CN107304668B - Oil and gas production method - Google Patents

Oil and gas production method Download PDF

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Publication number
CN107304668B
CN107304668B CN201610257272.9A CN201610257272A CN107304668B CN 107304668 B CN107304668 B CN 107304668B CN 201610257272 A CN201610257272 A CN 201610257272A CN 107304668 B CN107304668 B CN 107304668B
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oil
well
gas
tubing
production
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CN107304668A (en
Inventor
石在虹
崔斌
柯文奇
计秉玉
苏建政
刘尧文
李颖
牛骏
李孟涛
刘乔平
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China Petroleum and Chemical Corp
Sinopec Exploration and Production Research Institute
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China Petroleum and Chemical Corp
Sinopec Exploration and Production Research Institute
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/16Enhanced recovery methods for obtaining hydrocarbons

Abstract

The invention provides an oil and gas production method. The method comprises the following steps: judging the yield of a well; step two, when the yield is reduced to a preset value, plugging an original production pipe column of the well; thirdly, an oil pipe with the diameter smaller than that of the original production pipe column is put into the original production pipe column; and step four, communicating the bottom of the well with the oil pipe and using the bottom of the well as a production pipe column so as to enable the oil gas to be sprayed out through the production pipe column. By using the method, an oil pipe with a small diameter can be put into an original production pipe column, so that a new production pipe column is formed, the gas-liquid flow rate is kept higher than the critical liquid carrying flow rate, and the self-injection production of an oil-gas well is ensured. In addition, before the oil pipe is put into the well, the original production pipe column is plugged, the pressure of the well mouth is reduced to normal pressure, the oil pipe with smaller diameter can be put into the well without pressure, and the operation is safer and smoother.

Description

Oil and gas production method
Technical Field
The invention relates to the technical field of oil and gas field exploitation, in particular to an oil and gas extraction method.
Background
For most oil and gas wells in oil and gas fields, at the initial production stage, the formation pressure is high, the oil and gas yield is high, the flowing speed of gas and liquid in the bottom of a production well and a shaft exceeds the critical liquid carrying flow rate, at the moment, the liquid is completely carried to the ground by airflow, no liquid accumulation or less liquid accumulation exists in the bottom of the well, and the oil and gas wells can keep self-spraying production.
In the middle and later periods of production, along with the extension of exploitation time, formation pressure is gradually reduced, under the condition that an original production string is not changed, oil and gas yield is also reduced, the flow rate of gas and liquid in a production shaft is also reduced, so that the liquid carrying capacity of gas is poorer and poorer, finally, gas cannot effectively bring shaft bottom liquid to the ground, shaft accumulated liquid is gradually increased, and finally, formation energy self-injection production cannot be depended on. And because of the existence of the effusion, the back pressure to the stratum can be increased, the production pressure difference is reduced, and sometimes even the oil and gas well is completely pressed to shut down the well.
The problem that the self-injection production cannot be carried out by the formation energy in the middle and later stages of oil and gas production is solved. In the prior art, pumping or increased formation pressure methods are often used to produce higher yields. While these methods continue to produce hydrocarbons, pumping or formation pressure increasing methods increase operating costs and reduce well production efficiency, thereby ultimately affecting the economics of the overall field development.
Therefore, there is an urgent need for a method for producing oil and gas to ensure the production efficiency in the middle and late stages of oil and gas production.
Disclosure of Invention
The present invention provides a method for producing oil and gas, which aims at solving some or all of the technical problems in the prior art. By using the method, an oil pipe with a small diameter can be put into the original production pipe column, so that a new production pipe column is formed, and the stable production of the oil-gas well is ensured. In addition, before the oil pipe is put into the well, the original production pipe column is plugged, the pressure of the well mouth is reduced, the oil pipe with the smaller diameter can be put into the well without pressure, and the operation is safer. Meanwhile, the upper end of the original production string is in a non-pressure state by plugging the original production string, so that the pollution to the stratum can be reduced, and the operation time and the operation cost of running an oil pipe are reduced.
The invention provides an oil and gas production method, which comprises the following steps:
step one, judging the yield of a well,
step two, when the yield is reduced to a preset value, the original production pipe column of the well is plugged,
step three, an oil pipe with the diameter smaller than that of the original production pipe column is put into the original production pipe column,
and step four, communicating the bottom of the well with the oil pipe and using the bottom of the well as a production pipe column so as to enable the oil gas to be sprayed out through the production pipe column.
In one embodiment, steps one through four are repeated for a plurality of cycles, and during the first run, a penetrating first plug is lowered into the original production string in step two, a lowered tubing extends downwardly through the first plug in step three, a lower end of the tubing is provided with a communicable plug, and in step four, the plug is opened to allow communication between the bottom hole and the tubing.
In one embodiment, during a first operation, a first plug is lowered into the casing above the variable diameter of the wellbore and tubing is lowered into the production zone adjacent the well.
In one embodiment, during operations subsequent to the first operation, a second, communicable packer is lowered into the original production string in step two, tubing is lowered into the original production string above the second packer in step three, and the second packer is opened to allow the bottom hole to communicate with the tubing in step four.
In one embodiment, the second plug is lowered into the well a first time during an operation subsequent to the first operation, the second plug being lowered to a position no greater than 10 meters above a top boundary of a producing zone of the well.
In one embodiment, in step three, the lower end surfaces of the lowered oil pipes all extend below the liquid level of the well.
In one embodiment, during the first run, the tubing run in step three is an uncased tubing and the uncased tubing is slip sealed with the first stopper during the run in.
In one embodiment, a gas lift valve is provided in the tubing last run in.
In one embodiment, in the fourth step, the injection may be induced by injecting compressed nitrogen or natural gas.
In one embodiment, in the step one, the yield is a gas production rate QgIn the second step, the predetermined value Q is obtained by the formula (1)c
In the formula (1), d is the inner diameter of the original production string, ugIs a critical flow rate, and is obtained by equation (2),
in the formula (2), α is a constant coefficient, σ is an interfacial tension, ρLIs the density of the liquid, pGIs the gas density.
Compared with the prior art, the method has the advantages that an oil pipe with a small diameter can be put into the original production pipe column by using the method, so that a new production pipe column is formed, the gas-liquid flow rate is kept higher than the critical liquid carrying flow rate, and the self-injection production of the oil-gas well is ensured. In addition, before the oil pipe is put into the well, the original production pipe column is plugged, the pressure of the well mouth is reduced to normal pressure, the oil pipe with smaller diameter can be put into the well without pressure, and the operation is safer and smoother. Simultaneously, through the former production string of shutoff so that the upper end of former production string is in and not take the pressure state, can reduce the pollution to the stratum, reduce the operating time and the operating cost of running into oil pipe, also reduced the operation risk.
Drawings
Preferred embodiments of the present invention will be described in detail below with reference to the attached drawing figures, wherein:
FIG. 1 shows a flow diagram of a process for producing oil gas according to the present invention;
FIG. 2 shows a schematic representation of a wellbore after running a first plug and corresponding tubing into the casing of the well according to the present invention;
figure 3 shows a schematic representation of the wellbore after running a second plug and corresponding tubing into the tubing of the well according to the present invention;
FIG. 4 shows a schematic of a wellbore with nested oil tubes in a well according to the present invention;
figure 5 is a schematic structural view of a first embodiment of a through-penetrating first obturator according to the invention before release;
FIG. 5A is a partial enlarged view of portion A of FIG. 5;
FIG. 5B is a schematic diagram of the first embodiment of the through-penetrating first packer after being released and running into the sealing nipple according to the present invention;
FIG. 6 is a schematic structural view of a second embodiment of a through-penetrating first packer according to the present invention running a sealing sub after a release;
FIG. 7 is a schematic structural view of a third embodiment of a through-penetrating first packer according to the present invention running a sealing sub after a release;
FIG. 7A is a schematic structural view of a splice wedge plug;
fig. 8 is a schematic structural view of the sliding seal mechanism according to the present invention.
In the drawings, like parts are designated with like reference numerals, and the drawings are not drawn to scale.
Detailed Description
The invention will be further explained with reference to the drawings.
Fig. 1 shows a flow diagram of a method for producing oil gas according to the invention. As shown in fig. 1, the oil and gas production method comprises the following steps: s1, judging the yield of the well; s2, when the yield is reduced to a preset value, plugging the original production string of the well; s3, an oil pipe with the diameter smaller than that of the original production pipe column is put into the original production pipe column; s4, communicating the bottom of the well with the tubing and acting as a production string to allow hydrocarbon to be ejected through the production string.
In the initial stage of oil and gas production, the oil and gas well produces oil and gas by self-injection due to the large formation pressure ratio. After a period of self-injection, the formation energy is reduced, and when the formation energy is reduced to a preset value, an oil pipe with smaller diameter needs to be put into the original production pipe column to form a new production pipe column, so that the self-injection of the oil-gas well is ensured, and the yield is improved. According to the invention, before the oil pipe is put into the well, the original production pipe column is plugged, so that the pressure of the well head is reduced to normal pressure, thereby ensuring that the oil pipe with smaller diameter can be put into the well without pressure, and ensuring that the operation is safer and smoother. Simultaneously, through the former production string of shutoff so that the upper end of former production string is in and not take the pressure state, can reduce the pollution to the stratum, reduce the operating time and the operating cost of running into oil pipe, also reduced the operation risk.
In one embodiment, S1 through S4 in the oil and gas recovery method are repeated for multiple cycles of operation. That is, as shown in fig. 4, in the process of producing oil gas, the original production string may be plugged for many times, and then the oil pipe 200 is lowered in the environment without pressure, so that a plurality of nested oil pipes 200 may be formed in the wellbore, and the oil pipe 200 with the smallest diameter serves as the existing production string, so as to achieve the continuous reduction of the diameter of the production string, and optimize the oil gas production rate.
As shown in fig. 2, during the first run, a penetrating first packer 100 is run into the parent production string to block the parent production string so that subsequent operations of the production tubular 200 are not under pressure. Thereafter, without being depressed into tubing 200, tubing 200 is extended down through first plug 100 to communicate the producing zone with the surface. It should be noted that in order to ensure production safety, the lower end of the tubing 200 is provided with a communicable plug 300. After tubing 200 is run in place, plug 300 is reopened to allow downhole communication with tubing 200. During the first operation, the first plugging device 100 is run-through, and may not be limited to the run-in position of the first plugging device 100, as long as the run-in tubing 200 is ensured to be adjacent to the producing zone of the well. That is, the first occluding device 100 does not have to be lowered into the adjacent zone of the formation. Thus, the operation can be simplified through the arrangement, and the method can be suitable for different wells, such as a vertical well and a horizontal well, and is particularly suitable for a variable-diameter well bore. For a variable diameter wellbore, the first plug 100 may be lowered over the variable diameter. Since the lower end of the oil pipe 200 is provided with the plug 300, even if the original production string is in a plugged state during the running of the oil pipe 200 through the first plug 100, the communication of the oil pipe 200 by operating the plug 300 is enabled only after the production string is ready. By this arrangement, controllability and safety of operation are improved.
To achieve nesting of the tubing 200 as production progresses, it is necessary to sequentially run tubing 200 of different diameters into the wellbore. Further, in order to achieve non-push down of oil pipe 200, the first operation may be repeated during each operation after the first operation. For example, in the second operation, the first stopper 100 having a reduced diameter dimension is lowered into the crude oil pipe 200 (the oil pipe 200 lowered in the first operation), and the oil pipe 200 having a reduced diameter dimension is lowered into the crude oil pipe 200 as a new production string, and the stopper 300 is provided at the lower end of the oil pipe 200 having a reduced diameter dimension. By the operation, nesting of the oil pipe 200 can be realized, the requirement of production self-spraying is met, and the operation without pressure can be ensured when the oil pipe 200 is put down every time, so that the operation time and the operation cost are reduced. In addition, in this method, precise positioning of the first occluding device 100 is not required to simplify the operation.
In accordance with another embodiment of the invention, a second, communicable plugging device 400 may be lowered into the production string during operations subsequent to the first operation, as shown in figure 3. This second plug 400 is lowered into the production zone adjacent the well to plug the lower end of the production string. Then, the oil pipe 200 with the reduced diameter is inserted to the upper part of the second stopper 400, and the lower end of the oil pipe 200 does not need to be stopped. Thereafter, the second packer 400 is reopened to place the bottom hole in communication with the tubing 200. In this way, the oil pipe 200 does not need to pass through the second stopper 400, so the structure of the second stopper 400 is simplified, and the production cost is saved. Meanwhile, the structure of the oil pipe 200 which is put in is relatively simple, and the operation is convenient.
When the second plug 400 is first lowered into the wellbore, the second plug 400 is preferably lowered to a point no more than 10 meters above the top boundary of the producing zone of the well, as shown in figure 3. Through the arrangement, smooth self-spraying of oil gas is ensured.
According to the present invention, the lower end faces of the running oil pipes 200 all extend below the well's fluid level. The well level refers to oil, water, mud kill fluid, and the like, or mixtures thereof. The oil-gas self-blowing device can ensure the smooth running of oil-gas self-blowing and realize the low-cost exploitation of oil-gas wells.
It should be noted that after the first stopper 100 is run in, the corresponding tubing 200 that is run in is an uncased tubing to ensure that the tubing 200 is in sliding seal with the first stopper 100 during the run in. By this arrangement, the sealing between the first stopper 100 and the tubing 200 can be improved, thereby further improving the production safety.
As shown in fig. 3, after each run of the second plug 400, the tubing 200 needs to be run in. And the run-in position of the tubing 200 should be closer to the second stopper 400 for better communication. Preferably, the distance between the lower end surface of the oil pipe 200 and the upper end surface of the second stopper 400 adjacent therebelow is not more than 4 m.
When it is necessary to lower the second plugging device 400 into the oil pipe 200, it is necessary that the distance from the lower end surface of the second plugging device 400 to the lower end surface of the oil pipe 200 is not more than 5 m. For example, the lower end face of the second stopper 400 is 2 meters from the lower end face of the tubing 200 where it is located. Through the arrangement, the second plugging device 400 can be ensured to be capable of smoothly running in, continuous self-spraying of oil and gas is also ensured, and self-spraying production of the oil and gas well is kept.
In one embodiment, a gas lift valve (not shown) is provided in the last run of tubing 200, i.e., on the least diameter of the nested tubing 200. When the self-blowing is not available in the later production period, the self-gas production circulating gas lift can be used for maintaining production by arranging the gas lift valve so as to improve the yield of the well.
In the process of communicating the oil pipe 200, if the self-injection cannot be carried out, the injection can be induced by injecting compressed nitrogen or natural gas. For example, the production may be induced by nitrogen-making vehicles or compressed natural gas to self-injection.
According to the present invention, the timing of the lowering of the first stopper 100 or the second stopper 400 can be determined by judging the production of the well. When the yield is reduced to a preset value, the original production string is large in size and is not beneficial to self-injection, and the oil pipe 200 needs to be lowered to form a new production string with a small diameter so as to ensure the exploitation efficiency. For example, the production from a well may be gas production QgIn the second step, the predetermined value Q is obtained by the formula (1)c
In the formula (1), d is the inner diameter of the original production string, ugIs a critical flow rate, and is obtained by equation (2),
in the formula (2), α is a constant coefficient, σ is an interfacial tension, ρLIs the density of the liquid, pGIs the gas density.
Therefore, in the oil and gas production process, the temperature, the pressure and the gas production Q of the well head are monitoredgThe timing of running the oil pipe 200 can be judged. The monitoring and judging method is simple and easy to realize.
It should be noted that, as long as the plugging of the original production string and the plugging of the dynamic seal type penetration of the oil pipe 200 at the later stage can be realized, the plugging device can be applied to the invention. Meanwhile, the plug 300, which can be connected as needed as long as it can plug the lower end of the oil pipe 200 during the running process, can be applied to the present invention. For example, the oil pipe plugging device as described in chinese patent CN201310494357 can plug the communication channel of the oil pipe 200 in the first state, and because it has an inner core, after the oil pipe 200 is put into place, it can be opened by pressurizing to realize the communication of the oil pipe 200. Similarly, the second plugging device 400, which can be connected as needed and can be used for plugging the original production string, can also be used in the present invention.
However, in order to ensure the smooth operation of plugging and to ensure the plugging effect, the present invention also relates to a first plugging device 100 for the smooth operation of oil production gas. As shown in fig. 5, the through first occluder 100 comprises: the slip-type rubber tube sealing device comprises a mandrel 1, a pressure locking mechanism, a slip anchoring mechanism, a rubber tube sealing mechanism, an opening mechanism, a releasing mechanism and a sliding sealing mechanism, wherein the pressure locking mechanism, the slip anchoring mechanism and the rubber tube sealing mechanism are sleeved on the mandrel 1, the opening mechanism is arranged at the lower end of the mandrel 1, and the releasing mechanism and the sliding sealing mechanism are arranged at the.
Wherein, pressure locking mechanism is used for promoting and locks slips anchoring mechanism and packing element sealing mechanism, and it mainly includes: upper joint 2, lower joint 12, upper back ring 3, lower back ring 11, upper clamping ring 41 and lower clamping ring 42. The upper joint 2 and the upper compression ring 41 are sequentially sleeved on the upper part of the mandrel 1 from top to bottom, wherein the upper joint 2 is wrapped on the outer side of the upper back ring 3, and the bottom ends of the upper joint 2 and the upper back ring 3 are all abutted against the top end of the upper compression ring 41. The lower joint 12 and the lower pressing ring 42 are sequentially sleeved on the lower portion of the mandrel 1 from bottom to top, wherein the lower joint 12 is wrapped on the outer side of the lower back ring 11, and the top ends of the lower joint 12 and the lower back ring 11 respectively abut against the bottom end of the lower pressing ring 42.
The upper joint 2 and the upper back ring 3 are respectively connected with the mandrel 1 by adopting a one-way locking tooth-shaped structure, namely the upper joint 2 can drive the upper back ring 3 to move downwards relative to the mandrel 1 under the stress condition, and further push the upper pressing ring 41 to move downwards relative to the mandrel 1, but the upper joint 2 and the upper back ring 3 cannot move upwards relative to the mandrel 1. The lower joint 12 and the lower back ring 11 are respectively connected with the mandrel 1 in a threaded manner, so that the lower joint 12, the lower back ring 11 and the lower pressing ring 42 cannot move up and down relative to the mandrel 1.
The packing element sealing mechanism mainly comprises: a rubber cylinder 10, a rubber cylinder upper backing ring 91 and a rubber cylinder lower backing ring 92. The rubber cylinder 10 is sleeved on the mandrel 1 between the upper pressing ring 41 and the lower pressing ring 42, and the upper backing ring 91 and the lower backing ring 92 of the rubber cylinder are respectively arranged at the upper end and the lower end of the rubber cylinder 10.
The slip anchoring mechanism mainly comprises: the upper slip 61, the lower slip 62, the upper cone 81, the lower cone 82, the upper slip hoop 51, the lower slip hoop 52, the upper cone positioning pin 71 and the lower cone positioning pin 72, wherein the upper cone 81 is located at the upper end of the rubber cylinder 10, more specifically, the upper cone 81 abuts against the upper end of the upper cushion ring 91 of the rubber cylinder, and the lower cone 82 is located at the lower end of the rubber cylinder 10, more specifically, the lower cone 82 abuts against the lower end of the lower cushion ring 92 of the rubber cylinder. The upper cone 81 and the lower cone 82 are respectively positioned on the mandrel 1 through the upper cone positioning pin 71 and the lower cone positioning pin 72. The upper slip 61 is located between the upper press ring 41 and the upper cone 81, the outer inclined surface of the upper cone 81 is matched with the inner inclined surface of the upper slip 61, the lower slip 62 is located between the lower press ring 42 and the lower cone 82, and the outer inclined surface of the lower cone 82 is matched with the inner inclined surface of the lower slip 62. In addition, the inner inclined surfaces of the upper slip 61 and the lower slip 62 are respectively provided with a step surface, and the step surfaces are respectively connected with the upper cone positioning pin 71 and the lower cone positioning pin 72 in a pressing manner. And an upper slip hoop 51 and a lower slip hoop 52 are respectively arranged outside the upper slip 61 and the lower slip 62 and are used for pressing the upper slip 61 and the lower slip 62 towards the direction of the mandrel 1, and the pressing force is transmitted to the rubber cylinder sealing mechanism due to the matching of the step surface and the upper cone positioning pins 71 and 72, so that the setting of the penetrating type first plugging device 100 is realized.
The opening mechanism is used for realizing the constant pressure opening of the lower end of the first plugging device 100 and establishing a structure of a production channel, and mainly comprises: rupture disk 14 and O-ring 13. The O-shaped sealing ring 13 is arranged in an O-shaped ring sealing groove arranged in the lower end of the mandrel 1, the periphery of the rupture disc 14 realizes the positioning and sealing of the rupture disc 14 through the extrusion fit of the inner stepped end surface of the lower end of the mandrel 1 and the O-shaped sealing ring 13 on the inner side and the support and extrusion fit of the surface of the step inner cavity of the lower back ring 11 and the surface of the inner cavity of the lower connector 12, the spherical concave surface of the rupture disc 14 faces upwards, the spherical convex surface faces downwards, the spherical concave surface can bear the maximum positive pressure of 1-10MPa, and the maximum back pressure of the spherical convex surface can bear;
the releasing mechanism comprises a shearing ring 1a (see fig. 5A), the shearing ring 1a is arranged inside the upper end of the mandrel 1, and the wall thickness of the shearing ring 1a is smaller than that of the mandrel 1, so that the shearing ring 1a becomes a weak part of the mandrel 1, and the mandrel 1 is conveniently broken at the shearing ring 1 a.
As shown in fig. 5B and 8, the sliding sealing mechanism is a sealing nipple M, which includes: the sealing device comprises a sealing plug M1, a sealing pressure plate M2, a V-shaped sealing packing combination M3, a sealing joint M4, a VD-shaped rubber sealing ring M5 and a locking screw M6. The sealing joint M4 is a hollow structure having three steps, and the outer diameters of the three steps are sequentially reduced from top to bottom. The outer surface of the third step (lower end) of the sealing joint M4 can be in threaded connection with the inner surface of the mandrel 1 of the pressure locking mechanism, and the first step (upper end) of the sealing joint M4 can be in threaded connection with a delivery pipe (not shown). The sealing pressure plate M2 is also of a hollow structure, and is also provided with three steps, and the outer diameters of the three steps are sequentially reduced from top to bottom. The outer surface of the second step (middle part) of the sealing pressure plate M2 is in threaded connection with the inner surface of the first step of the sealing joint M4. A first annular space S1 is formed between the inner surface of the second step of the sealing joint M4 and the lower end of the third step of the sealing pressure plate M2, a V-shaped sealing packing combination M3 is installed in the first annular space S, and the V-shaped sealing packing combination M3 contacts with the coupling-free oil pipe 200 of the first plugging device 100 to form a high-pressure-resistant sliding seal. In addition, the inner surface above the first step of the sealing pressure plate M2 is in threaded connection with the outer surface of the sealing plug M1, the inner surface below the first step of the sealing pressure plate M2 and the lower end of the sealing plug M1 form a second annular space S2, a V-shaped sealing packing combination M3 is also installed in the second annular space S2, and similarly, the V-shaped sealing packing combination is in contact with the non-collar oil pipe 200 of the first packer 100 to form a high-pressure resistant sliding seal.
A third annular space S3 is formed between the outer surface of the third step of the sealing pressure plate M2 and the inner surface of the first step of the sealing joint M4, a VD-shaped rubber sealing ring M5 is installed in the third annular space S3, and the VD-shaped rubber sealing ring M5 has a certain elastic compression amount according to design requirements and plays a role in end face sealing; in addition, when the V-shaped sealing packing combination M3 is worn, the volume of the third annular space between the sealing pressure plate M2 and the sealing joint M4 may change, and the VD-shaped rubber sealing ring M5 also plays a role in elastic compensation.
The V-shaped sealing packing assembly M3 is composed of a support ring M31, at least one group (e.g., 9 groups) of V-shaped pvc packing M32, and a press ring M33. In addition, a locking screw 6 is installed on one side of the sealing plug M1 with the notch to ensure the stable structure of the sliding sealing mechanism.
The upper end of the mandrel 1 is connected with a central rod Z of the seat sealing tool through internal threads, and the lower end of the central rod Z is located above the shearing ring 1 a.
Preferably, the material of the mandrel 1 is aluminum but not limited to aluminum, which can realize the releasing function of the through-type first plugging device 100.
Preferably, the upper end surface and the lower end surface of the penetrating type first plugging device 100 of the present invention are designed by a bevel fin engagement mechanism, the upper end surface adopts a bevel fin structure to prevent the penetrating type first plugging device 100 from rotating when the penetrating type first plugging device 100 is drilled and ground, and the lower end surface adopts a bevel fin structure to play a guiding role when the penetrating type first plugging device 100 is inserted.
Preferably, the drillable penetrating type first plugging device 100 of the invention is made of composite material, has strong drillability and low density, and can be easily taken out of the ground in a circulating way, thereby avoiding the precipitation of metal debris generated after the conventional cast iron bridge plug is milled.
Preferably, the plugging device components of the penetrating type first plugging device 100 of the present invention are made of dacron fibers, polytetrafluoroethylene, nitrile rubber, nodular cast iron, and other materials capable of realizing the functions of the components and the overall performance requirements of the penetrating type first plugging device 100.
Preferably, the drillable through-penetrating first packer 100 of the present invention must be set using a setting tool, which may be selected from conventional drillable bridge plug-universal setting tools.
The working principle of the first embodiment of the through first obturator 100 according to the invention is:
setting: a seat sealing tool is put in, and when in seat sealing, a central rod Z of the seat sealing tool is still, and a mandrel 1 connected with the seat sealing tool, a lower back ring 11 connected with the mandrel and a lower joint 12 connected with the lower back ring 11 are also still; the setting tool outer pushing cylinder pushes the upper joint 2 and the upper back ring 3 downwards to slide relative to the mandrel 1, the extruding slip anchoring mechanism applies force to the upper cone 81 and the lower cone 82, the upper cone positioning pin 71 and the lower cone positioning pin 72 are stressed to reach a designed shearing value to be sheared, under the action of continuous force application, the upper cone 81 and the lower cone 82 act on the rubber cylinder sealing mechanism to enable the rubber cylinder 10 to be compressed to reach a complete sealing state, the reaction force of the rubber cylinder 10 compression and the pushing force of the upper pressing ring 41 and the lower pressing ring 42 act together to enable the upper slip 61 and the lower slip 62 to be expanded and pressed on the inner wall of the shaft, the upper joint 2 and the upper back ring 3 of the penetrating type first plugging device 100 are meshed and locked with the mandrel 1 through sawtooth threads, and the setting of the penetrating type first plugging device 100 is achieved.
Releasing: after the sealing, the outer push cylinder of the sealing tool continuously applies force to the upper joint 2 of the penetrating type first plugging device 100, and finally acts on the lower end of the mandrel 1 downwards through the lower joint 12 and the lower back ring 11, the outer push cylinder of the sealing tool and the central rod Z of the sealing tool perform relative motion, so that the mandrel 1 connected with the central rod Z of the sealing tool is in a stretching state, when the stretching force reaches a designed value, the mandrel 1 is broken at a shearing ring 1a (namely, the weak part of the mandrel 1), and the underground releasing of the penetrating type first plugging device 100 is realized.
And (3) setting a sealing short piece M: after the first plugging device 100 body is set and released, the sealing short section M is connected with the thread at the lower end of the conveying oil pipe through the first step of the sealing joint M4 and conveyed to the underground by the conveying oil pipe, and the sealing short section M and the first plugging device 100 body are connected into a whole through type first plugging device 100 through the thread connection of the third step of the sealing joint M4 and the mandrel 1.
Running in the non-coupling tubing 200: the non-collar tubing 200 is run through the sealing nipple M and reaches the bottom of the first packer 100 above the constant pressure opening mechanism. The lowering of the uncased tubing 200 continues, causing rupture disc 14 to rupture under pressure until the uncased tubing 200 is lowered into the design location.
Establishing a production channel: by means of positive pressure, the plug 300 in the oil pipe 200 is opened to establish a production channel.
Second embodiment
As shown in fig. 6, which is a schematic structural diagram according to a second embodiment of the present invention. The second embodiment differs from the first embodiment only in the opening mechanism. In the second embodiment, the opening mechanism mainly comprises a wedge plug 14a and a wedge plug shear pin 13 a. The tapered surface of the wedge-shaped plug 14a is in interference fit with the inner tapered surface of the lower joint 12 and is positioned by the wedge-shaped plug shearing pin 13a, the area of the upper end surface of the wedge-shaped plug 14a is small, the area of the lower end surface of the wedge-shaped plug 14a is large, and the lower end surface of the wedge-shaped plug is subjected to formation pressure so that the wedge-shaped plug 14a cannot be accidentally separated from the mandrel 1.
Preferably, the wedge 14a is made of rubber to withstand high pressure.
Third embodiment
As shown in fig. 7 and 7A, which are a schematic structural view of a spliced wedge plug and a schematic structural view of a third embodiment according to the present invention. The third embodiment differs from the second embodiment only in the opening mechanism. In a third embodiment, the opening mechanism essentially comprises two split wedge plugs 14b and two wedge plug shear pins 13 b. The conical surfaces of the two spliced wedge-shaped plugs 14b are in interference fit with the inner conical surface of the lower connector 12 and are positioned through the wedge-shaped plug shearing pins 13a, the upper end surfaces of the wedge-shaped plugs 14b are small in area, the lower end surfaces of the wedge-shaped plugs 14b are large in area, and the lower end surfaces of the wedge-shaped plugs 14b are under the action of formation pressure so that the wedge-shaped plugs 14b cannot be accidentally separated from the mandrel 1.
During running of the tubing 200, the wedge plug shear pin 13a is sheared by applying pressure to the tubing 200 and the wedge plug 14b is driven downhole against the interference fit friction. Compared with a complete wedge-shaped plug 14a, the two spliced wedge-shaped plugs 14b have the advantages that when the two spliced wedge-shaped plugs 14b are driven into the well bottom, the two spliced wedge-shaped plugs are automatically separated, even if pressure exists in the well bottom to push the wedge-shaped plugs 14b upwards, the spliced wedge-shaped plugs 14b cannot be automatically spliced when the bottom joint 12 is pushed back due to the fact that the spliced wedge-shaped plugs 14b are separated, and therefore the constant-pressure opening process is guaranteed to be completed smoothly.
Of course, the splice wedge plug may be composed of not only two splice structures, but also three, four, six, etc., as long as each splice structure is fixed in the inner conical surface of the lower joint 12 when the through first plugging device 100 is inserted, and can be effectively dispersed when pressed.
In this application, the orientation terms "upper" and "lower" are both referenced to the orientation of the formation.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily make changes or variations within the technical scope of the present invention disclosed, and such changes or variations should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (7)

1. A method of producing oil gas, comprising the steps of:
step one, judging the yield of a well,
step two, when the yield is reduced to a preset value, the original production pipe column of the well is plugged,
step three, nesting and setting an oil pipe with the diameter smaller than that of the original production pipe column into the original production pipe column,
communicating the bottom of the well with the oil pipe and using the bottom of the well as a production pipe column to enable oil gas to be sprayed out through the production pipe column;
repeating the first step to the fourth step to perform multiple circulation operations, and in the first operation process, in the second step, a penetrating first plugging device is put into the original production string to plug the original production string to enable the lowering operation of an oil pipe with the diameter smaller than that of the original production string to be free of pressure, in the third step, the put oil pipe passes through the first plugging device and extends downwards, the lower end of the oil pipe is provided with a communicated plugging device, and in the fourth step, the plugging device is opened to enable the bottom hole to be communicated with the oil pipe;
in the step one, the yield is the gas production rate QgIn the second step, the predetermined value Q is obtained by the formula (1)c
In the formula (1), d is the inner diameter of the original production string, ugIs a critical flow rate, and is obtained by equation (2),
in the formula (2), α is a constant coefficient, σ is an interfacial tension, ρLIs the density of the liquid, pGIs the gas density;
during the first operation, the tubing run in step three is a collar-free tubing, and the collar-free tubing is slidably sealed with the first stopper during the run in.
2. The method of producing oil of claim 1, wherein during the first operation a first plug is lowered into the casing above the variable diameter of the wellbore and tubing is lowered into the production zone adjacent the well.
3. The method of producing oil and gas of claim 1 wherein during operation after the first operation, a second packer is lowered into the original production string in step two, tubing is lowered into the original production string above the second packer in step three, and the second packer is opened to allow communication between the bottom of the well and the tubing in step four.
4. The method of producing oil and gas of claim 1, wherein the second plug is lowered into the well a first time during an operation subsequent to the first operation at a location no greater than 10 meters above the top boundary of the producing zone of the well.
5. The method of producing oil gas of claim 1, wherein in step three, the lower end faces of the running oil pipes all extend below the surface of the well.
6. A method for producing oil gas according to claim 1, characterized in that a gas lift valve is arranged in the tubing last run in.
7. The process for producing oil and gas according to claim 1, wherein in the fourth step, injection is induced by injecting compressed nitrogen or natural gas.
CN201610257272.9A 2016-04-22 2016-04-22 Oil and gas production method Active CN107304668B (en)

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CN110761743A (en) * 2018-07-27 2020-02-07 中国石油化工股份有限公司 Thick oil and thin oil mixed gas lift process pipe column and implementation method

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