CN112627785B - Low-frequency variable-pressure oil reservoir exploitation method, device and system for residual oil in pores - Google Patents
Low-frequency variable-pressure oil reservoir exploitation method, device and system for residual oil in pores Download PDFInfo
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- CN112627785B CN112627785B CN201910903838.4A CN201910903838A CN112627785B CN 112627785 B CN112627785 B CN 112627785B CN 201910903838 A CN201910903838 A CN 201910903838A CN 112627785 B CN112627785 B CN 112627785B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/30—Specific pattern of wells, e.g. optimizing the spacing of wells
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
Abstract
The invention provides a low-frequency variable-pressure oil reservoir exploitation method, device and system for residual oil in a pore, wherein the method comprises the following steps: acquiring a distribution diagram of gas in an oil reservoir and a pressure distribution diagram among injection and production wells in the gas injection process; determining the placement position of the low-frequency pressure-variable well device in the oil reservoir according to the distribution diagram of the gas in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process; intermittently increasing and reducing pressure at a preset frequency by adopting a placement position of the low-frequency pressure-variable well device in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position; and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well. The scheme utilizes the short-time high-pressure effect of the near-wellbore zone caused by the high flow rate of the low-frequency pressure-variable well device to realize the effects of desorbing residual oil and changing the direction of the main seepage channel, and continuously improves the recovery degree by expanding the sweep volume after gas drive channeling.
Description
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 for the later development of water injection and the development of low-permeability oil reservoirs, has the advantages of low seepage resistance, quick recovery of formation pressure, obvious oil displacement effect and the like, but has the defect that gas can easily flow along a hypertonic channel in the oil reservoir, once the gas is introduced into the oil reservoir and forms a channel in the oil reservoir, the gas injected in the later stage can hardly exert an oil displacement effect after being produced from a production well. In the oil reservoir, the residual oil containing high saturation is still contained in part of pores of the channeling channels, and the prior art has a method for plugging part of the channeling channels, but usually only can solve near-wellbore zones, and plugging agents are difficult to enter the deep part of the oil reservoir.
Disclosure of Invention
The embodiment of the invention provides a low-frequency variable-pressure oil reservoir exploitation method, device and system for residual oil in pores, which solve the technical problem that residual oil with higher saturation in partial pores of a channeling channel cannot be exploited in the prior art.
The embodiment of the invention provides a low-frequency transformer well device, which comprises: surface means and wellbore means;
the well bore device comprises a supporting packer, a supporting nipple, an oil layer packer, a ventilation sleeve, an electromagnetic pneumatic control valve and a high-pressure container from bottom to top, wherein the supporting packer, the supporting nipple, the oil layer packer, the ventilation sleeve, the electromagnetic pneumatic control valve and the high-pressure container are positioned in a casing;
wherein, support the packer and be used for: the expansion clamp is clamped between the inner wall of the casing and the supporting pup joint to support the supporting pup joint;
the lower part of the supporting nipple is connected with the supporting packer, the upper part of the supporting nipple is connected with the oil layer packer, the supporting nipple is tubular, and the side of the pipe is provided with holes for allowing gas in the lower oil layer to enter the oil layer packer through the holes;
the oil layer packer is used for: the upper oil layer is cut off, so that gas enters and exits from the lower oil layer;
the lower part and the outer part of the ventilation sleeve are connected with the oil layer packer, the inner part of the ventilation sleeve is connected with the high-pressure container, the wall of the ventilation sleeve is provided with a through hole, and the ventilation sleeve is a passage for gas in the oil layer packer to enter the upper sleeve 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 a 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 in butt joint 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;
the gas booster is used for compressing low-pressure gas in the high-pressure container into high-pressure gas;
the two end covers of the high-pressure container are embedded, and are connected with the ground device and the ventilation sleeve through the embedded type; the two ends of the outer cylinder of the high-pressure container are both provided with outer threads, and the outer threads are connected with the inside of the ventilation sleeve;
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, the electromagnetic pneumatic control valve is arranged below the constant-pressure valve, and the constant-pressure valve is used for: when the preset pressure is reached, the valve is opened, and the valve is kept in a continuously opened state until the fluid pressure inside and outside the high-pressure container is balanced, and then the valve is closed.
The embodiment of the invention also provides a low-frequency variable-pressure oil reservoir exploitation method of the residual oil in the pores, which comprises the following steps:
acquiring a distribution diagram of gas in an oil reservoir and a pressure distribution diagram among injection and production wells in the gas injection process;
determining the placement position of the low-frequency pressure-variable well device in the oil reservoir according to the distribution diagram of the gas in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
intermittently increasing and reducing pressure at a preset frequency by adopting a placement position of the low-frequency pressure-variable well device in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position;
and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well.
The embodiment of the invention also provides a low-frequency variable-pressure oil reservoir exploitation system for residual oil in pores, which comprises the following steps: the device comprises a low-frequency pressure-variable well device, a data analysis device and an oil extraction device;
wherein, the data analysis device is used for: acquiring a distribution diagram of gas 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 a low-frequency pressure-variable well device in the oil reservoir according to the distribution diagram of the gas in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
the low frequency transformer well device is used for: the method comprises the steps of placing the oil reservoir at a corresponding position in the oil reservoir, intermittently increasing and decreasing the pressure at a preset frequency at the placed position in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placed position;
the oil extraction device is used for: and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the method when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, which stores a computer program for executing the method.
According to the distribution diagram of gas in the oil reservoir and the pressure distribution diagram among the injection and production wells in the gas injection process, the low-frequency variable-pressure well device is determined to be placed at a certain position in the oil reservoir, and the pressure is intermittently increased and reduced at a preset frequency, so that the distribution state of the residual oil in the oil reservoir at the placed position is changed, the residual oil in the oil reservoir with the changed distribution state of the residual oil is exploited through the steam injection well and the production well, and the extraction degree can be improved.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of the distribution of gas in a reservoir during gas injection;
FIG. 2 is a schematic diagram of a cross-sectional gas distribution of gas in a reservoir during gas injection;
FIG. 3 is a schematic diagram of the distribution of the remaining oil in the enlarged region during the gas injection process;
FIG. 4 is a schematic diagram of pressure distribution between injection and production wells during gas injection;
fig. 5 is a schematic diagram of a low-frequency transformer reservoir exploitation method for residual oil in a pore according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of pressure distribution of a low frequency transformation method according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a low frequency transformer well bore device according to an embodiment of the present invention;
FIG. 8 is a schematic illustration of a wellbore apparatus in a low frequency transformer well wellbore apparatus provided in an embodiment of the present invention;
FIG. 9 is a schematic illustration of a venting sleeve provided by an embodiment of the present invention;
FIG. 10 is a schematic flow of gas through a breather sleeve provided by an embodiment of the present invention;
FIG. 11 is a schematic view of a high pressure vessel according to an embodiment of the present invention;
FIG. 12 is a schematic view of a combined structure of a high-pressure vessel portion provided by an embodiment of the present invention;
FIG. 13 is a front view of an electromagnetic pneumatic control valve provided by an embodiment of the present invention;
fig. 14 is a top view of an electromagnetic pneumatic control valve provided by an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the prior art, a one-dimensional columnar rock model is generally adopted to study a gas injection oil displacement mechanism. The larger the rock model diameter, the easier the gas channeling effect will manifest. If slug displacement is studied, the smaller the diameter the better, a 2.5cm diameter core is typically used. Rectangular long cores are also more commonly used if the effect of gas channeling on the extent of production is investigated, using cores of 3.8cm or greater diameter. FIG. 1 shows the fluid state in the model during gas injection in a rectangular long core. Fig. 1-3 show the fluid state in the reservoir during gas injection. FIG. 1 shows a section where after gas is produced, a main gas channel is formed in the middle of the core, and surrounding areas where gas is not swept. FIG. 2 is a cross-sectional view of the shape of the main gas passage and unswept area. Fig. 3 is an enlarged view of the partial area in fig. 2, showing that the residual oil remains in a portion of the pores of the main channel, because the gas flow in the main channel tends to be stable after the gas channeling, and is affected by the blocking, interfacial tension, adsorption, etc. of the rock particles, so that a portion of the residual oil cannot flow.
Figure 4 shows the distribution of pressure in the core model along the length at steady production of gas injection. The inlet pressure is highest, the injection pressure Pin, the outlet pressure is lowest, and the outlet pressure Pout. There is a pressure drop funnel at the core inlet, i.e. the pressure drop gradient is larger, then the pressure tends to be gentle, and the difference Δp between the pressures Pi and Pout at the i position is smaller. The curve 1 and the curve 2 are respectively the pressure distribution schematic diagrams of the hypertonic core and the hypotonic core, and the differential pressure hypotonic core at the i position is smaller than the hypertonic core, so that the residual oil in the pores of the hypotonic core is more than the hypertonic core. That is, the lower the permeability of the rock model, the more serious the influence of gas channeling, the higher the remaining oil saturation, and the lower the recovery.
Aiming at the distribution position and stress characteristics of 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 distribution diagram of gas in an oil reservoir and a pressure distribution diagram among injection and production wells in the gas injection process;
step 502: determining the placement position of the low-frequency pressure-variable well device in the oil reservoir according to the distribution diagram of the gas in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
step 503: intermittently increasing and reducing pressure at a preset frequency by adopting a placement position of the low-frequency pressure-variable well device in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position;
step 504: and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well.
I.e. the pressure is intermittently raised and lowered at a certain frequency at a low pressure location (i.e. the placement location) by means of a low frequency pressure varying well device, resulting in a change of pressure within a certain range around the location. The effect changes the original stable gas flow, and the gas seepage direction is changed in a reverse way in one frequency, so that the state of the residual oil in the pores of the sweep range is changed, and a part of the residual oil reaches the flowing state and is extracted, thereby improving the extraction degree. Meanwhile, the change of the residual state and the redistribution of seepage resistance in the influence area can be caused by the low-frequency gas injection well, so that the shape and even the direction of the original formed main seepage channel are changed, the swept volume of the gas drive is enlarged, and the extraction degree is improved more remarkably.
Fig. 6 shows that a low frequency transformer well is placed in the middle of the production well, where the gas is injected to cause a pressure increase, after which the well rapidly discharges the gas causing a pressure decrease, which will be lower than the starting pressure when the velocity is higher. From an analysis of the corresponding pressure curves (injection pressure line and discharge pressure line), it is known that the state of the seepage in the affected area is necessarily affected by the pressure change, where P fimax For maximum injection pressure, P fomin Is the discharge pressure minimum.
In the embodiment of the invention, whether the low-frequency transformation method principle can be realized is critical to the design of the low-frequency transformation well, namely the design of an internal core device. The effect of high flow rate of gas and short-time high pressure in near-wellbore zone is obvious that the larger the gas discharge capacity is, the more the gas is facilitated to be moved to a far-wellbore zone, and a full-wellbore device with a low-frequency pressure transformation function and a control mode are designed for achieving the aim at the maximum limit, and the structure of the low-frequency pressure transformation well device is shown in fig. 7.
The low-frequency pressure-variable well device comprises a well shaft device 1 and a surface device 2;
the wellbore device 1 comprises a support packer 11, a support nipple 12, an oil layer packer 13, a ventilation sleeve 14, a high-pressure container 15 and an electromagnetic pneumatic control valve 16 from bottom to top, wherein the support packer 11, the support nipple 12, the oil layer packer 13, the ventilation sleeve 14, the high-pressure container 15 and the electromagnetic pneumatic control valve 16 are positioned in a casing 19, as shown in fig. 7 and 8.
The supporting packer 11 is commonly used equipment for oil fields, and has the function of being expanded and clamped on the inner wall of the sleeve 19 by a slip mechanical device, and the sealing rubber cylinder is expanded to isolate an upper space and a lower space and also has the function of supporting a pipe column above as a whole. The invention can select the model with simple operation and good sealing effect, the upper part adopts Y445 packer, and the lower part adopts Y221 packer.
The support nipple 12 is a design device, tubular, and has holes on the side. The lower part is connected with the supporting packer 11, and the upper part is connected with the oil layer packer 13. The purpose of the perforations is to allow gas in the lower reservoir to pass unimpeded into the reservoir packer 13.
The oil layer packer 13 plays a role of blocking an oil layer, and the upper oil layer is blocked by packing rubber, so that gas enters and exits in the lower oil layer.
(1) Venting sleeve 14
The lower part of the venting sleeve 14 is externally provided with a nipple (the nipple is a common fitting in industrial pipeline connection, the common nipple is provided with threads, and the nipple is 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 inside of the venting sleeve is connected with the high-pressure container 15 through an inner thread 141. The structure of the air-permeable sleeve is shown in fig. 9, and the wall 142 of the air-permeable sleeve 14 is provided with a through hole 143, which is a passage for gas in the bottom oil layer packer 13 to enter the upper casing space. See fig. 10 for a schematic gas flow diagram. The through hole at the connecting position with 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 valve 16, so that the electromagnetic pneumatic valve has a valve function.
(2) High pressure vessel 15
The high-pressure container 15 has a simple structure and a hollow cylindrical shape, the end covers at the two ends are embedded, namely, the inner end covers are connected with the ventilation sleeve 14 through the inner screw threads 151, and the two ends of the outer cylinder are the outer screw threads 152, as shown in fig. 11. One end is connected to the inside of the breather sleeve 14. The bottom end cap is fitted with a constant pressure valve 153 after connection to the breather sleeve 14, see fig. 12. An electromagnetic pneumatic 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 the constant pressure valve keeps the opening state until the internal and external fluid pressures are balanced, and then the constant pressure 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 of the high-pressure container is the depth of the well bore. Normally, the depth of an oil reservoir of an oil field in China is more than 1000m, and if the inner diameter of a container is 6cm, the space volume of a 1000m constant diameter long tube is about 3m 3 。
The length of the high pressure vessel is thus determined to maximize the length of the high pressure vessel based on the specific casing usage of the well. Casing is typically divided into surface casing, technical casing, and its length varies depending on the well conditions. The minimum inner diameters of the surface casing, the technical casing and the oil casing are respectively as follows: 21.6cm, 15.0cm and 10.0cm. If the depth of the oil reservoir is 2000m, the surface layer sleeve 200m, the technical sleeve 1600m and the oil layer sleeve 200m are arranged, the high-pressure container can also be designed into a mode of gradually thickening from bottom to top, the inner diameter of the high-pressure container is respectively 12.0cm, 9.0cm and 6.0cm corresponding to different sleeve types, and if the length is equal to the corresponding sleeve, the space volume of the trapezoid high-pressure container is about 15m 3 。
Because the low-frequency pressure transformation method needs to establish 2 times of annular pressure conditions in a high-pressure container, the existing sleeve cannot be used as the container, the wall thickness is 5-10 mm, and the pressure resistance is not strong. The container designed by the method adopts 316 steel, the wall thickness is within 10-20 mm, and the pressure resistance can reach 70MPa at maximum.
Due to the field operation condition, the single high-pressure container has a length of 10m and is formed by connecting two ends of sealing couplings in series gradually. And in the reducing section, the sealing collar is reduced. The technology is mature technology and will not be described in detail.
(3) Electromagnetic pneumatic control valve 16
The electromagnetic pneumatic valve 16 includes a plurality of piston type cone plugs 161, as shown in fig. 13, the piston type cone plugs are L-shaped, and the plurality of piston type cone plugs 161 are connected by a multi-way vent joint 162. The piston type conical plug comprises a conical plug 1611, a connecting rod 1612, a magnetic attraction piston 1613, an electromagnetic block 1614 and an L-shaped frame; wherein, toper end cap 1611, connecting rod 1612, magnetism inhale piston 1613 and connect gradually, connecting rod 1612, magnetism inhale piston 1613 and electromagnetic block 1614 are located L type framework.
The electromagnetic pneumatic valve 16 utilizes part of 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 gas cannot enter the upper space through the ventilation sleeve 14, but only enters the stratum. When the pressure of the high-pressure gas is relieved, and the pressure of the outlet gas is balanced with the pressure of the surrounding environment, the magnetic attraction piston 1613 drives the conical plug 161 to move downwards under the electromagnetic attraction of the electromagnetic block 1614 through the connecting rod 1612, the piston type conical plug returns to the original position by means of self gravity, the electromagnetic pneumatic control valve 16 is opened, and low-pressure gas discharged from the oil layer enters the upper space. The electromagnetic pneumatic control valve 16 is matched with the ventilation sleeve 14 in number, and the front view is shown in fig. 13 and the top view is shown in fig. 14.
Wherein, as shown in fig. 7, the surface device 2 comprises a wellhead 21 and a gas booster 22, wherein, the high-pressure container 15 is in butt joint with an oil pipe interface of the wellhead 21, a sleeve of the wellhead 21 is connected with a low-pressure inlet of the gas booster 22, and the oil pipe interface of the wellhead 21 is connected with a high-pressure outlet of the gas booster 22;
wherein the gas booster 17 is used for compressing the low-pressure gas in the high-pressure vessel 15 into high-pressure gas.
A control device 23 may also be included, connected to the turbocharger 22, for controlling the operation of the turbocharger.
(1) Wellhead assembly 18
The wellhead device adopts a common wellhead system, the high-pressure container 15 is in butt joint with the original oil pipe interface, and a sealing reducing coupling is required to be installed during connection. The control lines etc. are led out from the casing of the wellhead 21 via the annular space in a sealed manner with the connection outlet of the wellhead 21.
The sleeve of the wellhead 21 is connected to the low pressure gas inlet 221 of the turbocharger 22 via a sleeve control valve 211, and the tubing interface of the wellhead 21 is connected to the high pressure gas outlet 222 of the turbocharger 22 via a tubing control valve 212.
(2) Gas booster 22
A gas booster is a conventional application device that functions to compress low pressure gas into high pressure gas under the power provided by an air compressor. The principle of the pressurizing process is in a mature application state, so that the description is omitted here.
Because the gas booster is arranged outside the wellhead and the space environment is not limited, the external dimension of the booster can be increased and large discharge capacity can be realized by connecting a plurality of boosters in parallel.
In the embodiment of the present invention, the working process of the low-frequency transformer well device is as follows (i.e. step 503 specifically includes:
taking a low-permeability reservoir with gas injection and oil displacement as an example, a low-frequency pressure transformation method is adopted. Low permeability oil reservoirs have low permeability and complex pore structures, so that water injection pressure is high, water injection is difficult, and the phenomenon of no-injection is common. The oil reservoir of the type is mined by adopting a gas injection mode and a low injection quantity mode, so that the fingering phenomenon is prevented.
Setting the depth of the oil reservoir to 2000m, and injecting gas daily for 3m under the condition of the bottom hole fluid pressure of 10MPa 3 (3000Nm 3 ). Injecting air according to single frequency of 60m 3 (formation pressure 10 MPa), and high-pressure radial injection is carried out on the oil reservoir by a target of 1 frequency in 7 days.
The core device dimensions are as follows:
the high-pressure container is configured according to the design, and the total volume is 15m 3 ；
The gas booster unit consists of 10 gas boosters. The maximum working pressure of the single gas booster is 60MPa, the discharge flow is 1000L/min, and the ratio of working time to rest time is 2:1. The fluid in the high pressure vessel can be compressed to 50MPa in 3 days.
The air booster needs a power air source, and the invention adopts a common air pump, and the air booster works on the ground, so that the discharge capacity requirement can be achieved through parallel connection, and the output pressure is more than 0.8 MPa.
The calculated parameters are as follows:
the gas density at normal pressure is about one thousandth of the water density, for example 1.25g/L nitrogen. The densities of nitrogen gas at 50℃and 10MPa and 50MPa were 0.1g/mL and 0.38g/mL, respectively. Namely, in a high-pressure container with the 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 the pressure into 10MPa 3 。
When the bottom hole flow pressure is kept stable at 10MPa, 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 gas volume in the container remains 12m 3 I.e. into the formation 60m 3 。
If the calculation accurately considers the influence of temperature and pressure gradients and the influence of unstable gas flow at the bottom of the well bore, the actual injected formation gas volume is slightly larger than 60m 3 。
(1) Setting of the apparatus in front of the well
And regulating the constant pressure valve pressure of the high-pressure container to be 50MPa.
The ground controls the opening and closing of the pneumatic control valve, and the working pressure of the gas booster is adjusted to be 50MPa.
(2) System installation of integrated devices
The construction shown in fig. 7 is followed to perform the downhole operation and installation.
(3) Implementing low frequency voltage transformation operations
And in the later period of gas injection, a great amount of gas is seen from the production well, and after gas channeling is formed, the gas injection well and the production well can be temporarily closed, and the injection process is stopped. When no gas channeling or a small amount of produced gas is formed, the oil increasing effect of the low-frequency pressure changing operation is better.
Executing the design scheme:
firstly, the electromagnetic pneumatic control valve is controlled to be opened on the ground, so that under the action of the existing ground pressure, the gas in the oil reservoir rapidly enters the high-pressure container and enters the upper annular space through the ventilation sleeve. The space is filled with gas in a short time (1 h), the pressure is distributed stably, and the bottom pressure keeps the formation fluid pressure to 10MPa.
Secondly, the ground controls the high-pressure gas booster unit to work, and the total duration is 3 days. Because the working time is longer, the ground program controls the machine set to rest. 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. At the same time, the gas in the oil reservoir flows into the upper annular space, the pressure of the gas is reduced to a certain extent, and the process is the process of discharging the gas from the oil reservoir, and the pressure change is seen as a discharge pressure line.
And when the pressure in the high-pressure container monitored on the ground reaches 49MPa, the electromagnetic pneumatic control valve is closed by ground control, and the gas in the upper space is isolated from the gas in the vicinity of the lower oil layer. And the gas booster unit continues to work until the pressure in the high-pressure container reaches 50MPa, the internal pressure valve in the high-pressure container is opened, high-pressure gas enters the stratum at a high speed, high pressure is caused in a near-wellbore zone, and the distribution state of residual oil formed before is changed. At the same time, the gas booster unit stops working.
And finally, when the gas pressure in the high-pressure container and the bottom hole fluid pressure are kept at normal level (about 3 hours), the constant-pressure valve of the high-pressure container is closed, and the injection boosting process is finished.
The above operation completes the transformation process for 1 frequency. If the method needs to be implemented again, repeating the steps.
(4) Continuing the gas injection process
In the state that the low-frequency pressure-variable well device stops working, the original gas injection and production well continue working, and in a certain stage, the production well has certain oil increasing degree, the gas-oil ratio is greatly reduced, and the process is 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 oil reservoir exploitation system for residual oil in pores, as described in the following embodiment. The principle of solving the problem of the low-frequency variable-pressure oil reservoir exploitation system of the residual oil in the pore is similar to that of the low-frequency variable-pressure oil reservoir exploitation method of the residual oil in the pore, so that the implementation of the low-frequency variable-pressure oil reservoir exploitation system of the residual oil in the pore can be referred to the implementation of the low-frequency variable-pressure oil reservoir exploitation method of the residual oil in the pore, and repeated parts are omitted.
The low-frequency variable-pressure oil reservoir exploitation system for residual oil in the pore comprises: the device comprises a low-frequency pressure-variable well device, a data analysis device and an oil extraction device;
wherein, the data analysis device is used for: acquiring a distribution diagram of gas 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 a low-frequency pressure-variable well device in the oil reservoir according to the distribution diagram of the gas in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
the low frequency transformer well device is used for: the method comprises the steps of placing the oil reservoir at a corresponding position in the oil reservoir, intermittently increasing and decreasing the pressure at a preset frequency at the placed position in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placed position;
the oil extraction device is used for: and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well.
The embodiment of the invention also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the method when executing the computer program.
The embodiment of the invention also provides a computer readable storage medium, which stores a computer program for executing the method.
In summary, 1. 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 pressure-variable well shaft device can cause short-time high-pressure effect in a near-wellbore zone, and the effects of desorbing residual oil and changing the direction of a main seepage channel are realized;
2. the used low-frequency pressure-variable well shaft device fully utilizes the injected gas, does not need repeated injection of the gas and exhaust of the gas, and has obvious economic benefit;
3. the gas compression process in the proposed low-frequency pressure-variable well shaft device does not need manual intervention;
4. the method for utilizing the well space to the maximum extent is invented by using the whole well bore as a core device of the low-frequency variable well;
5. the device has obvious advantages in the aspects of ground installation, control, operation, management and maintenance.
6. After the gas-driven channeling, the method continues to improve the extraction degree by expanding the swept volume.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, 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 flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, and various modifications and variations can be made to the embodiments of the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (14)
1. A low frequency transformer well device, comprising: surface means and wellbore means;
the well bore device comprises a supporting packer, a supporting nipple, an oil layer packer, a ventilation sleeve, an electromagnetic pneumatic control valve and a high-pressure container from bottom to top, wherein the supporting packer, the supporting nipple, the oil layer packer, the ventilation sleeve, the electromagnetic pneumatic control valve and the high-pressure container are positioned in a casing;
wherein, support the packer and be used for: the expansion clamp is clamped between the inner wall of the casing and the supporting pup joint to support the supporting pup joint;
the lower part of the supporting nipple is connected with the supporting packer, the upper part of the supporting nipple is connected with the oil layer packer, the supporting nipple is tubular, and the side of the pipe is provided with holes for allowing gas in the lower oil layer to enter the oil layer packer through the holes;
the oil layer packer is used for: the upper oil layer is cut off, so that gas enters and exits from the lower oil layer;
the lower part and the outer part of the ventilation sleeve are connected with the oil layer packer, the inner part of the ventilation sleeve is connected with the high-pressure container, the wall of the ventilation sleeve is provided with a through hole, and the ventilation sleeve is a passage for gas in the oil layer packer to enter the upper sleeve 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 a 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 in butt joint 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;
the gas booster is used for compressing low-pressure gas in the high-pressure container into high-pressure gas;
the two end covers of the high-pressure container are embedded, and are connected with the ground device and the ventilation sleeve through the embedded type; the two ends of the outer cylinder of the high-pressure container are both provided with outer threads, and the outer threads are connected with the inside of the ventilation sleeve;
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, the electromagnetic pneumatic control valve is arranged below the constant-pressure valve, and the constant-pressure valve is used for: when the preset pressure is reached, the valve is opened, and the valve is kept in a continuously opened state until the fluid pressure inside and outside the high-pressure container is balanced, and then the valve is closed.
2. The low frequency transformer well device of claim 1, wherein the exterior of the breather sleeve is connected to the oil layer packer by a nipple, and the interior of the breather sleeve is threaded to the high pressure vessel.
3. The low frequency transformer well device of claim 1, wherein the high pressure vessel comprises a plurality of vessels connected one to the other by sealing collars.
4. The low frequency transformer well device of claim 3, wherein the plurality of high pressure vessels have different inner diameters, and the high pressure vessels having different inner diameters are connected by a sealing reducing collar.
5. The low frequency transformer well device of claim 1, wherein the electromagnetic pneumatic control valve comprises a plurality of piston type cone plugs, wherein the piston type cone plugs are L-shaped, and the plurality of piston type cone plugs are connected through a multi-way ventilation joint;
the piston type conical plug comprises a conical plug body, a connecting rod, a magnetic attraction piston, an electromagnetic block and an L-shaped frame body; the conical plug, the connecting rod and the magnetic piston are connected in sequence, and the connecting rod, the magnetic piston and the electromagnetic block are positioned in the L-shaped frame; the magnetic piston is driven to push the connecting rod and the conical plug by the presence or absence of the electrification of the electromagnetic block, so that the through hole in the ventilation sleeve is opened and closed.
6. The low frequency transformer well device of claim 5, wherein the number of through holes in the high pressure vessel is the same as the number of piston cone plugs.
7. The low frequency variable pressure well device of claim 1, wherein the gas booster comprises a plurality of gas boosters connected in parallel to form a gas booster train.
8. The low frequency variable pressure well device of claim 7, wherein the surface device further comprises a control device coupled to the gas booster for controlling operation of the gas booster.
9. A method for producing a low frequency, variable pressure reservoir of residual oil in a pore, comprising:
acquiring a distribution diagram of gas in an oil reservoir and a pressure distribution diagram among injection and production 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 diagram of the gas in the oil reservoir and the pressure distribution diagram between injection and production wells in the gas injection process;
intermittently increasing and reducing pressure at a preset frequency by adopting a placement position of the low-frequency pressure-variable well device in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placement position;
and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well.
10. The method of low frequency variable pressure reservoir recovery of residual oil in a pore space according to claim 9, wherein intermittently increasing and decreasing the pressure at a predetermined frequency with the placement position of the low frequency variable pressure well device in the reservoir, and changing the residual oil distribution state in the reservoir at the placement position, 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;
the control device is used for controlling the gas booster unit to start working, gas in the upper annular space enters the high-pressure container, the gas pressure is increased, and the gas in the oil reservoir flows into the upper annular space;
when the gas pressure in the high-pressure container reaches a first preset pressure, the control device on the external ground controls the electromagnetic pneumatic control valve to be closed, the gas booster unit continues to work 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;
and when the gas pressure in the high-pressure container and the fluid pressure in the oil reservoir are kept at the same time, the constant-pressure valve of the high-pressure container is closed.
11. A low frequency, variable pressure reservoir recovery system for residual oil in a pore, comprising: the low frequency variable pressure well device of claim 8, further comprising a data analysis device and an oil recovery device;
wherein, the data analysis device is used for: acquiring a distribution diagram of gas 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 a low-frequency pressure-variable well device in the oil reservoir according to the distribution diagram of the gas in the oil reservoir and the pressure distribution diagram between the injection and production wells in the gas injection process;
the low frequency transformer well device is used for: the method comprises the steps of placing the oil reservoir at a corresponding position in the oil reservoir, intermittently increasing and decreasing the pressure at a preset frequency at the placed position in the oil reservoir, and changing the distribution state of residual oil in the oil reservoir at the placed position;
the oil extraction device is used for: and (3) extracting the residual oil in the oil reservoir with the changed distribution state of the residual oil through the steam injection well and the oil extraction well.
12. The low frequency, variable pressure reservoir recovery system of residual oil in a pore space of claim 11, 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;
the control device is used for controlling the gas booster unit to start working, gas in the upper annular space enters the high-pressure container, the gas pressure is increased, and the gas in the oil reservoir flows into the upper annular space;
when the gas pressure in the high-pressure container reaches a first preset pressure, the control device on the external ground controls the electromagnetic pneumatic control valve to be closed, the gas booster unit continues to work 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;
and when the gas pressure in the high-pressure container and the fluid pressure in the oil reservoir are kept at the same time, the constant-pressure valve of the high-pressure container is closed.
13. 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 9 to 10 when executing the computer program.
14. 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 9 to 10.
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| CN201910903838.4A CN112627785B (en) | 2019-09-24 | 2019-09-24 | Low-frequency variable-pressure oil 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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| CN201910903838.4A CN112627785B (en) | 2019-09-24 | 2019-09-24 | Low-frequency variable-pressure oil reservoir exploitation method, device and system for residual oil in pores |
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| US4319635A (en) * | 1980-02-29 | 1982-03-16 | P. H. Jones Hydrogeology, Inc. | Method for enhanced oil recovery by geopressured waterflood |
| CA1185119A (en) * | 1982-01-14 | 1985-04-09 | Jack A. Barnard | Method and apparatus for raising well fluids |
| CN100346053C (en) * | 2004-12-22 | 2007-10-31 | 西南石油学院 | Automatic boosting oil production and liquid discharge gas producing device and method for underwell gas |
| CN101566057A (en) * | 2009-05-26 | 2009-10-28 | 中国石油化工股份有限公司西北油田分公司工程技术研究院 | Deep well gas injection supercharging mechanical oil production method and device |
| US9719336B2 (en) * | 2014-07-23 | 2017-08-01 | Saudi Arabian Oil Company | Method and apparatus for zonal isolation and selective treatments of subterranean formations |
| CA2971030A1 (en) * | 2016-06-15 | 2017-12-15 | Pursuit Technologies Ltd. | Apparatus and method for testing an oil and/or gas well with a multiple-stage completion |
| CN106437639A (en) * | 2016-10-19 | 2017-02-22 | 中国石油化工股份有限公司 | Carbon dioxide mixed-phase flushing efficiency and remaining oil distribution evaluation method and isolated plant |
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