the sleeve; and

a packing tool (60) for running down to a horizontal wellbore section, the packing tool comprising a center tube (61) communicating with the tubing, an outer tube (62) concentrically arranged radially outside the center tube, a packer device (70) provided on an outer peripheral surface of the outer tube, and a backwash setting device (80) provided inside the center tube, wherein a hydraulic transfer joint (63) is provided on an outer wall of the center tube corresponding to the packer device; a filling through hole (611) is formed in the side wall of the central pipe, and the backwashing seat sealing device closes the filling through hole in an initial state;

wherein in a first condition the wellhead and the packing tool are capable of forming a first reverse circulation path for a first reverse circulation well wash to run the packing string (60) down to a predetermined depth while circulating the well wash;

in a second state, injecting liquid from the oil pipe through the wellhead device, closing the backwashing setting device by the liquid, transmitting the hydraulic pressure through the hydraulic transmission joint to set the packer device, further suppressing the pressure of the backwashing setting device until the filling through hole is opened to form a filling channel, and then performing filling construction through the filling channel;

in a third state, the packing tool can be closed by lifting the connecting pipe and the oil pipe, and a second reverse circulation channel can be formed to perform second reverse circulation well washing so as to wash out redundant gravel in the shaft, thereby completing sand prevention construction.

2. A sand wash and fill string system according to claim 1, characterised in that the tubing is fixedly connected to the lower end of the connection tube by means of a switching mechanism (51) which communicates the tubing with a first annulus (13) formed between the connection tube and the switching tube, and which communicates with a bypass port of the second connection cross.

3. A sand wash and fill string system according to claim 2, characterised in that a second annulus (14) is formed radially between the transfer pipe and the first connection cross, which second annulus communicates with an annular space (41) formed between the tubing and the casing and a bypass port of the second connection cross, respectively.

4. A sand wash and filling string system according to any one of claims 1 to 3, wherein two bypass ports of the first connecting four-way are connected with a first inlet control valve (21) and a first outlet control valve (22) respectively, two bypass ports of the second connecting four-way are connected with a second inlet control valve (31) and a second outlet control valve (32) respectively, the first inlet control valve and the second inlet control valve are communicated and then communicated with a pump truck connecting port,

in the first state, opening the first inlet control valve (21) and the second outlet control valve (32), closing the second inlet control valve (31), thereby forming the first reverse circulation passage;

in the second state, opening the second inlet control valve (31), closing the first inlet control valve (21), and forming the filling channel after opening the filling through hole;

and in a third state, after the connecting pipe and the oil pipe are lifted up, the first inlet control valve (21) and the second outlet control valve (32) are opened, and the second inlet control valve (31) is closed, so that the second reverse circulation channel is formed.

5. A sand wash and pack string system according to claim 1, characterized in that the packer device comprises slips (71) arranged on the outer wall surface of the outer tube by means of two slip setting cones (72) distributed axially spaced from each other, a hydraulic cylinder (74) arranged at the downstream end of the slips and a rubber cylinder (73) arranged between the slips and the hydraulic cylinder,

6. The sand wash and fill string system of claim 5, wherein the hydraulic transfer sub is circumferentially and evenly provided with a plurality of radially extending pressure transfer holes and a plurality of axially extending axial through holes, the pressure transfer holes and the axial through holes are circumferentially staggered, and the pressure transfer holes communicate with the internal passage of the central tube and the hydraulic cylinder.

7. A sand wash and fill string system according to claim 5 or 6, characterised in that the hydraulic cylinder comprises a lower hydraulic cylinder body (742) fixedly connected to the outer pipe and an upper hydraulic cylinder body (741) arranged between the lower hydraulic cylinder body and the outer pipe, which upper hydraulic cylinder body is fixedly connected to the lower hydraulic cylinder body in an initial state by means of a first shear pin (75).

8. A sand wash and packing string system according to claim 7, wherein the backwash setting device is in an initial state fixedly connected to the base pipe by a second shear pin (84) having a shear force greater than the shear force of the first shear pin, thereby closing the packing through hole.

9. A sand wash and fill string system according to claim 1 or 8, wherein the backwash setting device comprises a backwash and fill ball seat (81), a setting ball (82) arranged in the backwash and fill ball seat and a backwash baffle (83) arranged at the upper end of the backwash and fill ball seat, the backwash setting device being configured to be able to be closed by being held down in a forward direction and opened by being conducted in a reverse direction.

10. A sand wash and packing string system according to claim 1 or 8, characterised in that a ball seat locking ring (69) is provided on the lower inner wall of the central tube for axially confining the backwash setting.

11. The sand wash and pack string system as recited in claim 6, characterized in that a sand screen (66) and an outer packing tube (64) are connected in series at the downstream end of the outer tube, and the annular space formed between the outer tube, the sand screen and the base pipe is communicated through the axial through holes, so that a circulating fluid return passage (65) is formed, and the upper end of the circulating fluid return passage is communicated with the annular space.

12. A sand wash and pack string system according to claim 11, c h a r a c t e r i z e d in that a first compound seal (121) is provided between the connection pipe and the second connection cross and a second compound seal device (67) is provided between the outer packing pipe and the central pipe.

13. A sand wash and fill string system according to claim 12, characterised in that a door closing lock (68) for closing the filling tool is provided at the lower end of the second composite sealing means, which is able to block the filling outer tube after lifting the central tube.

14. A sand wash and pack process using a sand wash and pack string system according to any one of claims 1 to 13, comprising the steps of: