A method, apparatus, equipment, and medium for optimizing target layers in shale oil reservoirs.

Abstract

This invention relates to a method, apparatus, equipment, and medium for selecting target layers in shale oil reservoirs, relating to the field of oil and gas development. The method includes: obtaining the daily oil production during a predetermined operating period after the fracturing fluid flowback rate of each test section in the study area reaches 100%, and determining the lower limit of oil production for the test section based on the reserve calculation standard specified in DZ / T 0217-2020; obtaining the movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index of each section in the study area; obtaining the oil production index based on the movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index; establishing a fitting chart of daily oil production and oil production index; obtaining the lower limit of the oil production index based on the fitting chart and the lower limit of oil production; if the oil production index > the lower limit of the oil production index, the corresponding section is the target layer. The selection method provided by this invention can identify the optimal target layer, providing favorable technical support for the efficient development of shale oil reservoirs.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, specifically to a method, apparatus, equipment, and medium for selecting target layers in shale oil reservoirs, and more particularly to a method, apparatus, equipment, and medium for selecting the optimal target layer in complex shale oil reservoirs. Background Technology

[0002] Shale oil has become an extremely important unconventional oil and gas resource. The selection of optimal target layers for shale oil exploration is both a key focus and a challenge, as its evaluation results directly impact exploration decisions and development outcomes. Specialized logging technologies such as nuclear magnetic resonance logging, electrical imaging, and elemental logging can provide strong technical support for the accurate identification of sweet spots. Furthermore, these specialized logging techniques have become essential components of sweet spot evaluation in shale oil exploration wells.

[0003] Currently, there is a lack of systematic research on the identification of the golden target layer for shale oil. Previous studies have mainly focused on the evaluation of sweet spots in shale oil based on the "three qualities," which mainly characterize the relevant parameters of the "three qualities," such as total organic carbon (TOC), porosity, and brittleness index, and evaluate the sweet spot through comprehensive analysis of multiple parameters.

[0004] For example, CN120493785A discloses a method for identifying sweet spots in shale oil and gas reservoirs, including the following steps: acquiring core CT images, 3D seismic data, and production dynamic data and performing cross-scale preprocessing; constructing a fractional-order nonlocal seepage field model to characterize flow characteristics from nanometer to kilometer scale; predicting seepage field parameters through a Lie group symmetry-constrained neural network; establishing a cross-scale coupling model of quantum adsorption effect and macroscopic seepage law; dynamically updating model parameters based on real-time monitoring data; and performing multi-objective collaborative optimization to generate a 3D distribution of sweet spots and a development plan.

[0005] CN120722422A discloses a method for constructing a shale oil sweet spot evaluation system and a method for evaluating shale oil sweet spot. The method for constructing the evaluation system includes: obtaining geological characteristic parameters of several core samples; determining the main controlling influencing factors of shale oil enrichment based on the geological characteristic parameters through the control variable method and correlation analysis; and establishing a quantitative evaluation system for sweet spot based on the main controlling influencing factors.

[0006] However, existing logging methods have limited detection accuracy. Even when combined with special logging methods, the sweet spot evaluation is poorly universal due to the complex lithology, water properties, and wettability of shale reservoirs, which cannot meet the needs of field development and make it difficult to provide applicable development strategies for exploration and development. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method, apparatus, equipment and medium for the selection of target layers in shale oil reservoirs, so as to solve the defect of poor target layer identification effect in existing shale oil reservoirs.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a preferred method for a target layer in a shale oil reservoir, the preferred method comprising:

[0010] The daily oil production of each test section in the research area is obtained after the fracturing fluid flowback rate reaches 100% during the predetermined operation period. Combined with the reserve calculation standard specified in DZ / T 0217-2020, the lower limit of oil production of the test section is determined.

[0011] Obtain the movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index of each layer in the research area;

[0012] The oil production index is obtained based on movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index.

[0013] Establish a fitted graph of daily oil production and oil production index;

[0014] The lower limit of the oil production index is obtained based on the fitted graph, according to the lower limit of oil production.

[0015] If the oil production index is greater than the lower limit of the oil production index, then the corresponding layer is the target layer.

[0016] The preferred method provided by this invention, based on the macroscopic oil production characteristics scale of shale oil reservoirs, preferably combines the movable oil porosity related to the quality sweet spot evaluation and the fracture porosity, effective fracture ratio, and brittleness index related to the engineering sweet spot evaluation to create an oil production index, clarify the standards of various target layers, and determine the high-quality target layer, i.e. the golden target layer, thus providing favorable technical support for the efficient development of shale oil reservoirs.

[0017] As a preferred technical solution of the present invention, the acquisition of movable oil porosity includes: obtaining the T1-T2 spectrum based on the two-dimensional nuclear magnetic resonance logging data and the two-dimensional T1-T2 nuclear magnetic resonance results of the middle section of the research area, determining the fluid type and fluid distribution range inside the core, establishing a fluid identification chart, obtaining the movable oil nuclear magnetic resonance distribution range, and calculating the movable oil porosity.

[0018] As a preferred technical solution of the present invention, the acquisition of fracture porosity includes: acquiring high-conductivity fractures, high-resistance fractures, induced fractures, and wellbore collapse based on electrical imaging logging data, and calculating fracture porosity.

[0019] As a preferred technical solution of the present invention, the effective fracture ratio is obtained by: obtaining high-conductivity fractures, high-resistance fractures, induced fractures and wellbore collapse based on electrical imaging logging data, and calculating the proportion of fractures in high-conductivity fractures whose orientation is less than 60° from the direction of the maximum horizontal principal stress to obtain the effective fracture ratio.

[0020] As a preferred technical solution of the present invention, the brittleness index is obtained by: calculating the brittleness index of the shale oil reservoir using the mineral composition method based on the elemental logging results.

[0021] As a preferred embodiment of the present invention, the formula for calculating the oil production index includes:

[0022] ;

[0023] In the formula, IO is the oil production index, which is dimensionless; IB is the brittleness index, which is % (%). The movable oil porosity is % The value represents the crack porosity, %; P ef The percentage of effective cracks is %.

[0024] As a preferred technical solution of the present invention, the fitting chart includes: obtaining it by linearly fitting the daily oil production and the oil production index.

[0025] Preferably, obtaining the lower limit of the oil production index includes: inputting the lower limit of oil production into the fitted graph with the daily oil production to obtain the corresponding oil production index, which is the lower limit of the oil production index.

[0026] In a second aspect, the present invention provides a preferred apparatus for a target layer in a shale oil reservoir, the preferred apparatus comprising:

[0027] The oil production acquisition module is used to acquire the daily oil production of each test section in the research area during the predetermined operation period after the fracturing fluid flowback rate reaches 100%, and to determine the lower limit of oil production of the test section in conjunction with the reserve calculation standard specified in DZ / T 0217-2020.

[0028] The parameter module is used to obtain the movable oil porosity, fracture porosity, effective fracture ratio and brittleness index of each layer in the research area.

[0029] The oil production index module is used to obtain the oil production index based on movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index.

[0030] The chart module is used to create a fitted chart of daily oil production and oil production index.

[0031] The optimization module is used to obtain the lower limit of the oil production index based on the fitted map according to the lower limit of oil production; if the oil production index is greater than the lower limit of the oil production index, the corresponding segment is the target layer.

[0032] Thirdly, the present invention provides an electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the preferred method for target layers in shale oil reservoirs as described in the first aspect.

[0033] Fourthly, the present invention provides a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the preferred method for target layers in shale oil reservoirs as described in the first aspect.

[0034] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0035] (1) The preferred method provided by the present invention is based on the macroscopic oil production characteristics scale of shale oil reservoirs. It is preferred to combine the movable oil porosity related to the quality sweet spot evaluation and the fracture porosity, effective fracture ratio and brittleness index related to the engineering sweet spot evaluation to create an oil production index, clarify the standards of various target layers, determine the golden target layer, and provide favorable technical support for the efficient development of shale oil reservoirs.

[0036] (2) The preferred method provided by the present invention, based on the rich special logging and testing data of shale oil reservoirs, integrates the advantages of new logging techniques, eliminates the influence of lithology, water and wettability, and comprehensively considers the three major factors of movable oil volume, effective fracture volume and engineering fracturing (brittleness index, horizontal principal stress difference), making the selection of the golden target layer of complex shale oil reservoirs more practical and reliable, thereby significantly improving the selection accuracy and having a certain degree of universality. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a preferred method for target layers in shale oil reservoirs provided by an embodiment of the present invention;

[0038] Figure 2 This is a schematic diagram of a preferred apparatus for a target layer in a shale oil reservoir provided by an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of an electronic device provided in an embodiment of the present invention;

[0040] Figure 4 It is the T1-T2 fluid identification pattern obtained in Embodiment 1 of the present invention;

[0041] Figure 5 This is a diagram of crack porosity data obtained in Embodiment 1 of the present invention;

[0042] Figure 6This is the effective crack ratio diagram obtained in Embodiment 1 of the present invention;

[0043] Figure 7 This is a cross-plot of daily oil production and oil production index obtained in Embodiment 1 of the present invention.

[0044] In the picture:

[0045] 100 - Daily oil production module, 200 - Parameter module, 300 - Oil production index module, 400 - Chart module, 500 - Optimization module;

[0046] 10-Electronic device, 11-Processor, 12-ROM, 13-RAM, 14-Bus, 15-I / O interface, 16-Input unit, 17-Output unit, 18-Storage unit, 19-Communication unit.

[0047] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0048] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0049] Currently, there is a lack of systematic research on the identification of golden target layers for shale oil. Previous studies have mainly focused on the evaluation of sweet spots in shale oil based on the "three qualities" (total organic carbon (TOC), porosity, and brittleness index), and evaluated the sweet spots through comprehensive analysis of multiple parameters. However, existing logging methods have limited detection accuracy. Although special logging methods are combined, the complex lithology, water properties, and wettability of shale reservoirs result in poor universality of sweet spot evaluation, failing to meet the needs of field development and providing applicable development strategies. Therefore, this invention optimizes the selection process by comprehensively considering three major factors: movable oil volume, effective fracture volume, and engineering fracturing (brittleness index and horizontal principal stress difference). This method is more practical and reliable for sweet spot selection in complex shale oil reservoirs and has a certain degree of universality, as detailed below:

[0050] I. This embodiment provides a method for optimizing the target layer in a shale oil reservoir, the process of which is as follows: Figure 1 As shown, the preferred method includes:

[0051] The daily oil production of each test section in the research area is obtained after the fracturing fluid flowback rate reaches 100% during the predetermined operation period. Combined with the reserve calculation standard specified in DZ / T 0217-2020, the lower limit of oil production of the test section is determined.

[0052] Obtain the movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index of each layer in the research area;

[0053] The oil production index is obtained based on movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index.

[0054] Establish a fitted graph of daily oil production and oil production index;

[0055] The lower limit of the oil production index is obtained based on the fitted graph, according to the lower limit of oil production.

[0056] If the oil production index is greater than the lower limit of the oil production index, then the corresponding layer is the target layer.

[0057] In this invention, the predetermined operation period can be selected as ≥1 month, and the specific time can be selected according to actual requirements.

[0058] In this invention, the reserve calculation standard specified in DZ / T 0217-2020 is detailed in Table 1 of the standard. The specific process of determining the lower limit of oil production of the test section based on the reserve calculation standard is as follows: Based on the burial depth of the oil reservoir in the target section of the study area, the lower limit of daily oil production at the corresponding burial depth is obtained by referring to Table 1 of the reserve calculation standard specified in DZ / T 0217-2020, which is the lower limit of oil production.

[0059] The acquisition of movable oil porosity includes: obtaining the T1-T2 spectrum based on the two-dimensional nuclear magnetic resonance logging data and the two-dimensional T1-T2 nuclear magnetic resonance results of the middle section of the study area, determining the fluid type and fluid distribution range inside the core, establishing a fluid identification chart, obtaining the movable oil nuclear magnetic resonance distribution range, and calculating the movable oil porosity.

[0060] For example, the formula for calculating the porosity of movable oil based on two-dimensional NMR results is as follows:

[0061] ;

[0062] ;

[0063] ;

[0064] In the formula, Y mo denoted as , where is the signal intensity corresponding to the movable oil fluid component; P(i,j) is the signal intensity at the coordinate point where T2 is i and T1 is j in the two-dimensional nuclear magnetic resonance T1-T2 spectrum; Y is the total signal intensity of the two-dimensional nuclear magnetic resonance T1-T2 spectrum. The movable oil porosity is % The total porosity is expressed as %.

[0065] In this invention, the shale oil reservoir is dense, and the impact of drilling fluid intrusion is negligible. Since nuclear magnetic resonance logging only reflects the hydrogen nucleus signal in the pore fluid, it eliminates the constraints of complex lithology. Two-dimensional nuclear magnetic resonance logging successfully solves the core problem of fluid signal overlap in shale oil reservoirs by adding an information dimension, and realizes accurate identification, precise quantification and mobility evaluation of complex fluids.

[0066] The acquisition of fracture porosity includes: acquiring high-conductivity fractures, high-resistance fractures, induced fractures, and wellbore collapse based on electrical imaging logging data, and calculating fracture porosity; wherein, the direction of the maximum horizontal principal stress is determined according to the orientation of the induced fracture and the direction of the wellbore collapse; the orientation of the induced fracture is parallel to the direction of the maximum horizontal principal stress, and the direction of the wellbore collapse is perpendicular to the direction of the maximum horizontal principal stress.

[0067] For example, the formula for calculating crack porosity is as follows:

[0068] =V f / (π×R 2 ×W L In the formula, The value represents the crack porosity, %; V f Let m be the volume of the seam. 3 R is the wellbore radius, in meters; W L The length of the sliding window is 1m.

[0069] The acquisition of the effective fracture ratio includes: obtaining high-conductivity fractures, high-resistance fractures, induced fractures, and wellbore collapse based on electrical imaging logging data; calculating the proportion of fractures in high-conductivity fractures whose orientation is less than 60° from the direction of the maximum horizontal principal stress; and obtaining the effective fracture ratio.

[0070] For example, the formula for calculating the effective crack ratio is as follows:

[0071] P ef =(P10 cef / P10 cf )×100%, where P ef The percentage of effective cracks is %; P10 cef The number of cracks whose orientation forms an angle < 60° with the direction of the maximum horizontal principal stress, 1 / m; P10 cf For high guide joint count, 1 / m;

[0072] In this invention, electrical imaging can achieve high-resolution imaging and quantitative evaluation of the macroscopic structure, fractures, and foliation fractures of shale reservoirs. It demonstrates the advantages of being intuitive, precise, and multi-faceted in the evaluation of shale oil sweet spots, and has become one of the indispensable key technologies for identifying shale oil "sweet spots".

[0073] The brittleness index is obtained by calculating the brittleness index of the shale oil reservoir using the mineral composition method based on elemental logging results.

[0074] For example, the formula for calculating the brittleness index is as follows:

[0075] IB=(V 石英 +V 长石 +V 黄铁矿 +V 白云石 +V 方解石 ) / (V 石英 +V 长石 +V 黄铁矿 +V 白云石 +V 方解石 +V 粘土 +V 有机质 In the formula, V represents the mineral name and its mass percentage content.

[0076] The formula for calculating the oil production index includes:

[0077] ;

[0078] In the formula, IO is the oil production index, which is dimensionless; IB is the brittleness index, which is % (%). The movable oil porosity is % The value represents the crack porosity, %; P ef The percentage of effective cracks is %.

[0079] The fitted graph is obtained by linearly fitting daily oil production with the oil production index. The goodness of fit is selected reasonably according to actual needs. For example, r... 2 ≥0.9.

[0080] The process of obtaining the lower limit of the oil production index includes: inputting the lower limit of oil production into the fitted graph based on the daily oil production to obtain the corresponding oil production index, which is the lower limit of the oil production index.

[0081] II. This embodiment provides a preferred device for target layers in shale oil reservoirs, such as... Figure 2 As shown, the preferred device includes:

[0082] The oil production acquisition module 100 is used to acquire the daily oil production of each test section in the research area during the predetermined operation period after the fracturing fluid flowback rate reaches 100%, and to determine the lower limit of oil production of the test section in conjunction with the reserve calculation standard specified in DZ / T 0217-2020.

[0083] Parameter module 200 is used to obtain the movable oil porosity, fracture porosity, effective fracture ratio and brittleness index of each layer in the research area.

[0084] The oil production index module 300 is used to obtain the oil production index based on the movable oil porosity, fracture porosity, effective fracture ratio and brittleness index.

[0085] Module 400 is used to create a fitted graph of daily oil production and oil production index.

[0086] The preferred module 500 is used to obtain the lower limit of the oil production index based on the fitted map according to the lower limit of oil production; if the oil production index is greater than the lower limit of the oil production index, the corresponding segment is the target layer.

[0087] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0088] III. This embodiment provides an electronic device intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0089] like Figure 3 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded into the RAM 13 from storage unit 18. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An I / O interface 15 is also connected to the bus 14.

[0090] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0091] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, central processing unit (CPU), graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as preferred methods for target layers in shale oil reservoirs.

[0092] In some embodiments, the preferred method for target layers in shale oil reservoirs may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the preferred method for target layers in shale oil reservoirs described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the preferred method for target layers in shale oil reservoirs by any other suitable means (e.g., by means of firmware).

[0093] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0094] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0095] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0096] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0097] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0098] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0099] The server provided in this embodiment includes: a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the processor executes the program, it implements a preferred method for target layers in shale oil reservoirs.

[0100] Unless otherwise specifically stated, terms such as processing, calculation, operation, determination, display, etc., may refer to the actions and / or processes of one or more processing or computing systems or similar devices that represent the manipulation and conversion of data representing physical (e.g., electronic) quantities within the registers or memory of the processing system into other data similarly representing physical quantities within the memory, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0101] Those skilled in the art will also understand that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with embodiments of the present invention can all be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps described above are generally described in terms of their functionality. Whether this functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in alternative ways for each specific application; however, such implementation decisions should not be construed as departing from the scope of protection of the present invention.

[0102] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied in hardware, software modules executed by a processor, or a combination thereof. The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. The ASIC can reside in a user terminal. Alternatively, the processor and storage medium can exist as discrete components in the user terminal.

[0103] For software implementation, the techniques described in this invention can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described in this application. This software code can be stored in memory units and executed by a processor. The memory units can be implemented within the processor or externally; in the latter case, they are communicatively coupled to the processor via various means, as is well known in the art.

[0104] IV. To illustrate the optimal effects achievable by the method for selecting target layers in shale oil reservoirs provided by this invention, the following example is used for explanation:

[0105] Example 1

[0106] This embodiment provides a preferred method for target layers in shale oil reservoirs, the process of which is as follows: Figure 1 The details are as follows:

[0107] 1) Statistically analyze the fracturing, oil testing, and production data of the M1 well area in the Mahu Depression of the Junggar Basin, and check the sand addition rate (>50m³). 3 and the amount of liquid injected into the ground >200m 3 To exclude test data with insufficient fracturing scale, after the fracturing fluid flowback rate reached 100%, the average daily oil production of each test section was calculated over one month. Since the example study area mainly focused on production profile testing, this statistical analysis was conducted after the fracturing fluid flowback rate reached 100%. The average daily oil production of each fracturing section over 30 days after the flowback fluid was completely drained was calculated, which can effectively eliminate the interference of fracturing fluid on the actual oil production. In conjunction with the reserve calculation standard specified in DZ / T 0217-2020, the lower limit of oil production of the test section was determined to be 3m³. 3 / d, the lower limit is the critical point at which the investment can be quickly recovered after horizontal well drilling at the target layer in the block under the current reservoir development conditions and oil prices.

[0108] 2) Parameter determination

[0109] ① Movable Oil Porosity: Shale oil reservoirs are tight, and the impact of drilling fluid intrusion is negligible. Since nuclear magnetic resonance (NMR) logging only reflects the hydrogen nucleus signal in the pore fluid, eliminating the constraints of complex lithology, two-dimensional NMR logging successfully solves the core problem of fluid signal overlap in shale oil reservoirs by adding an information dimension, achieving accurate identification, precise quantification, and mobility evaluation of complex fluids. Based on two-dimensional NMR logging data and multi-state two-dimensional T1-T2 NMR experimental results of the target layer in the work area, data inversion is performed to obtain the T1-T2 spectrum, determine the fluid type and fluid distribution range inside the core, and establish a fluid identification chart (…). Figure 4 The NMR distribution range of movable oil was determined (T2: 5-200, T1 / T2: 3-20), and the porosity of movable oil was calculated.

[0110] ② Fracture porosity and effective fracture ratio: Electro-optical imaging (EIA) enables high-resolution imaging and quantitative evaluation of the macroscopic structure, fractures, and foliation fractures of shale reservoirs. It demonstrates intuitive, detailed, and multi-angle advantages in evaluating shale oil "sweet spots," becoming an indispensable key technology for identifying these spots. Based on EIA logging data, high-conductivity fractures, high-resistance fractures, induced fractures, and wellbore collapse are identified. Fracture porosity and the effective fracture ratio are calculated, as shown in the results. Figure 5 and Figure 6 .

[0111] ③ Brittleness index: Based on elemental logging results, the brittleness index of shale oil reservoirs is calculated using the mineral composition method.

[0112] 3) Determination of oil production index

[0113] By combining movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index, an oil production index was jointly constructed, and a cross-plot of the oil production index and the daily oil production was established. Figure 7 The figure shows a good positive correlation between the oil production index and the oil production on the test day, r 2 =0.937, thus forming the fitting formula for daily oil production and oil production index:

[0114] Daily oil production = 0.8138 × In(IO) + 0.5616, r 2 =0.937;

[0115] In the formula, IO is the oil production index, which is dimensionless.

[0116] Lower limit of daily oil production (3m) 3 / d) is used as the daily oil production and substituted into the fitting formula to obtain the corresponding lower limit of the oil production index (20.01).

[0117] If the oil production index is greater than the lower limit of the oil production index, then the corresponding layer is the target layer.

[0118] Furthermore, the target well's pilot well or adjacent well target layer is statistically analyzed, the oil production index of the target well section is calculated, the average oil production index of each target layer is statistically analyzed, and the target layer is classified according to the standard, and the target layer is determined according to the standard.

[0119] Specifically, for well X08 in the M1 well area, the parameters required for the IO calculation of the C9 sublayer were obtained through various special logging data: brittleness index IB is 85.93%, movable oil porosity... The porosity of the crack is 0.019. The effective crack ratio P is 0.038%. ef The value is 69.12%. Substituting this parameter into the formula, the calculated IO is 22.57, which is higher than the local oil production index of 20.01. Therefore, this layer is considered a target layer, and it is recommended that subsequent horizontal well deployments be carried out only on the C9 sublayer.

[0120] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0121] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0122] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0123] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for selecting the optimal target layer in a shale oil reservoir, characterized in that, The preferred method includes: The daily oil production of each test section in the research area is obtained after the fracturing fluid flowback rate reaches 100% during the predetermined operation period. Combined with the reserve calculation standard specified in DZ / T 0217-2020, the lower limit of oil production of the test section is determined. Obtain the movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index of each layer in the research area; The oil production index is obtained based on movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index. Establish a fitted graph of daily oil production and oil production index; The lower limit of the oil production index is obtained based on the fitted graph, according to the lower limit of oil production. If the oil production index is greater than the lower limit of the oil production index, then the corresponding layer is the target layer.

2. The preferred method as described in claim 1, characterized in that, The acquisition of movable oil porosity includes: obtaining the T1-T2 spectrum based on the two-dimensional nuclear magnetic resonance logging data and the two-dimensional T1-T2 nuclear magnetic resonance results of the middle section of the study area, determining the fluid type and fluid distribution range inside the core, establishing a fluid identification chart, obtaining the movable oil nuclear magnetic resonance distribution range, and calculating the movable oil porosity.

3. The preferred method as described in claim 1, characterized in that, The acquisition of fracture porosity includes: obtaining high-conductivity fractures, high-resistance fractures, induced fractures, and wellbore collapse based on electrical imaging logging data, and calculating fracture porosity.

4. The preferred method as described in claim 1, characterized in that, The effective fracture percentage is obtained by: acquiring high-conductivity fractures, high-resistance fractures, induced fractures, and wellbore collapse based on electrical imaging logging data, and calculating the percentage of fractures in high-conductivity fractures whose orientation is less than 60° from the direction of the maximum horizontal principal stress to obtain the effective fracture percentage.

5. The preferred method as described in claim 1, characterized in that, The brittleness index is obtained by calculating the brittleness index of shale oil reservoirs using the mineral composition method based on elemental logging results.

6. The preferred method as described in claim 1, characterized in that, The formula for calculating the oil production index includes: ； In the formula, IO is the oil production index, which is dimensionless; IB is the brittleness index, which is % (%). The movable oil porosity is % The value represents the crack porosity, %; P ef The percentage of effective cracks is %.

7. The preferred method as described in claim 1, characterized in that, The fitted graph is obtained by linearly fitting daily oil production with the oil production index. Preferably, obtaining the lower limit of the oil production index includes: inputting the lower limit of oil production into the fitted graph with the daily oil production to obtain the corresponding oil production index, which is the lower limit of the oil production index.

8. A preferred apparatus for a target layer in a shale oil reservoir, characterized in that, The preferred device includes: The oil production acquisition module is used to acquire the daily oil production of each test section in the research area during the predetermined operation period after the fracturing fluid flowback rate reaches 100%, and to determine the lower limit of oil production of the test section in conjunction with the reserve calculation standard specified in DZ / T 0217-2020. The parameter module is used to obtain the movable oil porosity, fracture porosity, effective fracture ratio and brittleness index of each layer in the research area. The oil production index module is used to obtain the oil production index based on movable oil porosity, fracture porosity, effective fracture ratio, and brittleness index. The chart module is used to create a fitted chart of daily oil production and oil production index. The optimization module is used to obtain the lower limit of the oil production index based on the fitted map according to the lower limit of oil production; if the oil production index is greater than the lower limit of the oil production index, the corresponding segment is the target layer.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; and a memory communicatively connected to said at least one processor; The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the preferred method for target layers in shale oil reservoirs according to any one of claims 1-7.

10. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which, when executed by a processor, implement the preferred method for target layers in shale oil reservoirs as described in any one of claims 1-7.

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