Relative permeability curve determination method and device based on online nuclear magnetism, equipment and medium

Abstract

The invention discloses a relative permeability curve determination method, device and equipment based on online nuclear magnetism and a medium, and the method comprises the following steps: respectively carrying out a water-oil displacement experiment and an oil-water displacement experiment on a to-be-measured rock core to obtain oil-measured absolute permeability and water-measured absolute permeability corresponding to the to-be-measured rock core; determining the water-phase permeability of the to-be-detected rock core under the water saturation based on the oil-phase fluid nuclear magnetic resonance information and the water-phase displacement information of the to-be-detected rock core in each displacement period of the water-oil displacement experiment; determining the oil phase permeability of the to-be-tested rock core under the water saturation based on the water phase fluid nuclear magnetic resonance information and the oil phase displacement information of the to-be-tested rock core in each displacement period of the oil-displacing-water experiment; and determining a target relative permeability curve of the to-be-measured rock core based on the oil measurement absolute permeability, the water measurement absolute permeability, and the water phase permeability and the oil phase permeability corresponding to each water saturation. The method realizes accurate determination of the relative permeability of the water-oil vector of the unconventional reservoir core, and draws a more accurate relative permeability curve.

Description

Technical Field

[0001] This invention relates to the field of petroleum industry development technology, and in particular to a method, apparatus, equipment and medium for determining phase permeability curves based on online nuclear magnetic resonance. Background Technology

[0002] With the continuous growth in demand for oil and gas resources, unconventional oil reservoirs have gradually become commercially viable. The seepage mechanism of multiphase fluids flowing in reservoirs is related to the issue of relative permeability.

[0003] Currently, the determination of phase permeability and relative permeability in unconventional reservoir cores is typically based on steady-state or non-steady-state methods. However, both methods rely on accurate measurement of the fluid volume within the core to accurately calculate phase permeability information. But during fluid flow in unconventional reservoir cores, the dead volume of the pipelines at the core's inlet and outlet can easily affect the accuracy of fluid volume measurements, leading to inaccurate determination of the corresponding phase permeability curve.

[0004] Therefore, it is necessary to improve the method for determining the relative permeability curve of the core. Summary of the Invention

[0005] This invention provides a method, apparatus, equipment, and medium for determining relative permeability curves based on online nuclear magnetic resonance (NMR) to solve the problem of inaccurate determination of the relative permeability of the water and oil phases in unconventional reservoir cores.

[0006] In a first aspect, embodiments of the present invention provide a method for determining phase permeation curves based on online nuclear magnetic resonance, comprising: Water-driven oil and oil-driven water experiments were conducted on the core samples to obtain the oil absolute permeability and water absolute permeability of the core samples. In each displacement cycle of the water-driven oil experiment, the water saturation of the core under test is determined based on the oil phase fluid nuclear magnetic resonance information of the core under test, and the water phase permeability of the core under test at the water saturation is determined based on the water phase displacement information of the core under test. In each displacement cycle of the oil-water flooding experiment, the water saturation of the core under test is determined based on the aqueous fluid nuclear magnetic resonance information of the core under test, and the oil phase permeability of the core under test at the water saturation is determined based on the oil phase displacement information of the core under test. Based on the oil absolute permeability, the water absolute permeability, and the water phase permeability and oil phase permeability corresponding to each water saturation, the target relative permeability curve of the core sample is determined.

[0007] Secondly, embodiments of the present invention also provide a device for determining phase permeation curves based on online nuclear magnetic resonance, comprising: The absolute permeability determination module is used to perform water-driven oil experiments and oil-driven water experiments on the core sample to obtain the oil-measured absolute permeability and water-measured absolute permeability of the core sample. A water phase permeability determination module is used to determine the water saturation of the core under test based on the oil phase fluid nuclear magnetic resonance information of the core under test in each displacement cycle of the water flooding experiment, and to determine the water phase permeability of the core under test at the water saturation based on the water phase displacement information of the core under test. The oil phase permeability determination module is used to determine the water saturation of the core under test based on the aqueous fluid nuclear magnetic resonance information of the core under test in each displacement cycle of the oil-water flooding experiment, and to determine the oil phase permeability of the core under test at the water saturation based on the oil phase displacement information of the core under test. The target relative permeability curve determination module is used to determine the target relative permeability curve of the core sample based on the oil absolute permeability, the water absolute permeability, and the water phase permeability and oil phase permeability corresponding to each water saturation.

[0008] Thirdly, embodiments of the present invention also provide 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 that can be executed by the at least one processor, which enables the at least one processor to perform the phase permeation curve determination method based on online NMR as described in any embodiment of the present invention.

[0009] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer instructions, which are used to cause a processor to execute the phase permeation curve determination method based on online NMR as described in any embodiment of the present invention.

[0010] Fifthly, embodiments of the present invention also provide a computer program product, including a computer program that, when executed by a processor, implements the method for determining phase permeation curves based on online NMR as described in any of the embodiments of the present invention.

[0011] The technical solution of this invention involves conducting water-driven oil and oil-driven water experiments on the core sample to obtain the absolute oil permeability and absolute water permeability of the core sample. Within each displacement cycle of the water-driven oil experiment, the water saturation of the core sample is determined based on the NMR information of the oil phase fluid, and the water phase permeability of the core sample at the water saturation level is determined based on the water phase displacement information of the core sample. Similarly, within each displacement cycle of the oil-driven water experiment, the water saturation of the core sample is determined based on the NMR information of the water phase fluid, and the oil phase permeability of the core sample at the water saturation level is determined based on the oil phase displacement information of the core sample. Finally, based on the absolute oil permeability, absolute water permeability, and the water and oil phase permeabilities corresponding to each water saturation level, the target phase permeability curve of the core sample is determined. In this technical solution, water-driven oil and oil-driven water experiments are conducted on the core sample to obtain the absolute oil permeability of the core sample under oil-phase fluid saturation and the absolute water permeability of the core sample under water-phase fluid saturation. Furthermore, through water-driven oil experiments, the oil-phase fluid in the core sample is analyzed using nuclear magnetic resonance (NMR) equipment. 1 H nuclei were scanned to obtain the first reference T2 spectrum of the core sample under oil-saturated fluid conditions, and the first usable T2 spectrum at different displacement cycles. Then, based on the ratio of the areas of each first usable T2 spectrum and the first reference T2 spectrum in the target coordinate system, the oil-phase fluid saturation of the core sample at at least one phase was determined. Each oil-phase fluid saturation was then converted to its corresponding water saturation. This allowed for the determination of the water phase permeability of the core sample at each water saturation level based on the water phase displacement information of the injected water phase fluid. Secondly, through oil-flooding experiments, the water phase fluid in the core sample was analyzed using nuclear magnetic resonance (NMR) equipment. 1 H atomic nuclei are scanned to obtain the second reference T2 spectrum of the core sample under aqueous saturated fluid conditions, and the second T2 spectrum to be used in different displacement cycles. Then, based on the ratio of the area of ​​each second T2 spectrum to the second reference T2 spectrum in the target coordinate system, the core sample is determined to have at least one water saturation level. This allows for the determination of the oil phase permeability of the core sample at each water saturation level based on the oil phase displacement information of the injected oil phase fluid. Furthermore, the relative oil permeability of the core sample at each water saturation level is obtained by comparing the ratio of oil phase permeability to absolute oil phase permeability, and the relative water permeability of the core sample at each water saturation level is obtained by comparing the ratio of oil phase permeability to absolute water phase permeability. This allows for the plotting of the target phase permeability curve corresponding to the core sample. The advantage of this technical solution is that during water-drive oil and oil-drive water experiments, nuclear magnetic resonance (NMR) equipment is used to scan the aqueous or oil phase fluid within the core sample to obtain the water phase or oil phase fluid within the core sample. 1The nuclear magnetic resonance signal of H atomic nuclei can directly reflect the distribution characteristics of core pores through transverse relaxation time (T2 spectrum), and the area ratio of the spectrum can dynamically characterize the changes in fluid saturation under different displacement cycles. It does not rely on fluid collection at the outlet end, which solves the problem of fluid metering deviation caused by the dead volume at the core outlet end in the existing technology. This makes the calculation of the relative permeability of the water and oil phases in the core no longer limited by the fluid collection error at the outlet end. It realizes the accurate determination of the relative permeability of the water and oil vectors in unconventional reservoir cores and the effect of drawing more accurate phase permeability curves. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0013] Figure 1 This is a flowchart of a method for determining phase permeation curves based on online nuclear magnetic resonance according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a displacement experiment on a core sample provided in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the relative permeability curve of a certain unconventional reservoir core provided in Embodiment 2 of the present invention; Figure 4 A schematic diagram of the relative permeability curve of another unconventional reservoir core provided in Embodiment 2 of the present invention. Figure 5 This is a schematic diagram of a phase permeation curve determination device based on online nuclear magnetic resonance according to Embodiment 3 of the present invention; Figure 6 This is a schematic diagram of the structure of an electronic device that implements the method for determining phase permeation curves based on online nuclear magnetic resonance according to embodiments of the present invention. Detailed Implementation

[0014] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. The acquisition, transmission, storage, use, and processing of data in the technical solutions of this application comply with the relevant provisions of national laws and regulations. It should be noted that in the embodiments of this application, certain software, components, or models and other existing solutions in the industry may be mentioned. These should be considered as exemplary, and their purpose is only to illustrate the feasibility of implementing the technical solutions of this application, but it does not mean that the applicant has or necessarily used such solutions.

[0015] It should be noted that the collection, gathering, updating, analysis, processing, use, transmission, and storage of user personal information involved in the technical solution disclosed herein all comply with relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. Necessary measures are taken to prevent unauthorized access to user personal information data and to maintain user personal information security and network security. It should also be noted that the collection, gathering, updating, analysis, processing, use, transmission, and storage of user personal information involved in the technical solution disclosed herein are all conducted with the user's knowledge and consent, and comply with relevant privacy protection regulations.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0017] Before elaborating on this technical solution in detail, let's briefly introduce its application scenarios to help us understand it more clearly.

[0018] With the continuous growth in demand for oil and gas resources, unconventional reservoirs have gradually gained commercial exploitation value. The seepage mechanism of multiphase fluid flow in reservoirs is related to relative permeability. When multiphase fluids flow in a medium, because the porous medium is highly dispersed, the fluid must overcome various resistances, including those generated by the fluid's own properties and those exerted by the porous medium. Therefore, phase permeability and relative permeability are closely related to the surface phenomena of porous media, reflecting the seepage characteristics and reservoir properties of actual reservoirs. This has guiding significance for actual production and is also the foundation for reservoir engineering analysis and numerical simulation.

[0019] Currently, methods for determining the relative permeability curves of oil-water two-phase systems (i.e., the relative permeability curves of core samples) include steady-state and unsteady-state methods. The steady-state method primarily relies on Darcy's law for steady flow, assuming a steady state is reached when the oil and water flow rates at the inlet and outlet of the core are equal. Key data such as pressure differential and outlet flow rate are then collected to calculate the relative permeability. However, unconventional reservoir cores are characterized by low porosity and low permeability, requiring a considerable amount of time to reach true equilibrium. Furthermore, due to the small saturated fluid volume, the amount of fluid that can be collected is significantly affected by the dead volume in the pipeline, leading to inaccurate results for the relative permeability of the core. The unsteady-state method primarily relies on the basic theory of waterflooding (i.e., the Berkeley-Lewelt front propulsion theory). The calculation process also requires collecting the produced fluid volume at the outlet. In other words, the unsteady-state method for determining the relative permeability of the core is also affected by the dead volume in the pipeline, resulting in inaccurate results.

[0020] Based on this, this technical solution proposes a method for nuclear magnetic resonance scanning of rock cores using online nuclear magnetic resonance equipment, which can accurately determine the relative permeability curve corresponding to the rock core.

[0021] Example 1 Figure 1 This invention provides a flowchart of a method for determining relative permeability curves based on online nuclear magnetic resonance (NMR) in Embodiment 1. This embodiment is applicable to accurately measuring the relative permeability of the water and oil phases in unconventional reservoir cores and plotting the relative permeability curves corresponding to the unconventional reservoir cores based on the measurement results to reflect the seepage characteristics of the unconventional reservoirs. This method can be executed by an online NMR-based relative permeability curve determination device, which can be implemented in hardware and / or software. This online NMR-based relative permeability curve determination device can be configured in a computing device capable of executing the online NMR-based relative permeability curve determination method.

[0022] like Figure 1 As shown, the method includes: S110. Water-driven oil and oil-driven water experiments were conducted on the core sample to be tested to obtain the oil absolute permeability and water absolute permeability of the core sample.

[0023] The core sample to be tested refers to an unconventional reservoir core for which the phase permeability and relative permeability need to be determined. A water-drive oil experiment is an experimental method that injects aqueous fluid into an oil-bearing core to displace and determine the crude oil recovery efficiency and core seepage characteristics. An oil-drive water experiment is an experimental method that injects oil-phase fluid into a water-bearing core to determine the oil phase seepage capacity and residual water distribution characteristics. Oil-phase absolute permeability is the capacity of the core sample to allow fluid to pass through under oil-phase fluid saturation conditions, used to reflect the inherent permeability characteristics of the core sample to oil-phase fluids. Water-phase absolute permeability is the capacity of the core sample to allow fluid to pass through under aqueous fluid saturation conditions, used to reflect the inherent permeability characteristics of the core sample to aqueous fluids.

[0024] Specifically, water-driven oil and oil-driven water experiments were conducted on the core samples to obtain the corresponding absolute permeability of oil and water. This included: conducting water-driven oil experiments on the core samples and determining the corresponding absolute permeability of oil based on Darcy's law algorithm when the core samples reached oil phase fluid saturation; and conducting oil-driven water experiments on the core samples and determining the corresponding absolute permeability of water based on Darcy's law algorithm when the core samples reached water phase fluid saturation.

[0025] S120. In each displacement cycle of the water-driven oil experiment, the water saturation of the core under test is determined based on the nuclear magnetic resonance information of the oil phase fluid of the core under test, and the water phase permeability of the core under test at the water saturation is determined based on the water phase displacement information of the core under test.

[0026] It should be noted that the nuclear magnetic resonance (NMR) spectrum in this technical solution refers to the horizontal relaxation time distribution spectrum, i.e., the T2 spectrum, obtained by scanning the hydrogen element in the aqueous or oil-phase fluid in the core sample using an NMR device. It is understood that the designations "first reference," "second reference," "first to be used," and "second to be used" associated with the NMR spectrum in this technical solution are only used to distinguish the NMR spectra corresponding to the core sample under different conditions, facilitating understanding of this technical solution, and do not have any other practical meaning.

[0027] The oil-phase fluid NMR information includes the first reference NMR spectrum of the core sample under oil-phase fluid saturation, and the first NMR spectrum to be used in each displacement cycle during the waterflooding experiment. Water saturation refers to the proportion of aqueous fluid in the core sample among all fluids. Aqueous displacement information refers to the information associated with the aqueous fluid injected into the core sample during the displacement process. For example, aqueous displacement information includes aqueous fluid viscosity, aqueous fluid volume, and the time of aqueous fluid injection into the core sample. Aqueous permeability can be understood as the ability of aqueous fluid to flow effectively at a specific water saturation level in a core containing both oil and water phases, reflecting the seepage characteristics of the aqueous phase in oil-bearing porous media.

[0028] Optionally, the water saturation of the core under test is determined based on the NMR information of the oil phase fluid in the core, including: acquiring a first reference NMR spectrum of the oil phase fluid in the core when the core reaches oil phase fluid saturation; acquiring a first unused NMR spectrum of the oil phase fluid in each displacement cycle of the waterflooding experiment; for each displacement cycle, determining the first unused area formed by the first unused NMR spectrum and the horizontal coordinate axis in the target coordinate system, and the first reference area formed by the first reference NMR spectrum and the horizontal coordinate axis; determining the oil phase fluid saturation of the core under test in the displacement cycle based on the ratio of the first unused area to the first reference area, and converting the oil phase fluid saturation into the water saturation of the core under test.

[0029] The first reference nuclear magnetic resonance spectrum can be understood as the spectrum of the core sample when it reaches oil phase fluid saturation, based on the nuclear magnetic resonance equipment. 1 The transverse relaxation time distribution spectrum obtained after scanning H nuclei. In this technical solution, the first reference NMR spectrum can be referred to as the first reference T2 spectrum. The first NMR spectrum to be used refers to the oil phase fluid in the core sample when the fluid transport in the core sample reaches a new saturation equilibrium state during each displacement cycle of the water-drive oil experiment, based on the NMR equipment. 1 The transverse relaxation time distribution spectrum obtained after scanning H nuclei. In this technical solution, the NMR spectrum to be used can also be referred to as the first T2 spectrum to be used.

[0030] The target coordinate system refers to a coordinate system with the transverse relaxation time of NMR as the transverse axis and the signal amplitude of NMR as the vertical axis. The first reference area refers to the area corresponding to the region formed by the first reference NMR spectrum and the transverse axis. The first area to be used refers to the area corresponding to the region formed by the first NMR spectrum to be used and the transverse axis. Oil phase fluid saturation is used to characterize the proportion of oil phase fluid in all fluids in the core sample.

[0031] Specifically, when conducting waterflooding experiments on the core sample, the core needs to undergo operations such as oil washing, salt washing, drying, and soaking to saturate the oil phase fluid within it and obtain the first reference T2 spectrum of the core sample under oil phase fluid saturation. Based on this, in subsequent waterflooding experiments, the oil phase fluid in the core sample is gradually replaced with water phase fluid by injecting water phase fluid one or more times until the water and oil phase fluids in the core sample reach equilibrium again, at which point the waterflooding experiment is complete.

[0032] Taking a displacement cycle as an example, the first T2 spectrum to be used within the displacement cycle is obtained, and the first reference area corresponding to the first reference T2 spectrum under the target system and the first area to be used corresponding to the first T2 spectrum to be used are determined. Based on the ratio of the first area to be used and the first reference area, the oil phase fluid saturation of the displacement cycle is obtained. For example, if the oil phase fluid saturation is 80%, the water saturation of the core to be tested can be obtained by converting the oil phase fluid saturation to 20%.

[0033] It should be noted that during the water-driven oil recovery experiment, the oil phase fluid contained... 1 The fluid contains H atomic nuclei, while the aqueous fluid injected into the core sample does not. 1 The H atom nucleus, in other words, is essentially the oil phase fluid in the core sample during waterflooding experiments. 1 Nuclear magnetic resonance (NMR) scans of H nuclei were performed to determine the composition of the oil phase fluid. 1 The nuclear magnetic resonance signal corresponding to the H atom nucleus is used to reflect the fluid seepage characteristics of the rock core being tested.

[0034] The advantage of this setup is that this technical solution determines whether the core sample has reached oil saturation by performing nuclear magnetic resonance (NMR) scanning to obtain the transverse relaxation time distribution parameters corresponding to the core sample. When a saturated single fluid exists in a porous rock medium (i.e., the core sample), the NMR signal indicates the fluid content, and the transverse relaxation time and pore size are linearly positively correlated. Furthermore, the T2 spectrum (used to characterize the transverse relaxation time distribution parameter set corresponding to the oil phase fluid in the core sample) reflects the fluid content in all pore throats. Therefore, characterizing the change in fluid content inside the core sample by the dynamic change of the NMR signal can compensate for the difficulty in collecting fluid at the outlet end due to the dead volume.

[0035] Based on the above example, the aqueous phase permeability of the core under water saturation is determined based on the aqueous phase displacement information of the core under test, including: obtaining the aqueous phase displacement information of the aqueous phase injection fluid in each displacement cycle of the core under test, and determining the aqueous phase permeability of the core under water saturation corresponding to each displacement cycle based on the aqueous phase displacement information.

[0036] S130. In each displacement cycle of the oil-water flooding experiment, the water saturation of the core under test is determined based on the water phase fluid nuclear magnetic resonance information of the core under test, and the oil phase permeability of the core under test at the water saturation is determined based on the oil phase displacement information of the core under test.

[0037] The aqueous phase NMR information includes the second reference NMR spectrum of the core sample under aqueous phase saturation, and the second NMR spectrum to be used for each displacement cycle during the oil-flooding experiment. Oil phase displacement information refers to the information associated with the oil phase fluid injected into the core sample during the displacement process. For example, oil phase displacement information includes oil phase fluid viscosity, oil phase fluid volume, and the time of oil phase fluid injection into the core sample. Oil phase permeability can be understood as the ability of the oil phase fluid to flow effectively at a specific water saturation level in a core where oil and water coexist, reflecting the seepage characteristics of the oil phase in oil-bearing porous media.

[0038] Optionally, the water saturation of the core sample is determined based on the aqueous phase fluid nuclear magnetic resonance (NMR) information of the core sample, including: acquiring a second reference NMR spectrum of the aqueous phase fluid in the core sample when the core sample reaches aqueous phase fluid saturation; acquiring a second unused NMR spectrum of the aqueous phase fluid in each displacement cycle of the oil-flooding experiment; for each displacement cycle, determining the second unused area formed by the second unused NMR spectrum and the horizontal coordinate axis in the target coordinate system, and the second reference area formed by the second reference NMR spectrum and the horizontal coordinate axis; and determining the water saturation of the core sample in the displacement cycle based on the ratio of the second unused area to the second reference area.

[0039] The second reference nuclear magnetic resonance spectrum can be understood as the spectrum of the aqueous fluid in the core sample when the core sample reaches a state of aqueous fluid saturation, based on the nuclear magnetic resonance equipment. 1 The transverse relaxation time distribution spectrum obtained after scanning H nuclei. In this technical solution, the second reference NMR spectrum can be referred to as the second reference T2 spectrum. The second NMR spectrum to be used refers to the water phase fluid in the core sample when the fluid transport in the core sample reaches a new saturation equilibrium state during each displacement cycle of the oil-flooding experiment, based on the NMR equipment. 1 The transverse relaxation time distribution spectrum obtained after scanning H nuclei. In this technical solution, the NMR spectrum to be used can also be referred to as the second T2 spectrum to be used.

[0040] The second reference area refers to the area corresponding to the region formed by the second reference NMR spectrum and the horizontal coordinate axis. The second area to be used refers to the area corresponding to the region formed by the second NMR spectrum to be used and the horizontal coordinate axis. Aqueous fluid saturation is used to characterize the proportion of oil-phase fluid in all fluids in the core sample. In this technical solution, aqueous fluid saturation can also be referred to as water saturation.

[0041] Specifically, when conducting oil-flooding experiments on the core sample, the core needs to undergo processes such as oil removal, desalination, drying, vacuuming, and pressurized saturated water treatment to saturate the aqueous phase fluid within the core and obtain the second reference T2 spectrum of the core sample under oil-phase fluid saturation. Based on this, in subsequent oil-flooding experiments, the aqueous phase fluid in the core sample is gradually replaced with oil-phase fluid by injecting oil-phase fluid one or more times until the aqueous and oil-phase fluids in the core sample reach equilibrium again, at which point the oil-flooding experiment is complete.

[0042] It should be noted that during the oil-flooding water experiment, the aqueous phase fluid contained... 1 The fluid contains H atomic nuclei, while the oil phase fluid injected into the core sample does not. 1 The H atom nucleus, in other words, is essentially the aqueous fluid in the core sample during the oil-water displacement experiment. 1 Nuclear magnetic resonance (NMR) scans of H nuclei were performed to determine the composition of the aqueous fluid. 1 The nuclear magnetic resonance signal corresponding to the H atom nucleus is used to reflect the fluid seepage characteristics of the rock core being tested.

[0043] The advantage of this setup is that this technical solution determines whether the core sample has reached a water-phase saturation state by performing nuclear magnetic resonance (NMR) scanning on the core sample to obtain the transverse relaxation time distribution parameters corresponding to the core sample. When a saturated single fluid exists in the porous rock medium (i.e., the core sample), the NMR signal quantity represents the fluid content, and the transverse relaxation time and pore size are linearly positively correlated. Furthermore, the T2 spectrum (used to characterize the transverse relaxation time distribution parameter set corresponding to the water-phase fluid in the core sample) reflects the fluid content in all pore throats. Therefore, characterizing the change in fluid content inside the core sample by the dynamic change of the NMR signal quantity can compensate for the difficulty in collecting fluid at the outlet end due to the dead volume.

[0044] Based on the above example, the oil phase permeability of the core under water saturation is determined based on the oil phase displacement information of the core under test, including: obtaining the oil phase displacement information of the oil phase injection fluid of the core under test in each displacement cycle, and determining the oil phase permeability of the core under test at the corresponding water saturation in each displacement cycle based on the oil phase displacement information.

[0045] S140. Based on the absolute permeability of oil and water, as well as the water phase permeability and oil phase permeability corresponding to each water saturation level, determine the target relative permeability curve of the core sample to be tested.

[0046] Among them, the target relative permeability curve characterizes the relative water permeability and relative oil permeability of the core sample at different water saturation levels.

[0047] In practical applications, the target relative permeability curve of the core under test is determined based on the absolute permeability of oil and water, as well as the water phase permeability and oil phase permeability corresponding to each water saturation. This includes: obtaining the relative water permeability of the core under test at the water saturation corresponding to each displacement cycle based on the ratio of water phase permeability to absolute water phase permeability; obtaining the relative oil permeability of the core under test at the water saturation corresponding to each displacement cycle based on the ratio of oil phase permeability to absolute oil phase permeability; and plotting the target relative permeability curve of the core under test based on the relative water permeability and relative oil permeability associated with the water saturation corresponding to all displacement cycles.

[0048] Specifically, the relative oil permeability of the core sample at the corresponding displacement cycle is obtained based on the ratio of oil phase permeability to measured absolute oil permeability, and the relative water permeability of the core sample at the corresponding displacement cycle is obtained based on the ratio of water phase permeability to measured absolute water permeability. A coordinate system is established with water saturation as the abscissa and relative permeability as the ordinate. Based on the obtained relative water permeability and relative oil permeability of the core sample at each water saturation level, the corresponding target phase permeability curve is plotted. (See [reference]). Figure 3 and Figure 4 ,in, Figure 3 This is a schematic diagram of the relative permeability curve of a core sample from an unconventional reservoir. Figure 4 This is a schematic diagram of the relative permeability curve of another unconventional reservoir core.

[0049] The technical solution of this invention involves conducting water-driven oil and oil-driven water experiments on the core sample to obtain the absolute oil permeability and absolute water permeability of the core sample. Within each displacement cycle of the water-driven oil experiment, the water saturation of the core sample is determined based on the NMR information of the oil phase fluid, and the water phase permeability of the core sample at the water saturation level is determined based on the water phase displacement information of the core sample. Similarly, within each displacement cycle of the oil-driven water experiment, the water saturation of the core sample is determined based on the NMR information of the water phase fluid, and the oil phase permeability of the core sample at the water saturation level is determined based on the oil phase displacement information of the core sample. Finally, based on the absolute oil permeability, absolute water permeability, and the water and oil phase permeabilities corresponding to each water saturation level, the target phase permeability curve of the core sample is determined. In this technical solution, water-driven oil and oil-driven water experiments are conducted on the core sample to obtain the absolute oil permeability of the core sample under oil-phase fluid saturation and the absolute water permeability of the core sample under water-phase fluid saturation. Furthermore, through water-driven oil experiments, the oil-phase fluid in the core sample is analyzed using nuclear magnetic resonance (NMR) equipment. 1 H nuclei were scanned to obtain the first reference T2 spectrum of the core sample under oil-saturated fluid conditions, and the first usable T2 spectrum at different displacement cycles. Then, based on the ratio of the areas of each first usable T2 spectrum and the first reference T2 spectrum in the target coordinate system, the oil-phase fluid saturation of the core sample at at least one phase was determined. Each oil-phase fluid saturation was then converted to its corresponding water saturation. This allowed for the determination of the water phase permeability of the core sample at each water saturation level based on the water phase displacement information of the injected water phase fluid. Secondly, through oil-flooding experiments, the water phase fluid in the core sample was analyzed using nuclear magnetic resonance (NMR) equipment. 1 H atomic nuclei are scanned to obtain the second reference T2 spectrum of the core sample under aqueous saturated fluid conditions, and the second T2 spectrum to be used in different displacement cycles. Then, based on the ratio of the area of ​​each second T2 spectrum to the second reference T2 spectrum in the target coordinate system, the core sample is determined to have at least one water saturation level. This allows for the determination of the oil phase permeability of the core sample at each water saturation level based on the oil phase displacement information of the injected oil phase fluid. Furthermore, the relative oil permeability of the core sample at each water saturation level is obtained by comparing the ratio of oil phase permeability to absolute oil phase permeability, and the relative water permeability of the core sample at each water saturation level is obtained by comparing the ratio of oil phase permeability to absolute water phase permeability. This allows for the plotting of the target phase permeability curve corresponding to the core sample. The advantage of this technical solution is that during water-drive oil and oil-drive water experiments, nuclear magnetic resonance (NMR) equipment is used to scan the aqueous or oil phase fluid within the core sample to obtain the water phase or oil phase fluid within the core sample. 1The nuclear magnetic resonance signal of H atomic nuclei can directly reflect the distribution characteristics of core pores through transverse relaxation time (T2 spectrum), and the area ratio of the spectrum can dynamically characterize the changes in fluid saturation under different displacement cycles. It does not rely on fluid collection at the outlet end, which solves the problem of fluid metering deviation caused by the dead volume at the core outlet end in the existing technology. This makes the calculation of the relative permeability of the water and oil phases in the core no longer limited by the fluid collection error at the outlet end. It realizes the accurate determination of the relative permeability of the water and oil vectors in unconventional reservoir cores and the effect of drawing more accurate phase permeability curves.

[0050] Example 2 In a specific example, a brief introduction to the displacement experiment will be given first to facilitate understanding of this technical solution. For example... Figure 2 As shown, the experimental pipeline was connected according to the experimental requirements to begin the displacement experiment. First, the target fluid was injected into the core through the displacement pump and intermediate container to achieve initial saturation. Next, a baseline spectrum was acquired using an online nuclear magnetic resonance (NMR) testing system. Then, the displacement pump was started to inject the displacement fluid, and the core environment was kept stable through a fluorinated oil circulation system. Pressure sensors and back pressure valves monitored and controlled the experimental pressure. During the displacement process, NMR spectra were continuously acquired. When the spectrum change value was lower than a preset threshold, it was determined that the core had reached a new fluid saturation state. At the same time, the produced fluid was separated by an oil-water separator. Data such as displacement time and pump volume were recorded by the data acquisition system and ultimately used to calculate parameters such as the phase permeability of the core.

[0051] Specifically, in the waterflooding experiment, when the oil phase fluid in the core reaches fluid saturation, the core is first scanned using nuclear magnetic resonance (NMR) to obtain the first baseline T2 spectrum of the core at this point. Based on this, aqueous fluid is injected into the core, and when the fluid transport within the core pores reaches a new saturation equilibrium, the current displacement cycle is considered complete. Then, the oil phase fluid in the core is scanned using NMR equipment to obtain the first usable T2 spectrum (i.e., the usable NMR spectrum, or T2 spectrum) corresponding to the core within the current displacement cycle.

[0052] Based on this, the area corresponding to the first reference area is determined by the region enclosed by the first reference T2 spectrum and the x-axis (i.e., the transverse coordinate axis) of the target coordinate system. S 1 Simultaneously, determine the first usable area corresponding to the region enclosed by the first usable T2 spectrum and the target coordinate system in each displacement cycle. S n The first usable area corresponding to each displacement cycle is denoted as . S 2 、S 3 …S nAccording to any time S n and S 1 The ratio is used to determine the oil phase fluid saturation in the core sample. E n (oil phase): in, This indicates the oil phase fluid saturation corresponding to the oil phase fluid in the core sample. S n This represents the first usable area corresponding to the oil phase fluid during the (n-1)th displacement cycle. This represents the first reference area of ​​the oil phase fluid.

[0053] Considering that this example is a water-driven oil recovery experiment, the above This refers to the fluid saturation of the oil phase fluid in the core sample. Therefore, the fluid saturation of the water phase fluid injected into the core sample at this time is: in, This indicates the fluid saturation (i.e., water saturation) of the water phase injected into the core being tested. E n This indicates the oil phase fluid saturation corresponding to the oil phase fluid in the core sample.

[0054] Based on this, during each displacement cycle in the water-driven oil recovery experiment, the displacement pump volume (i.e., the volume of the injected fluid), the displacement time, and the viscosity of the injected fluid are obtained. Then, the water phase permeability of the injected fluid is determined based on the following formula: in, K ni Indicates the first n Water phase permeability of the core sample within one displacement cycle μ i The viscosity of the injected aqueous fluid is represented by L, and the length of the core sample is represented by L. V n -V n-1 Indicates the first n The volume of the aqueous phase injected during each displacement cycle, where A represents the cross-sectional area of ​​the core sample. This represents the pressure difference between the two ends of the core sample during the displacement process. t n -t n-1 It indicates the duration of one displacement cycle.

[0055] In the oil-flooding experiment, when the aqueous phase fluid in the core reaches saturation, the core is first scanned using nuclear magnetic resonance (NMR) to obtain the second baseline T2 spectrum. Based on this, oil phase fluid is injected into the core, and when the fluid transport within the core pores reaches a new saturation equilibrium, the current displacement cycle is considered complete. Then, the aqueous phase fluid in the core is scanned using NMR to obtain the second T2 spectrum (i.e., the T2 spectrum to be used) corresponding to the core during the current displacement cycle.

[0056] Based on this, the area corresponding to the second reference spectrum and the x-axis (i.e., the transverse coordinate axis) of the target coordinate system is determined. S 1 ’ Simultaneously, determine the second usable area corresponding to the region enclosed by the second usable T2 spectrum and the target coordinate system in each displacement cycle. S n ’ The second usable area corresponding to each displacement cycle is denoted as follows: S 2 ’ 、S 3 ’ … S n ’ According to any time S n ’ and S 1 ’ The ratio of the two values ​​is used to determine the water phase fluid saturation in the core sample. E n (Aqueous phase): in, This indicates the water phase fluid saturation corresponding to the water phase fluid in the rock core being tested. This represents the second usable area corresponding to the aqueous phase fluid during the (n-1)th displacement cycle. The second reference area represents the aqueous phase fluid.

[0057] Based on the above example, the relative oil permeability of the core sample is determined using the following formula: in, Indicates the relative permeability of oil. Indicates oil phase permeability. This indicates the absolute permeability of the oil phase.

[0058] Similarly, the relative water permeability of the core sample is determined based on the following formula: in, Indicates the relative permeability of water. Indicates water phase permeability, This represents the absolute permeability of the aqueous phase.

[0059] Based on this, a coordinate system was established with water saturation as the abscissa and relative permeability as the ordinate. According to the obtained relative permeability of water and oil at various water saturations of the core sample, the target relative permeability curves for the core sample were plotted. (See [reference]). Figure 3 and Figure 4 ,in, Figure 3 This is a schematic diagram of the relative permeability curve of a core sample from an unconventional reservoir. Figure 4 This is a schematic diagram of the relative permeability curve of another unconventional reservoir core.

[0060] The technical solution of this invention involves conducting water-driven oil and oil-driven water experiments on the core sample to obtain the absolute oil permeability and absolute water permeability of the core sample. Within each displacement cycle of the water-driven oil experiment, the water saturation of the core sample is determined based on the NMR information of the oil phase fluid, and the water phase permeability of the core sample at the water saturation level is determined based on the water phase displacement information of the core sample. Similarly, within each displacement cycle of the oil-driven water experiment, the water saturation of the core sample is determined based on the NMR information of the water phase fluid, and the oil phase permeability of the core sample at the water saturation level is determined based on the oil phase displacement information of the core sample. Finally, based on the absolute oil permeability, absolute water permeability, and the water and oil phase permeabilities corresponding to each water saturation level, the target phase permeability curve of the core sample is determined. The advantage of this technical solution lies in the fact that, during water-drive oil and oil-drive water experiments, nuclear magnetic resonance (NMR) equipment is used to scan the aqueous or oil-phase fluid within the core sample, thereby obtaining the information about the aqueous or oil-phase fluid within the core sample. 1 The nuclear magnetic resonance signal of H atomic nuclei can directly reflect the distribution characteristics of core pores through transverse relaxation time (T2 spectrum), and the area ratio of the spectrum can dynamically characterize the changes in fluid saturation under different displacement cycles. It does not rely on fluid collection at the outlet end, which solves the problem of fluid metering deviation caused by the dead volume at the core outlet end in the existing technology. This makes the calculation of the relative permeability of the water and oil phases in the core no longer limited by the fluid collection error at the outlet end. It realizes the accurate determination of the relative permeability of the water and oil vectors in unconventional reservoir cores and the effect of drawing more accurate phase permeability curves.

[0061] Example 3 Figure 5This is a schematic diagram of a phase permeation curve determination device based on online NMR provided in Embodiment 3 of the present invention. Figure 5 As shown, the device includes: an absolute permeability determination module 210, an aqueous phase permeability determination module 220, an oil phase permeability determination module 230, and a target phase permeability curve determination module 240.

[0062] Among them, the absolute permeability determination module 210 is used to conduct water-driven oil experiments and oil-driven water experiments on the core to be tested to obtain the oil-measured absolute permeability and water-measured absolute permeability of the core to be tested. The water phase permeability determination module 220 is used to determine the water saturation of the core under test based on the oil phase fluid nuclear magnetic resonance information of the core under test in each displacement cycle of the water flooding experiment, and to determine the water phase permeability of the core under test at the water saturation based on the water phase displacement information of the core under test. The oil phase permeability determination module 230 is used to determine the water saturation of the core under test based on the water phase fluid nuclear magnetic resonance information of the core under test in each displacement cycle of the oil-water flooding experiment, and to determine the oil phase permeability of the core under test at the water saturation based on the oil phase displacement information of the core under test. The target relative permeability curve determination module 240 is used to determine the target relative permeability curve of the core sample based on the absolute permeability measured by oil, the absolute permeability measured by water, and the water phase permeability and oil phase permeability corresponding to each water saturation.

[0063] The technical solution of this invention involves conducting water-driven oil and oil-driven water experiments on the core sample to obtain the absolute oil permeability and absolute water permeability of the core sample. Within each displacement cycle of the water-driven oil experiment, the water saturation of the core sample is determined based on the NMR information of the oil phase fluid, and the water phase permeability of the core sample at the water saturation level is determined based on the water phase displacement information of the core sample. Similarly, within each displacement cycle of the oil-driven water experiment, the water saturation of the core sample is determined based on the NMR information of the water phase fluid, and the oil phase permeability of the core sample at the water saturation level is determined based on the oil phase displacement information of the core sample. Finally, based on the absolute oil permeability, absolute water permeability, and the water and oil phase permeabilities corresponding to each water saturation level, the target phase permeability curve of the core sample is determined. The advantage of this technical solution lies in the fact that, during water-drive oil and oil-drive water experiments, nuclear magnetic resonance (NMR) equipment is used to scan the aqueous or oil-phase fluid within the core sample, thereby obtaining the information about the aqueous or oil-phase fluid within the core sample. 1The nuclear magnetic resonance signal of H atomic nuclei can directly reflect the distribution characteristics of core pores through transverse relaxation time (T2 spectrum), and the area ratio of the spectrum can dynamically characterize the changes in fluid saturation under different displacement cycles. It does not rely on fluid collection at the outlet end, which solves the problem of fluid metering deviation caused by the dead volume at the core outlet end in the existing technology. This makes the calculation of the relative permeability of the water and oil phases in the core no longer limited by the fluid collection error at the outlet end. It realizes the accurate determination of the relative permeability of the water and oil vectors in unconventional reservoir cores and the effect of drawing more accurate phase permeability curves.

[0064] Optionally, the absolute permeability determination module includes: an oil-based absolute permeability determination unit, used for conducting water-drive oil experiments on the core sample, and determining the corresponding oil-based absolute permeability of the core sample based on Darcy's law algorithm when the core sample reaches oil phase fluid saturation; and The absolute permeability determination unit is used to conduct oil-drive water experiments on the core sample and determine the absolute permeability of the core sample based on Darcy's law algorithm when the core sample reaches the state of aqueous fluid saturation.

[0065] Optionally, the aqueous permeability determination module includes: a first reference nuclear magnetic resonance spectrum determination unit, used to obtain the first reference nuclear magnetic resonance spectrum of the oil phase fluid in the core under test when the core under test reaches the state of oil phase fluid saturation; The first nuclear magnetic resonance spectrum determination unit is used to obtain the first nuclear magnetic resonance spectrum of the oil phase fluid in each displacement cycle of the water-driven oil experiment. The first area determination unit is used to determine, for each displacement cycle, the first area to be used formed by the first nuclear magnetic resonance spectrum to be used and the horizontal coordinate axis in the target coordinate system, and the first reference area formed by the first reference nuclear magnetic resonance spectrum and the horizontal coordinate axis. The first water saturation determination unit is used to determine the oil phase fluid saturation corresponding to the core under test during the displacement cycle based on the ratio of the first area to be used to the first reference area, and to convert the oil phase fluid saturation into the water saturation corresponding to the core under test.

[0066] Optionally, a water phase permeability determination module is used to acquire water phase displacement information of the water phase injected fluid in each displacement cycle of the core under test, and to determine the water phase permeability of the core under test at the corresponding water saturation in each displacement cycle based on the water phase displacement information.

[0067] Optionally, the oil phase permeability determination module includes: a second reference nuclear magnetic resonance spectrum determination unit, used to obtain the second reference nuclear magnetic resonance spectrum of the aqueous phase fluid in the core under test when the core under test reaches the aqueous phase fluid saturation state; The second nuclear magnetic resonance spectrum determination unit is used to obtain the second nuclear magnetic resonance spectrum of the aqueous phase fluid in each displacement cycle of the oil-water flooding experiment. The second area determination unit is used to determine, for each displacement cycle, the second area to be used formed by the second NMR spectrum to be used and the horizontal coordinate axis in the target coordinate system, and the second reference area formed by the second reference NMR spectrum and the horizontal coordinate axis. The second water saturation determination unit is used to determine the water saturation of the core sample during the displacement cycle based on the ratio of the second area to be used and the second reference area.

[0068] Optionally, an oil phase permeability determination module is used to acquire oil phase displacement information of the oil phase injection fluid in each displacement cycle of the core under test, and to determine the oil phase permeability of the core under test at the corresponding water saturation in each displacement cycle based on the oil phase displacement information.

[0069] Optionally, the target relative permeability curve determination module includes: a water relative permeability determination unit, used to obtain the water relative permeability of the core sample at the corresponding water saturation level for each displacement cycle, based on the ratio of water phase permeability to water phase absolute permeability; and The oil relative permeability determination unit is used to obtain the oil relative permeability of the core sample at the corresponding water saturation in each displacement cycle based on the ratio of oil phase permeability to oil phase absolute permeability. The target relative permeability curve determination unit is used to plot the target relative permeability curve of the core under test based on the relative water permeability and relative oil permeability associated with the water saturation corresponding to all displacement cycles.

[0070] The phase permeability curve determination device based on online NMR provided in this embodiment of the invention can execute the phase permeability curve determination method based on online NMR provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0071] Example 4 Figure 6 A schematic diagram of the structure of an electronic device 10 according to an embodiment of the present invention is shown. The electronic device is 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 (such as 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.

[0072] like Figure 6 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 from storage unit 18 into the RAM 13. 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 input / output (I / O) interface 15 is also connected to the bus 14.

[0073] 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.

[0074] 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, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the method for determining phase infiltration curves based on in-line NMR.

[0075] In some embodiments, the method for determining the phase permeability curve based on online NMR can 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 can 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 method for determining the phase permeability curve based on online NMR described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the method for determining the phase permeability curve based on online NMR by any other suitable means (e.g., by means of firmware).

[0076] 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), system-on-a-chip (SoCs), complex 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.

[0077] Computer programs for implementing the online NMR-based phase permeation curve determination method of the present invention can be written in any combination of one or more programming languages. These computer programs can 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 functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer programs can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0078] 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.

[0079] 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).

[0080] 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.

[0081] 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.

[0082] Example 5 This invention also provides a computer program product, including a computer program that, when executed by a processor, implements the method for determining phase permeation curves based on online NMR as provided in any embodiment of this application.

[0083] In implementing the computer program product, computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof. Programming languages ​​include object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0084] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0085] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for determining phase permeation curves based on online NMR, characterized in that, include: Water-driven oil and oil-driven water experiments were conducted on the core samples to obtain the oil absolute permeability and water absolute permeability of the core samples. In each displacement cycle of the water-driven oil experiment, the water saturation of the core under test is determined based on the oil phase fluid nuclear magnetic resonance information of the core under test, and the water phase permeability of the core under test at the water saturation is determined based on the water phase displacement information of the core under test. In each displacement cycle of the oil-water flooding experiment, the water saturation of the core under test is determined based on the aqueous fluid nuclear magnetic resonance information of the core under test, and the oil phase permeability of the core under test at the water saturation is determined based on the oil phase displacement information of the core under test. Based on the oil absolute permeability, the water absolute permeability, and the water phase permeability and oil phase permeability corresponding to each water saturation, the target relative permeability curve of the core sample is determined.

2. The method according to claim 1, characterized in that, The core samples were subjected to water-driven oil flooding and oil-driven water flooding experiments to obtain the corresponding absolute oil permeability and absolute water permeability, including: A waterflooding experiment was conducted on the core sample, and the absolute oil permeability of the core sample was determined based on Darcy's law algorithm when the core sample reached oil phase fluid saturation. An oil-drive water experiment was conducted on the core sample, and when the core sample reached a state of aqueous fluid saturation, the absolute water permeability of the core sample was determined based on the Darcy's law algorithm.

3. The method according to claim 1, characterized in that, The determination of the water saturation corresponding to the core sample based on the oil phase fluid nuclear magnetic resonance information of the core sample includes: When the core sample reaches the state of oil phase fluid saturation, the first reference nuclear magnetic resonance spectrum of the oil phase fluid in the core sample is obtained; During each displacement cycle of the water-driven oil experiment, the first nuclear magnetic resonance spectrum of the oil phase fluid to be used is obtained; For each displacement cycle, determine the first area to be used formed by the first NMR spectrum to be used and the horizontal coordinate axis in the target coordinate system, and the first reference area formed by the first reference NMR spectrum and the horizontal coordinate axis. Based on the ratio of the first area to be used to the first reference area, the oil phase fluid saturation of the core under test during the displacement cycle is determined, and the oil phase fluid saturation is converted into the water saturation of the core under test.

4. The method according to claim 1, characterized in that, Determining the water phase permeability of the core sample at the specified water saturation level based on the water phase displacement information of the core sample includes: The aqueous phase displacement information of the core sample under test in each displacement cycle is obtained, and the aqueous phase permeability of the core sample under test at the water saturation corresponding to each displacement cycle is determined based on the aqueous phase displacement information.

5. The method according to claim 1, characterized in that, The determination of the water saturation corresponding to the core sample based on the aqueous fluid nuclear magnetic resonance information of the core sample includes: When the core sample reaches the state of aqueous fluid saturation, a second reference nuclear magnetic resonance spectrum of the aqueous fluid in the core sample is obtained; During each displacement cycle of the oil-water flooding experiment, a second nuclear magnetic resonance spectrum of the aqueous phase fluid is obtained for use. For each displacement cycle, determine the second area to be used formed by the second NMR spectrum to be used and the horizontal coordinate axis in the target coordinate system, and the second reference area formed by the second reference NMR spectrum and the horizontal coordinate axis. Based on the ratio of the second area to be used to the second reference area, the water saturation of the core sample to be tested during the displacement cycle is determined.

6. The method according to claim 1, characterized in that, Determining the oil phase permeability of the core sample at the specified water saturation based on the oil phase displacement information of the core sample includes: The oil phase displacement information of the injected fluid in the core under test during each displacement cycle is obtained, and the oil phase permeability of the core under test at the water saturation corresponding to each displacement cycle is determined based on the oil phase displacement information.

7. The method according to claim 1, characterized in that, The determination of the target relative permeability curve of the core sample based on the oil absolute permeability, the water absolute permeability, and the water phase permeability and oil phase permeability corresponding to each water saturation level includes: Within each displacement cycle, based on the ratio of the aqueous phase permeability to the absolute aqueous phase permeability, the relative water permeability of the core sample at the corresponding water saturation level for each displacement cycle is obtained; and Based on the ratio of the oil phase permeability to the absolute oil phase permeability, the relative oil permeability of the core under test at the water saturation corresponding to each displacement cycle is obtained. Based on the relative water permeability and relative oil permeability associated with the water saturation corresponding to all displacement cycles, the target relative permeability curve corresponding to the core sample is plotted.

8. A device for determining phase permeation curves based on online nuclear magnetic resonance, characterized in that, include: The absolute permeability determination module is used to perform water-driven oil experiments and oil-driven water experiments on the core sample to obtain the oil-measured absolute permeability and water-measured absolute permeability of the core sample. A water phase permeability determination module is used to determine the water saturation of the core under test based on the oil phase fluid nuclear magnetic resonance information of the core under test in each displacement cycle of the water flooding experiment, and to determine the water phase permeability of the core under test at the water saturation based on the water phase displacement information of the core under test. The oil phase permeability determination module is used to determine the water saturation of the core under test based on the aqueous fluid nuclear magnetic resonance information of the core under test in each displacement cycle of the oil-water flooding experiment, and to determine the oil phase permeability of the core under test at the water saturation based on the oil phase displacement information of the core under test. The target relative permeability curve determination module is used to determine the target relative permeability curve of the core sample based on the oil absolute permeability, the water absolute permeability, and the water phase permeability and oil phase permeability corresponding to each water saturation.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed 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 method for determining phase permeation curves based on online NMR as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause a processor to execute the method for determining phase permeation curves based on online NMR as described in any one of claims 1-7.

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