CN116104440A

CN116104440A - Tubular column for oil well injection and solution injection handling method

Info

Publication number: CN116104440A
Application number: CN202111325206.8A
Authority: CN
Inventors: 姬泽敏; 陈兴隆; 张群; 张帆; 高建; 韩海水
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2021-11-10
Filing date: 2021-11-10
Publication date: 2023-05-12

Abstract

The invention discloses a tubular column for oil well injection and a solution injection handling method. The oil well is annotated and is adopted tubular column includes: the oil pipe is characterized in that an oil discharge pipe is arranged at the top of the oil pipe, a liquid injection pipe is arranged at the top of an oil collar space formed between the oil pipe and the sleeve, a high-pressure sealing device is arranged at a wellhead of the oil pipe, and a flow direction control valve is arranged at the tail end of a downhole tubular column of the oil pipe. The invention can realize the same-well high-frequency intermittent injection and production, improve the action frequency of the solution and stratum crude oil, improve the oil production efficiency of a single throughput period, reduce the construction period between throughput processes and improve the oil production speed.

Description

Tubular column for oil well injection and solution injection handling method

Technical Field

The invention relates to a tubular column for oil well injection and a solution injection handling method, belonging to the technical field of oil field development

Background

The throughput technology of oil extraction is usually based on a gas medium (steam), and steam throughput is a yield increasing method for heavy oil extraction by injecting a certain amount of steam into an oil well, closing the well for a period of time, and opening the well after the heat energy of the steam is diffused to an oil layer. The steam huff and puff operation process can be divided into three stages, namely steam injection, well stewing and recovery. The steam huff and puff method is the most commonly used method in thick oil exploitation and is also the best thermal exploitation method for industrial application. Steam stimulation is also known as steam stimulation or cyclic steam injection. The steam throughput mainly utilizes the characteristic of strong compression/expansion performance of gas, and has better effect, but the production cost is high, and the input cost of gas injection equipment is high.

Compared with the gas injection throughput technology, the solution injection throughput technology has relatively poor development effect, but is an optimal development mode of a specific oil reservoir due to the characteristics of low cost, simple operation and the like, so that the technology has a certain application range.

The solution injection throughput technology is mainly applied to oil reservoirs which cannot be supplemented with energy, and corresponding relations cannot be established among oil wells of the oil reservoirs due to complex oil layer relations and other reasons. The solution may have a certain functionality, for example for thick oils, a solution with viscosity reducing function may be chosen.

The solution injection throughput technology is to inject solution into an oil well, soak the well for a period of time, then pump oil for production, and obtain more yield by utilizing the partial pressure increased by the injected solution and the oil carrying capacity of the solution. As can be seen from fig. 1, the fluid injected and extracted at the next time basically passes through the path of the fluid at the previous time, and the efficiency of new extraction gradually decreases with the increase of the times.

Disclosure of Invention

In view of the technical drawbacks and disadvantages of the prior art, embodiments of the present invention provide a tubing string for well injection and a solution injection throughput method that overcomes or at least partially solves the above-described problems.

An embodiment of the present invention provides a high pressure sealing device, including: the outer cylinder is sleeved with a telescopic sealing bag and a positioning ring inside the outer cylinder;

the outer cylinder is annular and can be sleeved on the polish rod, and a supporting table is arranged at the bottom of the outer cylinder;

the positioning ring is placed at the top of the telescopic sealing bag and is used for positioning and fixing the telescopic sealing bag;

the telescopic sealing bag is annular and is placed on the supporting table, and is tightly contacted with the polish rod in an extending state so as to realize sealing, and is not contacted with the polish rod in a contracting state so as to release sealing.

Another embodiment of the present invention provides a flow direction control valve, comprising: a control valve portion and a power portion;

the control valve portion includes: valve body, valve ball and gear set; the valve ball and the gear set are arranged in the valve body, and a channel for liquid to flow through is formed in the valve ball;

the power section includes: a housing and fan blades; the shell is annular and surrounds the valve body, and the fan blades are arranged in the shell;

the gear sets are respectively meshed with a valve ball shaft of the valve ball and a fan blade shaft of the fan blade;

the fan blades drive the gear set to enable the valve ball to rotate to close the channel under the condition that the fan blades rotate towards one direction under the impact of liquid; and in the state of rotating in the other direction, the gear set is driven to enable the valve ball to rotate to open the channel.

Yet another embodiment of the present invention provides a tubing string for well injection, comprising: oil pipe and sleeve pipe, the oil pipe top is provided with arranges oil pipe with the top in the oily lantern ring space that forms between the sleeve pipe is provided with annotates the liquid pipe, wherein:

the high-pressure sealing device is arranged at the wellhead of the oil pipe, and the flow direction control valve is arranged at the tail end of the underground pipe column of the oil pipe.

The invention further provides a solution injection handling method based on the tubing string for oil well injection, which comprises the following steps:

sealing the oil pipe by the high-pressure sealing device;

injecting a solution into the oil collar space through the liquid injection pipe to close the flow direction control valve;

when the injection pressure reaches a first threshold value, discharging the solution through the liquid injection pipe until the injection pressure is reduced to a second threshold value, so that the flow direction control valve is opened;

unsealing the oil pipe by the high-pressure sealing device;

withdrawing fluid from said tubing and draining it through said sucker tube;

repeating the above process until the preset injection and production frequency is reached.

The embodiment of the invention at least realizes the following technical effects: the method can realize the same-well high-frequency intermittent injection and production, improve the action frequency of the solution and stratum crude oil, improve the oil production efficiency of a single throughput period, reduce the construction period between throughput processes and improve the oil production speed.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:

FIG. 1 (a) is a cross-sectional view of the conventional well injection throughput, and (b) is a cross-sectional view of the reservoir;

FIG. 2 is a schematic diagram of a tubular column for oil well injection according to an embodiment of the present invention;

fig. 3 (a) shows an unsealed state of the high-pressure sealing device, and (b) shows a sealed state;

fig. 4 (a) shows a longitudinal cross-section of the bellows seal bag and (b) shows a top view;

fig. 5 (a) shows a longitudinal cross-sectional view of the outer tube 31 and (b) shows a top view;

FIG. 6 is a schematic diagram illustrating an installation of a flow direction control valve according to an embodiment of the present invention;

fig. 7 (a) shows a longitudinal sectional view of the flow direction control valve and (b) shows a top view;

FIG. 8 is a flow chart of a method of priming solution throughput provided by an embodiment of the present invention;

fig. 9 (a) shows a structure of the pumping unit for production, and (b) shows a structure of the screw pump for production.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of apparatus and methods consistent with aspects of the invention as detailed in the accompanying claims.

First, technical terms of the present invention will be briefly described:

reservoir raw energy: refers to the amount of energy that the reservoir has not been developed. This raw energy is part of the reservoir composition, is the condition and basis for reservoir development, and thus becomes a further focus of reservoir description. The reservoir raw energy may be evaluated using a reservoir energy index. The strength of the reservoir energy refers to the difficulty of the reservoir fluid flowing into the wellbore. The easier the flow, the stronger the reservoir energy; conversely, the weaker.

A well bore: the vertical or inclined engineering is used for mining or underground engineering construction, and the vertical engineering is called a vertical well and the inclined engineering is called an inclined well. The shaft is the main entrance and exit of the mine to the ground, and is the throat engineering for lifting and transporting coal (or gangue), transporting personnel, materials and equipment, and ventilating and draining water during the production of the mine.

Oil-water well: refers to a production well or a water injection well of an oil field, and the water injection well is a well for injecting water into an oil layer. In the development process of oil fields, water is injected into oil reservoirs through special water injection wells, and the pressure of the oil reservoirs is maintained or recovered, so that the oil reservoirs have stronger driving force, and the exploitation speed and the recovery ratio of the oil reservoirs are improved.

Dynamic sealing: refers to the seal between the relatively moving members.

Static seal: refers to the seal between two stationary surfaces.

Packing box: when the pumping unit is used for production, the wellhead dynamic sealing device for sealing the annular space between the oil pipe and the polish rod is used for multistage sealing, and has good sealing effect and high pressure resistance. Meanwhile, the universal joint is designed to adjust the eccentricity and the angle, so that the device is especially suitable for oil wells with deviated wellheads.

And (3) sealing the box: a device for sealing a wellhead when using a screw pump for production.

The present embodiment provides a tubing string for oil well injection, as shown in fig. 1, including: the oil pipe 10 and the sleeve 20, the top of the oil pipe 10 is provided with an oil discharge pipe 11, an oil collar space is formed between the oil pipe 10 and the sleeve 20, and the top of the oil collar is provided with a liquid injection pipe 21.

A high pressure seal 30 is provided at the wellhead of the tubing 10 and a flow control valve 40 is provided at the end of the tubing 10 down-hole string. Specifically, the high pressure seal 30 may be disposed below the tubing seal 60 at the top of the tubing 10. As shown in fig. 9 (a) described later, in the case of production using a pumping unit, the oil pipe sealing member 60 is specifically a packing box; as shown in fig. 9 (b) described later, in the case of production using a screw pump, the oil pipe sealing member 60 is specifically a seal box.

The specific structure of the high-pressure sealing device 30 and the flow direction control valve 40 will be described in detail with reference to the accompanying drawings as follows:

as shown in fig. 3, the high-pressure sealing device 30 includes: the outer cylinder 31 is sleeved with a telescopic sealing bag 32 and a positioning ring 33 inside the outer cylinder 31. The outer tube 31 is annular and can be fitted over the sucker rod shaft member 50. As shown in fig. 9 (a) described later, in the case of production using a pumping unit, the pumping rod shaft member 50 is a polished rod; in the case of production using a screw pump, the sucker rod shaft member 50 is a smooth shaft. For simplicity, the polish rod 50 is taken as an example, and the description is also applicable to the case of the polish rod, and will not be repeated.

The bottom of the outer cylinder 31 is provided with a supporting table 34, the telescopic sealing bag 32 is annular, the telescopic sealing bag 32 is placed on the supporting table 34, and a positioning ring 33 is placed on the top of the telescopic sealing bag 32 to position and fix the telescopic sealing bag 32. The bellows seal 32 is in close contact with the polish rod 50 in the extended state to effect sealing, and is not in contact with the polish rod 50 in the contracted state to release sealing.

Specifically, in order to expand and contract the expansion seal bag 32, a through hole 35 is formed in a side wall of the outer tube 31 at a position corresponding to the expansion seal bag 32, and an expansion liquid is injected or discharged into the expansion seal bag 32 through the through hole 35, thereby expanding and contracting the expansion seal bag 32.

Alternatively, there may be multiple bellows seal bladders 32 spaced apart from each other by spacer rings 36. Accordingly, each bellows seal 32 has a corresponding through hole 35, and a retaining ring 33 is placed on top of the uppermost bellows seal 32. The diameter of the intermediate hole between the spacer ring 36 and the positioning ring 33 is preferably greater than the diameter of the polish rod 50 by 4-6 mm, so that contact with the polish rod 50 is avoided, scratch is generated, and effective support for the telescopic sealing bag 32 is maintained.

As shown in fig. 4, which is a detailed structural schematic diagram of the bellows seal bag 32, wherein fig. 4 (a) shows a longitudinal sectional view of the bellows seal bag 32, fig. 4 (b) shows a plan view of the bellows seal bag 32,

the flexible sealing bag 32 is made of rubber, has good wear resistance and certain elasticity, and has a thickness not smaller than 2mm. As shown, the bellows seal bag 32 is annular, has a bellows structure at both ends, and has bellows surfaces formed on both sides of a flat surface, and extends in the axial direction by a distance of + -5 mm. An inflation fluid delivery pipe 47 is connected to the outside of the bellows seal bag 32, and extends out of the through hole 35 in the side surface of the outer tube 31.

The expansion fluid, such as lubricating oil, is injected to expand the bellows seal 32, axially expand and tightly contact the polish rod 50, and continue to raise the pressure to the design pressure differential, i.e., complete the sealing operation, see fig. 3 (b). When sealing is not required and the up-and-down movement of the polish rod 50 is not affected, the lubricating oil inside the bellows seal bag 32 is discharged through the inflation liquid transporting pipe 47, and sucked by the vacuum pump, so that the bellows seal bag 32 is in a contracted state, as shown in fig. 3 (a).

As shown in fig. 5, a specific structural schematic diagram of the outer tube 31 is shown, wherein fig. 5 (a) shows a longitudinal sectional view of the outer tube 31, and fig. 5 (b) shows a plan view of the outer tube 31.

The outer cylinder 31 can be made of stainless steel, the inner wall is smooth, the sealing performance of the telescopic sealing bag 32 is improved, two ends of the outer cylinder 31 are inner screw thread conical interfaces, the lower part of the outer cylinder is connected with the oil pipe 10, and the upper part of the outer cylinder is connected with an oil pipe sealing part (packing box or sealing box). The bottom of the outer cylinder 31 is provided with a supporting table 34, a first telescopic sealing bag 32 is placed on the supporting table, a spacing ring 36 is placed on the supporting table, a second sealing bag 32 is rotated, and a positioning ring 33 is placed on the top of the supporting table, so that the working space of the telescopic sealing bag 32 meets the design requirements.

Fig. 7 (a) shows a longitudinal cross-sectional view of the flow control valve, and fig. 7 (b) shows a top view. As shown in fig. 7, the flow direction control valve 40 includes: a control valve portion and a power portion. The control valve portion includes: a valve body 41, a valve ball 42 and a gear set 43; the power section includes: a housing 44 and fan blades 45.

Wherein a valve ball 42 and a gear set 43 are arranged in the valve body 41, wherein a channel 46 for liquid to flow through is arranged in the valve ball 42, in particular, the valve ball 42 can be arranged in the valve body 41 through a support bearing 48. The housing 44 is annular, surrounds the valve body 41, and the fan blades 45 are arranged in the housing 44; the gear set 43 is engaged with a ball shaft 47 of the ball 42 and a blade shaft (not shown) of the blade 45, respectively.

Specifically, the top of the valve body 41 may be provided with an upper joint 49 for connection with the oil pipe 10. As shown in fig. 6, the flow control valve 40 is connected to the end of the tubular string of the tubing 10 by an upper joint 49, thereby installing the flow control valve 40 on the tubing 10. The housing 44 has a larger diameter than the oil pipe 10 so that the fan blades 45 can be exposed to the outside of the radial range of the oil pipe 10 in a state where the valve body 41 is mounted on the oil pipe 10.

In operation, the fan blade 45 drives the gear set 43 to rotate the valve ball 42 to close the channel 46 under the condition that the fan blade rotates in one direction under the impact of liquid; in the state of rotating in the other direction, the gear set 43 is driven to rotate the valve ball 42 to open the passage 46.

The flow control valve 40 is used in conjunction with the high pressure seal 30 to more precisely control the flow direction of the fluid.

When the flow direction control valve 40 is not used in the prior art, in the process of injecting the solution, the solution enters not only the oil layer but also the oil pipe 10, and reversely enters the oil pipe 10 and the sucker rod annulus along the oil well pump, the pressure is the same as the injection pressure, and the high-pressure sealing device 30 bears the whole pressure-resistant sealing function.

When the flow direction control valve 40 is used in this embodiment, the flow direction control valve 40 is closed during the injection of the solution, so that the solution only enters the oil layer, and the high pressure sealing device 30 hardly takes on the pressure-resistant sealing effect. During the production phase, the flow control valve 40 is opened and formation fluids can only enter the tubing 10. In the event that the formation is prone to sand formation or has a blockage, etc., the flow control valve 40 reduces the risk of blockage of the pump inlet.

Downhole fluid control may also be provided by flow control valve 40 in the event of failure of high pressure seal 30.

An embodiment of a method of handling a solution injection based on a well injection using a tubular string with a high pressure seal 30 and a flow control valve 40 is described below with reference to the accompanying drawings, as shown in fig. 8, and includes the steps of:

at step 100, the tubing 10 is sealed by the high pressure sealing device 30.

As shown in fig. 5, the expansion liquid is injected into the bellows seal bag 32 through the through hole 35 of the high-pressure seal device 30, and the bellows seal bag 32 is stretched until it is brought into close contact with the polish rod 50, thereby sealing the oil pipe 10. The telescopic sealing bag 32 is tightly contacted with the polished rod 50 under the support of internal liquid to realize the toroidal sealing, and the pressure-resistant difference can reach more than 10MPa, so that the high pressure in the process of injecting the solution can be borne, and the pressure difference between the inside and the outside of the oil pump or the screw pump is in a balanced state.

In contrast, if only the existing tubing sealing components (packing or seal boxes) are employed to effect the seal, the effective pressure of the seal at dynamic sealing conditions is no greater than 1MPa; the effective pressure under the static sealing condition is not more than 3Mpa, and the high pressure in the process of injecting the solution cannot be borne.

Step 200, injecting the solution into the oil jacket space through the injection pipe, and closing the flow direction control valve 40.

Specifically, the pre-fluid and the displacement fluid may be sequentially injected. The pad fluid generally has special functions such as viscosity reduction, solubilization, etc.; the displacement fluid is typically formation water or injection water.

As described above, when the oil jacket is filled with the solution, the fan blade 45 is impacted downward by the solution, so that the fan blade 45 rotates counterclockwise, the gear set 43 is driven to rotate the valve ball 42, and after the channel 46 is closed, the gear set 43 limits to stop the fan blade 45 from continuing to rotate, so that the flow direction control valve 40 is closed. At this point, the solution will only enter the reservoir and not the tubing 10.

And 300, discharging the solution through the liquid injection pipe until the injection pressure drops to a second threshold value when the injection pressure reaches the first threshold value, and opening the flow direction control valve.

The step is a pressure relief process. The first threshold is, for example, 10MPa and the second threshold is, for example, 3MPa. When the oil layer fluid is discharged reversely through the oil sleeve ring, the fan blades 45 are impacted upwards by the fluid, the fan blades 45 rotate clockwise to drive the gear set 43 to rotate the valve ball 42, the channel 46 is opened, the gear set 43 limits to stop the fan blades 45 from continuing to rotate, and accordingly the flow direction control valve 40 is opened.

Step 400, unsealing the oil pipe by the high-pressure sealing device 30.

As shown in fig. 3, the expansion liquid inside the bellows seal bag may be discharged through the through hole 35, and the bellows seal bag 32 may be contracted to be separated from the polish rod, thereby releasing the seal of the oil pipe. When the telescopic sealing bag 32 is contracted, a gap is kept between the telescopic sealing bag and the polish rod 50, abrasion resistance is avoided, and normal operation of the packing box or the sealing box above is not affected.

Step 500, liquid is withdrawn from the tubing 10 and discharged through the tubing.

Specifically, fluid is drawn from the tubing 10 by the pump, and the fan 45 is always impacted upward by the fluid during operation of the pump, so that the flow control valve 40 is always open. The design avoids the construction problems of cable layout and the like of the electric control valve.

The above process is repeated until a predetermined injection and production frequency, for example, 3 injection and production frequencies, is reached.

The following illustrates an example of a specific implementation of the solution injection throughput method according to the present invention.

(1) Mounting apparatus

The primary installation requires tripping of the well string. After the oil well injection pipe column is installed, a high-pressure pump truck, related injection solution and other matched equipment are connected at a wellhead sleeve valve, see figure 2

(2) Sealing is implemented by a high-pressure sealing device

And lubricating oil is filled into the two liquid injection pipes, and an external pipeline is connected with the liquid injection pipes and forms a seal with the outer cylinder. And stopping filling when the pressure is 17MPa, observing the pressure change condition, and if the pressure is kept stable, indicating that the high-pressure sealing device enters into an operating state.

(3) Injecting solution, closing flow direction control valve

In this example, the first pass of the pad solution is 20m ³ Displacement fluid 40m ³ 。

Continuously injecting the solution into the oil jacket ring, and ensuring no intermittence between the pre-liquid and the displacement liquid. The solution has larger drop in the initial stage in the oil jacket annular space and has strong kinetic energy; entry into the formation remains 30m ³ Flow rate/d. Under the impact of the flow, the fan blade flowing to the control valve rotates anticlockwise and closes the control valve, so that the solution does not enter the oil pipe.

After injection is completed, the change of injection pressure is observed, and if the pressure reduction speed is slow, the stratum absorption state is saturated. If the reduction speed is fast, the stratum energy is not supplemented in place, and a reference is provided for the next throughput design.

(4) High-frequency intermittent injection and production of first throughput period

In the prior art, after the solution is injected, the well is closed off, and the injection pressure is waited to be reduced to about 3MPa, so that the tubular column tripping operation can be implemented. The method cancels the operation of well shut-in. After the solution is injected, repeated injection and production operation, namely high-frequency intermittent injection and production, is started.

The injection pressure after the solution is injected is 10MPa, the injection direction of a wellhead is changed, and liquid is discharged into a liquid storage tank of the high-pressure pump truck through a sleeve valve. When the liquid is discharged, the fan blade of the underground flow direction control valve rotates clockwise and opens the flow direction control valve, so that part of the solution enters the oil pipe. When the casing discharge pressure reaches 3MPa, the flow direction control valve is closed, and the discharge is stopped. Opening a liquid injection pipe valve of the high-pressure sealing device, releasing pressure, and sucking after the pressure is lower than 3MPa to enable the sealing bag to shrink and not contact with the polish rod.

The pumping unit is started, the pumped oil-free solution can enter the pump truck, and when the pumped liquid contains oil, the pumping unit is stopped or the liquid enters the production output pipeline. The structure of the pumping unit is shown in fig. 9 (a), and the structure of the screw pump is shown in fig. 9 (b).

When the total discharge liquid amount reaches 40m ³ And entering the next injection stage of the throughput round.

Repeating the related operations of steps (2) to (4) until the design frequency, for example, 3 injection and production frequencies, is completed. As the throughput period is extended, the injection and extraction frequency is gradually reduced.

(5) The oil pump works and continuously produces

After the design of the injection and production frequency is completed, the normal production state is already entered. And (3) carrying out dynamic production monitoring, judging the effectiveness of the method according to the information such as the water content change of the produced fluid, the accumulated oil production and the like, and making a next working scheme.

(6) Implementing a second throughput cycle

When the well production decreases to the design level of the plan, a second throughput plan is implemented. The steps refer to the relevant operations in (1) - (5), and tripping of the tubular string is no longer required.

In the existing solution injection handling technology, a tubular column in an oil well is started, a solution (containing a functional solvent) is injected into a stratum along the space of an oil pipe or an oil/casing pipe through a high-pressure pump truck until the injection pressure is increased to Pin, and then the well is closed. And (3) flushing, discharging a certain amount of liquid from the injection port when the pressure is reduced to Pou, then performing pumping construction, and performing a mechanical oil production mode after the pumping unit or the screw pump is installed. The well is usually braised for at least more than 10 days, mainly waiting for the injection pressure to drop to a level capable of being mined, and when the pressure is higher than Pou, the sealing between the packing box of the pumping unit and the polished rod, the sealing box of the screw pump and the motor shaft is invalid, so that leakage, thorn leakage and even out-of-control spray are generated.

According to the oil well injection pipe column, high-pressure sealing is achieved through the arrangement of the high-pressure sealing device, so that the time for well shut-in can be shortened, and components such as an oil pump in an oil well can be omitted. Namely, after the solution is injected into the oil jacket ring at any time, the production of the oil pump can be started at any time. Therefore, the invention has the following advantages:

1. the method realizes the same-well high-frequency intermittent injection and production method, so that the high frequency of the functional solution acts on the crude oil of the stratum in the one-time throughput process, the one-time contact is changed into the reciprocating contact with controllable times, and the oil production efficiency of the single throughput period is improved by more than 2 times;

2. the same-well high-frequency intermittent injection and production method is easier to implement, the construction period between the handling processes is reduced, the oil production speed is improved, and the production cost is greatly reduced. In the prior art, under the condition of higher throughput pressure, the operation of tripping a pipe column is required, and the construction period and waiting pressure recovery time are at least 1 month;

3. the application efficiency and the yield increasing effect of the solution injection throughput technology are improved, so that the technology can be popularized and applied to oil reservoirs with complicated small broken blocks, oil product difference/pressure incapable of being supplemented and the like.

The technical effects of the present invention are further illustrated by comparative experiments below.

The compression coefficient of the solution is basically the same as that of water and is 4.0-5.0X10 when the solution injection throughput is carried out ^-4 MPa ^-1 The temperature is 20-120 deg. and the pressure is 7-42 MPa. From the isothermal compression coefficient formula (1):

wherein, the isothermal compression coefficient refers to the volume change rate of the gas along with the pressure change under isothermal conditions. When the pressure difference of 10MPa is estimated, the volume compression amount of the solution is less than 1%, namely the liquid has weak energy storage capacity, and the pressure difference mainly plays a role in pushing the liquid in the oil reservoir. The kinetic energy released by the liquid storage energy when the pressure difference is reduced is also low, so that the solution injection throughput mode is basically similar to the equivalent exploitation after the liquid injection amount, and a small amount of crude oil is exploited by utilizing the action of the injection solution and the crude oil in the pores. And as throughput rounds increase, the working distance gets farther and the invalid flow time gets longer.

Taking the implementation solution throughput of a certain well as an example, setting the well depth to 1000m, the thickness of an oil layer to 5m, and the radius of an effective reserve to 50m; porosity of 30%, saturation of oil in new wave pore of 70%, and oil reserves Qt of 8242m can be calculated ³ . Injecting the oil into a wellhead with the highest pressure of 15MPa, and pumping oil after the wellhead pressure is 3MPa after well soaking.

The calculation results are shown in Table 1:

TABLE 1 parametric analysis of prior art solution injection throughput techniques

According to the data, the prior art is adopted for solution injection throughput, the single throughput efficiency is rapidly reduced along with the increase of throughput times, and the construction time is prolonged. The recovery after 4 throughputs in table 1 is only 8%.

In contrast, the solution injection throughput technology provided by the invention limits single oil production efficiency, but can obviously improve single oil production efficiency by accelerating the action frequency of the solution and crude oil, namely, after the injected fluid reaches a preset pressure, the front edge (functional solution part) of the injected solution is contacted with the high-saturation crude oil for multiple times by adopting a pressure relief and repressurization mode, and meanwhile, the fluid in the whole flow passage pore related to the injected fluid also reciprocates, so that the oil film stripping action is enhanced. Thereby achieving the effect of greatly increasing the yield in one huff and puff round.

In accordance with the principles of the present invention, the results of the above-described examples are shown in Table 2:

TABLE 2 parametric analysis of the solution injection throughput technique of the present invention

As can be seen from the data shown in Table 2, when the solution injection throughput technology is adopted, the single throughput efficiency is greatly improved, the recovery ratio after 4 times of throughput is improved to 15%, and the construction time for tripping a tubular column and the well-logging time are saved.

It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, magnetic disk storage, optical storage, and the like) having computer-usable program code embodied therein.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high pressure seal, comprising: the outer cylinder is sleeved with a telescopic sealing bag and a positioning ring inside the outer cylinder;

2. The high pressure seal of claim 1, wherein: and a through hole is formed in the side wall of the outer cylinder at a position corresponding to the telescopic sealing bag, and the telescopic sealing bag is expanded and contracted by injecting or discharging expansion liquid into the telescopic sealing bag through the through hole.

3. The high pressure seal of claim 1 wherein said bellows seal is a plurality of bellows seal pockets spaced from one another by spacer rings.

4. The high pressure seal of claim 1 wherein the ends of the bellows seal bladder have a bellows configuration.

5. A flow direction control valve, comprising: a control valve portion and a power portion;

6. The flow direction control valve of claim 5, wherein the valve ball is disposed in the valve body by a support bearing.

7. The flow direction control valve according to claim 5, wherein the top of the valve body is provided with an upper joint for connection with an oil pipe.

8. An oil well string comprising: oil pipe and sleeve pipe, the oil pipe top is provided with arranges oil pipe with the top in the oily lantern ring space that forms between the sleeve pipe is provided with notes liquid pipe, its characterized in that:

a high pressure seal as claimed in any one of claims 1 to 4 provided at the wellhead of the tubing and a flow control valve as claimed in any one of claims 5 to 7 provided at the end of the tubing string.

9. The well string for injecting oil according to claim 8, wherein: the high-pressure sealing device is arranged below an oil pipe sealing part at the top of the oil pipe, and an outer cylinder of the high-pressure sealing device is sleeved on a rod shaft part for oil pumping penetrating through the oil pipe sealing part.

10. The well string for injecting oil according to claim 8, wherein: and the upper joint of the flow direction control valve is connected with the tail end of the underground pipe column of the oil pipe.

11. A method of handling injection solutions based on the tubing string for oil well injection according to any one of claims 8 to 10, comprising:

sealing the oil pipe by the high-pressure sealing device;

unsealing the oil pipe by the high-pressure sealing device;

withdrawing fluid from said tubing and draining it through said sucker tube;

12. The method of claim 11, wherein said sealing said tubing by said high pressure sealing means comprises: and injecting an expansion liquid into the telescopic sealing bag through the through hole, so that the telescopic sealing bag stretches until the telescopic sealing bag is in close contact with the sucker rod shaft component, and the oil pipe is sealed.

13. The method of claim 11, wherein the injecting a solution into the oil collar space comprises: and sequentially injecting a pre-liquid and a displacement liquid.

14. The method of claim 11, wherein said closing said flow control valve comprises: the solution injected into the oil collar space rotates the fan blades in the flow direction control valve in a direction to close the passage in the valve ball.

15. The method of claim 11, wherein said causing the flow direction control valve to open comprises: the solution discharged through the liquid injection pipe rotates the fan blade in the flow direction control valve in the other direction so as to open the channel in the valve ball.

16. The method of claim 11, wherein said unsealing of said tubing by said high pressure seal comprises: and discharging the expansion liquid in the telescopic sealing bag through the through hole, so that the telescopic sealing bag is contracted and separated from the sucker rod shaft component, and the sealing of the oil pipe is released.