WO2021022908A1

WO2021022908A1 - Method for replacing filling layer without changing pipe string, flowback service device and well completion structure

Info

Publication number: WO2021022908A1
Application number: PCT/CN2020/096066
Authority: WO
Inventors: 裴柏林; 冯国江
Original assignee: 安东柏林石油科技（北京）有限公司
Priority date: 2019-08-06
Filing date: 2020-06-15
Publication date: 2021-02-11
Also published as: CN110424912B; CN110424912A

Abstract

A method for replacing a down-hole packer particle filling layer (5) without changing the flowback of a down-hole pipe string (6). The filling layer (5) filled with packer particles is arranged in an annulus (A) between the down-hole pipe string (6) and a borehole wall (7), and a sliding sleeve type filling tool (3) is provided at the heel end of the down-hole pipe string (6). The method comprises the following steps: opening a sliding sleeve (21) of the sliding sleeve type filling tool (3), and establishing a flowback channel; and injecting flowback fluid into the down-hole pipe string (6) by means of a feeding pipe string, the flowback fluid entering the annulus through a flow control device of the down-hole pipe string (6), discharging the packer particles carried in the annulus (A) from a wellhead through a filling hole (20) and an outer annulus (C), and then filling the packer particles after flowback.

Description

The method of replacing the packing layer without changing the string, the flowback service device and the completion structure

Technical field

The invention belongs to the technical field of oil and natural gas exploitation, and relates to a method for not changing the downhole pipe string backflow and replacing the downhole packing particle packing layer, and a method for not changing the downhole pipe string backflow and replacing the downhole packing particle packing layer The flowback service device, and a completion structure that does not change the flowback of the downhole pipe string and replace the downhole packing particle packing layer.

Background technique

There are a large number of loose sandstone reservoirs that are easy to produce sand in oil and gas fields around the world. For oil and gas wells in loose sandstone reservoirs, whether they are vertical wells, inclined wells or horizontal wells, sand production is one of the frequently encountered problems in oil field development. Sand production in oil wells is more harmful, which will result in a significant decrease in oil well production, serious damage to the downhole pipe string, surge in operating costs, and serious economic losses. Therefore, it is extremely important to prevent sand production in underground formations. There are two conventional sand control methods, one is the use of sand control screens, and the other is gravel packing.

Oil and gas wells that rely solely on sand control screens for sand control will soon block the filter screens of the sand control screens due to mud or other particles produced by the geology, resulting in a significant drop in oil well fluid production. Gravel Packing and Sand Control As the gravel layer is packed outside the sand control pipe, the time for the sand control pipe to be blocked will be delayed, but it will eventually be blocked, resulting in a drop in fluid production. The conventional method to remove the blockage is acidification, but the effect of acidification generally lasts for a short period of time, one or two months long, and only ten days short. If you want to solve it completely, it is best to pull out the downhole sand control string, return the gravel layer in the well, and replace the sand control screen and gravel layer in the well.

However, for oil and gas wells that directly run sand control strings in the oil and gas wells, due to the large amount of sand produced in the formation, the formation sand fills the annulus between the sand control string and the well wall and tightly wraps the sand control string; for gravel When filling the well, the filled gravel sand control layer also tightly wraps the sand control string.

When the pipe is pulled out, the sand or gravel in the formation and the sand control string that it clings to will produce huge frictional resistance, which can generally reach more than 1 ton/meter, and the length of the underground sand control string is hundreds of meters. Lifting force requires hundreds of tons. Even oil and gas wells with only a few tens of meters or more than a dozen meters of sand control string will produce hundreds of tons of resistance in many cases. General workover equipment simply cannot provide such a high lifting force, and the connection strength of the sand control string cannot withstand such a high tensile force. At the same time, due to frictional resistance during lifting, self-locking may occur between the formation sand or gravel packing ring and the sand control pipe string, making it more difficult to pull out the sand control pipe. Therefore, if no other measures are taken, it is almost impossible to pull out the sand control string by means of direct lifting.

For oil and gas wells that cannot be pulled out of the sand control string, the solution generally adopted by the oil field is the sleeve milling operation. The sleeve milling operation is to insert a sleeve milling pipe into the annulus of the sand control pipe string and the well wall and sleeve it outside the sand control pipe string, while rotating and washing the down pipe while removing the formation sand or gravel surrounding the sand control pipe string , So that the sand control pipe string is easy to pull out. The milling operation needs to pull up the sand control pipe string once after each set of milling one sand control pipe. The entire operation cycle is very long and the cost is high, especially for offshore oil fields. The cost of milling operations may be as high as five or six million yuan, which is difficult to accept. In addition, the casing milling operation has requirements for the width of the gap between the sand control string and the well wall. If the size is small and the tool cannot be run, the oil and gas well cannot be extruded by the casing milling operation, and the oil and gas well may even be scrapped.

In addition, an international patent application (application number: PCT/CN2010/002014) proposes a method called "Oil and Gas Well Production Section Anti-channeling Packing Particles, Well Completion Method Using Such Particles and Oil Recovery Method" using continuous packing particles The technical solution for segmented flow control is based on the use of the axial isolation effect of the particle packing layer to segment the production wellbore, and then use the flow control screen to control the flow, and the particle packing layer also plays a role in sand blocking , Thus effectively solving the problem of water and sand production in the wellbore. In this technical solution, in order to fill the annulus between the flow control screen and the well wall with packing particles, a sliding sleeve type filling tool is required, such as Halliburton’s STMZ sand control tool and Weatherford’s sliding sleeve type Filling tools, and Baker Hughes' sliding sleeve filling tools, etc. After the packing of the packing particles is completed and the well is completed, as shown in Figure 1, the flow control screen 6 is located in the production section of the wellbore as a whole, and the annulus between the flow control screen 6 and the well wall 7 is filled with packing particles. First, the filling layer can prevent the sand from the sandstone layer from flowing to the position of the flow control screen with the liquid, avoiding sand production and blocking the flow control screen, and the second is the filling layer to inhibit the flow of water in the direction of the wellbore. Reduce the water content of the oil well produced fluid.

However, for many oil and gas wells, especially oil and gas wells in loose sandstone reservoirs, when the continuous packer segmented flow control technology is used for a period of time, due to geological reasons, the formation fluid will carry some impurities (such as mud Fine or sandy particles, etc.) are produced at the same time, the impurities are blocked in the seepage pores between the packing particles, and the seepage pores are blocked, thereby reducing the oil and water passage rate, and ultimately leading to the daily fluid production capacity of the oil well dramatically drop. To solve this problem, the conventional solution is to acidify the impurities. However, the acidification process is complicated and costly, especially the maintenance time is very short, usually only ten days to one or two months, which cannot effectively meet the continuous production operations of oil wells. Requirements.

For the above problems, there is an urgent need for a method of directly returning the particles in the screen annulus without changing the downhole string, so as to solve the problem of blockage of the filling layer and realize the recovery of production one or more times.

Summary of the invention

The purpose of the present invention is to overcome the defects of the prior art, and provide a plugging removal method without changing the downhole pipe string flowback and replacing the downhole packing particle packing layer, and a method for not changing the downhole pipe string flowback and replacing the downhole seal The flowback service device for the particle-separated packing layer, as well as a completion structure that does not change the flowback of the downhole tubing string and the replacement of the downhole packing particle packing layer, can realize the downhole pipe string without unsealing the downhole pipe string. The packing particles in the filling layer of the well wall annulus are returned and discharged, and new packing particles are filled into the annulus to form a new packing layer.

In order to achieve the above objectives, the present invention adopts the following technical solutions:

A method for the flowback of downhole tubing strings and replacement of the downhole packing particle packing layer without changing the downhole tubing string. The annulus between the downhole tubing string and the well wall is provided with a packing layer 5 filled with packing particles. The downhole tubing string The heel end is provided with a sliding sleeve filling tool; it is characterized in that: the method includes the following steps: (1) opening the sliding sleeve 21 of the sliding sleeve filling tool to establish a flowback channel; (2) by feeding the pipe string to the The flowback fluid is injected into the downhole tubing string, and the flowback fluid enters the annulus through the flow control device of the downhole tubing string, and carries the packing particles in the annulus through the filling hole 20 and the outer annulus, and is discharged from the wellhead.

In order to achieve the above objective, the present invention also adopts the following technical solutions:

A flowback service device for keeping the downhole string flowback and replacing the downhole packing particle packing layer is characterized in that: the flowback service device has a lumen-like structure as a whole, and the front end is provided with a liquid outlet channel 16, and The rear end is provided with a connecting device 10 for connecting the flowback pipe string, and a cavity 13 connecting the liquid outlet channel 16 and the flowback pipe string is provided in the axial direction; the middle and outer circumference of the flowback service device is provided with a sliding slide for pushing away The switch device 15 of the sliding sleeve 21 of the sleeve filling tool, and the sealing insert 14 used in conjunction with the sealing barrel of the sliding sleeve filling tool to realize the sealing between the heel end of the downhole pipe string and the wellbore; the flowback service device and the sliding sleeve Used in conjunction with the sleeve filling tool, it is used to establish a flowback channel for the packed particles in the filling layer.

A well completion structure that does not change the flowback of downhole tubing string and replace the downhole packing particle packing layer. The annulus between the downhole tubing string and the well wall is provided with a packing layer filled with packing particles. The downhole tubing The heel end of the column is provided with a sliding sleeve type filling tool, which is characterized in that the wellbore is provided with a flowback service device as described in the above technical solution.

A completion structure without changing the flowback of downhole tubing string and replacing the downhole packing particle packing layer is characterized in that: a perforated pipe 23 is provided in the wellbore, and the perforated pipe 23 is sealed by a hanger or suspension. The hole is suspended in the upper casing 1 of the open hole; the perforated pipe 23 is provided with a downhole string 6, and the heel of the downhole string 6 is provided with a top packer 2 and a sliding sleeve filling tool 3. The top packer 2 is set in the casing 1 above the hanging position of the perforated pipe 23; between the downhole string 6 and the perforated pipe 23, and between the perforated pipe 23 and the open hole wall 7 A filling layer 5 filled with packing particles is provided in the annulus.

The invention provides a method for replacing the packing layer without changing the pipe string, a flowback service device and a well completion structure, which avoids the fishing operation of the traditional downhole packer and flow control screen string, improves the efficiency of understanding the plugging, and also improves the understanding The plugging effect extends the normal production time after understanding the plugging, simplifies the workover process, shortens the operation time, and reduces the costs and losses caused by the workover and production shutdown. At the same time, this kind of completion structure can prevent the well wall from collapsing and blocking the passage for later flowback and replacement of the particle packing layer. The above-mentioned completion structure utilizes the perforated pipe to play a supporting role in advance to reserve channels for particle flowback and replacement filling.

Description of the drawings

Figure 1 is a schematic diagram of the wellbore structure in an open hole with continuous packer segmented flow control technology completion;

Figure 2 Schematic diagram of the wellbore structure of a cased perforated well with a continuous packer segmented flow control technology completion;

Fig. 3 is a schematic diagram of the wellbore structure and the flowback process of the packed particles in the process of applying the method of not changing the downhole string flowback and replacing the downhole packing particle packing layer in the open hole well.

Figure 4 is a schematic diagram of the wellbore structure and the flowback process of the packing particles in the process of applying the method of not changing the downhole string flowback and replacing the downhole packing particle packing layer described in Example 1 and the casing perforation well .

5 is a schematic diagram of the structure of the flowback service device described in Embodiment 2.

Fig. 6 is a schematic diagram of a completion structure in Example 3 without changing the downhole pipe string flowback and replacing the downhole packing particle packing layer.

detailed description

Hereinafter, in conjunction with the accompanying drawings 1 to 6, the specific implementation of the method for replacing the packing layer without changing the pipe string, the flowback service device and the completion structure of the present invention will be further described. The method for replacing the packing layer without changing the pipe string, the flowback service device and the completion structure of the present invention are not limited to the description of the following embodiments.

As shown in Figure 1 and Figure 2, they are respectively a schematic diagram of the wellbore structure in an open hole with a continuous packer segmented flow control technology completion in an open hole, and a cased perforated well with a continuous packer. Schematic diagram of the wellbore structure of a well completed with volume segmented flow control technology. Referring to Figure 1, the open-hole wellbore structure includes the bare well wall 7 of the production section, and the top packer 2 set in the casing 1 (that is, the casing installed in the upper part of the production section), The lower part of the top packer 2 is connected with a sliding sleeve filling tool 3, the sliding sleeve filling tool 3 itself has a sealing cylinder 4, a filling hole 20 and a sliding sleeve 21, and the lower part of the sliding sleeve filling tool is connected with a flow control screen 6, which controls The bottom of the flow screen 6 is provided with a guide shoe 8, and the annulus between the flow control screen 6 and the open hole wall 7 is provided with a filling layer 5 filled with packing particles. Referring to Fig. 2, the casing perforated well bore structure is different from the open hole structure shown in Fig. 1 only in that the borehole wall is a perforated casing borehole 9. The casing wall 9 is connected to the casing 1.

The downhole pipe string in the present invention refers to a screen or sand control screen with flow control device installed, flow control function, for example, flow control screen in the prior art, including ICD screen, AICD screen, AICV Screens and so on. Among them, the full name of ICD is Inflow Control Device, that is, flow control device. The flow control device can control the flow rate of fluid flowing out or into the pipe. The specific types include orifice type, flow channel type, nozzle type, or any combination of the above three types. Type. The ICD screen is the sand control screen with the flow control device installed; the full name of AICD is Autonomous Inflow Control Device, which is the automatic flow control device, and the AICD screen is the sand control screen with the flow control device installed; the full name of AICV is Autonomous Inflow Control Valve. , That is, the automatic flow control valve, the AICV screen is installed with the automatic flow control valve. In the present invention, the "bottom" of the downhole tubular string refers to the end of the tubular string that enters the deep part of the wellbore, and the "heel end" refers to the end of the tubular string closest to the wellhead.

The delivery string mentioned in this article refers to a string of pipes connected by drill pipes or tubing used to deliver various service tools to target locations in the wellbore. The perforated pipe mentioned in this article refers to a steel pipe that has holes in the steel pipe to support the shaft wall. The casing described in this article refers to the steel pipe used to support the wall of the oil and gas well to ensure the normal operation of the entire oil well after the drilling process is carried out and the well is completed.

The "packaging particles" that are filled into the annulus (or flow back from the annulus) as described herein include ultralight particles, hollow glass beads, fly ash, etc. Among them, the density of ultralight particles is between 0.96g/cm ³ -1.06g/cm ³ (real density instead of bulk density, the same below), and the particle size is between 0.05-1mm, including cross-linked styrene and polyvinylbenzene Copolymer; the density of hollow glass beads is between 0.5g/cm ³ -1.8g/cm ³ and the particle size is between 0.03-1mm; the density of hollow beads in fly ash is between 0.5g/cm ³ -1.8g/ cm ³ , the particle size is between 0.03-1mm.

Example 1:

Regarding the completion structure shown in Figure 1 and Figure 2, this embodiment provides a method of not changing the downhole pipe string flowback and replacing the downhole packing particle packing layer, which includes the following steps:

(1) Open the sliding sleeve 21 of the sliding sleeve filling tool to establish a flowback channel; the path of the flowback channel according to the flow direction of the flowback liquid is: feeding pipe string, flow control screen, flow control screen The annulus A between the well wall, the filling hole 20 of the sliding sleeve filling tool, and the outer annulus C between the pipe string and the well wall.

The specific method for opening the sliding sleeve 21 of the sliding sleeve filling tool is as follows: (1.1) The flowback service device 10 used in conjunction with the sliding sleeve filling tool is lowered by the pipe string, and (1.2) After the flowback service device 10 is in place , The positioning device 12 of the flowback service device 10 conflicts with the positioning surface of the sliding sleeve filling tool and realizes the limit; the sealing insert 14 of the flowback service device 10 is inserted into the sealing cylinder 4 of the sliding sleeve filling tool to realize the flow control screen The sealing between the heel end of the pipe and the wellbore; the switch device 15 of the flowback service device pushes the sliding sleeve 21 of the sliding sleeve filling tool to open the filling hole 20; the filling hole 20 and the outer annulus A are filled by sliding sleeve The gap B between the tool and the flowback service device is connected to form a flowback channel.

As shown in Fig. 3 and Fig. 4, it is a schematic diagram of the well structure and the flow-back process of packed particles after the flow-back service device 10 is installed.

(2) The flowback fluid is injected into the flow control screen through the pipe string from the wellhead, and the flowback fluid enters the annulus A through the flow control device of the flow control screen, and carries the packing particles in the annulus A It is discharged from the wellhead through the filling hole 20, the gap B and the outer annulus C.

Specifically, all the flow control screens are equipped with flow control devices with flow restriction, so the flow control screens can be evenly configured with the injected fluid, so that fluid flows out of each screen, and no additional installation is required. Into the flushing pipe to configure the flow of fluid on each screen. The flowback liquid enters the annulus A outside the flow control screen through the screen, so that the particles in the filling layer 5 start from the heel end of the flow control screen, and continue to loosen and peel off under the washing of the flowback liquid, and follow the flowback. The liquid migrates outward, passes through the filling hole 20, the gap B, the through hole 11 and the outer annular space C of the flowback service device 10, and finally flows back to the ground.

Specifically, the flowback liquid is pumped into the pipe string through the ground pumping equipment, and enters the flow control screen through the flowback service device. The injection pressure of the flowback liquid, that is, the injection pressure of the ground pump is 1-35 MPa. In actual operation, the pump injection pressure needs to be set and adjusted according to the throttling strength of the flow control device on the flow control screen 6. The injection flow rate of the flowback liquid is greater than the minimum carrying flow rate of the packer particles moving upward to ensure that the flowback liquid can carry the packer particles back to the ground. The flowback fluid is formation water or formation water containing lubricating components, such as slippery water containing surfactant components.

(3) After the flowback of the packed particles in the annulus is completed, take out the flowback service device. At this time, the sliding sleeve 21 of the sliding sleeve filling tool retracts, and the filling hole 20 is closed.

(4) According to needs, the filling service device used in conjunction with the sliding sleeve filling tool is inserted into the pipe string to refill the annulus with packing particles.

Example 2:

This embodiment provides a specific structure of the flowback service device 10 applied to the method described in the first embodiment for not changing the flowback of downhole tubing string and replacing the downhole packing particle packing layer.

As shown in Figure 5, the flowback service device 10 has a lumen-like structure as a whole. The front end is provided with a liquid outlet channel 16, and the rear end is provided with a connecting device for connecting the flowback pipe string. The passage 16 and the cavity 13 of the return pipe string are connected by a conventional sealed screw thread connection. Specifically, the liquid outlet channel 16 is an open structure (that is, the front end is directly the open end of the cavity), a porous structure (a porous structure similar to a shower head), or a plurality of slit structures (along the top of the flowback service device) A plurality of long slits are provided on the circumferential surface, and the slits may be arranged along the axial or circumferential direction of the flowback service device, or arranged in an oblique direction).

A switch device 15 and a sealing insert 14 are provided on the outer circumference of the middle of the flowback service device. The switch device 15 is an elastic protrusion structure arranged on the outer circumference of the middle of the flowback service device, and its purpose is to push the switch device 15 of the sliding sleeve 21 of the sliding sleeve filling tool during the process of running into the flowback service device. , Thereby exposing (ie opening) the filling hole 20 sealed by the sliding sleeve 21; in the process of removing the flowback service device, the sliding sleeve 21 of the sliding sleeve filling tool is pushed back by the switch device 15, and the filling hole 20 is closed. The sealing insert 14 is used in conjunction with the sealing barrel of the sliding sleeve filling tool to realize the sealing between the heel end of the flow control screen and the wellbore, so as to ensure that the flow-back fluid injected into the flow control screen can only pass through the flow control The flow control channel of the screen enters the annulus. More specifically, the structure of the switch device 15 and the sealing insert 14 are the same as the structure and principle of the switch device and the sealing insert provided on the existing filling service tool.

The flowback service device is also provided with a positioning device that conflicts with the positioning surface of the sliding sleeve type filling tool to achieve position limitation. Specifically, the positioning device is a step structure arranged on the outside of the flowback service device, and the front end of the flowback service device is circumferentially provided with a positioning flange, which is used in conjunction with the top surface of the packer and is used in the flowback service device. When descending to a predetermined position, the positioning device conflicts with the positioning surface, preventing the flowback service device 10 from continuing to descend, thereby realizing the limit of the flowback service device in the sliding sleeve filling tool.

The connecting device is also provided with a through hole 11 for passing the flow-back liquid. The through hole 11 is not limited to a circular shape, as long as it can lead out the flowback liquid. The flowback service device 10 is used in conjunction with a sliding sleeve filling tool to establish a flowback channel for packing particles in the filling layer.

Referring to Figures 3 and 4, the matching relationship between the flowback service device 10 and the sliding sleeve filling tool in the wellbore is illustrated after the flowback service device 10 is installed.

Example 3:

This example provides a well completion structure that does not change the downhole string flowback and replaces the downhole packing particle packing layer. The device described in Example 2 can be used to realize the particle packing of the packing layer according to the method described in Example 1. Flowback and replacement.

As shown in Figures 3 and 4, a completion structure that does not change the downhole pipe string flowback and replace the downhole packing particle packing layer. The completion is an open hole or a perforated cased well, and the corresponding well wall It is the wellbore of an open hole wellbore or a wellbore of a perforated cased well. The annulus between the downhole pipe string and the well wall is provided with a packing layer filled with packing particles, and the heel end of the downhole pipe string is equipped with a sliding sleeve type filling tool;的 Fuckback service device 10.

Preferably, the downhole pipe string is a flow control screen, and a guide shoe 8 is provided at the bottom of the flow control screen. The guide shoe 8 is a dead-block guide shoe without a flow channel, or a flow control screen Floating guide shoes with unidirectional flow from the inside of the tube to the outside. The advantage of using floating guide shoes is that at the end of the flowback, since the resistance of the flowback fluid flowing through the floating guide shoes is small, the flowback fluid mainly flows from the position of the floating guide shoes, which can more thoroughly pack particles in the annulus. Scour and flowback.

Example 4:

This example provides another completion structure without changing the downhole string flowback and replacing the downhole packing particle packing layer. The device described in Example 2 can be used to realize the packing layer packing particles according to the method described in Example 1. Flowback and replacement.

As shown in Fig. 6, the difference between this embodiment and Embodiment 4 is only that: a perforated pipe 23 is also provided in the wellbore. Specifically, a well completion structure that does not change the downhole pipe string flowback and replaces the downhole packing particle packing layer, the wellbore is provided with a perforated pipe 23, and the perforated pipe 23 is suspended on the upper casing of the open hole 1; inside the perforated pipe 23 is provided with a flow control screen 6, the heel of the flow control screen 6 is provided with a top packer 2 and a sliding sleeve filling tool 3, the top packer 2 sits Is sealed in the casing 1 above the hanging position of the perforated pipe 23; the annulus between the flow control screen 6 and the perforated pipe 23, and between the perforated pipe 23 and the open hole wall 7 is provided with a filling seal Particle-separated packing layer 5; the wellbore is provided with the flowback service device described in embodiment 2.

Preferably, the downhole pipe string is a flow control screen, and a guide shoe 8 is provided at the bottom of the flow control screen. The guide shoe 8 is a dead-block guide shoe without a flow channel, or a flow control screen Floating guide shoes with unidirectional flow from the inside of the tube to the outside.

Example 5:

This embodiment provides a practical application of the technical solutions described in the foregoing embodiments 1-4.

The horizontal section of an open-hole well is 300 meters in length, 8-1/2in open-hole well, with 9-5/8in casing on the upper part, 9-5/8in packer in the well, set at 9-5/8in In the casing, the lower part is connected with a sliding sleeve filling tool, and the lower part is connected with 50 5.5in flow control screens. Each flow control screen is equipped with a set of ICD flow control devices. The bottom of the flow control screen is equipped with floating guide shoes to control the flow. The outer annulus of the flow screen is filled with a packing layer of particles, with a volume of about 8.8 cubic meters. After the completion of the well, the electric pump was put into production. At the initial stage of production, it produced 845 barrels of fluid and 830 barrels of oil per day. After 3 months of production, mud and other particles from the formation blocked the packing layer of the packing particles, resulting in a drop in daily fluid production to 135 barrels and daily oil production to 83 barrels.

In order to solve the blocking problem of the packed particle packing layer, the method described in Example 1 was used to perform flowback and replacement of the downhole packing particle packing layer for the well. During the period, the surface pumping pressure was 15MPa and the maximum pumping rate was 1.2 m3/min. , The operation time is 5 hours, the flowback rate is 100%, and the outer annulus of the flow control screen is basically cleared. Then put forward the flowback service pipe string, run the filling service pipe string, according to the filling operation process, fill the new packing particles into the outer annulus of the flow control screen to form a new packing layer of packed particles, and finally put forward the filling service pipe column. The electric pump and the production pipe string were installed again, and the pump was turned on. After stable production, the daily output of 685 barrels of fluid and 642 barrels of daily oil was restored to more than 80% of the daily output of the initial stage of production, and the effect of blocking removal was obvious.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

A method that does not change the downhole pipe string flowback and replaces the downhole packing particle packing layer. The annulus between the downhole pipe string and the well wall is provided with a packing layer filled with packing particles. The heel end is provided with a sliding sleeve filling tool; it is characterized in that the method includes the following steps:

(1) Open the sliding sleeve of the sliding sleeve filling tool to establish a flowback channel;

(2) The flowback fluid is injected into the downhole tubing string through the pipe string. The flowback fluid enters the annulus through the flow control device of the downhole tubing string, and carries the packing particles in the annulus through the filling hole and the oil sleeve annulus. , Discharged from the wellhead.
The method for flowback and replacement of downhole packing particles without changing the downhole string according to claim 1, characterized in that: the method for establishing flowback channels comprises the following steps:

(1.1) The flowback service device used in conjunction with the sliding sleeve filling tool is lowered through the feeding pipe string;

(1.2) After the flowback service device is in place, the sealing insert of the flowback service device is inserted into the sealing barrel of the sliding sleeve filling tool to realize the sealing between the heel end of the downhole string and the wellbore; the switch of the flowback service device The device pushes the sliding sleeve of the sliding sleeve filling tool to open the filling hole; the filling hole and the annulus of the oil sleeve are communicated through the gap between the sliding sleeve filling tool and the flowback service device.
The method for flowback without changing downhole tubing string and replacement of downhole packing particle packing layer according to claim 1, characterized in that: the surface injection pressure of the flowback fluid is 1-35MPa; the injection of the flowback fluid The flow rate is greater than the minimum carrying flow rate of the packing particles moving upward; the flowback fluid is formation water or formation water containing lubricating components.
The method for flowback and replacement of downhole packing particles without changing the downhole string according to claim 1, characterized in that it further comprises the following steps:

(3) After the flowback of the packing particles in the annulus is completed, the annulus is filled with packing particles again.
The method for flowback and replacement of downhole packing particles without changing the downhole string according to claim 2, characterized in that it further comprises the following steps:

(3) After the flowback of the packed particles in the annulus is completed, take out the flowback service device;

(4) The filling service device used in conjunction with the sliding sleeve type filling tool is fed into the pipe string to refill the annulus with the packing particles.
A flowback service device for keeping the downhole string flowback and replacing the downhole packing particle packing layer is characterized in that: the flowback service device has a lumen-like structure as a whole, with a liquid outlet channel at the front end, and The end is provided with a connecting device for connecting the flowback pipe string, and a cavity connecting the liquid outlet channel and the flowback pipe string is provided in the axial direction; the middle and outer circumference of the flowback service device is provided with a sliding sleeve type filling tool for pushing away The sliding sleeve switch device of the sliding sleeve, and the sealing plug used in conjunction with the sealing barrel of the sliding sleeve filling tool to realize the sealing between the heel end of the downhole string and the wellbore; the flowback service device is used in conjunction with the sliding sleeve filling tool, It is used to establish a flowback channel for the particles in the packing layer.
The flowback service device for flowback without changing the downhole tubing string and replacement of the downhole packing particle packing layer according to claim 6, wherein the connecting device is provided with a through hole for passing the flowback fluid inside.
The flowback service device for flowback without changing the downhole tubing string and replacement of the downhole packing particle packing layer according to claim 7, wherein the liquid outlet channel is an open structure, a porous structure, or multiple Slot structure.
A well completion structure that does not change the flowback of downhole tubing string and replace the downhole packing particle packing layer. The annulus between the downhole tubing string and the well wall is provided with a packing layer filled with packing particles. The downhole tubing The heel end of the column is provided with a sliding sleeve type filling tool, which is characterized in that the flowback service device according to any one of claims 6 to 8 is provided in the wellbore.
The completion structure without changing the downhole string flowback and replacing the downhole packing particle packing layer according to claim 9, wherein the well wall is an open hole well bore or a well bore of a perforated casing well.
The completion structure without changing the flowback of the downhole tubing string and the replacement of the downhole packing particle packing layer according to claim 9, wherein the downhole tubing string is a flow control screen, and the bottom of the flow control screen There is a guide shoe, and the guide shoe is a dead-block type guide shoe without a flow channel, or a floating guide shoe that flows unidirectionally from the inside of the flow control screen to the outside.
A well completion structure without changing the downhole pipe string flowback and replacing the downhole packing particle packing layer is characterized in that: a perforated pipe is provided in the wellbore, and the perforated pipe passes through a hanger or a suspension packer, The casing is suspended in the upper part of the open hole; the perforated pipe is provided with a downhole string, the heel of the downhole string is provided with a top packer and a sliding sleeve filling tool, and the top packer is set in Inside the casing above the hanging position of the perforated pipe; between the downhole pipe string and the perforated pipe, and between the perforated pipe and the open hole wall, a packing layer filled with packing particles is provided.
The completion structure without changing the downhole string flowback and replacing the downhole packing particle packing layer according to claim 12, characterized in that: the wellbore is provided with any one of claims 6 to 8 Flowback service device.
The completion structure without changing the flowback of downhole tubing string and replacing the downhole packing particle packing layer according to claim 12, wherein the downhole tubing string is a flow control screen, and the bottom of the flow control screen There is a guide shoe, and the guide shoe is a dead-block type guide shoe without a flow channel, or a floating guide shoe that flows unidirectionally from the inside of the flow control screen to the outside.