CN113982573B

CN113982573B - Method and processor for inhibiting displacement front fingering

Info

Publication number: CN113982573B
Application number: CN202111388911.2A
Authority: CN
Inventors: 李宜强; 陈鑫; 唐永强; 隋铭月; 刘哲宇; 高文彬
Original assignee: China University of Petroleum Beijing
Current assignee: China University of Petroleum Beijing
Priority date: 2021-11-22
Filing date: 2021-11-22
Publication date: 2023-07-07
Anticipated expiration: 2041-11-22
Also published as: CN113982573A

Abstract

The invention relates to the technical field of oil and gas field development, and discloses a method and a processor for inhibiting displacement front fingering. The method comprises the following steps: injecting a displacement phase in the displaced phase in a pressure pulse injection manner to perform a displacement experiment, wherein the displacement manner comprises continuous displacement and pressure pulse displacement; acquiring images of a displacement experiment under a plurality of different pressure pulse parameters; processing the image to obtain a processing result; determining the sweep degree of displacement and the fractal dimension of the displacement front according to the processing result; the corresponding sweep level and fractal dimension for a plurality of different pressure pulse parameters are compared to determine a target pressure pulse parameter and displacement is performed based on the target pressure pulse parameter. In the technical scheme, the method for inhibiting fingering by pressure pulse injection is provided, the sweep degree can be enlarged on the premise of no chemical additive, the recovery ratio is improved, and the method is simple, convenient and easy to implement and has strong adaptability.

Description

Method and processor for inhibiting displacement front fingering

Technical Field

The invention relates to the technical field of oil and gas field development, in particular to a method and a processor for inhibiting displacement front fingering.

Background

In petroleum engineering, for porous medium immiscible fluid displacement processes, the displacement front may behave as capillary, viscous, and stable displacement under control of capillary and viscous forces. Oil phase viscosity, injection rate, interfacial tension and wettability all have an effect on fingering. Fingering can be understood as the phenomenon of flooding due to unstable fluctuations in the drive front during non-miscible displacement. Fingering affects the extent of the displaced phase, resulting in a significant reduction in recovery in field development.

The displacement front edge fingering can be restrained, the recovery ratio can be improved in oil and gas field development, the fingering phenomenon of the displacement front edge is improved by increasing the viscosity of the displacement phase, the displacement front edge fingering is restrained, the restraining effect is poor, and the contribution to the final improvement of the recovery ratio is small.

Disclosure of Invention

In order to overcome the deficiencies of the prior art, embodiments of the present invention provide a method and processor for inhibiting displacement front fingering.

To achieve the above object, a first aspect of the present invention provides a method for suppressing displacement front fingering, comprising:

injecting a displacement phase in the displaced phase in a pressure pulse injection manner to perform a displacement experiment, wherein the displacement manner comprises pressure pulse displacement;

Acquiring images of a displacement experiment under a plurality of different pressure pulse parameters;

processing the image to obtain a processing result;

determining the sweep degree of displacement and the fractal dimension of the displacement front according to the processing result;

the corresponding sweep level and fractal dimension for a plurality of different pressure pulse parameters are compared to determine a target pressure pulse parameter and displacement is performed based on the target pressure pulse parameter.

In an embodiment of the present invention, the pressure pulse parameters include: pulse frequency, median pulse velocity, and pulse amplitude;

the case of a plurality of different pressure pulse parameters includes:

the median pulse velocity and the pulse amplitude are the same, and the pulse frequency is different;

the median pulse speed and the pulse frequency are the same, and the pulse amplitude is different;

the pulse frequency and the pulse amplitude are the same, and the median pulse velocity is different.

In the embodiment of the invention, the pulse frequency ranges from 0.1Hz to 10Hz, the pulse median speed ranges from 40nl/min to 5000nl/min, and the pulse amplitude relative to the pulse median speed ranges from 0.25 to 1 time.

In an embodiment of the present invention, comparing the corresponding sweep-up degree and fractal dimension for a plurality of different pressure pulse parameters includes:

Under the condition that the pulse median speed is the same as the pulse amplitude, a first influence curve of pressure pulse injection of different pulse frequencies on the sweep degree is established to determine the inhibition effect of the pressure pulse injection of different pulse frequencies on fingering;

under the condition that the median pulse speed and the pulse frequency are the same, a second influence curve of pressure pulse injection with different pulse amplitudes on the sweep degree is established so as to determine the inhibition effect of the pressure pulse injection with different pulse amplitudes on fingering;

and under the condition that the pulse frequency is the same as the pulse amplitude, establishing a third influence curve of pressure pulse injection of different pulse median speeds on the sweep degree so as to determine the inhibition effect of the pressure pulse injection of different pulse median speeds on fingering.

In the embodiment of the invention, the method further comprises the following steps:

determining a target pulse frequency, a target pulse median velocity and a target pulse amplitude according to the first influence curve, the second influence curve and the third influence curve;

the target pressure pulse parameter is determined based on the target pulse frequency, the target pulse median velocity, and the target pulse amplitude.

and determining the pressure pulse parameters corresponding to the conditions of higher sweep degree and larger fractal dimension as target pressure pulse parameters.

In an embodiment of the present invention, acquiring an image of a displacement experiment includes:

acquiring an image of a displacement experiment at the middle moment in the displacement process;

and acquiring an image of a displacement experiment after the displacement is completed.

In an embodiment of the invention, the displacement phase comprises deionized water and the displaced phase comprises saturated oil; the processing results include the shape of the displacement front.

In an embodiment of the present invention, the displacement manner further includes: constant-speed displacement, wherein the speed range of the constant-speed displacement is 40nl/min to 5000nl/min.

A second aspect of the invention provides a processor configured to perform the method for inhibiting displacement front fingering described above.

A third aspect of the invention provides a machine-readable storage medium having stored thereon instructions for causing a machine to perform the above-described method for inhibiting displacement front fingering.

In the technical scheme, the pressure pulse is combined with the displacement front edge fingering inhibition, so that the fingering inhibition method by pressure pulse injection is provided, the sweep degree can be expanded on the premise of no chemical additive, the recovery ratio is improved, and the method is simple, convenient and easy to implement and has strong adaptability. The method comprises the steps of obtaining an image of a displacement experiment, processing the image, determining the sweep degree of displacement and the fractal dimension of the displacement front edge, comparing the sweep degree and the fractal dimension corresponding to a plurality of different pressure pulse parameters, determining the influence rule of the different pressure pulse parameters on fingering, determining the pressure pulse parameters corresponding to the condition of higher sweep degree and larger fractal dimension as target pressure pulse parameters, optimizing pulse injection parameters, further improving the suppression effect on fingering, further expanding the sweep degree, and finally improving the recovery ratio in oil and gas field development.

Drawings

The accompanying drawings are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain, without limitation, the embodiments of the invention. In the drawings:

FIG. 1 schematically illustrates a flow chart of a method for inhibiting displacement front fingering in accordance with an embodiment of the invention;

FIG. 2 schematically illustrates a capillary finger status diagram according to an embodiment of the invention;

FIG. 3 schematically illustrates a schematic of stable displacement according to an embodiment of the invention;

FIG. 4 schematically shows a schematic of an apparatus for a displacement experiment according to an embodiment of the invention;

fig. 5 schematically shows an image of breakthrough time instant of a pressure pulse displacement experiment No. 1 according to an embodiment of the invention;

FIG. 6 schematically shows an image of the end state of a pressure pulse displacement experiment number 1 according to an embodiment of the invention;

fig. 7 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 2 according to an embodiment of the invention;

FIG. 8 schematically shows an image of the end state of a pressure pulse displacement experiment number 2 according to an embodiment of the invention;

fig. 9 schematically shows an image of the breakthrough time instant of a pressure pulse displacement experiment according to embodiment 3 of the invention;

FIG. 10 schematically shows an image of the end state of a pressure pulse displacement experiment No. 3 according to an embodiment of the invention;

fig. 11 schematically shows an image of the breakthrough time of the constant velocity displacement experiment No. 11 according to the embodiment of the present invention;

fig. 12 schematically shows an image of the end state of the No. 11 constant velocity displacement experiment according to the embodiment of the present invention;

FIG. 13 schematically illustrates a schematic view of a first influence curve according to an embodiment of the invention;

fig. 14 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 4 according to an embodiment of the invention;

fig. 15 schematically shows an image of the end state of a pressure pulse displacement experiment No. 4 according to an embodiment of the invention;

fig. 16 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 5 according to an embodiment of the invention;

fig. 17 schematically shows an image of the end state of the pressure pulse displacement experiment No. 5 according to an embodiment of the invention;

fig. 18 schematically shows an image of the breakthrough time instant of a pressure pulse displacement experiment according to embodiment 6 of the invention;

fig. 19 schematically shows an image of the end state of the pressure pulse displacement experiment No. 6 according to an embodiment of the invention;

fig. 20 schematically shows an image of the breakthrough time of a constant velocity displacement experiment No. 10 according to the embodiment of the present invention;

Fig. 21 schematically shows an image of the end state of a constant velocity displacement experiment No. 10 according to an embodiment of the present invention;

fig. 22 schematically shows an image of the breakthrough time of the constant velocity displacement experiment No. 12 according to the embodiment of the present invention;

fig. 23 schematically shows an image of the end state of the No. 12 constant velocity displacement experiment according to the embodiment of the invention;

fig. 24 schematically shows an image of the breakthrough time of the constant velocity displacement experiment No. 13 according to the embodiment of the present invention;

fig. 25 schematically shows an image of the end state of the No. 13 constant velocity displacement experiment according to the embodiment of the present invention;

FIG. 26 schematically illustrates a schematic diagram of a third influence curve according to an embodiment of the invention;

fig. 27 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 7 according to an embodiment of the invention;

FIG. 28 schematically illustrates an image of the end state of a pressure pulse displacement experiment No. 7, according to an embodiment of the invention;

fig. 29 schematically shows an image of breakthrough time of a pressure pulse displacement experiment No. 8 according to an embodiment of the invention;

FIG. 30 schematically illustrates an image of the end state of a pressure pulse displacement experiment number 8 according to an embodiment of the present invention;

fig. 31 schematically shows an image of the breakthrough time instant of the pressure pulse displacement experiment according to embodiment 9 of the invention;

FIG. 32 schematically shows an image of the end state of a pressure pulse displacement experiment No. 9 according to an embodiment of the invention;

fig. 33 schematically shows a schematic of a second influence curve according to an embodiment of the invention.

Description of the reference numerals

10 oil phase injection pump 11 water phase injection pump

12 first pressure sensor 13 second pressure sensor

14 camera 15 lens

16 laser light source 17 dichroic mirror

18 etching model 19 computer

Detailed Description

The following describes the detailed implementation of the embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.

In the present embodiment, if directional indications (such as up, down, left, right, front, and rear … …) are included, the directional indications are merely used to explain the relative positional relationship, movement, and the like between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present application, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the protection scope of the present application.

FIG. 1 schematically illustrates a flow chart of a method for inhibiting displacement front fingering in accordance with an embodiment of the invention. As shown in fig. 1, in one embodiment of the present invention, a method for inhibiting displacement front fingering is provided, comprising the steps of:

step 101, injecting a displacement phase in a pressure pulse injection mode to perform a displacement experiment, wherein the displacement mode comprises continuous displacement and pressure pulse displacement;

step 102, under the condition of a plurality of different pressure pulse parameters, acquiring an image of a displacement experiment;

step 103, processing the image to obtain a processing result;

104, determining the sweep degree of displacement and the fractal dimension of the displacement front according to the processing result;

step 105, comparing the corresponding sweep level and fractal dimension for a plurality of different pressure pulse parameters to determine a target pressure pulse parameter, and performing displacement based on the target pressure pulse parameter.

Finger-feed: in the non-miscible displacement process, the phenomenon of the sudden advance of the displacement phase caused by the unstable fluctuation of the displacement front; the sweep degree of the displaced phase can be influenced, and the recovery ratio can be greatly reduced in the field of oil and gas field development. Inhibiting displacement front fingering can improve recovery in field development. Fig. 2 schematically shows a schematic view of capillary finger status according to an embodiment of the invention. The displacement of saturated oil with deionized water is understood to be an immiscible displacement process, as exemplified by the saturated oil being the saturated oil, the displacement phase being deionized water, the saturated oil being immiscible with the deionized water. The black area in fig. 2 is understood as a form of saturated oil, the white area in fig. 2 is understood as a form of deionized water, and the phenomenon that deionized water (white area) is spiked in fig. 2 affects the extent of the saturated oil (black area).

The extent of sweep may be understood as the degree of completion of a displacement when the displacement phase displaces the displaced phase (e.g., deionized water displaces saturated oil). For example, as shown in fig. 2, if the sum of the white area and the black area is the total area, the sweep degree may be understood as the proportion of the white area to the total area, that is, the proportion of the displacement phase after the completion of the displacement within a preset time. When the deionized water (white area) is larger, the saturated oil (black area) is smaller, the saturated oil is better in the completion degree of displacement, the sweep degree is higher, and the recovery effect is better.

The contact portion (contact edge) between the displaced phase and the displaced phase can be understood as a displacement front, for example in fig. 2, the contact edge between the white area (deionized water) and the black area (saturated oil) can displace the front. Fig. 3 schematically shows a schematic diagram of stable displacement according to an embodiment of the invention, similarly the white area in fig. 3 may be understood as the displaced phase and the black area in fig. 3 may be understood as the displaced phase. The fractal dimension may describe the complexity of the shape of the displacement front more quantitatively. As can be seen by comparing fig. 2 and 3, the displacement front shape of fig. 2 is more complex and the displacement front shape of fig. 3 is less complex. The value of the fractal dimension is typically between 1 and 2, the greater the value of the fractal dimension (closer to 2), the lower the complexity of the shape representing the displacement front, the closer to stable displacement and piston displacement. The fractal dimension in fig. 3 is larger in value than in fig. 2.

The displacement front fingering is suppressed in order to increase the value of the fractal dimension, increase the sweep of the displaced phase and improve the recovery of the displaced phase (such as saturated oil).

Pressure pulse: is an injection mode that generates wave energy in the reservoir by periodically varying the injection rate. The pressure pulse parameters include: pulse frequency, pulse median velocity, and pulse amplitude.

Pulse frequency: the number of effective discharges per second occurs in the discharge gap per unit time, and the number of periodic pulses per second is frequency, for example, the pulse frequency is 0.1, that is, the injection speed changes every 10 seconds.

Median pulse velocity: the average value of the maximum value and the minimum value in a single period is the median speed of pulse fluctuation, for example, the median speed of the pulse is 40nl/min, the amplitude is 0.5 times of the median, and then the maximum value of the single period speed is 60nl/min, and the minimum value is 20nl/min.

Fig. 4 schematically shows a schematic of an apparatus for a displacement experiment according to an embodiment of the invention, as shown in fig. 4, the apparatus for a displacement experiment comprising: an oil phase injection pump 10, an aqueous phase injection pump 11, a first pressure sensor 12, a second pressure sensor 13, a camera 14, a lens 15, a laser light source 16, a dichroic mirror 17, an etching model 18, and a computer 19.

The etch model 18, which may also be referred to as a large-scale microscopic etch model, may be chosen to be 5cm by 3cm in size to ensure adequate development of the displacement front morphology. The water phase injection pump 11 can be a micro-flow injection pump, and the periodic variation of the injection speed can be realized through a pulse program, so that the pressure pulse injection is realized. The camera can record the form of the displacement front edge and the sweep degree of the displacement in real time, so that the experimental process is visualized, the image is processed by image processing software in a computer, and the irregularity degree (which can be characterized by fractal dimension) of the displacement front edge and the sweep degree of the displacement can be determined. Repeated experiments can be carried out by changing the pressure pulse parameters, the suppression effect of the pressure pulse on fingering is clear, and the suppression rule of the pulse frequency, the pulse median speed and the pulse amplitude on fingering is clear.

Optionally, the displacing method further comprises: and (5) constant-speed displacement. Constant velocity displacement may be used as a control experiment for pressure pulse displacement. Constant-speed displacement refers to the injection rate of the displacement phase being constant.

In one embodiment, the following steps may be referred to:

(1) And (3) sealing one end of the large-size micro etching model, and connecting the other end of the large-size micro etching model with a special vacuumizing pipeline and a vacuum pump of the microfluidic model to perform vacuumizing treatment. And injecting saturated crude oil by using a micro-flow injection pump after vacuumizing for 1h, and standing for 2h after saturation so as to uniformly distribute the crude oil in the model.

(2) According to fig. 4, the experimental device is connected, the micro-flow injection pump is started, deionized water is injected into saturated oil for displacement, first constant-speed displacement is carried out according to a set speed, images are recorded every 10 seconds, and the experiment is ended when the spreading degree is no longer enlarged. Constant velocity displacement was used as a control experiment for pressure pulse displacement. A sweep no longer expands is understood to be a completion of the displacement, such as a no longer decrease in the black area (saturated oil) in fig. 2.

(3) And (3) connecting the water phase injection pump 11 to pulse injection software, repeating the step (1) and starting the water phase injection pump 11 to displace under the condition of pressure pulse, changing the pulse median speed under the condition that the pulse frequency and the pulse amplitude are unchanged, and researching the influence of the pulse median speed on the inhibition of finger-in.

(4) Repeating the step (1) and starting the water phase injection pump 11 to perform displacement under the condition of pressure pulse, changing the pulse amplitude under the condition that the pulse median speed and the pulse frequency are unchanged, and researching the influence of the pulse amplitude on inhibiting fingering.

(5) Repeating the step (1) and starting the water phase injection pump 11 to perform displacement under the condition of pressure pulse, changing the pulse frequency under the condition that the pulse median speed and the pulse amplitude are unchanged, and researching the influence of the pulse frequency on inhibiting fingering.

(6) And processing the images of the displacement front edge of each group of experiments, calculating the fractal dimension, and characterizing the fingering degree. And selecting an image in the whole process, identifying the sweep degree, drawing a change curve of the extraction degree, and determining the influence of pressure pulse injection on the final extraction degree.

In the embodiment of the invention, 9 groups of experimental schemes are designed by selecting reasonable pulse median speed, pulse frequency and pulse period, and as shown in table 1, table 1 is a 9 groups of pressure pulse experimental scheme. Experiments according to the specific implementation steps of the invention can clearly show that pulse injection has good inhibition effect on the finger advancing front and can expand the sweep degree. Finally, the pulse injection parameters are preferred, resulting in a method of pulse injection to inhibit viscous fingering.

TABLE 1

In addition, as a control experiment, an experiment in which 4 sets of constant-speed displacement methods were provided correspondingly, and the speeds of the 4 sets of constant-speed displacement methods were respectively: 40nl/min, 1000nl/min, 3000nl/min and 5000nl/min. The constant-speed displacement experiment with the speed of 40nl/min is marked as a No. 10 experiment, the constant-speed displacement experiment with the speed of 1000nl/min is marked as a No. 11 experiment, the constant-speed displacement experiment with the speed of 3000nl/min is marked as a No. 12 experiment, and the constant-speed displacement experiment with the speed of 5000nl/min is marked as a No. 13 experiment.

Please refer to table 1, experiments No. 1, no. 2 and No. 3 were performed for inhibition of finger-feed by pulse frequency. The viscosity of crude oil is 100cp, the displacement phase is deionized water, the pulse median speed is 1000nl/min, the amplitude is 0.5 times the median speed (500 nl/min), and the control pulse frequency is 0.1Hz, 1Hz and 10Hz respectively.

Fig. 5 schematically shows an image of breakthrough time instant of a pressure pulse displacement experiment No. 1 according to an embodiment of the invention; FIG. 6 schematically shows an image of the end state of a pressure pulse displacement experiment number 1 according to an embodiment of the invention; fig. 7 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 2 according to an embodiment of the invention; FIG. 8 schematically shows an image of the end state of a pressure pulse displacement experiment number 2 according to an embodiment of the invention; fig. 9 schematically shows an image of the breakthrough time instant of a pressure pulse displacement experiment according to embodiment 3 of the invention; fig. 10 schematically shows an image of the end state of the pressure pulse displacement experiment No. 3 according to an embodiment of the present invention.

Referring to fig. 5, the breakthrough time is understood as the time when the white area reaches the left side of the image in fig. 5, and corresponds to the time when the deionized water reaches the end opposite to the injection end from the injection end.

As a control experiment, a constant-speed displacement experiment at a speed of 1000nl/min was labeled as experiment No. 11, fig. 11 schematically showing an image of the breakthrough time of the constant-speed displacement experiment No. 11 according to the embodiment of the present invention; fig. 12 schematically shows an image of the end state of the No. 11 constant-speed displacement experiment according to the embodiment of the present invention.

By analyzing fig. 5 to 12, i.e. analyzing the effect on finger advance for pulse frequency in experiments No. 1, no. 2 and No. 3. It was found that the effect of suppressing fingering can be achieved by controlling the pulse frequency. In pressure pulse displacement experiments, the breakthrough time of the displacement front was postponed as the pulse frequency increased. From the advancing profile of the displacement front, it can be seen that as the pulse frequency increases, the multi-finger profile of the displacement front improves, the fingers transitioning from thin to long to thick to short, i.e., from viscous fingers to capillary fingers, with greater pulse frequency and ultimately greater sweep. When the pulse frequency is increased to 10Hz, the final sweep may reach 80% and above, see fig. 10, with a white area of 80% or above.

Fig. 13 schematically illustrates a schematic diagram of a first influence curve, i.e. a curve of influence of pressure pulse injection with different pulse frequencies on the extent of sweep, according to an embodiment of the present invention. As shown in fig. 13, in the end state of the pressure pulse displacement experiment, the degree of spread of experiment No. 3 (pulse frequency 10Hz, pulse median velocity 1000nl/min, pulse amplitude 0.5 times) was highest, at 80% or more, when the injection amount was 2 PV; experiment No. 1 (pulse frequency of 0.1Hz, median pulse speed of 1000nl/min, pulse amplitude of 0.5 times) had the lowest degree of sweep, below 60%, lower than the corresponding constant-velocity displacement experiment; experiment No. 2 (pulse frequency 1Hz, pulse median speed 1000nl/min, pulse amplitude 0.5 times) had a higher extent of sweep than the corresponding constant-velocity displacement experiment at an injection of 2 PV.

The impact of pulse median velocity on finger-in suppression is discussed below. Please refer to tables 1,4, 5 and 6 experiments were performed for inhibition of finger-in by median pulse velocity. The crude oil viscosity is 100cp, the displacement phase is deionized water, the pulse median speed is 40nl/min, 3000nl/min and 5000nl/min, the amplitude is 0.5 times the median speed, and the pulse frequency is 1Hz.

Fig. 14 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 4 according to an embodiment of the invention; fig. 15 schematically shows an image of the end state of a pressure pulse displacement experiment No. 4 according to an embodiment of the invention; fig. 16 schematically shows an image of breakthrough time instant for a pressure pulse displacement experiment No. 5 according to an embodiment of the invention; fig. 17 schematically shows an image of the end state of the pressure pulse displacement experiment No. 5 according to an embodiment of the invention; fig. 18 schematically shows an image of the breakthrough time instant of a pressure pulse displacement experiment according to embodiment 6 of the invention; fig. 19 schematically shows an image of the end state of the pressure pulse displacement experiment No. 6 according to an embodiment of the present invention.

As a control experiment, a constant-speed displacement experiment at a speed of 40nl/min was labeled as experiment No. 10, a constant-speed displacement experiment at a speed of 3000nl/min was labeled as experiment No. 12, and a constant-speed displacement experiment at a speed of 5000nl/min was labeled as experiment No. 13. Fig. 20 schematically shows an image of the breakthrough time of a constant velocity displacement experiment No. 10 according to the embodiment of the present invention; fig. 21 schematically shows an image of the end state of a constant velocity displacement experiment No. 10 according to an embodiment of the present invention; fig. 22 schematically shows an image of the breakthrough time of the constant velocity displacement experiment No. 12 according to the embodiment of the present invention; fig. 23 schematically shows an image of the end state of the No. 12 constant velocity displacement experiment according to the embodiment of the invention; fig. 24 schematically shows an image of the breakthrough time of the constant velocity displacement experiment No. 13 according to the embodiment of the present invention; fig. 25 schematically shows an image of the end state of the No. 13 constant-speed displacement experiment according to the embodiment of the present invention.

It can be seen from fig. 14 to 25 that the median velocity of the control pulse can have a certain effect on the finger-slip phenomenon. Comparing the pressure pulse displacement experiment No. 4 (pulse frequency is 1Hz, pulse median speed is 40nl/min, pulse amplitude is 0.5 times) with the constant-speed displacement experiment No. 10 (constant speed is 40 nl/min), the pulse injection does not change the finger type, still is capillary finger, and the displacement front still keeps a double-finger and single-finger thicker form for pushing, and the difference is that compared with the constant-speed displacement, the single-finger injection is thin and more dispersive after the pulse injection.

Comparing the pressure pulse displacement experiment No. 5 (pulse frequency is 1Hz, pulse median speed is 3000nl/min, pulse amplitude is 0.5 times) with the constant-speed displacement experiment No. 12 (constant speed is 3000 nl/min), the multi-finger phenomenon is obvious during constant-speed displacement, single fingers are thinner, each branch is more dispersed, and the viscous finger-shaped structure is typical. When pulse injection is carried out, the single-finger form of the displacement front becomes thicker, the index is reduced, each branch is more compact, and the phenomenon of branch convergence occurs at the tail end, so that the capillary finger form is more typical, and the final sweep degree is greatly increased.

Comparing the pressure pulse displacement experiment No. 6 (pulse frequency is 1Hz, pulse median speed is 5000nl/min, pulse amplitude is 0.5 times) with the constant-speed displacement experiment No. 13 (constant speed is 5000 nl/min), the typical viscous finger-advancing form is shown at constant-speed displacement. When pulse injection is performed, the number of branches becomes smaller, and no lateral development trend exists. Combining the above analyses, it was found that the median pulse velocity increased and the pulse effect increased and then decreased.

FIG. 26 schematically illustrates a schematic diagram of a third influence curve according to an embodiment of the invention; the third influence curve is the influence curve of the injection of pressure pulses with different pulse median speeds on the sweep degree. As shown in fig. 26, in the case where the injection amount is 2PV, the sweep degree of the pressure pulse displacement experiment No. 5 (pulse frequency 1Hz, pulse median velocity 3000nl/min, pulse amplitude 0.5 times) is high for the end state of the pressure pulse displacement experiment; the degree of spread of the No. 6 pressure pulse displacement experiment (pulse frequency 1Hz, pulse median speed 5000nl/min, pulse amplitude 0.5 times) was the lowest, and the degree of spread of the No. 4 pressure pulse displacement experiment (pulse frequency 1Hz, pulse median speed 40nl/min, pulse amplitude 0.5 times) was also lower.

The impact of pulse amplitude on finger hold-down control is discussed below. Please refer to table 1, experiments No. 7, no. 8 and No. 9 were performed for the suppression of finger-feed by pulse amplitude. The viscosity of crude oil is 100cp, the displacement phase is deionized water, the pulse median speed is 1000nl/min, the amplitude is 0.25, 0.75 and 1 times of the median speed, and the control pulse frequency is 1.

It can be seen from fig. 27 to 32 that varying the pulse amplitude has a certain suppressing effect on the finger-in phenomenon. As the pulse amplitude increases, the time required for breakthrough shortens and the final sweep increases significantly. When the pulse amplitude is greater than 0.5 times the median speed, the amplification of the extent of spread becomes smaller as the pulse amplitude increases. When the pulse amplitude is smaller than 0.25 times of the median speed, the vibration amplitude is smaller, the finger-feed inhibition effect is not obvious, and the pulse is difficult to play a role. Therefore, when the finger-in phenomenon is suppressed by controlling the pulse amplitude, the pulse amplitude should be controlled to be 0.5 times and above the median speed.

FIG. 33 schematically illustrates a schematic diagram of a second influence curve according to an embodiment of the invention; the second influence curve is the influence curve of the injection of pressure pulses with different pulse amplitudes on the degree of sweep, and as shown in fig. 33, the degree of sweep of the pressure pulse displacement experiment No. 9 (pulse frequency is 1Hz, median pulse speed is 1000nl/min, pulse amplitude is 1 time) is highest for the end state of the pressure pulse displacement experiment when the injection amount is 2 PV; the extent of the sweep of the pressure pulse displacement experiment No. 7 (pulse frequency 1Hz, pulse median speed 1000nl/min, pulse amplitude 0.25 times) was the lowest.

By the 9 groups of pressure pulse displacement experiments and the 4 groups of constant-speed displacement control experiments, the pressure pulse injection has obvious influence on the displacement front edge, and the occurrence of fingering can be restrained under certain conditions, so that the following conclusion is obtained:

(1) As the pulse frequency increases, the break-through time delays, the fingers of the displacement front transition from thin to long to thick to short, i.e., from viscous fingers to capillary fingers, and the greater the frequency, the greater the final sweep, and when the pulse frequency increases to 10Hz, the final sweep can reach 80% and above.

(2) When the median speed of the pulse is 40nl/min, the inhibiting effect of the pulse on finger-feed is not obvious; when the median speed of the pulse is 3000nl/min, the pulse converts the displacement front edge from viscous fingering to capillary fingering, so that the sweep degree and the sweep range are enlarged; when the median speed of the pulse is 5000nl/min, the pulse reduces the sweep degree and sweep range.

(3) With the increase of the pulse amplitude, the breakthrough time is advanced, and the final sweep range and sweep degree are obviously increased; when the pulse amplitude is greater than 0.5 times the median speed, the amplification of the extent of the spread becomes smaller as the amplitude increases, and when the pulse amplitude is less than 0.25 median speed, the vibration amplitude is smaller, the effect of suppressing fingering is not obvious, and the pulse is difficult to function.

(3) The pulse can inhibit the occurrence of finger-stepping to a certain extent. When the pulse frequency is changed, the pulse frequency should be controlled to be more than 1; when the median pulse speed is changed, the median pulse speed is increased, the pulse effect is increased and then weakened, the pulse is found to be suitable for viscous fingering, and the displacement speed is controlled to be moderate; when the pulse amplitude is changed, the pulse amplitude should be above 0.5 times the median velocity.

It should be noted that the above 9 sets of pressure pulse displacement experiments and 4 sets of constant-speed displacement control experiments are embodiments of a part of the present invention, an operator may perform other more pressure pulse displacement experiments under different pressure pulse parameters according to the method provided by the embodiments of the present invention to discuss the influence of different pressure pulse parameters on the sweep degree of displacement, the fractal dimension of the displacement front and the recovery ratio of the displaced phase, determine the pressure pulse parameters corresponding to the conditions of higher sweep degree, larger fractal dimension and higher recovery ratio of the displaced phase as target pressure pulse parameters, and then perform displacement based on the target pressure pulse parameters, so as to improve the suppression effect on fingering, thereby expanding the sweep degree and finally improving the recovery ratio in oil and gas field development.

Pressure pulses are one of the physical vibration-based oil recovery techniques, and originally originated from occasional events that cause changes in individual well production from some seismic source. The fluctuation energy generated by the pressure pulse is used for acting on the reservoir to cause the physical and chemical changes of the oil layer and the fluid thereof, so as to achieve the effects of improving the reservoir and improving the recovery ratio. The current pressure pulse is mainly applied to the aspects of improving the seepage condition of an oil layer, removing the blockage of the oil layer, creating an environment beneficial to the flow of crude oil and the like.

The method is combined with the suppression displacement leading edge fingering, the method is applied to the suppression fingering on the basis of researching the pressure pulse, and relevant experiments are carried out, and experimental results show that the method has good suppression fingering effect, is simple and convenient to operate and has strong universality. Aiming at the phenomenon of unstable leading edge in the non-miscible displacement process, a method for suppressing the finger-advance leading edge is provided based on a pressure pulse injection mode, and the injection mode of pressure pulses is carried out through a large-size microscopic etching model so as to change the distribution of a seepage field in a porous medium, achieve the effect of expanding the sweep (the sweep can be expanded by more than 20% in a microscopic visual model) and optimize the pulse parameters related to the best. The finger-advancing front inhibition method with universality and simple operation provided by the embodiment of the invention can improve the recovery ratio at the lowest cost if being implemented in a mine, and the future physical oil extraction method can play an effective role in the aspect.

Embodiments of the present invention provide a processor configured to perform the method of any of the above embodiments for inhibiting displacement front fingering.

In particular, the processor may be configured to:

processing the image to obtain a processing result;

In an embodiment of the present invention, the processor may be configured to:

the pressure pulse parameters include: pulse frequency, median pulse velocity, and pulse amplitude;

the case of a plurality of different pressure pulse parameters includes:

In an embodiment of the present invention, the processor may be configured to:

the pulse frequency ranges from 0.1Hz to 10Hz, the pulse median velocity ranges from 40nl/min to 5000nl/min, and the pulse amplitude relative to the pulse median velocity ranges from 0.25 to 1 times.

In an embodiment of the present invention, the processor may be configured to:

Comparing the corresponding sweep level and fractal dimension for a plurality of different pressure pulse parameters includes:

In an embodiment of the invention, the processor is further configured to:

In an embodiment of the invention, the processor is configured to:

acquiring images of the displacement experiment includes:

In an embodiment of the invention, the processor is further configured to:

the displacement phase comprises deionized water, and the displaced phase comprises saturated oil; the processing results include the shape of the displacement front.

In an embodiment of the invention, the processor is further configured to:

the manner of displacement further includes: constant-speed displacement, wherein the speed range of the constant-speed displacement is 40nl/min to 5000nl/min.

Embodiments of the present invention provide a machine-readable storage medium having stored thereon instructions for causing a machine to perform the above-described method for inhibiting displacement front fingering.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application 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 application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. 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.

In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.

The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.

Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.

It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises an element.

The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.

Claims

1. A method for inhibiting displacement front fingering, comprising:

Acquiring images of the displacement experiment under a plurality of different pressure pulse parameters;

processing the image to obtain a processing result;

comparing the extent of sweep and the fractal dimension corresponding to a plurality of different pressure pulse parameters to determine a target pressure pulse parameter and performing displacement based on the target pressure pulse parameter;

the pressure pulse parameters include: pulse frequency, median pulse velocity, and pulse amplitude; the plurality of different pressure pulse parameters may include:

the median pulse velocity is the same as the pulse amplitude, and the pulse frequency is different;

the median pulse velocity is the same as the pulse frequency, while the pulse amplitude is different;

the pulse frequency is the same as the pulse amplitude, and the median pulse velocity is different;

said comparing said extent of sweep and said fractal dimension corresponding to a plurality of different pressure pulse parameters includes:

Under the condition that the pulse median speed is the same as the pulse frequency, establishing a second influence curve of pressure pulse injection with different pulse amplitudes on the sweep degree so as to determine the inhibition effect of the pressure pulse injection with different pulse amplitudes on fingering;

under the condition that the pulse frequency and the pulse amplitude are the same, establishing a third influence curve of pressure pulse injection of different pulse median speeds on the sweep degree so as to determine the inhibition effect of the pressure pulse injection of different pulse median speeds on fingering;

the acquiring the image of the displacement experiment comprises:

acquiring an image of the displacement experiment at the middle moment in the displacement process;

and acquiring an image of the displacement experiment after the displacement is completed.

2. The method of claim 1, wherein the pulse frequency ranges from 0.1Hz to 10Hz, the pulse median velocity ranges from 40nl/min to 5000nl/min, and the pulse amplitude relative to the pulse median velocity ranges from 0.25 to 1 times.

3. The method as recited in claim 1, further comprising:

determining a target pulse frequency, a target pulse median velocity, and a target pulse amplitude from the first, second, and third impact curves;

The target pressure pulse parameter is determined from the target pulse frequency, the target pulse median velocity, and the target pulse amplitude.

4. The method as recited in claim 1, further comprising:

and determining the pressure pulse parameters corresponding to the conditions of higher sweep degree and larger fractal dimension as the target pressure pulse parameters.

5. The method of claim 1, wherein the displaced phase comprises deionized water and the displaced phase comprises saturated oil; the processing results include the shape of the displacement front.

6. The method of claim 1, wherein the manner of displacing further comprises: and (3) constant-speed displacement, wherein the speed range of the constant-speed displacement is 40nl/min to 5000nl/min.

7. A processor configured to perform the method for inhibiting displacement front fingering according to any one of claims 1 to 6.