Shale oil recovery method

Abstract

The invention discloses a shale oil recovery method, and relates to the technical field of oil and gas reservoir development. The method comprises the steps that aiming at a shale oil reservoir, a development well pattern is deployed, and the development well pattern comprises at least two wells; fracturing the shale oil reservoir by developing a well pattern, so that at least two wells are communicated with each other; injecting a fluid medium into the shale oil reservoir by developing a well pattern; and the shale oil reservoir injected with the fluid medium is recovered by developing a well pattern. According to the method, in a fluid medium imbibition oil displacement mode, large-scale shale oil recovery is achieved through the communicated development well pattern, and the whole-reservoir recovery rate of the shale oil reservoir is increased.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of oil and gas reservoir development, and in particular to a shale oil recovery method. Background Art

[0002] As the development of old oil fields 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] At present, in order to solve the problem of dense shale oil reservoirs and difficulty in exploitation, shale oil development is mostly carried out through single-well volume fracturing, forming a complex fracture network around the wellbore in the shale oil reservoir, thereby establishing an oil flow channel.

[0004] However, the above method is based on shale oil recovery from a single well, and it is difficult to improve the full-reservoir recovery rate of shale oil reservoirs from the perspective of large-scale application. Summary of the invention

[0005] The embodiment of the present application provides a shale oil recovery method. The technical solution provided by the embodiment of the present application is as follows:

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

[0007] For a shale oil reservoir, deploy a development well network, wherein the development well network includes at least two wells;

[0008] The shale oil reservoir is fractured through the development well pattern so that the at least two wells are interconnected;

[0009] injecting fluid medium into the shale oil reservoir through the development well pattern;

[0010] The shale oil reservoir after the fluid medium is injected is recovered through the development well network.

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

[0012] In some embodiments, when the at least two wells are at least two horizontal wells, injecting a fluid medium into the shale oil reservoir through the development well pattern comprises:

[0013] Injecting gaseous medium into the shale oil reservoir through a high-position well among the at least two horizontal wells;

[0014] and / or,

[0015] Liquid medium is injected into the shale oil reservoir through a lower well among the at least two horizontal wells.

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

[0017] Determining an injection well from the at least two wells according to the oil reservoir distribution of the shale oil reservoir;

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

[0019] In some embodiments, after fracturing the shale oil reservoir through the development well pattern so that the at least two wells are interconnected, the method further comprises:

[0020] Performing a well blocking treatment for a first set time on the development well pattern;

[0021] The shale oil reservoir after fracturing is recovered through the development well network.

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

[0023] When the recovery efficiency of the shale oil reservoir after fracturing 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 pattern comprises:

[0025] injecting a fluid medium into the shale oil reservoir at a first rate through an injection well among the at least two wells;

[0026] When the fluid medium is obtained through the remaining wells of the at least two wells except the injection well, closing the remaining wells;

[0027] In the case where all the remaining wells are shut down, injecting fluid medium into the shale oil reservoir through the injection well at a second rate, wherein the second rate is greater than the first rate;

[0028] After a first set amount of fluid medium is injected into the shale oil reservoir through the injection well, the injection well is closed.

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

[0030] The development well pattern is subjected to a well blocking treatment for a second set time period, wherein the second set time period is related to the type of the fluid medium.

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

[0032] Determining the order of opening wells according to the type of the fluid medium and the height positions of the at least two horizontal wells;

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

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

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

[0036] The technical solution provided by the embodiments of the present application includes at least the following beneficial effects:

[0037] By deploying a development well network including at least two wells, and after the at least two wells are interconnected by fracturing, a fluid medium is injected into the shale oil reservoir. Furthermore, the shale oil reservoir after the fluid medium is injected is recovered through the development well network. By means of fluid medium permeation and oil displacement, large-scale shale oil recovery is achieved through the connected development well network, and the total reservoir recovery rate of the shale oil reservoir is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic diagram of a shale oil recovery method provided by an embodiment of the present application;

[0039] Figure 2 is a schematic diagram of a three-dimensional structure of a development well pattern provided in one embodiment of the present application;

[0040] Figure 3 is a schematic diagram of a front view of a development well pattern provided by an embodiment of the present application;

[0041] Figure 4 It is a schematic diagram of the three-dimensional structure of a development well network provided in another embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0043] Please refer to Figure 1 , which shows a flow chart of a shale oil recovery method provided by an embodiment of the present application. The method may include at least one of the following steps 110 to 140.

[0044] Step 110, deploying a development well network for the shale oil reservoir, wherein the development well network includes at least two wells.

[0045] Shale oil refers to the oil resources contained in shale formations dominated by shale, including the oil in the pores and cracks of mudstone, as well as the oil resources in the adjacent layers and interlayers of dense carbonate or clastic rocks in the mudstone formations.

[0046] In the embodiment of the present application, the shale oil reservoir may be a shale oil-rich formation, i.e., a shale oil "sweet spot" layer. The wells in the development well pattern may be used as production wells for shale oil recovery or as injection wells for injecting fluid medium into the shale oil reservoir. For the selection of injection wells, see the embodiment 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 types in the development well network. In addition, the wells included in the development well network can be of the same well type (such as all horizontal wells) or of different well types (such as some horizontal wells and others vertical wells). For example, please refer to Figure 2 , which shows a schematic diagram of the three-dimensional structure of a development well network provided in one embodiment of the present application. In this example, all the wells included in the development well network are horizontal wells.

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

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

[0050] In the oil field, fracturing refers to the artificial creation of cracks in the formation through hydraulic or gas effects, thereby improving the flow environment of oil and gas underground.

[0051] Step 120, fracturing the shale oil reservoir by developing a well network so that at least two wells are interconnected.

[0052] At least two wells are interconnected, which means 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, a network of fractures is established in a shale oil reservoir by developing a well network and utilizing large-scale volume fracturing, so that at least two wells form a fingertip-interlaced connection relationship.

[0054] Volume fracturing refers to the process of expanding natural fractures and causing shear slip in brittle rocks during the fracturing process, forming a fracture network in which natural fractures and artificial fractures are intertwined, thereby increasing the transformation volume.

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

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

[0057] In some embodiments, hydraulic fracturing can be used to inject fluid into each well of the development well network at high speed through a high-pressure pump, and the high pressure at the bottom of the well is used to break the oil layer rock and generate cracks. In some other embodiments, high-energy gas can also be used for fracturing, and the present application does not limit the specific method of fracturing.

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

[0059] 1. Carry out well blocking treatment for the development well network for the first set time.

[0060] The method of sealing off the development well network is to instruct all the wells in the development well network to remain closed, so that the formation (shale oil reservoir) remains closed.

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

[0062] 2. Recover the shale oil reservoir after fracturing through the development well network.

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

[0064] The methods for recovering shale oil may include self-flowing oil production, artificial lifting, etc., which are not limited in this application.

[0065] Step 130, injecting fluid medium into the shale oil reservoir through the development well network.

[0066] In some embodiments, when the recovery efficiency of the shale oil reservoir after fracture is lower than a first threshold, a fluid medium is injected into the shale oil reservoir through the development well network.

[0067] The first threshold is set by the technicians as needed, for example, it can be a threshold of the oil production per hour, which is not limited in this application.

[0068] The above method improves the recovery efficiency by timely injection after the development well network operates 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 (reasons for low recovery efficiency), reservoir conditions, oil-increasing mechanisms, action mechanisms, and applicable conditions of various fluid media.

[0070] In some embodiments, before injecting the fluid medium, the relevant parameters of the injected fluid medium are determined by indoor tests, numerical simulations, etc. Exemplarily, the relevant parameters of the injected fluid medium include at least one of the following: injection and production well design (selection of injection wells and production wells during the injection process), segment plug combination (segment plug refers to the oil-displacing zone formed after the fluid is injected into the oil layer), injection amount of the fluid medium, injection speed, well blocking time after injection, and drainage fluid (liquid that provides power for the produced shale oil in the well, such as liquid pumped out by a downhole jet pump).

[0071] In some embodiments, the parameters related to the injected fluid medium may be designed in combination with factors such as inter-well connectivity, spatial position relationship, and production flowback conditions (such as the amount of flowback 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 gas medium, a liquid medium, and a gas-liquid composite medium.

[0073] Exemplarily, the gaseous medium may include at least one of the following: carbon dioxide, natural gas, nitrogen, and oxygen-reduced air. The liquid medium may include at least one of the following: water, an oil displacement agent, a surfactant, a surface-polymerizing agent, a viscosity reducer, and a plugging and adjusting agent. The gas-liquid composite medium may be a mixture of any gaseous medium and any liquid medium.

[0074] In some embodiments, before injecting fluid medium (especially gas medium), each well in the development well network may be subjected to pressure treatment, for example, by replacing pressure-resistant components (such as pressure-resistant wellheads) for each well.

[0075] In some embodiments, when the at least two wells included in the development well pattern are at least two horizontal wells, step 130 includes:

[0076] A gas medium is injected into the shale oil reservoir through a high-position well among at least two horizontal wells, and / or a liquid medium is injected into the shale oil reservoir through a low-position well among at least two horizontal wells.

[0077] For example, please refer to Figure 3 , which shows a schematic diagram of the main view of the development well network provided by an embodiment of the present application. In this example, Well No. 1 is a high-position well, Wells No. 3, 4, and 5 are mid-position wells, and Well No. 2 is a low-position well. During the injection process, only the high-position well (Well No. 1) can be selected as an injection well, and a gas medium can be injected into the shale oil reservoir, and gravity can be used to form a gas cap drive. Alternatively, only the low-position well (Well No. 2) can be selected as an injection well, and a liquid medium can be injected into the shale oil reservoir, and gravity can be used to form a liquid phase drive. Alternatively, a high-position well (Well No. 1) and a low-position well (Well No. 2) can be selected as injection wells at the same time, and the synergistic effect of gas cap dissolution gas drive and liquid phase imbibition drive can be achieved by injecting gas into the high-position well, injecting liquid into the low-position well, and producing oil in the mid-position well.

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

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

[0080] 1. According to the distribution of shale oil reservoirs, determine the injection well from at least two wells.

[0081] For example, wells at locations where oil reservoirs are rich can be selected as injection wells.

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

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

[0084] In some embodiments, when the injection of the fluid medium starts through the injection well, the remaining wells in the development well pattern are closed. That is, when the injection of the fluid medium starts, the oil production operation of the remaining wells in the development well pattern is stopped.

[0085] In some embodiments, during the process of injecting the fluid medium through the injection well, the remaining wells in the development well pattern may also maintain oil production operations for a period of time. For details, please refer to the following embodiments.

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

[0087] 1. Injecting a fluid medium into a shale oil reservoir through at least two injection wells at a first rate.

[0088] 2. When fluid medium is obtained through at least two wells except the injection well, the remaining wells are closed.

[0089] This step can also be expressed as: when gas or agent is found in the remaining wells except the injection well among the at least two wells, shut down the remaining wells.

[0090] 3. When all other wells are shut down, fluid medium is injected into the shale oil reservoir through the injection well at a second rate, where the second rate is greater than the first rate.

[0091] 4. After a first set amount of fluid medium is injected into the shale oil reservoir through the injection well, the injection well is closed.

[0092] The above-mentioned first set amount can be set by technicians as needed, and this application does not limit this.

[0093] The above method adopts low-speed injection in the initial stage of injecting fluid medium into the injection well, so that the other oil production wells can recover shale oil. After the other wells see gas or agent, the injection wells are blocked in coordination, and the injection wells increase the injection rate to speed up the injection of fluid medium.

[0094] In some embodiments, after step 130, the development well pattern is blocked for a second set time period, where the second set time period is related to the type of fluid medium.

[0095] Exemplarily, the well sealing time for injecting gas medium is determined according to the specific medium. The well sealing time for injecting natural gas is 10-20 days, the well sealing time for injecting reduced oxygen air is 20-30 days, and the well sealing time for injecting carbon dioxide is 30-40 days; the well sealing time for injecting liquid medium is 20-30 days; and the well sealing time for injecting gas-liquid composite medium is 30-40 days.

[0096] During the second set time of well blocking, the fluid medium injected into the formation fractures will play the role of imbibition replacement, miscibility and viscosity reduction, and dissolution and permeability enhancement, thereby increasing the oil saturation in the fractures.

[0097] In some embodiments, when the at least two wells included in the development well pattern are at least two horizontal wells, after the development well pattern is blocked for a second set time, at least one of the following steps is further included:

[0098] 1. Determine the order of well opening based on the type of fluid medium and the height 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 a gas medium, then the horizontal wells are opened in order from low to high, that is, the low-level well (Well 2) is opened first, then the middle-level wells (Wells 3, 4, and 5), and finally the high-level well (Well 1). If the fluid medium is a liquid medium, then the horizontal wells are opened in order from high to low, that is, the high-level well (Well 1) is opened first, then the middle-level wells (Wells 3, 4, and 5), and finally the low-level well (Well 2).

[0101] After the well is opened, due to the pressure difference between the ground and the bottom of the well, the injected fluid medium will play an oil-displacing role, driving the shale oil out of the ground, thereby effectively increasing the production of the development well network.

[0102] Step 140, recovering the shale oil reservoir after the fluid medium is injected through the development well network.

[0103] For example, after the well is blocked, the development well network can be made to produce by self-flowing first, and when the oil production efficiency of self-flowing production is low, pumps can be lowered for artificial lifting.

[0104] The technical solution provided in the embodiment of the present application is to deploy a development well network including at least two wells. And, after the at least two wells are interconnected by fracturing, a fluid medium is injected into the shale oil reservoir. And, through the development well network, the shale oil reservoir after the fluid medium is injected is recovered. In the way of fluid medium percolation and oil displacement, large-scale shale oil recovery is achieved through the connected development well network, and the total reservoir recovery rate of the shale oil reservoir is improved.

[0105] In addition, it should be noted that in the actual production process, the production enhancement effect after fluid injection cannot be sustained for a long time. Therefore, in order to maximize the total recovery rate of the shale oil reservoir, the above steps 130 to 140 and the steps included therein can be repeatedly performed.

[0106] In the embodiment of the present application, each injection and recovery after injection (i.e., each execution of step 130 to step 140) can be referred to as a round of recovery of shale oil.

[0107] In some embodiments, after a round of recovery, the injection scheme used in the round still has the potential for increased recovery (i.e., it can still effectively increase the recovery rate of the entire reservoir). At this time, the injection scheme for the next round may remain unchanged (i.e., the injection wells in the development well network and the type of fluid medium used do not change).

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

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

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

[0111] That is, in some embodiments, when the recovery efficiency of the shale oil reservoir after the fluid medium is injected 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 started again from step 130.

[0112] In the following, an exemplary description is given by taking the at least two wells included in the development well pattern as horizontal wells.

[0113] Exemplarily, in the first round, a high-position well in the development well network is used to inject a gas medium into the shale oil reservoir. After the designed injection volume is completed, the development well network enters the well blocking stage. After the well blocking is completed, the development well network is used to recover shale oil. After the production-enhancing effect of the gas medium injected in the first round fails (that is, after the recovery efficiency is lower than the second threshold), the second round of injection and recovery can be started. The second round adopts the same injection scheme as the first round, and the following rounds are also implemented repeatedly according to this scheme. Until the top gas injection (i.e., high-position well gas injection) scheme can no longer effectively improve the recovery rate, the injection wells used in the next round are moved down in sequence according to the same process (for example, from high-position wells to mid-position wells, and from mid-position wells to low-position wells), so as to explore 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 according to the distribution characteristics of the remaining oil reservoirs.

[0116] Below, a specific application example is used to further illustrate the implementation of this solution and the production improvement effect achieved. The application example includes the following steps:

[0117] 1. Deploy development well pattern. According to the geological characteristics of reservoir, 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 production. Using large-scale volume fracturing technology, a complex fracture network is established in the shale oil reservoir, and four horizontal wells are connected at the same time, that is, the four horizontal wells form a finger-tip interlaced connection relationship. After fracturing, the well is sealed for several days and then produced by self-flowing. When the efficiency of self-flowing production is low, pumps are lowered for artificial lifting to continuously produce shale oil; EUR (Estimated Ultimate Recovery) is 10.38 tons. During this stage, a total of 27,100 tons of shale oil were produced, with a recovery rate of 26%.

[0119] 3. Determine the fluid medium to be injected. After the inefficient operation of the development well network, it was analyzed that the reasons for the inefficiency of the development well network were high crude oil viscosity, poor fluidity, insufficient formation energy, etc. Therefore, carbon dioxide, which has the functions of reducing viscosity, replenishing energy, and miscibility, was selected as the fluid medium to be injected.

[0120] 4. Design and commissioning of injection scheme. In combination with well connectivity, spatial position relationship, and production flowback conditions, optimize the design of injection wells, production wells, injection carbon dioxide volume, well blocking time, and production fluid volume, and formulate an injection scheme. In the first round, the scheme designs high-level wells to inject carbon dioxide, and mid-level wells and low-level wells to block wells in coordination. After the conditions for blowout are met, the low-level wells, mid-level wells, and injection wells (i.e., high-level wells) are opened for oil production in sequence.

[0121] Furthermore, the plan included three rounds of carbon dioxide injection into high-level wells, three rounds of simultaneous carbon dioxide injection into two middle-level wells, and three rounds of carbon dioxide injection into low-level wells. A total of nine rounds were implemented, with a cumulative oil production of 25,200 tons and an oil recovery rate of 50.29%, an increase of 21.28 percentage points compared with depletion-type production (a production method that only uses the natural energy of the oil and gas field for production).

[0122] 5. Adjustment of the plan. Combined with the implementation results of the previous steps, it is calculated that there are still 51,600 tons of EUR reserves that have not been produced, and the development well network still has the potential for increased production. Therefore, the design adjusted the injection plan, adopting the injection plan of injecting carbon dioxide into high-level wells and medium-level wells and injecting oil displacement agents into low-level wells. A total of 3 rounds have been implemented, producing 12,500 tons of oil and a recovery rate of 62.33%, which increased the recovery rate by 12.04 percentage points on the basis of the previous steps.

[0123] In summary, the shale oil recovery method provided in the embodiments of the present application can effectively improve the recovery rate of the entire shale oil reservoir, and has good application prospects and promotion value.

[0124] It should be understood that the "multiple" mentioned in this article refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. In addition, the step numbers described in this article only illustrate a possible execution sequence between the steps. In some other embodiments, the above steps may not be executed in the order of the numbers, such as two steps with different numbers are executed at the same time, or two steps with different numbers are executed in the opposite order to the diagram. The embodiments of the present application are not limited to this.

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

Claims

1. A shale oil recovery method, characterized in that: The method comprises: For a shale oil reservoir, deploy a development well network, wherein the development well network includes at least two wells; The shale oil reservoir is fractured through the development well pattern so that the at least two wells are interconnected; injecting fluid medium into the shale oil reservoir through the development well pattern; The shale oil reservoir after the fluid medium is injected is recovered through the development well network.

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

3. The method according to claim 1, characterized in that In the case where the at least two wells are at least two horizontal wells, injecting a fluid medium into the shale oil reservoir through the development well pattern comprises: Injecting gaseous medium into the shale oil reservoir through a high-position well among the at least two horizontal wells; and / or, Liquid medium is injected into the shale oil reservoir through a lower well among the at least two horizontal wells.

4. The method according to claim 1, characterized in that: The step of injecting a fluid medium into the shale oil reservoir through the development well pattern comprises: Determining an injection well from the at least two wells according to the oil reservoir distribution of the shale oil reservoir; Through the injection well, gas medium and liquid medium are alternately injected into the shale oil reservoir.

5. The method according to claim 1, characterized in that After fracturing the shale oil reservoir through the development well pattern so that the at least two wells are interconnected, the method further includes: Performing a well blocking treatment for a first set time on the development well pattern; The shale oil reservoir after fracturing is recovered through the development well network.

6. The method according to claim 5, characterized in that The step of injecting a fluid medium into the shale oil reservoir through the development well pattern comprises: When the recovery efficiency of the shale oil reservoir after fracturing is lower than a first threshold, the fluid medium is injected into the shale oil reservoir through the development well network.

7. The method according to claim 5, characterized in that The step of injecting a fluid medium into the shale oil reservoir through the development well pattern comprises: injecting a fluid medium into the shale oil reservoir at a first rate through an injection well among the at least two wells; When the fluid medium is obtained through the remaining wells of the at least two wells except the injection well, closing the remaining wells; In the case where all the remaining wells are shut down, injecting fluid medium into the shale oil reservoir through the injection well at a second rate, wherein the second rate is greater than the first rate; After a first set amount of fluid medium is injected into the shale oil reservoir through the injection well, the injection well is closed.

8. The method according to claim 1, characterized in that After injecting fluid medium into the shale oil reservoir through the development well pattern, the method further comprises: The development well pattern is subjected to a well blocking treatment for a second set time period, wherein the second set time period is related to the type of the fluid medium.

9. The method according to claim 8, characterized in that In the case where the at least two wells are at least two horizontal wells, the method further comprises: Determining the order of opening wells according to the type of the fluid medium and the height positions of the at least two horizontal wells; According to the well opening sequence, the at least two horizontal wells are opened in sequence.

10. The method according to claim 1, characterized in that The method further comprises: When the recovery efficiency of the shale oil reservoir after the fluid medium is injected is lower than a second threshold, the injection wells in the development well network are changed, and / or the type of the fluid medium is changed.

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