CN112627785A - Low-frequency variable-pressure reservoir exploitation method, device and system for residual oil in pores - Google Patents

Low-frequency variable-pressure reservoir exploitation method, device and system for residual oil in pores Download PDF

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Publication number
CN112627785A
CN112627785A CN201910903838.4A CN201910903838A CN112627785A CN 112627785 A CN112627785 A CN 112627785A CN 201910903838 A CN201910903838 A CN 201910903838A CN 112627785 A CN112627785 A CN 112627785A
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China
Prior art keywords
pressure
gas
oil
oil reservoir
low
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CN201910903838.4A
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Chinese (zh)
Inventor
陈兴隆
姬泽敏
张善严
王敬瑶
伍家忠
任重
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Petrochina Co Ltd
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Petrochina Co Ltd
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Priority to CN201910903838.4A priority Critical patent/CN112627785A/en
Priority claimed from RU2021114279A external-priority patent/RU2768835C1/en
Publication of CN112627785A publication Critical patent/CN112627785A/en
Pending legal-status Critical Current

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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
    • E21B43/166Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
    • E21B43/168Injecting a gaseous medium
    • 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
    • E21B43/30Specific pattern of wells, e.g. optimizing the spacing of wells

Abstract

The invention provides a low-frequency variable-pressure oil reservoir exploitation method, a device and a system for residual oil in pores, wherein the method comprises the following steps: acquiring a gas distribution map in an oil reservoir and a pressure distribution map between injection wells in the gas injection process; determining the placement position of the low-frequency variable pressure well device in the oil reservoir according to the distribution map of the gas in the oil reservoir and the pressure distribution map between injection wells in the gas injection process; intermittently raising and lowering pressure at a preset frequency by adopting a placement position of a low-frequency variable-pressure well device in an oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position; and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well. The scheme utilizes the short-time high-pressure effect of a near-wellbore area caused by the high flow velocity of the low-frequency variable-pressure well device to realize the desorption of residual oil and the effect of changing the direction of the main seepage channel, and the extraction degree is continuously improved by a method of expanding the swept volume after the gas drive channeling.

Description

Low-frequency variable-pressure reservoir exploitation method, device and system for residual oil in pores
Technical Field
The invention relates to the technical field of oilfield development, in particular to a low-frequency variable-pressure oil reservoir exploitation method, device and system for residual oil in pores.
Background
The gas injection oil displacement technology is an advantageous technology in the later stage of water injection development and low-permeability reservoir development, has the advantages of low seepage resistance, fast recovery of stratum pressure, obvious oil displacement effect and the like, but also has the defect difficult to overcome, namely, gas easily flows in the reservoir along a high-permeability channel, once the gas advances, a channel is formed in the reservoir, and after the gas is produced from a production well, the later-stage injected gas can hardly play an oil displacement role. In the oil deposit, partial pores including the channeling channel still contain residual oil with higher saturation, the prior art has a method for blocking the partial channeling channel, but generally only can solve the near-wellbore region, and the blocking agent is difficult to enter the deep part of the oil deposit.
Disclosure of Invention
The embodiment of the invention provides a low-frequency variable-pressure oil reservoir exploitation method, a low-frequency variable-pressure oil reservoir exploitation device and a low-frequency variable-pressure oil reservoir exploitation system for residual oil in pores, and solves the technical problem that the residual oil with higher saturation contained in part of the pores of a channeling channel cannot be exploited in the prior art.
The embodiment of the invention provides a low-frequency variable-pressure well device, which comprises: surface and wellbore devices;
the shaft device comprises a support packer, a support short section, an oil layer packer, a ventilation sleeve, an electromagnetic pneumatic control valve and a high-pressure container from bottom to top, wherein the support packer, the support short section, the oil layer packer, the ventilation sleeve, the electromagnetic pneumatic control valve and the high-pressure container are positioned in a sleeve;
wherein the support packer is configured to: the expansion is clamped between the inner wall of the sleeve and the support short section to support the support short section;
the lower part of the support short section is connected with a support packer, the upper part of the support short section is connected with an oil layer packer, the support short section is tubular, and a hole is formed in the side of the pipe and used for enabling gas in an oil layer at the lower part to enter the oil layer packer;
the oil layer packer is used for: separating the upper oil layer to allow gas to enter and exit the lower oil layer;
the lower part and the outer part of the ventilation sleeve are connected with an oil layer packer, the inner part of the ventilation sleeve is connected with a high-pressure container, and the wall of the ventilation sleeve is provided with a through hole which is a channel for gas in the oil layer packer to enter the upper casing space;
the electromagnetic pneumatic control valve is connected with the ventilation sleeve through a through hole of the ventilation sleeve and is used for opening and closing the through hole so that gas of the lower oil layer enters the high-pressure container and the upper space;
the lower end of the high-pressure container is connected with the inside of the ventilation sleeve, and the high-pressure container is hollow and cylindrical;
the ground device comprises a wellhead device and a gas booster, wherein the high-pressure container is butted with an oil pipe interface of the wellhead device, a sleeve of the wellhead device is connected with a low-pressure inlet of the gas booster, and the oil pipe interface of the wellhead device is connected with a high-pressure outlet of the gas booster;
wherein the gas booster is used for compressing low-pressure gas in the high-pressure container into high-pressure gas.
The embodiment of the invention also provides a low-frequency pressure-changing oil reservoir exploitation method for residual oil in pores, which comprises the following steps:
acquiring a gas distribution map in an oil reservoir and a pressure distribution map between injection wells in the gas injection process;
determining the placement position of the low-frequency variable pressure well device in the oil reservoir according to the distribution map of the gas in the oil reservoir and the pressure distribution map between injection wells in the gas injection process;
intermittently raising and lowering pressure at a preset frequency by adopting a placement position of a low-frequency variable-pressure well device in an oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position;
and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well.
The embodiment of the invention also provides a low-frequency pressure-changing oil reservoir exploitation system for residual oil in pores, which comprises: the system comprises a low-frequency variable-pressure well device, a data analysis device and an oil extraction device;
wherein the data analysis device is configured to: acquiring a gas distribution diagram in an oil reservoir and a pressure distribution diagram between injection and production wells in the gas injection process, and determining the placement position of the low-frequency variable pressure well device in the oil reservoir according to the gas distribution diagram in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
the low-frequency variable-pressure well device is used for: the oil pump is placed at a corresponding position in the oil reservoir, and the pressure is intermittently increased and decreased at a preset frequency at the placement position in the oil reservoir, so that the distribution state of the residual oil in the oil reservoir at the placement position is changed;
the oil recovery device is used for: and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well.
The embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the method when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, and the computer readable storage medium stores a computer program for executing the method.
In the embodiment of the invention, the low-frequency variable pressure well device is determined to be placed at a certain position in the oil reservoir according to the distribution diagram of gas in the oil reservoir and the pressure distribution diagram between injection and extraction wells in the gas injection process, and the pressure is intermittently increased and decreased at a preset frequency, so that the distribution state of the residual oil in the oil reservoir at the placed position is changed, and the extraction degree can be improved by extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the gas injection well and the oil extraction well.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of the distribution of gas within a reservoir during gas injection;
FIG. 2 is a schematic diagram of a cross-sectional gas-expanded distribution of gas within a reservoir during gas injection;
FIG. 3 is a schematic view showing the distribution of remaining oil in an enlarged area during gas injection;
FIG. 4 is a schematic of the pressure distribution between injection and production wells during gas injection;
FIG. 5 is a schematic diagram of a low-frequency variable-pressure reservoir extraction method for residual oil in pores according to an embodiment of the invention.
FIG. 6 is a schematic diagram of a pressure distribution of a low frequency transformation method provided by an embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a low-frequency variable-pressure well casing device provided by an embodiment of the invention;
FIG. 8 is a schematic diagram of a wellbore device in a low frequency variable pressure wellbore device provided by an embodiment of the present invention;
FIG. 9 is a schematic structural view of a venting sleeve provided in accordance with an embodiment of the present invention;
FIG. 10 is a schematic view of the flow of gas through the vent sleeve provided by an embodiment of the present invention;
FIG. 11 is a schematic structural view of a high-pressure vessel according to an embodiment of the present invention;
FIG. 12 is a schematic view of a partially assembled structure of a high pressure vessel according to an embodiment of the present invention;
fig. 13 is a front view of an electromagnetic pneumatic control valve provided in an embodiment of the present invention;
fig. 14 is a top view of an electromagnetic pneumatic control valve provided in an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the prior art, a one-dimensional columnar rock model is generally adopted to research a gas injection oil displacement mechanism. The larger the diameter of the rock model is, the more easily the gas channeling effect appears. If slug displacement is studied, the smaller the diameter the better, typically 2.5cm diameter cores are used. If the influence of gas channeling on the production level is studied, cores with a diameter of 3.8cm or more are used, and rectangular long cores are also more commonly used. Fig. 1 shows the fluid state in the model during the injection of gas into a rectangular long core. Fig. 1-3 show the fluid conditions within the reservoir during gas injection. FIG. 1 shows that after gas is produced on a cross section, a main gas channel is formed in the middle of a core, and an unswept gas area exists around the core. Fig. 2 shows the shape of the main gas channel and unswept region in cross-section. Fig. 3 is an enlarged view of a partial area in fig. 2, showing that residual oil remains in a part of pores of the main channel, because after gas channeling, the gas flow in the main channel tends to be stable, and a part of the residual oil cannot flow due to the blocking, interfacial tension, adsorption and other effects of rock particles.
FIG. 4 shows the pressure profile along the length of the core model for steady production of gas injection. The highest pressure at the inlet is the injection pressure Pin and the lowest pressure at the outlet is the outlet pressure Pout. There is a pressure drop funnel at the core inlet, i.e. the pressure drop gradient is large, after which the pressure tends to be flat and the difference Δ P between the pressure Pi and Pout at the i-position is small. And the curve 1 and the curve 2 respectively show the pressure distribution of the high-permeability core and the low-permeability core, and the differential pressure low-permeability core at the position i is smaller than that of the high-permeability core, so that the residual oil in the pores of the low-permeability core is more than that of the high-permeability core. That is, the lower the permeability of the rock model, the more severe the effects of gas channeling, the higher the remaining oil saturation, and the lower the degree of recovery.
Aiming at the distribution position and the stress characteristics of the residual oil in the oil reservoir pores, a low-frequency pressure transformation method is provided. As shown in fig. 5, the method includes:
step 501: acquiring a gas distribution map in an oil reservoir and a pressure distribution map between injection wells in the gas injection process;
step 502: determining the placement position of the low-frequency variable pressure well device in the oil reservoir according to the distribution map of the gas in the oil reservoir and the pressure distribution map between injection wells in the gas injection process;
step 503: intermittently raising and lowering pressure at a preset frequency by adopting a placement position of a low-frequency variable-pressure well device in an oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position;
step 504: and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well.
That is, a low frequency variable pressure well device is used to intermittently raise and lower pressure at a low pressure location (i.e., a placement location) at a frequency that causes a range of pressure variations around the location. The effect makes the original stable gas flow changed, the gas seepage direction undergoes reversal change within a frequency, thereby the state of the residual oil in the pore space of the swept range is changed, a part of the residual oil reaches the flowing state and is extracted, and the extraction degree is improved. Meanwhile, the change of the residual state and the low-frequency gas injection well can cause the redistribution of seepage resistance in an affected area, so that the shape and even the direction of an originally formed main seepage channel are changed, the swept volume of gas drive is enlarged, and the extraction degree is improved more obviously.
Figure 6 shows that in the middle of the injection and production well, a low frequency variable pressure well is provided, which is filled with gas causing a pressure increase, after which the well is rapidly vented causing a pressure decrease, which at higher speeds will be lower than the initial pressure. From the analysis of the corresponding pressure curves (injection pressure line and discharge pressure line), it can be seen that the state of the seepage in the affected area is necessarily affected by the pressure change, where PfimaxAt maximum injection pressure, PfominIs a rowAnd (4) outputting a pressure minimum value.
In the embodiment of the invention, the key to the realization of the principle of the low-frequency voltage transformation method is the design of the low-frequency voltage transformation well, namely the design of an internal core device. The gas flows at high speed and causes short-time high pressure in a near well zone, obviously the larger the gas discharge capacity is, the more the gas is beneficial to the movement of the gas to a far well zone, and a full well barrel device with a low-frequency variable-pressure function and a control mode are designed for achieving the aim to the maximum limit, and the structure of the low-frequency variable-pressure well device is shown in figure 7.
The low-frequency variable pressure well device comprises a well shaft device 1 and a ground device 2;
as shown in fig. 7 and 8, the wellbore device 1 includes, from bottom to top, a support packer 11, a support pup joint 12, an oil layer packer 13, a ventilation sleeve 14, a high-pressure container 15, and an electromagnetic pneumatic control valve 16, and the support packer 11, the support pup joint 12, the oil layer packer 13, the ventilation sleeve 14, the high-pressure container 15, and the electromagnetic pneumatic control valve 16 are located in a casing 19.
The supporting packer 11 is a common device in oil field, and is used for expanding and clamping the slip mechanical device on the inner wall of the casing 19, and the sealing rubber sleeve is propped open to play a role in isolating the upper space from the lower space, and the whole packer also plays a role in supporting the upper pipe column. The packer has a plurality of models, the packer can be selected from models which are simple to operate and good in packing effect, the upper part of the packer adopts a Y445 packer, and the lower part of the packer adopts a Y221 packer.
The support nipple 12 is a design device, tubular and provided with a hole on the side surface. The lower part is connected to the support packer 11 and the upper part is connected to the production packer 13. The purpose of the perforations is to allow gas in the lower zone to pass without passing through into the zone packer 13.
The oil layer packer 13 plays a role of separating an oil layer, an upper oil layer is separated by packing rubber, and gas enters and exits in the lower oil layer.
[ air vent sleeve 14 ]
The lower part and the outer part of the ventilation sleeve 14 are provided with short joints (the short joints are a fitting commonly used in industrial pipeline connection, the common threaded short joints are divided into a double-head external thread, a single-head external thread and a flat-head external thread) to be connected with the oil layer packer 13, and the inner part of the ventilation sleeve is connected with the high-pressure container 15 through an inner thread 141. The configuration is shown in FIG. 9, where the wall 142 of the breather sleeve 14 has through holes 143 that allow gas in the bottom packer 13 to pass into the upper casing space. See fig. 10, gas flow diagram. The through hole at the connecting position of the high-pressure container 15 has good roundness and smooth inner wall, and the through hole is matched with the rubber column of the electromagnetic pneumatic control valve 16 and has the valve function.
② high-pressure vessel 15
The high pressure container 15 has a simple structure, and is hollow and cylindrical, and the end caps at both ends are embedded, i.e. connected to the inside of the ventilation sleeve 14 through the inner screw threads 151, and the outer screw threads 152 are arranged at both ends of the outer cylinder, as shown in fig. 11. One end is connected to the interior of the breather sleeve 14. The bottom end cap mounts a constant pressure valve 153 after attachment to the vent sleeve 14, see fig. 12. An electromagnetic pneumatic control valve 16 is installed below the constant pressure valve 153. When the constant pressure valve reaches the design pressure, the high pressure air outlet 154 is opened and kept in a continuous opening state until the pressure of the fluid inside and outside is balanced, and then the valve is closed.
Because the inner diameter of the casing in the well bottom is only 10cm, if the volume of the high-pressure container is increased, only a lengthening mode can be adopted, and the maximum length is the depth of the well shaft. Generally, the oil deposit depth of oil fields in China is more than 1000m, the inner diameter of a container is 6cm, and the space volume of a 1000m equal-diameter long pipe is about 3m3
The high pressure vessel length is thus determined to maximize its use in accordance with the particular casing usage of the well. Generally, casing is divided into surface casing, technical casing and reservoir casing, and its length varies depending on well conditions. The minimum inner diameters of the surface casing, the technical casing and the oil layer casing are respectively as follows: 21.6cm, 15.0cm and 10.0 cm. If the oil reservoir depth is 2000m, the surface casing is 200m, the technical casing is 1600m and the oil layer casing is 200m, the high-pressure container can also be designed to be gradually thickened from bottom to top, the inner diameters of the high-pressure container are respectively 12.0cm, 9.0cm and 6.0cm corresponding to different casing types, and if the length of the high-pressure container is equal to that of the corresponding casing, the space volume of the trapezoidal high-pressure container is about 15m3
Because the low-frequency transformation method needs to establish a condition 2 times of annular pressure in a high-pressure container, the existing sleeve can not be used as the container, the wall thickness of the sleeve is within 5-10 mm, and the pressure resistance is not strong. The vessel designed by the method is made of 316 steel, the wall thickness is within 10-20 mm, and the maximum pressure resistance can reach 70 MPa.
Due to field operation conditions, a single high-pressure container with the length of 10m is formed by connecting two ends of a sealing coupling in series gradually. And in the diameter-changing section, the sealing coupling is changed in diameter. The technology is mature and will not be described in detail.
③ electromagnetic pneumatic control valve 16
The solenoid pneumatic valve 16 includes a plurality of piston-type conical plugs 161, as shown in fig. 13, each piston-type conical plug is L-shaped, and the plurality of piston-type conical plugs 161 are connected by a multi-way vent connector 162. The piston type conical plug comprises a conical plug 1611, a connecting rod 1612, a magnetic suction piston 1613, an electromagnetic block 1614 and an L-shaped frame body; the tapered plug 1611, the connecting rod 1612 and the magnetic suction piston 1613 are sequentially connected, and the connecting rod 1612, the magnetic suction piston 1613 and the electromagnetic block 1614 are located in the L-shaped frame.
The electromagnetic pneumatic control valve 16 utilizes partial energy generated when high-pressure gas is discharged to push the piston type conical plug to move upwards, and the conical plug 1611 is plugged at the position of the through hole 143 of the ventilation sleeve 14, so that the gas cannot enter the upper space through the ventilation sleeve 14 and only can enter the stratum. When the pressure relief of the high-pressure gas is finished and the pressure of the outlet gas is balanced with the pressure of the surrounding environment, the magnetic suction piston 1613 drives the conical plug 161 to move downwards through the connecting rod 1612 under the action of the electromagnetic suction force of the electromagnetic block 1614, the piston type conical plug returns to the original position by virtue of the gravity of the piston type conical plug, the electromagnetic pneumatic control valve 16 is opened, and the low-pressure gas discharged from the oil layer enters the upper space. The number of plugs of the solenoid operated valve 16 is matched with the number of the ventilation sleeves 14, and the front view is shown in fig. 13, and the top view is shown in fig. 14.
As shown in fig. 7, the surface device 2 includes a wellhead device 21 and a gas booster 22, wherein the high-pressure container 15 is butted with an oil pipe interface of the wellhead device 21, a sleeve of the wellhead device 21 is connected with a low-pressure inlet of the gas booster 22, and an oil pipe interface of the wellhead device 21 is connected with a high-pressure outlet of the gas booster 22;
the gas booster 17 is used to compress a low-pressure gas in the high-pressure vessel 15 into a high-pressure gas.
A control device 23 may also be included and connected to the gas booster 22 for controlling the operation of the gas booster.
Well head apparatus 18
The wellhead device can be a common wellhead system, the high-pressure container 15 is in butt joint with an original oil pipe interface, and a sealing reducing coupling needs to be installed during connection. Control lines etc. are led out hermetically from the annulus from the casing of the wellhead 21 to the connection outlet of the wellhead 21.
The casing of the wellhead 21 is connected to the low-pressure gas inlet 221 of the gas booster 22 via the casing control valve 211, and the tubing connection of the wellhead 21 is connected to the high-pressure gas outlet 222 of the gas booster 22 via the tubing control valve 212.
② gas booster 22
The gas booster is a conventional application device which functions to compress low pressure gas into high pressure gas under the power of an air compressor. The principle of the supercharging process is in a mature application state, and therefore, the details are not described here.
Because the gas superchargers are arranged outside the well head, the space environment is not limited any more, so that the overall dimension of the superchargers can be increased, and the large discharge capacity can be realized by connecting a plurality of superchargers in parallel.
In the embodiment of the present invention, the operation process of the low-frequency variable pressure well device is as follows (i.e. step 503 specifically includes):
for example, a low-frequency pressure changing method is adopted for a gas injection oil displacement low-permeability oil reservoir. The permeability of the low-permeability reservoir is low, the pore structure is complex, the water injection pressure is high, the water injection is difficult, and the phenomenon of non-injection is common. The oil deposit of the type adopts a gas injection mode and also adopts a low injection quantity mode to mine, so that the fingering phenomenon is prevented.
Setting the oil reservoir depth of 2000m, injecting gas 3m daily under the condition of bottom hole fluid pressure of 10MPa3(3000Nm3). Gas injection at a single frequency of 60m3(formation pressure 10MPa), and high-pressure radial injection is carried out on the oil reservoir by 7 days and 1 frequency target.
The core device dimensions are as follows:
the high-pressure container is configured according to the design, and the total volume is 15m3
The gas booster set consists of 10 gas boosters. The maximum working pressure of a single gas booster is 60MPa, the discharge flow is 1000L/min, and the ratio of the working time to the rest time is 2: 1. The fluid in the high-pressure container can be compressed to 50MPa within 3 days.
The gas booster needs a power gas source, and the invention adopts a common air pump, and because the invention works on the ground, the requirement of discharge capacity can be achieved by parallel connection, and the output pressure is more than 0.8 MPa.
The parameters were calculated as follows:
the gas density at atmospheric pressure is about one thousandth of the density of water, for example 1.25g/L nitrogen. The nitrogen densities of 10MPa and 50MPa at 50 deg.C were 0.1g/mL and 0.38g/mL, respectively. That is, in a high-pressure container with a length of 2000m, when the bottom pressure is 50MPa, the top pressure is only 43MPa, and the volume is 72m under the condition of converting to 10MPa3
When the bottom hole flow pressure is kept to be 10MPa stable, the bottom of the high-pressure container still keeps 10MPa pressure after being injected into the stratum, the top pressure is about 8MPa, and the volume of the gas in the container is remained by 12m3I.e. injected into the formation 60m3
If the influence of temperature and pressure gradient and the influence of unstable condition flow of gas at the bottom of a shaft are accurately considered in calculation, the volume of the actually injected formation gas is slightly larger than 60m3
Setting the device before entering the well
The pressure of a constant pressure valve of the high-pressure container is adjusted to be 50 MPa.
The ground control pneumatic control valve is opened and closed, and the working pressure of the gas booster is adjusted to 50 MPa.
System installation of integral device
Downhole operations and installations were carried out according to the configuration shown in fig. 7.
Implementing low frequency voltage transformation operation
In the later stage of gas injection, the gas is seen in the production well in a large amount, and after gas channeling is formed, the gas injection well and the production well can be temporarily closed, and the injection process is stopped. The oil increasing effect is better when gas channeling is not formed or gas is produced in a small amount, namely, the low-frequency pressure swing operation is carried out.
The above design scheme is implemented:
firstly, the ground control electromagnetic pneumatic control valve is opened, and then under the action of the existing ground pressure, gas in the oil reservoir quickly enters the high-pressure container and enters the upper annular space through the ventilation sleeve. Usually, the gas fills the space in a short time (1h), the pressure is stably distributed, and the bottom pressure keeps the formation fluid pressure at 10 MPa.
Secondly, the ground controls the high-pressure gas booster set to work, and the total time length is 3 days. The ground program controls the machine set to have a rest due to the long working time. In the working process, the gas in the upper annular space enters the high-pressure container, and the pressure of the gas in the upper annular space is continuously increased. Meanwhile, gas in the oil reservoir flows into the upper annular space, the gas pressure is reduced to a certain degree, the process is the process of gas discharging from the oil reservoir, and the pressure change is seen in a discharging pressure line.
And thirdly, when the pressure in the ground monitoring high-pressure container reaches 49MPa, the ground controls to close the electromagnetic pneumatic control valve, and at the moment, the gas in the upper space is isolated from the gas near the oil layer at the lower part. The gas booster set continues to work until the pressure in the high-pressure container reaches 50MPa, the pressure-setting valve in the high-pressure container is opened, high-pressure gas enters the stratum at high speed, the near-wellbore area is high in pressure, and the residual oil distribution state formed before is changed. At the same time, the gas booster set stops working.
And finally, when the gas pressure in the high-pressure vessel and the pressure of the bottom fluid are kept flat (about 3h), the constant-pressure valve of the high-pressure vessel is closed, and the injection and pressure boosting process is finished.
The above operation completes the transformation process of 1 frequency. If the method needs to be implemented again, the steps are repeated.
Fourthly, the gas injection process is continued
In the state that the low-frequency variable-pressure well device stops working, the original gas injection and production well continues working, the production well has certain oil increment in a certain stage, the gas-oil ratio is greatly reduced, and the process is also the key stage for improving the recovery ratio.
Based on the same inventive concept, the embodiment of the invention also provides a low-frequency variable-pressure reservoir exploitation system for residual oil in pores, as described in the following embodiments. Because the principle of the problem solving of the low-frequency variable-pressure reservoir exploitation system of the residual oil in the pore is similar to the low-frequency variable-pressure reservoir exploitation method of the residual oil in the pore, the implementation of the low-frequency variable-pressure reservoir exploitation system of the residual oil in the pore can refer to the implementation of the low-frequency variable-pressure reservoir exploitation method of the residual oil in the pore, and repeated parts are not repeated.
This low frequency vary voltage oil reservoir exploitation system of surplus oil in hole includes: the system comprises a low-frequency variable-pressure well device, a data analysis device and an oil extraction device;
wherein the data analysis device is configured to: acquiring a gas distribution diagram in an oil reservoir and a pressure distribution diagram between injection and production wells in the gas injection process, and determining the placement position of the low-frequency variable pressure well device in the oil reservoir according to the gas distribution diagram in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
the low-frequency variable-pressure well device is used for: the oil pump is placed at a corresponding position in the oil reservoir, and the pressure is intermittently increased and decreased at a preset frequency at the placement position in the oil reservoir, so that the distribution state of the residual oil in the oil reservoir at the placement position is changed;
the oil recovery device is used for: and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well.
The embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the method when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, and the computer readable storage medium stores a computer program for executing the method.
In summary, the invention provides a low-frequency variable-pressure oil reservoir development and application method capable of effectively driving residual oil in pores; the high flow rate generated by the low-frequency variable-pressure well shaft device can cause short-time high-pressure effect in a near well zone, and the effects of desorption of residual oil and change of the direction of a main seepage channel are realized;
2. the used low-frequency variable-pressure well casing device fully utilizes injected gas, does not need to repeatedly inject gas and discharge gas, and has remarkable economic benefit;
3. the gas compression process in the low-frequency variable-pressure well casing device does not need manual intervention;
4. the method for utilizing the shaft space to the maximum extent is invented by utilizing the full shaft as the core device of the low-frequency variable pressure well;
5. and part of the devices are installed and controlled on the ground, and have obvious advantages in the aspects of operation, management and maintenance.
6. According to the method, after the gas drive channeling, the recovery degree is continuously improved by a method of expanding swept volume.
As will be appreciated by one skilled in the art, 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, disk storage, CD-ROM, 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 flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams 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.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the embodiment of the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (16)

1. A low frequency variable pressure well device, comprising: surface and wellbore devices;
the shaft device comprises a support packer, a support short section, an oil layer packer, a ventilation sleeve, an electromagnetic pneumatic control valve and a high-pressure container from bottom to top, wherein the support packer, the support short section, the oil layer packer, the ventilation sleeve, the electromagnetic pneumatic control valve and the high-pressure container are positioned in a sleeve;
wherein the support packer is configured to: the expansion is clamped between the inner wall of the sleeve and the support short section to support the support short section;
the lower part of the support short section is connected with a support packer, the upper part of the support short section is connected with an oil layer packer, the support short section is tubular, and a hole is formed in the side of the pipe and used for enabling gas in an oil layer at the lower part to enter the oil layer packer;
the oil layer packer is used for: separating the upper oil layer to allow gas to enter and exit the lower oil layer;
the lower part and the outer part of the ventilation sleeve are connected with an oil layer packer, the inner part of the ventilation sleeve is connected with a high-pressure container, and the wall of the ventilation sleeve is provided with a through hole which is a channel for gas in the oil layer packer to enter the upper casing space;
the electromagnetic pneumatic control valve is connected with the ventilation sleeve through a through hole of the ventilation sleeve and is used for opening and closing the through hole so that gas of the lower oil layer enters the high-pressure container and the upper space;
the lower end of the high-pressure container is connected with the inside of the ventilation sleeve, and the high-pressure container is hollow and cylindrical;
the ground device comprises a wellhead device and a gas booster, wherein the high-pressure container is butted with an oil pipe interface of the wellhead device, a sleeve of the wellhead device is connected with a low-pressure inlet of the gas booster, and the oil pipe interface of the wellhead device is connected with a high-pressure outlet of the gas booster;
wherein the gas booster is used for compressing low-pressure gas in the high-pressure container into high-pressure gas.
2. The low frequency variable pressure well device according to claim 1, wherein the outside of the ventilation sleeve is connected with a packer by a pup joint, and the inside of the ventilation sleeve is connected with a high pressure vessel by screw thread.
3. The low frequency transformer well device as claimed in claim 1, wherein the end caps of the high pressure vessel are embedded to connect the ground device and the vent sleeve; and two ends of the outer cylinder of the high-pressure container are both provided with outer screw threads, and are connected with the inside of the ventilation sleeve through the outer screw threads.
4. The low-frequency variable pressure well device according to claim 3, wherein the high-pressure container comprises a constant pressure valve, the bottom end cover of the high-pressure container is provided with the constant pressure valve after being connected with the ventilation sleeve, an electromagnetic pneumatic control valve is arranged below the constant pressure valve, and the constant pressure valve is used for: when the pressure reaches the preset pressure, the valve is opened and is kept in a continuous opening state until the pressure of fluid inside and outside the high-pressure container is balanced, and then the valve is closed.
5. The low frequency variable pressure well device according to claim 1, 3 or 4, wherein the high pressure vessel comprises a plurality of high pressure vessels, and the high pressure vessels are connected with each other through a sealing coupling.
6. The low frequency variable pressure well device according to claim 5, wherein the high pressure vessels have different inner diameters, and the high pressure vessels with different inner diameters are connected through a seal reducing coupling.
7. The low-frequency variable pressure well device according to claim 1, wherein the electromagnetic pneumatic control valve comprises a plurality of piston type conical plugs, the piston type conical plugs are L-shaped, and the plurality of piston type conical plugs are connected through a multi-way ventilation connector;
the piston type conical plug comprises a conical plug, a connecting rod, a magnetic suction piston, an electromagnetic block and an L-shaped frame body; the connecting rod, the magnetic suction piston and the electromagnetic block are positioned in the L-shaped frame; the magnetic suction piston is driven to push the connecting rod and the conical plug by the electrification or non-electrification of the electromagnetic block, so that the through hole in the ventilation sleeve is opened and closed.
8. The low frequency variable pressure well device according to claim 7, wherein the number of the through holes in the high pressure vessel is the same as the number of the piston type conical plugs.
9. The low frequency variable pressure well device of claim 1, wherein the gas booster comprises a plurality of gas boosters connected in parallel.
10. The low frequency variable pressure well device as claimed in claim 1, wherein the surface device further comprises a control device connected to the gas booster for controlling the operation of the gas booster.
11. A low-frequency variable-pressure oil reservoir exploitation method for residual oil in pores is characterized by comprising the following steps:
acquiring a gas distribution map in an oil reservoir and a pressure distribution map between injection wells in the gas injection process;
determining the placement position of the low-frequency variable-pressure well device in the oil deposit according to the distribution graph of the gas in the oil deposit and the pressure distribution graph between injection wells during gas injection;
intermittently raising and lowering pressure at a preset frequency by adopting a placement position of a low-frequency variable-pressure well device in an oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position;
and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well.
12. The method of low frequency swing reservoir exploration of remaining oil in pore space of claim 11, wherein changing the remaining oil distribution within the reservoir at a location of placement by intermittently raising and lowering pressure at a predetermined frequency using the location of a low frequency swing well device within the reservoir comprises:
the electromagnetic pneumatic control valve is controlled to be opened by the control device, and gas in the oil reservoir enters the high-pressure container and enters the upper annular space through the ventilation sleeve;
controlling the gas booster set to start working through the control device, enabling gas in the upper annular space to enter the high-pressure container, increasing the gas pressure, and enabling the gas in the oil reservoir to flow into the upper annular space;
when the gas pressure in the high-pressure container reaches a first preset pressure, the external ground control device controls the electromagnetic gas control valve to be closed, the gas booster set continues to work, and until the gas pressure in the high-pressure container reaches a second preset pressure, the constant pressure valve in the high-pressure container is opened, high-pressure gas enters the oil reservoir, and the distribution state of residual oil in the oil reservoir is changed;
when the gas pressure in the high-pressure container and the fluid pressure in the oil reservoir are kept constant, the constant-pressure valve of the high-pressure container is closed.
13. A low frequency pressure swing reservoir production system for residual oil in a pore space, comprising: a low frequency variable pressure well device, data analysis device, oil recovery device as claimed in any one of claims 1 to 10;
wherein the data analysis device is configured to: acquiring a gas distribution diagram in an oil reservoir and a pressure distribution diagram between injection and production wells in the gas injection process, and determining the placement position of the low-frequency variable pressure well device in the oil reservoir according to the gas distribution diagram in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
the low-frequency variable-pressure well device is used for: the oil pump is placed at a corresponding position in the oil reservoir, and the pressure is intermittently increased and decreased at a preset frequency at the placement position in the oil reservoir, so that the distribution state of the residual oil in the oil reservoir at the placement position is changed;
the oil recovery device is used for: and exploiting the residual oil in the oil reservoir with the changed residual oil distribution state through the steam injection well and the oil extraction well.
14. The system for low frequency variable pressure reservoir production of residual oil in pore space of claim 13, wherein the low frequency variable pressure well device is specifically configured to:
the electromagnetic pneumatic control valve is controlled to be opened by the control device, and gas in the oil reservoir enters the high-pressure container and enters the upper annular space through the ventilation sleeve;
controlling the gas booster set to start working through the control device, enabling gas in the upper annular space to enter the high-pressure container, increasing the gas pressure, and enabling the gas in the oil reservoir to flow into the upper annular space;
when the gas pressure in the high-pressure container reaches a first preset pressure, the external ground control device controls the electromagnetic gas control valve to be closed, the gas booster set continues to work, and until the gas pressure in the high-pressure container reaches a second preset pressure, the constant pressure valve in the high-pressure container is opened, high-pressure gas enters the oil reservoir, and the distribution state of residual oil in the oil reservoir is changed;
when the gas pressure in the high-pressure container and the fluid pressure in the oil reservoir are kept constant, the constant-pressure valve of the high-pressure container is closed.
15. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 11 to 12 when executing the computer program.
16. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 11 to 12.
CN201910903838.4A 2019-09-24 2019-09-24 Low-frequency variable-pressure reservoir exploitation method, device and system for residual oil in pores Pending CN112627785A (en)

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CN201910903838.4A CN112627785A (en) 2019-09-24 2019-09-24 Low-frequency variable-pressure reservoir exploitation method, device and system for residual oil in pores
RU2021114279A RU2768835C1 (en) 2019-09-24 2020-09-23 Method, device and system for extraction of residual oil contained in pores of oil reservoir using pressure varied with low frequency
PCT/CN2020/116982 WO2021057760A1 (en) 2019-09-24 2020-09-23 Method, device, and system for low-frequency variable-pressure oil reservoir exploitation of remaining oil in pores

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113153242A (en) * 2021-04-19 2021-07-23 中国石油天然气股份有限公司 Gas injection oil displacement method and system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113153242A (en) * 2021-04-19 2021-07-23 中国石油天然气股份有限公司 Gas injection oil displacement method and system

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