A method of shale oil recovery

Abstract

The application discloses a shale oil recovery method and relates to the technical field of oil and gas reservoir development. The method comprises the following steps: deploying a development well pattern for a shale oil reservoir, wherein the development well pattern comprises at least two wells; fracturing the shale oil reservoir through the development well pattern, so that the at least two wells are communicated with each other; injecting a fluid medium into the shale oil reservoir through the development well pattern; and recovering the shale oil reservoir after the fluid medium is injected through the development well pattern. The shale oil recovery method realizes large-scale shale oil recovery through the communicated development well pattern in the mode of fluid medium imbibition oil displacement, and improves the overall reservoir recovery ratio of the shale oil reservoir.

Description

Technical Field

[0001] This application relates to the field of oil and gas reservoir development technology, and in particular to a shale oil recovery method. Background Technology

[0002] As the development of old oilfields enters the middle and late stages, the pressure to improve efficiency and stabilize production is increasing. In order to improve the level of oil and gas development, shale oil reservoirs are gradually entering the scope of exploration and development.

[0003] Currently, to address the problem of tight shale oil reservoirs and the difficulty in extraction, shale oil development often employs single-well volumetric fracturing to create a complex network of fractures around the wellbore within the shale oil reservoir, thereby establishing oil flow channels.

[0004] However, the above methods are based on single-well shale oil recovery and are difficult to improve the overall recovery rate of shale oil reservoirs from the perspective of large-scale application. Summary of the Invention

[0005] This application provides a method for shale oil recovery. The technical solution provided by this application is as follows:

[0006] According to one aspect of the embodiments of this application, a shale oil recovery method is provided, the method comprising:

[0007] For shale oil reservoirs, a development well network is deployed, wherein the development well network includes at least two wells;

[0008] The shale oil reservoir is fractured using the development well network, so that at least two wells are interconnected.

[0009] Fluid media are injected into the shale oil reservoir through the development well network;

[0010] The shale oil reservoir is recovered by the well network described above after the fluid medium has been injected.

[0011] In some embodiments, the fluid medium includes at least one of the following: a gaseous medium, a liquid medium, and a gas-liquid composite medium.

[0012] In some embodiments, where the at least two wells are at least two horizontal wells, the injection of fluid media into the shale oil reservoir through the development well network includes:

[0013] Gas medium is injected into the shale oil reservoir through the high-level well of the at least two horizontal wells;

[0014] And / or,

[0015] Liquid media are injected into the shale oil reservoir through the lower well of the at least two horizontal wells.

[0016] In some embodiments, injecting a fluid medium into the shale oil reservoir through the development well network includes:

[0017] Based on the reservoir distribution of the shale oil reservoir, an injection well is determined from the at least two wells;

[0018] Through the injection well, gaseous and liquid media are alternately injected into the shale oil reservoir.

[0019] In some embodiments, after fracturing the shale oil reservoir through the development well network to connect at least two wells, the method further includes:

[0020] The development well network is subjected to a first set period of well shut-in treatment;

[0021] The aforementioned development well network is used to recover shale oil reservoirs after fracturing.

[0022] In some embodiments, injecting a fluid medium into the shale oil reservoir through the development well network includes:

[0023] If the recovery efficiency of the fracturing shale oil reservoir is lower than a first threshold, the fluid medium is injected into the shale oil reservoir through the development well network.

[0024] In some embodiments, injecting a fluid medium into the shale oil reservoir through the development well network includes:

[0025] A fluid medium is injected into the shale oil reservoir through the injection well in at least two of the wells at a first rate.

[0026] If the fluid medium is obtained through the remaining wells (excluding the injection well) of the at least two wells, the remaining wells shall be shut down.

[0027] With all the remaining wells closed, fluid medium is injected into the shale oil reservoir through the injection well at a second rate greater than the first rate.

[0028] After injecting a first predetermined amount of fluid medium into the shale oil reservoir through the injection well, the injection well is shut down.

[0029] In some embodiments, after injecting a fluid medium into the shale oil reservoir through the development well network, the method further includes:

[0030] The development well network is subjected to a second set duration of well shut-in treatment, the second set duration being related to the type of fluid medium.

[0031] In some embodiments, where the at least two wells are at least two horizontal wells, the method further includes:

[0032] The well-opening sequence is determined based on the type of fluid medium and the elevation of the at least two horizontal wells;

[0033] According to the well-opening sequence, the at least two horizontal wells are opened sequentially.

[0034] In some embodiments, the method further includes:

[0035] If the recovery efficiency of the shale oil reservoir after the injection of the fluid medium is lower than the second threshold, the injection wells in the development well network shall be changed, and / or the type of the fluid medium shall be changed.

[0036] The technical solutions provided in this application have at least the following beneficial effects:

[0037] By deploying a development well network comprising at least two wells, and by fracturing to connect these wells, a fluid medium is injected into the shale oil reservoir. The reservoir is then harvested using the developed well network after the fluid medium injection. This fluid-medium adsorption displacement method, through the interconnected development well network, enables large-scale shale oil recovery and improves the overall recovery rate of shale oil reservoirs. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a shale oil recovery method provided in one embodiment of this application;

[0039] Figure 2 This is a schematic diagram of a three-dimensional structure of a development well network provided in one embodiment of this application;

[0040] Figure 3 This is a schematic diagram of the front view of a development well pattern provided in one embodiment of this application;

[0041] Figure 4 This is a schematic diagram of the three-dimensional structure of a development well network provided in another embodiment of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0043] Please refer to Figure 1 The diagram illustrates a flowchart of a shale oil recovery method according to an embodiment of this application. The method may include at least one of steps 110 to 140.

[0044] Step 110: For shale oil reservoirs, deploy a development well network, which includes at least two wells.

[0045] Shale oil refers to petroleum resources contained in shale formations, which are mainly composed of shale. This includes petroleum in the pores and fractures of mudstone and shale, as well as petroleum resources in adjacent and interlayered layers of dense carbonate or clastic rocks in mudstone and shale formations.

[0046] In this embodiment, the shale oil reservoir can be a shale oil-rich formation, i.e., a shale oil "sweet spot" layer. Wells in the development well network can serve as either production wells for shale oil recovery or injection wells for injecting fluid media into the shale oil reservoir. The selection of injection wells is detailed in the embodiments below.

[0047] It should be noted that the wells included in the development well network can be vertical wells or directional wells (such as horizontal wells). This application does not limit the well type in the development well network. Furthermore, the wells included in the development well network can be of the same type (e.g., all horizontal wells) or different types (e.g., some are horizontal wells and others are vertical wells). For an example, please refer to... Figure 2 The illustration shows a schematic diagram of a three-dimensional structure of a development well network provided in one embodiment of this application. In this example, the wells included in the development well network are all horizontal wells.

[0048] In some embodiments, development well patterns are deployed based on the geological characteristics of the shale oil reservoir.

[0049] In some embodiments, parameters such as the location and spacing of each well in the development well network are determined based on information such as the lithology of the shale oil reservoir, the morphology of natural fractures (and the designed fracturing scale), thereby deploying the development well network.

[0050] In the petroleum industry, fracturing refers to the artificial creation of fractures in the formation through hydraulic or gas action, thereby improving the underground flow environment for oil and gas.

[0051] Step 120: By developing a well network, the shale oil reservoir is fractured to make at least two wells interconnected.

[0052] At least two wells are interconnected, meaning that in a shale oil reservoir, at least two wells are interconnected through fractures between the wells (including natural fractures and fractures formed by hydraulic fracturing of the formation).

[0053] In some embodiments, by developing a well network, large-scale volumetric fracturing is used to create a network of fractures in shale oil reservoirs, such that at least two wells form an interlocking connection.

[0054] Volumetric fracturing refers to the process of expanding natural fractures and causing shear slippage in brittle rocks during fracturing, thereby creating a network of intersecting natural and artificial fractures and increasing the volume of fracturing.

[0055] In some embodiments, fracturing parameters (such as pressure, displacement, pump power, etc. of fracturing equipment) are designed based on the geological characteristics of the shale oil reservoir.

[0056] In some embodiments, fracturing parameters are designed based on information such as the lithology of shale oil reservoirs, the distribution characteristics of natural fractures, reservoir temperature, and pressure.

[0057] In some embodiments, hydraulic fracturing can be used, in which high-pressure pumps inject fluid at high speed into each well of the development well network. The high pressure generated at the bottom of the well causes the oil-bearing rock to fracture and create cracks. In some other embodiments, high-energy gas can also be used for fracturing. This application does not limit the specific method of fracturing.

[0058] In some embodiments, after step 120, the above-described shale oil recovery method further includes at least one of the following steps:

[0059] 1. Perform a first set period of well shut-in treatment on the development well network.

[0060] The process of shutting down a development well network involves instructing all wells in the network to remain closed, thereby keeping the formation (shale oil reservoir) sealed.

[0061] During the initial well-sealing process of the first set duration, the injected fluid in the formation fractures (the fluid injected during the fracturing process) and the shale oil in the matrix will undergo oil-water replacement under the action of formation seepage dynamics (capillary force, osmotic pressure), thereby increasing the oil saturation in the fractures. The first set duration can be set according to fracturing parameters (such as the amount of fluid injected during fracturing), and can be set, for example, to 1 to 10 days.

[0062] 2. By developing a well network, the fracturing shale oil reservoir can be recovered.

[0063] In the embodiments of this application, the recovery of shale oil reservoirs refers to the recovery of shale oil from shale oil reservoirs.

[0064] Methods for recovering shale oil may include self-flowing oil recovery, artificial lift, etc., and this application does not limit them.

[0065] Step 130: Inject fluid media into the shale oil reservoir by developing a well network.

[0066] In some embodiments, when the recovery efficiency of recovering the fractured shale oil reservoir is lower than a first threshold, fluid media are injected into the shale oil reservoir by developing a well pattern.

[0067] The aforementioned first threshold shall be set by the technician as needed, such as a threshold for the amount of oil produced per hour, which is not limited in this application.

[0068] The above method improves recovery efficiency by injecting flow in a timely manner after the development well network has been operating inefficiently.

[0069] In some embodiments, before injecting the fluid medium, the fluid medium to be injected is determined based on factors such as the reasons for the inefficient operation of the development well network (the reasons for low recovery efficiency), reservoir conditions, the oil enhancement mechanism, action mechanism, and applicable conditions of various fluid media.

[0070] In some embodiments, before injecting the fluid medium, relevant parameters of the injected fluid medium are determined through methods such as laboratory tests and numerical simulations. Exemplarily, the relevant parameters of the injected fluid medium include at least one of the following: injection-production well design (selection of the injection well and the production well during the injection process), slug assembly (a slug refers to the oil-dispatch zone formed after fluid is injected into the oil layer), injection volume of the fluid medium, injection rate, well shut-in time after injection, and volume of drainage fluid (the downhole fluid that powers the extracted shale oil, such as the fluid pumped out by a downhole jet pump).

[0071] In some embodiments, the relevant parameters of the injected fluid medium can be designed by taking into account factors such as the inter-well connectivity, spatial relationship, and production backflow situation (e.g., the amount of backflow fluid returned to the surface) of the development well network.

[0072] In some embodiments, the fluid medium includes at least one of the following: a gaseous medium, a liquid medium, and a gas-liquid composite medium.

[0073] For example, the gaseous medium may include at least one of the following: carbon dioxide, natural gas, nitrogen, and deoxygenated air. The liquid medium may include at least one of the following: water, oil displacement agent, surfactant, polymerizer, viscosity reducer, and plugging agent. The gas-liquid composite medium may be a mixture of any gaseous medium and any liquid medium.

[0074] In some embodiments, each well in the development network may be pressure-treated before the injection of a fluid medium (especially a gaseous medium), for example, by replacing pressure-resistant components (such as pressure-resistant wellheads) for each well.

[0075] In some embodiments, where the well network being developed includes at least two horizontal wells, step 130 includes:

[0076] Inject gaseous media into the shale oil reservoir through at least two high-level horizontal wells. And / or, inject liquid media into the shale oil reservoir through at least two low-level horizontal wells.

[0077] For example, please refer to Figure 3 This document illustrates a schematic diagram of the main view of a development well network provided in one embodiment of this application. In this example, Well 1 is a high-level well, Wells 3, 4, and 5 are mid-level wells, and Well 2 is a low-level well. During the injection process, only the high-level well (Well 1) can be selected as the injection well to inject a gaseous medium into the shale oil reservoir, utilizing gravity to form gas-cap displacement. Alternatively, only the low-level well (Well 2) can be selected as the injection well to inject a liquid medium into the shale oil reservoir, utilizing gravity to form liquid-phase displacement. Furthermore, both the high-level well (Well 1) and the low-level well (Well 2) can be selected as injection wells simultaneously, utilizing gas injection in the high-level well, liquid injection in the low-level well, and oil production in the mid-level well to achieve a synergistic effect of gas-cap dissolution gas drive and liquid-phase infiltration displacement.

[0078] It should be noted that when injecting gaseous media into shale oil reservoirs through injection wells, a certain amount of liquid media (such as water, plugging agents, oil displacement agents, etc.) can also be used to expand the volume of the gas wave and improve the oil displacement efficiency.

[0079] In some embodiments, step 130 includes at least one of the following steps:

[0080] 1. Based on the reservoir distribution of shale oil, determine the injection well from at least two wells.

[0081] For example, wells located in areas of high oil reservoir concentration can be selected as injection wells.

[0082] 2. Through injection wells, gaseous and liquid media are alternately injected into the shale oil reservoir.

[0083] The above method, through alternating gas and liquid injection, can effectively control phenomena such as gas channeling and liquid channeling, expand the swept volume of the injected fluid, and further improve the recovery rate of shale oil.

[0084] In some embodiments, when fluid medium injection begins through the injection well, the remaining wells in the development well network are shut down. That is, when fluid medium injection begins, oil production operations of the remaining wells in the development well network are stopped.

[0085] In some embodiments, during the injection of fluid media through injection wells, the remaining wells in the development well network may also maintain oil production operations for a period of time. See the embodiments below for details.

[0086] In some embodiments, step 130 includes at least one of the following steps:

[0087] 1. Inject fluid media into the shale oil reservoir at a first rate through injection wells in at least two wells.

[0088] 2. If fluid medium has been obtained through at least two wells other than the injection well, shut down the remaining wells.

[0089] This step can also be described as follows: if gas or fuel is found in at least two wells other than the injection well, shut down the remaining wells.

[0090] 3. With all other wells closed, fluid medium is injected into the shale oil reservoir through injection wells at a second rate, which is greater than the first rate.

[0091] 4. After injecting the first predetermined amount of fluid medium into the shale oil reservoir through the injection well, shut down the injection well.

[0092] The aforementioned first setting can be set by a technician as needed, and this application does not limit it.

[0093] The above method employs a low-rate injection rate in the initial stage of fluid medium injection in the injection well, allowing the remaining production wells to recover shale oil. After the remaining wells reach gas or catalyst, the injection wells are coordinated with the stalled wells to increase the injection rate, thereby accelerating the completion of fluid medium injection.

[0094] In some embodiments, after step 130, the development well network is subjected to a second set duration of well shut-in treatment, the second set duration being related to the type of fluid medium.

[0095] For example, the well-closing time for gaseous media is determined according to the specific media. The well-closing time for natural gas injection is 10-20 days, for oxygen-reduced air injection it is 20-30 days, for carbon dioxide injection it is 30-40 days, for liquid media injection it is 20-30 days, and for gas-liquid composite media injection it is 30-40 days.

[0096] During the second set period of well suffocation, the fluid medium injected into the formation fractures will play a role in permeation and replacement, mixing and viscosity reduction, and dissolution and permeability enhancement, thereby increasing the oil saturation in the fractures.

[0097] In some embodiments, when the development well network includes at least two horizontal wells, after performing a second set period of well shut-in treatment on the development well network, the method further includes at least one of the following steps:

[0098] 1. Determine the well opening sequence based on the type of fluid medium and the elevation of at least two horizontal wells.

[0099] 2. According to the well opening sequence, open at least two horizontal wells in sequence.

[0100] For example, please refer to Figure 3 If the fluid medium is gas, the horizontal wells will be opened in ascending order: first the low-level well (well 2), then the intermediate wells (wells 3, 4, and 5), and finally the high-level well (well 1). If the fluid medium is liquid, the horizontal wells will be opened in descending order: first the high-level well (well 1), then the intermediate wells (wells 3, 4, and 5), and finally the low-level well (well 2).

[0101] After well drilling, the injected fluid medium will play an oil displacement role due to the pressure difference between the surface and the bottom of the well, displacing shale oil from the surface and thus effectively increasing the production of the development well network.

[0102] Step 140: Harvest shale oil reservoirs after fluid medium injection by developing a well network.

[0103] For example, after the well is shut down, the development well network can be allowed to produce oil by flowing water first. When the oil production efficiency of the flowing water production is low, the pump can be used for artificial lifting.

[0104] The technical solution provided in this application involves deploying a development well network comprising at least two wells. After connecting these wells through fracturing, a fluid medium is injected into the shale oil reservoir. The shale oil reservoir is then harvested using the development well network after the fluid medium has been injected. By employing fluid medium-driven oil displacement through a connected development well network, large-scale shale oil recovery is achieved, improving the overall recovery rate of the shale oil reservoir.

[0105] Furthermore, it should be noted that in actual production processes, the production enhancement effect after injection cannot be sustained indefinitely. Therefore, to maximize the overall recovery rate of shale oil reservoirs, steps 130 to 140 and their sub-steps can be repeated.

[0106] In the embodiments of this application, each injection and subsequent recovery (i.e., each execution of steps 130-140) can be referred to as a round of shale oil recovery.

[0107] In some embodiments, after a round of production has been completed, the injection scheme used in that round still has the potential to improve production (i.e., it can still effectively improve the overall recovery rate). In this case, the injection scheme for the next round can remain unchanged (i.e., the injection wells in the development well network and the type of fluid medium used are not changed).

[0108] That is, in some embodiments, if the recovery efficiency of the shale oil reservoir after the injection of fluid medium is lower than the second threshold, the process starts again from step 130. In other words, when the current development well pattern enters inefficient operation, the original injection wells are used again to inject the original type of fluid medium into the shale oil reservoir.

[0109] The aforementioned second threshold can be set by a technician as needed, and this application does not limit it.

[0110] In some embodiments, after a round of production, the recovery potential of the injection scheme used in that round is exhausted. At this point, if the injection scheme for the next round is not changed, it will be difficult to improve the recovery rate of the development well network. Therefore, in this case, it is necessary to change the injection scheme for the next round (i.e., change the type of injection wells and / or the fluid medium used in the development well network).

[0111] That is, in some embodiments, if the recovery efficiency of the shale oil reservoir after the injection of fluid medium is lower than the second threshold, the injection wells in the development well network are changed, and / or the type of fluid medium is changed, and the process is repeated from step 130.

[0112] The following example illustrates the development of a well network, with at least two wells being horizontal wells.

[0113] For example, in the first round, gaseous media are injected into the shale oil reservoir using high-level wells in the development well network. After the designed injection volume is completed, the development well network enters the shut-in phase. After the shut-in phase, shale oil is recovered using the development well network. Once the production-enhancing effect of the gaseous media injected in the first round becomes ineffective (i.e., the recovery efficiency falls below the second threshold), the second round of injection and recovery can begin. The second round adopts the same injection scheme as the first round, and subsequent rounds are also implemented according to this scheme. Until the top gas injection scheme (i.e., high-level well gas injection) can no longer effectively improve the recovery rate, the injection wells used in the subsequent rounds are moved down in the same manner (e.g., from high-level wells to mid-level wells, from mid-level wells to low-level wells), thereby exploring the production-enhancing potential of each well in the development well network as an injection well.

[0114] In some embodiments, the method of changing the fluid medium type may include at least one of the following: changing the liquid medium to a gas medium, changing the gas medium to a liquid medium, changing the liquid medium to a gas-liquid composite medium, changing the gas medium to a gas-liquid composite medium, changing the gas-liquid composite medium to a gas medium, and changing the gas-liquid composite medium to a liquid medium.

[0115] In some embodiments, after step 140, the development well pattern may be redeployed based on the distribution characteristics of the remaining reservoirs.

[0116] The following is a specific application example to further illustrate the implementation of this solution and the resulting production increase. This application example includes the following steps:

[0117] 1. Deploy the development well network. Based on the reservoir geological characteristics, such as... Figure 4As shown, a development well network consisting of four horizontal wells (one high, two medium, and one low) with a well spacing of 130 to 200 meters was established.

[0118] 2. Large-scale fracturing and commissioning. Utilizing large-scale volumetric fracturing technology, a complex network of fractures was established in the shale oil reservoir, simultaneously connecting four horizontal wells to form a fingertip-like interconnected network. After fracturing, the wells were shut in for several days to begin natural flow production. When the natural flow production efficiency decreased, pumps were used for artificial lift to continue shale oil production. The estimated ultimate recovery (EUR) was 10.38 tons. During this stage, a total of 27,100 tons of shale oil were produced, representing a recovery rate of 26%.

[0119] 3. Determine the injected fluid medium. Analysis of the inefficient operation of the development well network revealed that the inefficiency was due to issues such as high crude oil viscosity, poor fluidity, and insufficient formation energy. Therefore, carbon dioxide, which has viscosity-reducing, energy-replenishing, and miscibility-enhancing effects, was selected as the injected fluid medium.

[0120] 4. Injection Scheme Design and Commissioning. Based on well connectivity, spatial relationships, and production runback conditions, optimize parameters such as injection wells, production wells, injected carbon dioxide volume, shut-in time, and drainage fluid volume to formulate an injection scheme. In the first round, the scheme designs for injecting carbon dioxide into high-level wells, while shutting in mid-level and low-level wells in conjunction. Once the blowout conditions are met, the low-level wells, mid-level wells, and injection wells (i.e., high-level wells) are sequentially commissioned for oil production.

[0121] Furthermore, the design and implementation included three rounds of carbon dioxide injection at high-level wells, three rounds of simultaneous carbon dioxide injection at two mid-level wells, and three rounds of carbon dioxide injection at low-level wells, totaling nine rounds and producing a cumulative oil recovery of 25,200 tons, achieving a recovery rate of 50.29%, which is 21.28 percentage points higher than depletion-type extraction (extraction methods that utilize only the natural energy of the oil and gas field).

[0122] 5. Scheme Adjustment. Based on the implementation results of the previous steps, it was calculated that 51,600 tons of EUR reserves remained unrecovered, indicating that the development well network still had potential for improved production. Therefore, the injection scheme was adjusted, adopting a scheme of injecting carbon dioxide into high-level wells, mid-level wells, and oil displacement agents into low-level wells. This scheme was implemented in three rounds, producing 12,500 tons of oil and achieving a recovery rate of 62.33%, which is 12.04 percentage points higher than the previous steps.

[0123] In summary, the shale oil recovery method provided in this application can effectively improve the overall recovery rate of shale oil reservoirs, and has good application prospects and promotion value.

[0124] It should be understood that "multiple" as used herein refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. Furthermore, the step numbers described herein are merely illustrative of one possible execution order. In some other embodiments, the steps may not be executed in numerical order, such as two steps with different numbers being executed simultaneously, or two steps with different numbers being executed in the reverse order of the illustration. This application does not limit this.

[0125] The above are merely exemplary embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims

1. A method for shale oil recovery, characterized in that, The method includes: For shale oil reservoirs, a development well network is deployed, wherein the development well network includes at least two wells; The shale oil reservoir is fractured through the development well network, so that at least two wells are interconnected through the fractures between the wells. The development well network is subjected to a first set period of well shut-in treatment; The fracturing shale oil reservoir is recovered through the aforementioned development well pattern; A fluid medium is injected into the shale oil reservoir through the injection well in at least two of the wells at a first rate. If the fluid medium is obtained through the remaining wells (excluding the injection well) of the at least two wells, the remaining wells shall be shut down. With all the remaining wells closed, fluid medium is injected into the shale oil reservoir through the injection well at a second rate greater than the first rate. After injecting a first predetermined amount of fluid medium into the shale oil reservoir through the injection well, the injection well is shut down; The shale oil reservoir is recovered by the well network described above after the fluid medium has been injected.

2. The method according to claim 1, characterized in that, The fluid medium includes at least one of the following: gas medium, liquid medium, and gas-liquid composite medium.

3. The method according to claim 1, characterized in that, The method further includes: If the recovery efficiency of the fracturing shale oil reservoir is lower than a first threshold, the step of injecting fluid medium into the shale oil reservoir at a first rate from the injection wells of the at least two wells shall be initiated.

4. The method according to claim 1, characterized in that, After closing the injection well, the method further includes: The development well network is subjected to a second set duration of well shut-in treatment, the second set duration being related to the type of fluid medium.

5. The method according to claim 4, characterized in that, In the case that at least two wells are at least two horizontal wells, the method further includes: The well-opening sequence is determined based on the type of fluid medium and the elevation of the at least two horizontal wells; According to the well-opening sequence, the at least two horizontal wells are opened sequentially.

6. The method according to claim 1, characterized in that, The method further includes: If the recovery efficiency of the shale oil reservoir after the injection of the fluid medium is lower than the second threshold, the injection wells in the development well network shall be changed, and / or the type of the fluid medium shall be changed.

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