WO2024108689A1 - Method for determining reservoir porosity and/or reservoir permeability of graniphyric carbonate rock - Google Patents

Method for determining reservoir porosity and/or reservoir permeability of graniphyric carbonate rock Download PDF

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WO2024108689A1
WO2024108689A1 PCT/CN2022/138976 CN2022138976W WO2024108689A1 WO 2024108689 A1 WO2024108689 A1 WO 2024108689A1 CN 2022138976 W CN2022138976 W CN 2022138976W WO 2024108689 A1 WO2024108689 A1 WO 2024108689A1
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core sample
reservoir
target
piebald
carbonate
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PCT/CN2022/138976
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French (fr)
Chinese (zh)
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张文旗
刘达望
王宇宁
许家铖
邓亚
张磊夫
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中国石油天然气股份有限公司
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Publication of WO2024108689A1 publication Critical patent/WO2024108689A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]

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  • the invention belongs to the technical field of oil and gas field development, and in particular relates to a method for determining reservoir porosity and/or reservoir permeability of piebald carbonate rocks.
  • Speckled carbonate rocks usually show patches of white, dark gray and other colors (as shown in Figure 1). Speckled carbonate formations usually show complex porosity and permeability relationships in core sample testing and analysis (as shown in Figure 2). The microscopic pore structure of speckled carbonate rocks usually shows multimodality (as shown in Figure 3).
  • Marine speckled carbonate formations have similar appearance characteristics but different geological and production characteristics: some marine speckled carbonate formations show poor reservoirs with low production capacity in both logging and production; some marine speckled carbonate formations show tight reservoirs or non-reservoirs in logging, but show high-yield layers in production.
  • Reservoir porosity and permeability are important parameters for evaluating reservoir physical properties, calculating oil and gas reserves, and conducting reservoir engineering research. Reservoir porosity and permeability are usually determined by laboratory testing of reservoir core samples.
  • Reservoir porosity refers to the ratio of the pore space volume of the reservoir to its total volume, and is an inherent property of the reservoir. In order to reasonably evaluate the original oil and gas reserves of the reservoir, the pore space volume occupied by hydrocarbons and water in the reservoir should be understood.
  • Reservoir permeability is a measure of the reservoir's ability to allow fluid to pass through. By measuring the flow of fluid in a certain direction in the reservoir, the permeability of the reservoir in that direction can be obtained.
  • the volume flow rate i.e., volume flow rate
  • the gas measurement method is mainly used to measure the permeability of reservoir core samples. This method uses pressurized gas to establish a pressure difference at both ends of the core sample to be tested, measures the gas flow at the outlet of the core sample, and uses Darcy's formula to calculate the permeability of the rock.
  • the dark patches in the mottled carbonate formations are reservoirs, which develop between the white tubercle-like patches of non-reservoir layers.
  • the development width of the dark patch reservoir is mostly between 1-2 cm, while the diameter of the cylindrical core samples used in the laboratory to determine the porosity and permeability is usually 2.5 or 3.8 cm, which is larger than the development width of the dark patches.
  • the reservoir core samples drilled from the core samples include reservoirs (dark patches) and non-reservoir layers (white patches).
  • the object of the present invention is to provide a method capable of accurately evaluating the porosity and/or permeability of a dark patch reservoir in a mottled carbonate formation.
  • the present invention provides a method for determining reservoir porosity and/or reservoir permeability of a piebald carbonate rock, wherein the method comprises:
  • the porosity and/or permeability of the target piebald carbonate rock core sample is corrected to determine that the porosity and/or permeability of the reservoir in the target piebald carbonate rock core sample is the reservoir porosity and/or reservoir permeability of the target piebald carbonate rock.
  • the step of correcting the porosity of the target piebald carbonate core sample comprises:
  • the porosity of the target piebald carbonate rock core sample is corrected using the following formula:
  • ⁇ is the porosity of the reservoir in the target piebald carbonate core sample (i.e., the reservoir porosity of the target piebald carbonate); ⁇ 0 is the porosity of the target piebald carbonate core sample; and m is the volume proportion of the reservoir in the target piebald carbonate core sample.
  • the step of correcting the permeability of the target piebald carbonate rock core sample comprises:
  • the permeability of the target piebald carbonate rock core sample is corrected using the following formula:
  • k is the permeability of the reservoir in the target piebald carbonate core sample (i.e., the reservoir permeability of the target piebald carbonate); k0 is the permeability of the target piebald carbonate core sample (specifically, the permeability of the target piebald carbonate core sample in the axial direction of the core sample); A is the area ratio of the reservoir on the cross section (i.e., the cross section perpendicular to the axial direction of the core sample) in the target piebald carbonate core sample.
  • the step of obtaining the proportion of the reservoir in the target piebald carbonate rock core sample comprises:
  • Reservoir identification is performed on each cross-sectional CT scan image of the core sample using the reservoir grayscale threshold of the CT scan image, and the proportion of the reservoir in the core sample is determined based on the reservoir identification result.
  • the CT scan image is a grayscale image; further, the CT scan image is a grayscale image that has been subjected to noise reduction processing.
  • the step of obtaining a reservoir grayscale threshold of a CT scan image includes: obtaining a microscopic thin-section image of a certain cross-section of a core sample; and determining a reservoir grayscale threshold of the CT scan image based on the microscopic thin-section image of a certain cross-section of the core sample and the CT scan image of the cross-section of the core sample.
  • reservoir identification on the cross-sectional CT scan of the core sample includes:
  • the reservoir grayscale threshold of the CT scan image is used to determine whether each pixel point in the cross-sectional CT scan image of the core sample is a reservoir.
  • the step of obtaining CT scan images of different cross sections of the core sample includes: obtaining CT scan images of at least two cross sections of the core sample;
  • the step of determining the proportion of the reservoir in the core sample based on the reservoir identification result includes: based on the reservoir identification result of each cross-sectional CT scan image of the core sample, and then based on the area proportion of the reservoir on each cross-sectional area of the core sample, determining the volume proportion of the reservoir in the core sample, that is, the proportion of the reservoir in the core sample.
  • the step of obtaining the porosity of the target piebald carbonate rock core sample comprises:
  • the porosity of the target piebald carbonate rock core sample is determined based on the surface volume of the target piebald carbonate rock core sample and the rock skeleton volume of the target piebald carbonate rock core sample.
  • the permeability of the target piebald carbonate rock core sample is the permeability of the target piebald carbonate rock core sample measured by gas logging.
  • the technical solution provided by the present invention uses the proportion of the reservoir in the core sample to correct the porosity and/or permeability of the core sample, thereby accurately determining the porosity and/or reservoir permeability of the piebald carbonate reservoir.
  • the technical solution provided by the present invention fills the gap in the experimental test of the porosity and permeability of the piebald carbonate formation reservoir, and can more accurately determine the porosity and permeability of the piebald carbonate formation reservoir, laying the foundation for more accurate porosity-permeability relationship and permeability logging interpretation of the piebald carbonate formation, providing more objective porosity and permeability values for the reserve calculation of marine carbonate reservoirs, and laying the foundation for objectively evaluating the economic value of marine carbonate reservoirs and formulating development strategies.
  • Figure 1 is a core characteristic map of the piebald carbonate formation.
  • Figure 2 is a porosity and permeability characteristic diagram of the mottled carbonate formation.
  • Figure 3 is a characteristic diagram of the microscopic pore structure of the mottled carbonate formation.
  • FIG4 is a flow chart of a method for determining reservoir porosity and/or reservoir permeability of a mottled carbonate rock provided in one embodiment of the present invention.
  • FIG5 is a schematic diagram of the core thin section sample selection position and CT scanning cross-section position in Example 1 of the present invention.
  • Figure 6 shows the distribution characteristics of reservoirs (dark patches) and non-reservoir layers (white patches) in cores, thin section samples, and CT scan grayscale images.
  • FIG. 7 is a schematic diagram of a device for determining the volume of a rock skeleton using the gas expansion method.
  • FIG8 is a schematic diagram of a gas permeability measurement device.
  • FIG. 9 is a porosity-permeability relationship diagram of the piebald carbonate rock before porosity and permeability correction in Example 1.
  • FIG. 10 is a porosity-permeability relationship diagram of the piebald carbonate rock after porosity and permeability correction in Example 1.
  • the present invention provides a method for determining the porosity and/or reservoir permeability of a piebald carbonate reservoir. As shown in FIG4, in a specific embodiment of the present invention, the method for determining the porosity and/or reservoir permeability of a piebald carbonate reservoir includes:
  • Step S1 obtaining the porosity and/or permeability of a target piebald carbonate rock core sample
  • Step S2 obtaining the proportion of the reservoir in the target piebald carbonate rock core sample
  • Step S3 Based on the proportion of the reservoir in the target piebald carbonate rock core sample, the porosity and/or permeability of the target piebald carbonate rock core sample is corrected to determine that the porosity and/or permeability of the reservoir in the target piebald carbonate rock core sample is the reservoir porosity and/or reservoir permeability of the target piebald carbonate rock.
  • step S3 the step of correcting the porosity of the target piebald carbonate rock core sample based on the proportion of the reservoir in the target piebald carbonate rock core sample includes:
  • the porosity of the target piebald carbonate rock core sample is corrected using the following formula:
  • ⁇ is the porosity of the reservoir in the target piebald carbonate core sample (i.e., the reservoir porosity of the target piebald carbonate); ⁇ 0 is the porosity of the target piebald carbonate core sample; m is the volume percentage of the reservoir in the target piebald carbonate core sample;
  • Vf is the surface volume of the target mottled carbonate rock core sample
  • Vs is the rock skeleton volume of the target mottled carbonate rock core sample
  • Vp is the pore volume of the target mottled carbonate rock core sample.
  • step S3 the step of correcting the permeability of the target piebald carbonate core sample based on the proportion of the reservoir in the target piebald carbonate core sample includes:
  • the permeability of the target piebald carbonate rock core sample is corrected using the following formula:
  • k is the permeability of the reservoir in the target piebald carbonate core sample (i.e., the reservoir permeability of the target piebald carbonate); k0 is the permeability of the target piebald carbonate core sample (specifically, the permeability of the target piebald carbonate core sample in the axial direction of the core sample); A is the area ratio of the reservoir on the cross section (i.e., the cross section perpendicular to the axial direction of the core sample) in the target piebald carbonate core sample.
  • step S2 the step of obtaining the proportion of the reservoir in the target piebald carbonate rock core sample comprises:
  • Step S21 obtaining CT scan images of different cross sections of the core sample
  • Step S22 obtaining a reservoir grayscale threshold of the CT scan image
  • Step S23 using the reservoir grayscale threshold of the CT scan image, respectively perform reservoir identification on each cross-section CT scan image of the core sample, and determine the proportion of the reservoir in the core sample based on the reservoir identification result.
  • the acquired CT scan image is a grayscale image; in some specific embodiments, the acquired CT scan image is a grayscale image that has been subjected to noise reduction processing.
  • step S21 the step of obtaining CT scan images of different cross sections of the core sample includes: obtaining CT scan images of at least two cross sections of the core sample;
  • the step of determining the proportion of the reservoir in the core sample based on the reservoir identification result includes: determining the area proportion of the reservoir on each cross section of the core sample based on the reservoir identification result of each cross section CT scan image of the core sample, and then determining the volume proportion of the reservoir in the core sample based on the area proportion of the reservoir on each cross section of the core sample, that is, the proportion of the reservoir in the core sample; the volume proportion of the reservoir in the core sample is greater than 0 and less than or equal to 1, and the sum of the volume proportion of the non-reservoir in the core sample and the volume proportion of the reservoir in the core sample is 1;
  • the step of obtaining the proportion of the reservoir in the target piebald carbonate core sample includes: obtaining CT scan images of at least two cross sections of the core sample; obtaining the reservoir grayscale threshold of the CT scan image; using the reservoir grayscale threshold of the CT scan image to perform reservoir identification on each cross-sectional CT scan image of the core sample, and based on the reservoir identification results of the CT scan images of each cross-sectional area of the core sample, determine the area proportion of the reservoir on each cross section of the core sample, and then determine the volume proportion of the reservoir in the core sample, that is, the proportion of the reservoir in the core sample, based on the area proportion of the reservoir on each cross section of the core sample combined with the distance between adjacent cross sections in the core sample and the distance between the end face and the cross section adjacent to the end face.
  • step S2 the step of obtaining the reservoir grayscale threshold of the CT scan image includes:
  • a microscopic thin-section image of a certain cross section of a core sample is obtained, and the development of reservoirs and non-reservoir layers in the microscopic thin-section image is observed and determined, and the distribution range of reservoirs and non-reservoir layers is delineated; using the distribution range of reservoirs and non-reservoir layers delineated in the microscopic thin-section image, a CT scan image of the cross section of the core sample is calibrated to determine that the grayscale segmentation threshold of the reservoir and non-reservoir layers in the CT scan image is the reservoir grayscale threshold of the CT scan image;
  • step S2 performing reservoir identification on the cross-sectional CT scan of the core sample includes:
  • the grayscale value of each pixel point in the cross-sectional CT scan of the core sample is obtained; and the reservoir is separated for each pixel point of the CT scan based on the following formula:
  • g(i, j) is the value of the pixel at position (i, j); F(i, j) is the gray value of the pixel at position (i, j); T is the reservoir gray threshold of the CT scan image; i and j are the positions of the pixel in the x and y directions respectively; M and N are the number of pixels in the CT scan image in the x and y directions respectively; if the value of g(i, j) is 1, the pixel at position (i, j) is a reservoir, and if the value of g(i, j) is 0, the pixel at position (i, j) is a non-reservoir.
  • step S1 the step of obtaining the porosity of the target piebald carbonate rock core sample includes:
  • Step S11 obtaining the surface volume of the target piebald carbonate rock core sample
  • Step S12 obtaining the rock skeleton volume of the target piebald carbonate rock core sample
  • Step S13 determining the porosity of the target piebald carbonate rock core sample based on the surface volume of the target piebald carbonate rock core sample and the rock skeleton volume of the target piebald carbonate rock core sample;
  • step S12 the rock skeleton volume of the target piebald carbonate rock core sample is measured by a gas expansion method
  • a rock skeleton volume test device as shown in FIG7 is used to test the rock skeleton volume of a target mottled carbonate core sample; specifically, the device comprises a core chamber 1, a standard chamber 2 and a gas source 8 connected in sequence, a sample valve 5 is arranged on the connecting pipeline between the core chamber 1 and the standard chamber 2, a vent valve 6, a second pressure gauge 9, a gas supply valve 7, a pressure regulating valve 3 and a gas source valve 4 are arranged in sequence on the connecting pipeline between the standard chamber 2 and the gas source 8, and a first pressure gauge 10 is arranged on the core chamber 1; wherein, the volume of the core chamber 1 is V, and the remaining volume of the core chamber 1 after the core sample is placed is V-Vs, Vs is the rock skeleton volume of the core sample, and the pressure of the core chamber 1 is 0Pa; the volume of the standard chamber 2 is ⁇ V, the pressure in the standard chamber 2 is P2 (relative pressure), and the core chamber 1 and the standard chamber 2
  • the target piebald carbonate rock core sample is cylindrical, and the surface volume of the target piebald carbonate rock core sample is determined by the following formula:
  • Vf is the surface volume of the target mottled carbonate rock core sample
  • D is the diameter of the target mottled carbonate rock core sample
  • L is the length of the target mottled carbonate rock core sample.
  • the permeability of the target piebald carbonate rock core sample is the permeability of the target piebald carbonate rock core sample measured by gas logging method
  • a gas permeability test device as shown in FIG8 is used to test the permeability of a target mottled carbonate core sample; specifically, the device includes a core holder 13, a gas source 20 connected to an inlet 12 of the core holder 13, a gas source 25 connected to an annular pressure fluid inlet 32 of the core holder 13, an orifice flowmeter 19 connected to an outlet 14 of the core holder 13, a first pressure gauge 15, and a second pressure gauge 16, wherein the first pressure gauge 15 is connected to the inlet 12 of the core holder 13, and the second pressure gauge 16 ...
  • the connecting pipeline at the outlet 14 of the core holder 13 and the connecting pipeline at the inlet 12 of the core holder 13 are connected to test the pressure difference between the inlet 12 and the outlet 14 of the core holder 13.
  • the second pressure gauge 16 is respectively connected to the connecting pipeline at the outlet 14 of the core holder 13 and the connecting pipeline at the inlet 12 of the core holder 13 to test the pressure difference between the inlet 12 and the outlet 14 of the core holder 13; wherein the gas source 25 and the annular pressure fluid inlet of the core holder 13 are connected.
  • a valve 24 and a pressure gauge 22 are sequentially arranged on the connecting pipeline between the gas source 20 and the inlet 12 of the core holder 13, and a vent valve 21 and a vent valve 23 are arranged on the connecting pipeline between the gas source 20 and the inlet 12 of the core holder 13; wherein, a pressure regulating valve 26, a valve 27, a dryer 31, a pressure regulating valve 28, a valve 30, and a pressure gauge 11 are sequentially arranged on the connecting pipeline between the dryer 31 and the pressure regulating valve 28, and a valve 29 is arranged on the connecting pipeline; wherein, a third flowmeter 17 and a valve 18 are arranged on the connecting pipeline between the outlet 14 of the core holder 13 and the orifice flowmeter 19; when the permeability test of the target piebald carbonate core sample is performed, the target piebald carbonate core sample is placed in the core holder 13, a pressure difference is established between the inlet 12 and the outlet 14 of the core holder 13 by pressurized gas, the gas flow rate of the outlet 14 is measured, and the permeabil
  • k0 is the permeability of the target piebald carbonate core sample, ⁇ m2 ;
  • Q0 is the volume flow rate of the gas, cm3/s;
  • P0 is the atmospheric pressure, 10-1 Mpa;
  • ⁇ is the viscosity of the gas, mPa ⁇ s;
  • L is the length of the target piebald carbonate core sample, cm;
  • A0 is the cross-sectional area of the target piebald carbonate core sample, cm2;
  • Pin is the pressure at the inlet 12 of the core holder 13, 10-1 Mpa;
  • Pout is the pressure at the outlet 14 of the core holder 13, 10-1 Mpa.
  • This embodiment provides a method for determining reservoir porosity and reservoir permeability of a piebald carbonate rock.
  • the porosity and reservoir permeability of a piebald carbonate rock reservoir in region A are determined.
  • the method provided in this embodiment specifically includes:
  • Step 1 obtaining a piebald carbonate core in region A, sampling the piebald carbonate core in region A to obtain a piebald carbonate core sample in region A;
  • the core sample is cylindrical.
  • Step 2 Obtain the porosity and permeability of each core sample of the piebald carbonate rock
  • the permeability of each core sample is tested by using a gas permeability test device as shown in FIG8 , and the rock skeleton volume of each core sample is determined;
  • the porosity and permeability of each core sample determined are shown in FIG9 .
  • Step S3 Obtaining the area ratio of the reservoir on each cross section in each core sample and the volume ratio of the reservoir in each core sample;
  • the area proportion of the reservoir on each cross section in each core sample and the volume proportion of the reservoir in each core sample are determined by the following steps:
  • the core micro/nano CT scanning technology is used to perform CT scanning on six cross sections of the core sample (see Figure 5), and the scanned image is subjected to noise reduction processing to obtain a grayscale image, so as to obtain the CT scanning image of each cross section in the core sample;
  • a cross section of the core sample is sampled to prepare a thin section sample of the cross section, and the thin section sample is observed by a microscope to obtain a microscopic thin section image of the thin section sample, and the development of the reservoir and the non-reservoir in the microscopic thin section image is observed and determined, and the distribution range of the reservoir and the non-reservoir is delineated;
  • the CT scan image of the cross section of the core sample is calibrated using the distribution range of the reservoir and the non-reservoir delineated in the microscopic thin section image (as shown in FIG. 6 ) to determine that the grayscale segmentation threshold of the reservoir and the non-reservoir in the CT scan image is the reservoir grayscale threshold of the CT scan image;
  • Step S3 For each core sample, based on the volume proportion of the reservoir in the core sample, the porosity of the core sample is corrected using the following formula to determine that the porosity of the reservoir in the core sample is the reservoir porosity of the piebald carbonate rock in region A:
  • ⁇ is the porosity of the reservoir in the target mottled carbonate core sample
  • ⁇ 0 is the porosity of the target mottled carbonate core sample
  • m is the volume percentage of the reservoir in the target mottled carbonate core sample
  • the permeability of the core sample is corrected using the following formula to determine the permeability of the reservoir in the core sample, which is the reservoir permeability of the piebald carbonate rock in area A:
  • k is the permeability of the reservoir in the target mottled carbonate core sample
  • k0 is the permeability of the target mottled carbonate core sample
  • A is the area ratio of the reservoir on the cross section in the target mottled carbonate core sample.
  • the porosity and permeability of the reservoir in each core sample determined are shown in FIG10 .
  • the porosity-permeability relationship diagram established using the porosity and permeability correction data of the core samples measured in the laboratory shows a significantly improved porosity-permeability relationship compared to the porosity-permeability relationship diagram established using the porosity and permeability correction data of the core samples measured in the laboratory.
  • the reservoir porosity and reservoir permeability of the piebald carbonate rock determined by the method provided by the present invention can be better used for the porosity-permeability relationship interpretation, laying the foundation for the later reservoir permeability logging interpretation.

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Abstract

A method for determining the reservoir porosity and/or reservoir permeability of a graniphyric carbonate rock. The method comprises: acquiring the porosity and/or permeability of a core sample of a target graniphyric carbonate rock (S1); acquiring the ratio of a reservoir in the core sample of the target graniphyric carbonate rock (S2); and on the basis of the ratio of the reservoir in the core sample of the target graniphyric carbonate rock, correcting the porosity and/or permeability of the core sample of the target graniphyric carbonate rock, and determining the porosity and/or permeability of the reservoir in the core sample of the target graniphyric carbonate rock, that is, the reservoir porosity and/or reservoir permeability of the target graniphyric carbonate rock (S3). By means of the method for determining the reservoir porosity and/or reservoir permeability of a graniphyric carbonate rock, the porosity and/or permeability of a deep-color plaque reservoir in a graniphyric carbonate rock stratum can be accurately evaluated.

Description

一种花斑状碳酸盐岩的储层孔隙度和/或储层渗透率确定方法A method for determining reservoir porosity and/or reservoir permeability of piebald carbonate rock 技术领域Technical Field
本发明属于油气田开发技术领域，具体涉及一种花斑状碳酸盐岩的储层孔隙度和/或储层渗透率确定方法。The invention belongs to the technical field of oil and gas field development, and in particular relates to a method for determining reservoir porosity and/or reservoir permeability of piebald carbonate rocks.
背景技术Background technique
海相碳酸盐岩油气资源丰富，但海相碳酸盐岩地层非均质性极强，相当规模的海相碳酸盐岩地层呈现特殊的“花斑状”非均质特征。“花斑状”是依据岩石构造形态特征的形意定名的。花斑状碳酸盐岩通常表现出白色、深灰色等颜色的斑块(如图1所示)。花斑状碳酸盐岩地层在岩心样品测试分析方面通常表现出复杂的孔渗关系(如图2所示)。花斑状碳酸盐岩微观孔隙结构通常表现为多模态(如图3所示)。海相花斑状碳酸盐岩地层表象特征相似但地质及生产特征差异大：部分海相花斑状碳酸盐岩地层在测井和生产上均表现为低生产能力的差储层；部分海相花斑状碳酸盐岩地层在测井上表现为致密储层或非储层，但生产上却表现为高产层。Marine carbonate rocks are rich in oil and gas resources, but marine carbonate rock formations are extremely heterogeneous, and marine carbonate rock formations of considerable scale show special "speckled" heterogeneous characteristics. "Speckled" is named based on the shape and meaning of the rock structural morphology. Speckled carbonate rocks usually show patches of white, dark gray and other colors (as shown in Figure 1). Speckled carbonate formations usually show complex porosity and permeability relationships in core sample testing and analysis (as shown in Figure 2). The microscopic pore structure of speckled carbonate rocks usually shows multimodality (as shown in Figure 3). Marine speckled carbonate formations have similar appearance characteristics but different geological and production characteristics: some marine speckled carbonate formations show poor reservoirs with low production capacity in both logging and production; some marine speckled carbonate formations show tight reservoirs or non-reservoirs in logging, but show high-yield layers in production.
通过薄片镜下鉴定，花斑状碳酸盐岩的发育不受岩性控制，各类岩性皆有白色、深灰色斑块发育。镜下观察孔隙结构显示，白色斑块碳酸盐岩碎屑颗粒间孔隙不发育或发育孤立孔隙，孔隙位置被亮晶方解石胶结。深色斑块碳酸盐岩亮晶方解石胶结作用弱，碎屑颗粒间孔隙发育。实验室测定花斑状碳酸盐岩孔隙度、渗透率相关性极差，严重制约了油藏表征的精确性及合理开发方案的制定。Through thin section microscopic identification, the development of mottled carbonate rocks is not controlled by lithology, and all types of lithology have white and dark gray patches. Microscopic observation of pore structure shows that the pores between the clastic particles of white patch carbonate rocks are not developed or isolated pores are developed, and the pore positions are cemented by sparry calcite. The sparry calcite cementation of dark patch carbonate rocks is weak, and the pores between the clastic particles are developed. The laboratory determination of the porosity and permeability of mottled carbonate rocks has a very poor correlation, which seriously restricts the accuracy of reservoir characterization and the formulation of reasonable development plans.
储层孔隙度、渗透率是评价油藏储层物性、计算油气储量、油藏工程研究的重要参数。通常采用实验室测定储层岩心样品孔隙度、渗透率的方式确定储层的孔隙度、渗透率。Reservoir porosity and permeability are important parameters for evaluating reservoir physical properties, calculating oil and gas reserves, and conducting reservoir engineering research. Reservoir porosity and permeability are usually determined by laboratory testing of reservoir core samples.
储层孔隙度指储层的孔隙空间体积与其总体积之比，是储层的固有性质。为了合理地评价油藏原始油气储量，应了解油藏储层中碳氢化合物和水占据的孔隙空间体积。实验室孔隙度测定方法包括如下步骤：基于波义耳定律通过体积膨胀法测定岩心样品骨架体积Vs和岩心样品孔隙体积Vp，通过体积公式确定岩心样品外表体积V f，进而通过如下公式确定孔隙度：φ＝Vp÷(Vs+Vp)×100％＝(Vf-Vs)÷V f×100％。 Reservoir porosity refers to the ratio of the pore space volume of the reservoir to its total volume, and is an inherent property of the reservoir. In order to reasonably evaluate the original oil and gas reserves of the reservoir, the pore space volume occupied by hydrocarbons and water in the reservoir should be understood. The laboratory porosity determination method includes the following steps: based on Boyle's law, the core sample skeleton volume Vs and the core sample pore volume Vp are determined by the volume expansion method, and the core sample surface volume Vf is determined by the volume formula, and then the porosity is determined by the following formula: φ = Vp ÷ (Vs + Vp) × 100% = (Vf-Vs) ÷ Vf × 100%.
储层渗透率是储层允许流体通过能力的度量。通过测定流体在储层中某一方向上的流动就可得到储层在该方向的渗透率。根据达西定律，单位横截面积渗透性介质的体积流速(即体积流量)与势能梯度成正比、与流体的黏度成反比，其中涉及的比例系数即为渗透率。目前，主要采用气测法测定储层岩心样品渗透率，该方法通过加压气体在被 测岩心样品两端建立压差，测量岩心样品出口端的气体流量，并利用达西公式计算岩石的渗透率。Reservoir permeability is a measure of the reservoir's ability to allow fluid to pass through. By measuring the flow of fluid in a certain direction in the reservoir, the permeability of the reservoir in that direction can be obtained. According to Darcy's law, the volume flow rate (i.e., volume flow rate) of a permeable medium per unit cross-sectional area is proportional to the potential energy gradient and inversely proportional to the viscosity of the fluid, and the proportional coefficient involved is the permeability. At present, the gas measurement method is mainly used to measure the permeability of reservoir core samples. This method uses pressurized gas to establish a pressure difference at both ends of the core sample to be tested, measures the gas flow at the outlet of the core sample, and uses Darcy's formula to calculate the permeability of the rock.
花斑状碳酸盐岩地层中深色斑块为储层，发育在非储层的白色结核状斑块之间。通过薄片镜下鉴定，深色斑块储层发育宽度多为1-2cm之间，而实验室测定孔隙度、渗透率使用的圆柱状岩心样品的直径通常为2.5或3.8cm，大于深色斑块的发育宽度。从岩心样品中钻取的储层岩心样品包括储层(深色斑块)和非储层(白色斑块)。因此，利用热处理进行孔隙度、渗透率测定时没有消除白色非储层斑块的影响，这导致实验室测定的孔隙度、渗透率不能反应花斑状碳酸盐岩地层中储层(深色斑块)的真实孔隙度、渗透率。The dark patches in the mottled carbonate formations are reservoirs, which develop between the white tubercle-like patches of non-reservoir layers. Through thin-section microscopic identification, the development width of the dark patch reservoir is mostly between 1-2 cm, while the diameter of the cylindrical core samples used in the laboratory to determine the porosity and permeability is usually 2.5 or 3.8 cm, which is larger than the development width of the dark patches. The reservoir core samples drilled from the core samples include reservoirs (dark patches) and non-reservoir layers (white patches). Therefore, when using heat treatment to determine the porosity and permeability, the influence of the white non-reservoir patches is not eliminated, which results in the porosity and permeability determined in the laboratory not being able to reflect the true porosity and permeability of the reservoir (dark patches) in the mottled carbonate formations.
发明内容Summary of the invention
本发明的目的在于提供一种能够准确评价花斑状碳酸盐岩地层中深色斑块储层的孔隙度和/或渗透率的方法。The object of the present invention is to provide a method capable of accurately evaluating the porosity and/or permeability of a dark patch reservoir in a mottled carbonate formation.
为了实现上述目的，本发明提供了一种花斑状碳酸盐岩的储层孔隙度和/或储层渗透率确定方法，其中，该方法包括：In order to achieve the above object, the present invention provides a method for determining reservoir porosity and/or reservoir permeability of a piebald carbonate rock, wherein the method comprises:
获取目标花斑状碳酸盐岩岩心样品的孔隙度和/或渗透率；Obtaining the porosity and/or permeability of a target piebald carbonate core sample;
获取所述目标花斑状碳酸盐岩岩心样品中储层的占比；Obtaining the proportion of reservoir in the target piebald carbonate rock core sample;
基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的孔隙度和/或渗透率进行校正，确定所述目标花斑状碳酸盐岩岩心样品中储层的孔隙度和/或渗透率即为目标花斑状碳酸盐岩的储层孔隙度和/或储层渗透率。Based on the proportion of the reservoir in the target piebald carbonate rock core sample, the porosity and/or permeability of the target piebald carbonate rock core sample is corrected to determine that the porosity and/or permeability of the reservoir in the target piebald carbonate rock core sample is the reservoir porosity and/or reservoir permeability of the target piebald carbonate rock.
在一优选实施方式中，基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的孔隙度进行校正的步骤包括：In a preferred embodiment, based on the proportion of reservoirs in the target piebald carbonate core sample, the step of correcting the porosity of the target piebald carbonate core sample comprises:
基于所述目标花斑状碳酸盐岩岩心样品中储层的体积占比，利用如下公式对所述目标花斑状碳酸盐岩岩心样品的孔隙度进行校正：Based on the volume proportion of the reservoir in the target piebald carbonate rock core sample, the porosity of the target piebald carbonate rock core sample is corrected using the following formula:
Figure PCTCN2022138976-appb-000001
Figure PCTCN2022138976-appb-000001
式中，φ为目标花斑状碳酸盐岩岩心样品中储层的孔隙度(即目标花斑状碳酸盐岩的储层孔隙度)；φ 0为目标花斑状碳酸盐岩岩心样品的孔隙度；m为目标花斑状碳酸盐岩岩心样品中储层的体积占比。 Wherein, φ is the porosity of the reservoir in the target piebald carbonate core sample (i.e., the reservoir porosity of the target piebald carbonate); φ0 is the porosity of the target piebald carbonate core sample; and m is the volume proportion of the reservoir in the target piebald carbonate core sample.
在一优选实施方式中，基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的渗透率进行校正的步骤包括：In a preferred embodiment, based on the proportion of the reservoir in the target piebald carbonate rock core sample, the step of correcting the permeability of the target piebald carbonate rock core sample comprises:
基于所述目标花斑状碳酸盐岩岩心样品中横截面上储层的面积占比，利用如下公式 对所述目标花斑状碳酸盐岩岩心样品的渗透率进行校正：Based on the area ratio of the reservoir on the cross section of the target piebald carbonate rock core sample, the permeability of the target piebald carbonate rock core sample is corrected using the following formula:
Figure PCTCN2022138976-appb-000002
Figure PCTCN2022138976-appb-000002
式中，k为目标花斑状碳酸盐岩岩心样品中储层的渗透率(即目标花斑状碳酸盐岩的储层渗透率)；k 0为目标花斑状碳酸盐岩岩心样品的渗透率(具体为目标花斑状碳酸盐岩岩心样品在岩心样品轴向方向上的渗透率)；A为目标花斑状碳酸盐岩岩心样品中横截面(即为与岩心样品轴向方向垂直的截面)上储层的面积占比。 Wherein, k is the permeability of the reservoir in the target piebald carbonate core sample (i.e., the reservoir permeability of the target piebald carbonate); k0 is the permeability of the target piebald carbonate core sample (specifically, the permeability of the target piebald carbonate core sample in the axial direction of the core sample); A is the area ratio of the reservoir on the cross section (i.e., the cross section perpendicular to the axial direction of the core sample) in the target piebald carbonate core sample.
在一优选实施方式中，获取所述目标花斑状碳酸盐岩岩心样品中储层的占比的步骤包括：In a preferred embodiment, the step of obtaining the proportion of the reservoir in the target piebald carbonate rock core sample comprises:
获取所述岩心样品的不同截面CT扫描图；Obtaining CT scan images of different cross sections of the core sample;
获取CT扫描图的储层灰度阈值；Obtaining reservoir grayscale threshold of CT scan image;
利用CT扫描图的储层灰度阈值，分别对岩心样品的各截面CT扫描图进行储层识别，并基于储层识别结果确定所述岩心样品中储层的占比。Reservoir identification is performed on each cross-sectional CT scan image of the core sample using the reservoir grayscale threshold of the CT scan image, and the proportion of the reservoir in the core sample is determined based on the reservoir identification result.
进一步地，所述CT扫描图为灰度图；更进一步地，所述CT扫描图为经过降噪处理的灰度图。Furthermore, the CT scan image is a grayscale image; further, the CT scan image is a grayscale image that has been subjected to noise reduction processing.
进一步地，获取CT扫描图的储层灰度阈值的步骤包括：获取岩心样品某一截面的显微薄片图像；基于所述岩心样品某一截面的显微薄片图像与岩心样品该截面的CT扫描图，确定CT扫描图的储层灰度阈值。Furthermore, the step of obtaining a reservoir grayscale threshold of a CT scan image includes: obtaining a microscopic thin-section image of a certain cross-section of a core sample; and determining a reservoir grayscale threshold of the CT scan image based on the microscopic thin-section image of a certain cross-section of the core sample and the CT scan image of the cross-section of the core sample.
进一步地，对岩心样品的截面CT扫描图进行储层识别包括：Furthermore, reservoir identification on the cross-sectional CT scan of the core sample includes:
获取岩心样品的截面CT扫描图中各像素点的灰度值；Obtain the gray value of each pixel in the cross-sectional CT scan of the core sample;
利用CT扫描图的储层灰度阈值，判断岩心样品的截面CT扫描图中各像素点是否为储层。The reservoir grayscale threshold of the CT scan image is used to determine whether each pixel point in the cross-sectional CT scan image of the core sample is a reservoir.
进一步地，获取所述岩心样品的不同截面CT扫描图的步骤包括：获取所述岩心样品中至少两个横截面的CT扫描图；Further, the step of obtaining CT scan images of different cross sections of the core sample includes: obtaining CT scan images of at least two cross sections of the core sample;
更进一步地，各横截面的间距相同；Furthermore, the spacing between the cross sections is the same;
更进一步地，基于储层识别结果确定所述岩心样品中储层的占比的步骤包括：基于岩心样品的各横截面CT扫描图的储层识别结果，进而基于岩心样品各横截面上储层的面积占比确定岩心样品中储层的体积占比即岩心样品中储层的占比。Furthermore, the step of determining the proportion of the reservoir in the core sample based on the reservoir identification result includes: based on the reservoir identification result of each cross-sectional CT scan image of the core sample, and then based on the area proportion of the reservoir on each cross-sectional area of the core sample, determining the volume proportion of the reservoir in the core sample, that is, the proportion of the reservoir in the core sample.
在一优选实施方式中，获取目标花斑状碳酸盐岩岩心样品的孔隙度的步骤包括：In a preferred embodiment, the step of obtaining the porosity of the target piebald carbonate rock core sample comprises:
获取目标花斑状碳酸盐岩岩心样品的外表体积；Obtain the apparent volume of the target piebald carbonate core sample;
获取目标花斑状碳酸盐岩岩心样品的岩石骨架体积；Obtain the rock skeleton volume of the target piebald carbonate core sample;
基于目标花斑状碳酸盐岩岩心样品的外表体积和目标花斑状碳酸盐岩岩心样品的岩石骨架体积，确定目标花斑状碳酸盐岩岩心样品的孔隙度。The porosity of the target piebald carbonate rock core sample is determined based on the surface volume of the target piebald carbonate rock core sample and the rock skeleton volume of the target piebald carbonate rock core sample.
在一优选实施方式中，所述目标花斑状碳酸盐岩岩心样品的渗透率为气测法测定的目标花斑状碳酸盐岩岩心样品的渗透率。In a preferred embodiment, the permeability of the target piebald carbonate rock core sample is the permeability of the target piebald carbonate rock core sample measured by gas logging.
本发明提供的技术方案利用岩心样品中储层的占比对岩心样品的孔隙度和/或渗透率进行校正，从而准确的确定出花斑状碳酸盐岩储层的孔隙度和/或储层渗透率。本发明提供的技术方案填补了花斑状碳酸盐岩地层储层孔隙度、渗透率实验测试的空白，能够更准确的确定花斑状碳酸盐岩地层储层孔隙度、渗透率，为花斑状碳酸盐岩地层更高精度的孔渗关系、渗透率测井解释奠定了基础，为海相碳酸盐岩油藏的储量计算提供了更加客观的孔隙度、渗透率值，为客观评价海相碳酸盐岩油藏的经济价值以及制定开发策略奠定了基础。The technical solution provided by the present invention uses the proportion of the reservoir in the core sample to correct the porosity and/or permeability of the core sample, thereby accurately determining the porosity and/or reservoir permeability of the piebald carbonate reservoir. The technical solution provided by the present invention fills the gap in the experimental test of the porosity and permeability of the piebald carbonate formation reservoir, and can more accurately determine the porosity and permeability of the piebald carbonate formation reservoir, laying the foundation for more accurate porosity-permeability relationship and permeability logging interpretation of the piebald carbonate formation, providing more objective porosity and permeability values for the reserve calculation of marine carbonate reservoirs, and laying the foundation for objectively evaluating the economic value of marine carbonate reservoirs and formulating development strategies.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1为花斑状碳酸盐岩地层岩心特征图。Figure 1 is a core characteristic map of the piebald carbonate formation.
图2为花斑状碳酸盐岩地层孔渗特征图。Figure 2 is a porosity and permeability characteristic diagram of the mottled carbonate formation.
图3为花斑状碳酸盐岩地层微观孔隙结构特征图。Figure 3 is a characteristic diagram of the microscopic pore structure of the mottled carbonate formation.
图4为本发明一实施方式提供的花斑状碳酸盐岩的储层孔隙度和/或储层渗透率确定方法的流程图。FIG4 is a flow chart of a method for determining reservoir porosity and/or reservoir permeability of a mottled carbonate rock provided in one embodiment of the present invention.
图5为本发明实施例1中岩心薄片样品选取位置及CT扫描横截面位置示意图。FIG5 is a schematic diagram of the core thin section sample selection position and CT scanning cross-section position in Example 1 of the present invention.
图6为岩心、薄片样品、CT扫描灰度图像下储层(深色斑块)和非储层(白色斑块)的分布特征图。Figure 6 shows the distribution characteristics of reservoirs (dark patches) and non-reservoir layers (white patches) in cores, thin section samples, and CT scan grayscale images.
图7为气体膨胀法测定岩石骨架体积用装置示意图。FIG. 7 is a schematic diagram of a device for determining the volume of a rock skeleton using the gas expansion method.
图8为气测渗透率装置示意图。FIG8 is a schematic diagram of a gas permeability measurement device.
图9为实施例1中孔隙度、渗透率校正前花斑状碳酸盐岩的孔隙度-渗透率关系图。FIG. 9 is a porosity-permeability relationship diagram of the piebald carbonate rock before porosity and permeability correction in Example 1.
图10为实施例1中孔隙度、渗透率校正后花斑状碳酸盐岩的孔隙度-渗透率关系图。FIG. 10 is a porosity-permeability relationship diagram of the piebald carbonate rock after porosity and permeability correction in Example 1.
具体实施方式Detailed ways
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚完整的描述。显然，所描述的实施例是本发明的一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本发明的保护范围。In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.
花斑状碳酸盐岩地层中储层发育在非储层之间，储层发育宽度通常较窄小于实验室 测定孔隙度、渗透率使用的岩心样品的直径，这使得花斑状碳酸盐岩孔隙度、渗透率测试使用的岩心样品不仅发育储层还发育非储层，因此，测试得到的花斑状碳酸盐岩孔隙度、渗透率并不是花斑状碳酸盐岩中储层的真实孔隙度、渗透率。为了能够准确获得花斑状碳酸盐岩中储层的真实孔隙度、渗透率，本发明提供了一种花斑状碳酸盐岩储层的孔隙度和/或储层渗透率确定方法。如图4所示，在本发明一具体实施方式中，花斑状碳酸盐岩储层的孔隙度和/或储层渗透率确定方法包括：Reservoirs in the piebald carbonate formations are developed between non-reservoirs, and the width of reservoir development is usually narrower than the diameter of the core samples used in the laboratory to measure porosity and permeability. This makes the core samples used in the porosity and permeability tests of the piebald carbonate rocks develop not only reservoirs but also non-reservoirs. Therefore, the porosity and permeability of the piebald carbonate rocks obtained by the test are not the true porosity and permeability of the reservoirs in the piebald carbonate rocks. In order to accurately obtain the true porosity and permeability of the reservoirs in the piebald carbonate rocks, the present invention provides a method for determining the porosity and/or reservoir permeability of a piebald carbonate reservoir. As shown in FIG4, in a specific embodiment of the present invention, the method for determining the porosity and/or reservoir permeability of a piebald carbonate reservoir includes:
步骤S1：获取目标花斑状碳酸盐岩岩心样品的孔隙度和/或渗透率；Step S1: obtaining the porosity and/or permeability of a target piebald carbonate rock core sample;
步骤S2：获取所述目标花斑状碳酸盐岩岩心样品中储层的占比；Step S2: obtaining the proportion of the reservoir in the target piebald carbonate rock core sample;
步骤S3：基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的孔隙度和/或渗透率进行校正，确定所述目标花斑状碳酸盐岩岩心样品中储层的孔隙度和/或渗透率即为目标花斑状碳酸盐岩的储层孔隙度和/或储层渗透率。Step S3: Based on the proportion of the reservoir in the target piebald carbonate rock core sample, the porosity and/or permeability of the target piebald carbonate rock core sample is corrected to determine that the porosity and/or permeability of the reservoir in the target piebald carbonate rock core sample is the reservoir porosity and/or reservoir permeability of the target piebald carbonate rock.
进一步地，步骤S3中，基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的孔隙度进行校正的步骤包括：Furthermore, in step S3, the step of correcting the porosity of the target piebald carbonate rock core sample based on the proportion of the reservoir in the target piebald carbonate rock core sample includes:
基于所述目标花斑状碳酸盐岩岩心样品中储层的体积占比，利用如下公式对所述目标花斑状碳酸盐岩岩心样品的孔隙度进行校正：Based on the volume proportion of the reservoir in the target piebald carbonate rock core sample, the porosity of the target piebald carbonate rock core sample is corrected using the following formula:
Figure PCTCN2022138976-appb-000003
Figure PCTCN2022138976-appb-000003
式中，φ为目标花斑状碳酸盐岩岩心样品中储层的孔隙度(即目标花斑状碳酸盐岩的储层孔隙度)；φ 0为目标花斑状碳酸盐岩岩心样品的孔隙度；m为目标花斑状碳酸盐岩岩心样品中储层的体积占比； Wherein, φ is the porosity of the reservoir in the target piebald carbonate core sample (i.e., the reservoir porosity of the target piebald carbonate); φ0 is the porosity of the target piebald carbonate core sample; m is the volume percentage of the reservoir in the target piebald carbonate core sample;
在一些具体实施例中，
Figure PCTCN2022138976-appb-000004
V f为目标花斑状碳酸盐岩岩心样品的外表体积，V s为目标花斑状碳酸盐岩岩心样品的岩石骨架体积，V p为目标花斑状碳酸盐岩岩心样品的孔隙体积，由此，
Figure PCTCN2022138976-appb-000005
In some specific embodiments,
Figure PCTCN2022138976-appb-000004
Vf is the surface volume of the target mottled carbonate rock core sample, Vs is the rock skeleton volume of the target mottled carbonate rock core sample, and Vp is the pore volume of the target mottled carbonate rock core sample.
Figure PCTCN2022138976-appb-000005
进一步地，步骤S3中，基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的渗透率进行校正的步骤包括：Furthermore, in step S3, the step of correcting the permeability of the target piebald carbonate core sample based on the proportion of the reservoir in the target piebald carbonate core sample includes:
基于所述目标花斑状碳酸盐岩岩心样品中横截面上储层的面积占比，利用如下公式对所述目标花斑状碳酸盐岩岩心样品的渗透率进行校正：Based on the area ratio of the reservoir on the cross section of the target piebald carbonate rock core sample, the permeability of the target piebald carbonate rock core sample is corrected using the following formula:
Figure PCTCN2022138976-appb-000006
Figure PCTCN2022138976-appb-000006
式中，k为目标花斑状碳酸盐岩岩心样品中储层的渗透率(即目标花斑状碳酸盐岩 的储层渗透率)；k 0为目标花斑状碳酸盐岩岩心样品的渗透率(具体为目标花斑状碳酸盐岩岩心样品在岩心样品轴向方向上的渗透率)；A为目标花斑状碳酸盐岩岩心样品中横截面(即为与岩心样品轴向方向垂直的截面)上储层的面积占比。 Wherein, k is the permeability of the reservoir in the target piebald carbonate core sample (i.e., the reservoir permeability of the target piebald carbonate); k0 is the permeability of the target piebald carbonate core sample (specifically, the permeability of the target piebald carbonate core sample in the axial direction of the core sample); A is the area ratio of the reservoir on the cross section (i.e., the cross section perpendicular to the axial direction of the core sample) in the target piebald carbonate core sample.
进一步地，步骤S2中，获取所述目标花斑状碳酸盐岩岩心样品中储层的占比的步骤包括：Furthermore, in step S2, the step of obtaining the proportion of the reservoir in the target piebald carbonate rock core sample comprises:
步骤S21：获取所述岩心样品的不同截面CT扫描图；Step S21: obtaining CT scan images of different cross sections of the core sample;
步骤S22：获取CT扫描图的储层灰度阈值；Step S22: obtaining a reservoir grayscale threshold of the CT scan image;
步骤S23：利用CT扫描图的储层灰度阈值，分别对岩心样品的各截面CT扫描图进行储层识别，并基于储层识别结果确定所述岩心样品中储层的占比。Step S23: using the reservoir grayscale threshold of the CT scan image, respectively perform reservoir identification on each cross-section CT scan image of the core sample, and determine the proportion of the reservoir in the core sample based on the reservoir identification result.
进一步地，步骤S21中，获取得到的CT扫描图为灰度图；在一些具体实施例中，获取得到的CT扫描图为经过降噪处理的灰度图。Furthermore, in step S21, the acquired CT scan image is a grayscale image; in some specific embodiments, the acquired CT scan image is a grayscale image that has been subjected to noise reduction processing.
进一步地，步骤S21中，获取所述岩心样品的不同截面CT扫描图的步骤包括：获取所述岩心样品中至少两个横截面的CT扫描图；Further, in step S21, the step of obtaining CT scan images of different cross sections of the core sample includes: obtaining CT scan images of at least two cross sections of the core sample;
更进一步地，各横截面的间距相同；Furthermore, the spacing between the cross sections is the same;
更进一步地，步骤S23中，基于储层识别结果确定所述岩心样品中储层的占比的步骤包括：基于岩心样品的各横截面CT扫描图的储层识别结果，确定岩心样品各横截面上储层的面积占比，进而基于岩心样品各横截面上储层的面积占比确定岩心样品中储层的体积占比即岩心样品中储层的占比；岩心样品中储层的体积占比大于0小于等于1，岩心样品中非储层的体积占比与岩心样品中储层的体积占比之和为1；Furthermore, in step S23, the step of determining the proportion of the reservoir in the core sample based on the reservoir identification result includes: determining the area proportion of the reservoir on each cross section of the core sample based on the reservoir identification result of each cross section CT scan image of the core sample, and then determining the volume proportion of the reservoir in the core sample based on the area proportion of the reservoir on each cross section of the core sample, that is, the proportion of the reservoir in the core sample; the volume proportion of the reservoir in the core sample is greater than 0 and less than or equal to 1, and the sum of the volume proportion of the non-reservoir in the core sample and the volume proportion of the reservoir in the core sample is 1;
在一些具体实施例中，步骤S2中，获取所述目标花斑状碳酸盐岩岩心样品中储层的占比的步骤包括：获取所述岩心样品中至少两个横截面的CT扫描图；获取CT扫描图的储层灰度阈值；利用CT扫描图的储层灰度阈值，分别对岩心样品的各横截面CT扫描图进行储层识别，并基于岩心样品的各横截面CT扫描图的储层识别结果，确定岩心样品各横截面上储层的面积占比，进而基于岩心样品各横截面上储层的面积占比结合岩心样品中相邻横截面之间的距离以及端面及与端面相邻的横截面之间的距离确定岩心样品中储层的体积占比即岩心样品中储层的占比。In some specific embodiments, in step S2, the step of obtaining the proportion of the reservoir in the target piebald carbonate core sample includes: obtaining CT scan images of at least two cross sections of the core sample; obtaining the reservoir grayscale threshold of the CT scan image; using the reservoir grayscale threshold of the CT scan image to perform reservoir identification on each cross-sectional CT scan image of the core sample, and based on the reservoir identification results of the CT scan images of each cross-sectional area of the core sample, determine the area proportion of the reservoir on each cross section of the core sample, and then determine the volume proportion of the reservoir in the core sample, that is, the proportion of the reservoir in the core sample, based on the area proportion of the reservoir on each cross section of the core sample combined with the distance between adjacent cross sections in the core sample and the distance between the end face and the cross section adjacent to the end face.
进一步地，步骤S2中，获取CT扫描图的储层灰度阈值的步骤包括：Furthermore, in step S2, the step of obtaining the reservoir grayscale threshold of the CT scan image includes:
获取岩心样品某一截面的显微薄片图像；Obtain a microscopic thin-section image of a certain cross section of the core sample;
基于所述岩心样品某一截面的显微薄片图像与岩心样品该截面的CT扫描图，确定CT扫描图的储层灰度阈值；Determining a reservoir grayscale threshold of the CT scan image based on a microscopic thin-section image of a certain cross section of the core sample and a CT scan image of the cross section of the core sample;
在一些具体实施例中，获取岩心样品某一截面的显微薄片图像，观察确定显微薄片 图像中储层和非储层的发育情况并圈定储层和非储层分布范围；利用显微薄片图像中圈定的储层和非储层分布范围，标定岩心样品该截面的CT扫描图确定该CT扫描图中储层和非储层的灰度分割阈值即为CT扫描图的储层灰度阈值；In some specific embodiments, a microscopic thin-section image of a certain cross section of a core sample is obtained, and the development of reservoirs and non-reservoir layers in the microscopic thin-section image is observed and determined, and the distribution range of reservoirs and non-reservoir layers is delineated; using the distribution range of reservoirs and non-reservoir layers delineated in the microscopic thin-section image, a CT scan image of the cross section of the core sample is calibrated to determine that the grayscale segmentation threshold of the reservoir and non-reservoir layers in the CT scan image is the reservoir grayscale threshold of the CT scan image;
在CT扫描图的灰度图像中，颜色越暗的区域密度越低，颜色越亮的区域密度越大、越致密。In the grayscale image of the CT scan, the darker the area, the lower the density, and the brighter the area, the greater the density and the denser it is.
进一步地，步骤S2中，对岩心样品的截面CT扫描图进行储层识别包括：Further, in step S2, performing reservoir identification on the cross-sectional CT scan of the core sample includes:
获取岩心样品的截面CT扫描图中各像素点的灰度值；利用CT扫描图的储层灰度阈值，判断岩心样品的截面CT扫描图中各像素点是否为储层；Obtain the gray value of each pixel point in the cross-sectional CT scan image of the core sample; use the reservoir gray threshold of the CT scan image to determine whether each pixel point in the cross-sectional CT scan image of the core sample is a reservoir;
在一些具体实施例中，获取岩心样品的截面CT扫描图中各像素点的灰度值；基于如下公式对该CT扫描图各像素点进行储层分隔：In some specific embodiments, the grayscale value of each pixel point in the cross-sectional CT scan of the core sample is obtained; and the reservoir is separated for each pixel point of the CT scan based on the following formula:
Figure PCTCN2022138976-appb-000007
Figure PCTCN2022138976-appb-000007
式中，g(i，j)为位置为(i，j)的像素点的值；F(i，j)为位置为(i，j)的像素点的灰度值；T为CT扫描图的储层灰度阈值；i、j分别为像素点对应x、y方向的位置；M、N分别为CT扫描图在x、y方向的像素点数；g(i，j)的值为1则位置为(i，j)的像素点为储层，g(i，j)的值为0则位置为(i，j)的像素点为非储层。Wherein, g(i, j) is the value of the pixel at position (i, j); F(i, j) is the gray value of the pixel at position (i, j); T is the reservoir gray threshold of the CT scan image; i and j are the positions of the pixel in the x and y directions respectively; M and N are the number of pixels in the CT scan image in the x and y directions respectively; if the value of g(i, j) is 1, the pixel at position (i, j) is a reservoir, and if the value of g(i, j) is 0, the pixel at position (i, j) is a non-reservoir.
进一步地，步骤S1中，获取目标花斑状碳酸盐岩岩心样品的孔隙度的步骤包括：Furthermore, in step S1, the step of obtaining the porosity of the target piebald carbonate rock core sample includes:
步骤S11：获取目标花斑状碳酸盐岩岩心样品的外表体积；Step S11: obtaining the surface volume of the target piebald carbonate rock core sample;
步骤S12：获取目标花斑状碳酸盐岩岩心样品的岩石骨架体积；Step S12: obtaining the rock skeleton volume of the target piebald carbonate rock core sample;
步骤S13：基于目标花斑状碳酸盐岩岩心样品的外表体积和目标花斑状碳酸盐岩岩心样品的岩石骨架体积，确定目标花斑状碳酸盐岩岩心样品的孔隙度；Step S13: determining the porosity of the target piebald carbonate rock core sample based on the surface volume of the target piebald carbonate rock core sample and the rock skeleton volume of the target piebald carbonate rock core sample;
更进一步地，步骤S12中，目标花斑状碳酸盐岩岩心样品的岩石骨架体积通过气体膨胀法测得；Furthermore, in step S12, the rock skeleton volume of the target piebald carbonate rock core sample is measured by a gas expansion method;
在一些具体实施例中，采用如图7所示的岩石骨架体积测试装置进行目标花斑状碳酸盐岩岩心样品的岩石骨架体积测试；具体而言，该装置包括依次连接的岩心室1、标准室2和气源8，岩心室1与标准室2之间的连接管路上设置样品阀5，标准室2与气源8之间的连接管路上依次设置放空阀6、第二压力表9、供气阀7、调压阀3和气源阀4，岩心室1设置第一压力表10；其中，岩心室1的容积为V，放入岩心样品后岩心室1剩余容积为V-Vs，Vs为岩心样品的岩石骨架体积，岩心室1压力为0Pa；标准室2容积为ΔV，标准室2内压力为P 2(相对压力)，岩心室1与标准室2之间用样品阀5隔开；打开样品阀5，使标准室2与岩心室1中的压力趋于一致，最终压力平衡于P 1(相 对压力)，整个过程为等温过程，由波义耳定律可得：
Figure PCTCN2022138976-appb-000008
In some specific embodiments, a rock skeleton volume test device as shown in FIG7 is used to test the rock skeleton volume of a target mottled carbonate core sample; specifically, the device comprises a core chamber 1, a standard chamber 2 and a gas source 8 connected in sequence, a sample valve 5 is arranged on the connecting pipeline between the core chamber 1 and the standard chamber 2, a vent valve 6, a second pressure gauge 9, a gas supply valve 7, a pressure regulating valve 3 and a gas source valve 4 are arranged in sequence on the connecting pipeline between the standard chamber 2 and the gas source 8, and a first pressure gauge 10 is arranged on the core chamber 1; wherein, the volume of the core chamber 1 is V, and the remaining volume of the core chamber 1 after the core sample is placed is V-Vs, Vs is the rock skeleton volume of the core sample, and the pressure of the core chamber 1 is 0Pa; the volume of the standard chamber 2 is ΔV, the pressure in the standard chamber 2 is P2 (relative pressure), and the core chamber 1 and the standard chamber 2 are separated by a sample valve 5; the sample valve 5 is opened to make the pressure in the standard chamber 2 and the core chamber 1 tend to be consistent, and the final pressure balance is P1 (relative pressure), the whole process is an isothermal process, and Boyle's law can be obtained:
Figure PCTCN2022138976-appb-000008
在一些具体实施例中，目标花斑状碳酸盐岩岩心样品为圆柱状，目标花斑状碳酸盐岩岩心样品的外表体积通过下述公式确定的到：In some specific embodiments, the target piebald carbonate rock core sample is cylindrical, and the surface volume of the target piebald carbonate rock core sample is determined by the following formula:
Figure PCTCN2022138976-appb-000009
Figure PCTCN2022138976-appb-000009
式中，V f为目标花斑状碳酸盐岩岩心样品的外表体积；D为目标花斑状碳酸盐岩岩心样品的直径；L为目标花斑状碳酸盐岩岩心样品的长度。 Wherein, Vf is the surface volume of the target mottled carbonate rock core sample; D is the diameter of the target mottled carbonate rock core sample; L is the length of the target mottled carbonate rock core sample.
进一步地，目标花斑状碳酸盐岩岩心样品的渗透率为气测法测定的目标花斑状碳酸盐岩岩心样品的渗透率；Further, the permeability of the target piebald carbonate rock core sample is the permeability of the target piebald carbonate rock core sample measured by gas logging method;
在一些具体实施例中，采用如图8所示的气测渗透率装置进行目标花斑状碳酸盐岩岩心样品的渗透率测试；具体而言，该装置包括岩心夹持器13、与岩心夹持器13的入口12连接的气源20、与岩心夹持器13的环压流体入口32连接的气源25、与岩心夹持器13的出口14连接的孔板流量计19、第一压力计15、第二压力及16，第一压力计15分别与岩心夹持器13的出口14处的连接管路、岩心夹持器13的入口12处的连接管路连接用于测试岩心夹持器13的入口12与出口14的压力差，第二压力计16分别与岩心夹持器13的出口14处的连接管路、岩心夹持器13的入口12处的连接管路连接用于测试岩心夹持器13的入口12与出口14的压力差；其中，气源25与岩心夹持器13的环压流体入口32之间的连接管路上依次设置有阀门24、压力表22，压力表22的连接管路上设置放空阀21、放空阀23；其中，气源20与岩心夹持器13的入口12之间的连接管路上依次设置有压力调节阀26、阀门27、干燥器31、压力调节阀28、阀门30、压力表11，压力表11还与干燥器31和压力调节阀28之间的连接管路连接且连接管路上设置有阀门29；其中，岩心夹持器13的出口14与孔板流量计19之间的连接管路上设置有第三流量计17、阀门18；进行目标花斑状碳酸盐岩岩心样品的渗透率测试时，将目标花斑状碳酸盐岩岩心样品放入岩心夹持器13中，通过加压气体在岩心夹持器13的入口12和出口14之间建立压差，测量出口14的气体流量，并利用达西公式确定岩心样品的渗透率：In some specific embodiments, a gas permeability test device as shown in FIG8 is used to test the permeability of a target mottled carbonate core sample; specifically, the device includes a core holder 13, a gas source 20 connected to an inlet 12 of the core holder 13, a gas source 25 connected to an annular pressure fluid inlet 32 of the core holder 13, an orifice flowmeter 19 connected to an outlet 14 of the core holder 13, a first pressure gauge 15, and a second pressure gauge 16, wherein the first pressure gauge 15 is connected to the inlet 12 of the core holder 13, and the second pressure gauge 16 ... The connecting pipeline at the outlet 14 of the core holder 13 and the connecting pipeline at the inlet 12 of the core holder 13 are connected to test the pressure difference between the inlet 12 and the outlet 14 of the core holder 13. The second pressure gauge 16 is respectively connected to the connecting pipeline at the outlet 14 of the core holder 13 and the connecting pipeline at the inlet 12 of the core holder 13 to test the pressure difference between the inlet 12 and the outlet 14 of the core holder 13; wherein the gas source 25 and the annular pressure fluid inlet of the core holder 13 are connected. A valve 24 and a pressure gauge 22 are sequentially arranged on the connecting pipeline between the gas source 20 and the inlet 12 of the core holder 13, and a vent valve 21 and a vent valve 23 are arranged on the connecting pipeline between the gas source 20 and the inlet 12 of the core holder 13; wherein, a pressure regulating valve 26, a valve 27, a dryer 31, a pressure regulating valve 28, a valve 30, and a pressure gauge 11 are sequentially arranged on the connecting pipeline between the dryer 31 and the pressure regulating valve 28, and a valve 29 is arranged on the connecting pipeline; wherein, a third flowmeter 17 and a valve 18 are arranged on the connecting pipeline between the outlet 14 of the core holder 13 and the orifice flowmeter 19; when the permeability test of the target piebald carbonate core sample is performed, the target piebald carbonate core sample is placed in the core holder 13, a pressure difference is established between the inlet 12 and the outlet 14 of the core holder 13 by pressurized gas, the gas flow rate of the outlet 14 is measured, and the permeability of the core sample is determined by using the Darcy formula:
Figure PCTCN2022138976-appb-000010
Figure PCTCN2022138976-appb-000010
式中，k 0为目标花斑状碳酸盐岩岩心样品的渗透率，μm 2；Q 0为气体的体积流量，cm3/s；P 0为大气压力，10 -1Mpa；μ为气体的粘度，mPa·s；L为目标花斑状碳酸盐岩岩心样品的长度，cm；A 0为目标花斑状碳酸盐岩岩心样品的横截面积，cm2；P in为岩心 夹持器13的入口12处的压力，10 -1Mpa；P out为岩心夹持器13的出口14处的压力，10 -1Mpa。 Wherein, k0 is the permeability of the target piebald carbonate core sample, μm2 ; Q0 is the volume flow rate of the gas, cm3/s; P0 is the atmospheric pressure, 10-1 Mpa; μ is the viscosity of the gas, mPa·s; L is the length of the target piebald carbonate core sample, cm; A0 is the cross-sectional area of the target piebald carbonate core sample, cm2; Pin is the pressure at the inlet 12 of the core holder 13, 10-1 Mpa; Pout is the pressure at the outlet 14 of the core holder 13, 10-1 Mpa.
实施例1Example 1
本实施例提供一种花斑状碳酸盐岩的储层孔隙度和储层渗透率确定方法，对A地区的花斑状碳酸盐岩储层孔隙度、储层渗透率进行确定，本实施例提供的方法具体包括：This embodiment provides a method for determining reservoir porosity and reservoir permeability of a piebald carbonate rock. The porosity and reservoir permeability of a piebald carbonate rock reservoir in region A are determined. The method provided in this embodiment specifically includes:
步骤1：获取A地区的花斑状碳酸盐岩岩心，自A地区的花斑状碳酸盐岩岩心中进行取样制备得到A地区的花斑状碳酸盐岩岩心样品；Step 1: obtaining a piebald carbonate core in region A, sampling the piebald carbonate core in region A to obtain a piebald carbonate core sample in region A;
其中，岩心样品为圆柱状。Among them, the core sample is cylindrical.
步骤2：获取花斑状碳酸盐岩各岩心样品的孔隙度、渗透率；Step 2: Obtain the porosity and permeability of each core sample of the piebald carbonate rock;
具体而言，通过
Figure PCTCN2022138976-appb-000011
确定各岩心样品的外表体积，其中，V f为岩心样品的外表体积，D为岩心样品的直径，L为岩心样品的长度；采用如图7所示的岩石骨架体积测试装置使用气体膨胀法对各岩心样品的岩石骨架体积进行测试，确定出各岩心样品的岩石骨架体积；基于岩心样品的外表体积和岩心样品的岩石骨架体积，通过
Figure PCTCN2022138976-appb-000012
确定目标花斑状碳酸盐岩岩心样品的孔隙度，其中，V f为岩心样品的外表体积，V s为岩心样品的岩石骨架体积，V p为岩心样品的孔隙体积； Specifically, through
Figure PCTCN2022138976-appb-000011
Determine the surface volume of each core sample, where Vf is the surface volume of the core sample, D is the diameter of the core sample, and L is the length of the core sample; use the rock skeleton volume testing device shown in Figure 7 to test the rock skeleton volume of each core sample using the gas expansion method to determine the rock skeleton volume of each core sample; based on the surface volume of the core sample and the rock skeleton volume of the core sample,
Figure PCTCN2022138976-appb-000012
Determine the porosity of the target piebald carbonate rock core sample, where Vf is the surface volume of the core sample, Vs is the rock skeleton volume of the core sample, and Vp is the pore volume of the core sample;
采用如图8所示的气测渗透率装置使用气测法对各岩心样品的渗透率进行测试，确定出各岩心样品的岩石骨架体积；The permeability of each core sample is tested by using a gas permeability test device as shown in FIG8 , and the rock skeleton volume of each core sample is determined;
确定得到的各岩心样品的孔隙度、渗透率参见图9。The porosity and permeability of each core sample determined are shown in FIG9 .
步骤S3：获取各岩心样品中各横截面上储层的面积占比和各岩心样品中储层的体积占比；Step S3: Obtaining the area ratio of the reservoir on each cross section in each core sample and the volume ratio of the reservoir in each core sample;
具体而言，分别通过如下步骤确定各岩心样品中各横截面上储层的面积占比和各岩心样品中储层的体积占比：Specifically, the area proportion of the reservoir on each cross section in each core sample and the volume proportion of the reservoir in each core sample are determined by the following steps:
利用岩心微/纳米CT扫描技术对岩心样品的6个横截面(参见图5)进行CT扫描，并对扫描得到的图像进行降噪处理得到灰度图，实现岩心样品中各横截面的CT扫描图获取；The core micro/nano CT scanning technology is used to perform CT scanning on six cross sections of the core sample (see Figure 5), and the scanned image is subjected to noise reduction processing to obtain a grayscale image, so as to obtain the CT scanning image of each cross section in the core sample;
针对岩心样品一截面进行取样，制备该截面的薄片样品，利用显微镜对该薄片样品进行纤维观察并获取该薄片样品的显微薄片图像，观察确定显微薄片图像中储层和非储层的发育情况并圈定储层和非储层分布范围；利用显微薄片图像中圈定的储层和非储层分布范围，标定岩心样品该截面的CT扫描图(如图6所示)确定该CT扫描图中储层 和非储层的灰度分割阈值即为CT扫描图的储层灰度阈值；A cross section of the core sample is sampled to prepare a thin section sample of the cross section, and the thin section sample is observed by a microscope to obtain a microscopic thin section image of the thin section sample, and the development of the reservoir and the non-reservoir in the microscopic thin section image is observed and determined, and the distribution range of the reservoir and the non-reservoir is delineated; the CT scan image of the cross section of the core sample is calibrated using the distribution range of the reservoir and the non-reservoir delineated in the microscopic thin section image (as shown in FIG. 6 ) to determine that the grayscale segmentation threshold of the reservoir and the non-reservoir in the CT scan image is the reservoir grayscale threshold of the CT scan image;
获取岩心样品各截面的CT扫描图中各像素点的灰度值；基于
Figure PCTCN2022138976-appb-000013
对该CT扫描图各像素点进行储层分隔，g(i，j)为位置为(i，j)的像素点的值，F(i，j)为位置为(i，j)的像素点的灰度值，T为CT扫描图的储层灰度阈值，i、j分别为像素点对应x、y方向的位置，M、N分别为CT扫描图在x、y方向的像素点数；其中，g(i，j)的值为1则位置为(i，j)的像素点为储层，g(i，j)的值为0则位置为(i，j)的像素点为非储层；基于岩心样品的各横截面CT扫描图的储层识别结果，确定岩心样品各横截面上储层的面积占比，进而基于岩心样品各横截面上储层的面积占比结合岩心样品中相邻横截面之间的距离确定岩心样品中储层的；其中，岩心样品中储层的体积占比通过下述公式计算得到：
Figure PCTCN2022138976-appb-000014
A i为岩心样品第i个横截面上储层的面积占比分比，m为目标花斑状碳酸盐岩岩心样品中储层的体积占比，L i为岩心样品第i个横截面与第i+1个横截面之间的距离； Obtain the gray value of each pixel in the CT scan image of each cross section of the core sample; based on
Figure PCTCN2022138976-appb-000013
Reservoir separation is performed on each pixel point of the CT scan image, g(i, j) is the value of the pixel point at position (i, j), F(i, j) is the gray value of the pixel point at position (i, j), T is the reservoir gray threshold of the CT scan image, i and j are the positions of the pixel point in the x and y directions respectively, and M and N are the number of pixels in the CT scan image in the x and y directions respectively; wherein, if the value of g(i, j) is 1, the pixel point at position (i, j) is a reservoir, and if the value of g(i, j) is 0, the pixel point at position (i, j) is a non-reservoir; based on the reservoir identification results of the CT scan images of each cross section of the core sample, the area proportion of the reservoir on each cross section of the core sample is determined, and then the reservoir in the core sample is determined based on the area proportion of the reservoir on each cross section of the core sample combined with the distance between adjacent cross sections in the core sample; wherein the volume proportion of the reservoir in the core sample is calculated by the following formula:
Figure PCTCN2022138976-appb-000014
A i is the area ratio of the reservoir on the i-th cross section of the core sample, m is the volume ratio of the reservoir in the target piebald carbonate core sample, and L i is the distance between the i-th cross section and the i+1-th cross section of the core sample;
步骤S3：针对各岩心样品，分别基于岩心样品中储层的体积占比，利用如下公式对岩心样品的孔隙度进行校正，确定岩心样品中储层的孔隙度即为A地区的花斑状碳酸盐岩的储层孔隙度：Step S3: For each core sample, based on the volume proportion of the reservoir in the core sample, the porosity of the core sample is corrected using the following formula to determine that the porosity of the reservoir in the core sample is the reservoir porosity of the piebald carbonate rock in region A:
Figure PCTCN2022138976-appb-000015
Figure PCTCN2022138976-appb-000015
式中，φ为目标花斑状碳酸盐岩岩心样品中储层的孔隙度；φ 0为目标花斑状碳酸盐岩岩心样品的孔隙度；m为目标花斑状碳酸盐岩岩心样品中储层的体积占比； Wherein, φ is the porosity of the reservoir in the target mottled carbonate core sample; φ0 is the porosity of the target mottled carbonate core sample; m is the volume percentage of the reservoir in the target mottled carbonate core sample;
针对各岩心样品，分别基于岩心样品中横截面上储层的面积占比，利用如下公式对岩心样品的渗透率进行校正，确定岩心样品中储层的渗透率即为A地区的花斑状碳酸盐岩的储层渗透率：For each core sample, based on the area ratio of the reservoir on the cross section of the core sample, the permeability of the core sample is corrected using the following formula to determine the permeability of the reservoir in the core sample, which is the reservoir permeability of the piebald carbonate rock in area A:
Figure PCTCN2022138976-appb-000016
Figure PCTCN2022138976-appb-000016
式中，k为目标花斑状碳酸盐岩岩心样品中储层的渗透率；k 0为目标花斑状碳酸盐岩岩心样品的渗透率；A为目标花斑状碳酸盐岩岩心样品中横截面上储层的面积占比。 Wherein, k is the permeability of the reservoir in the target mottled carbonate core sample; k0 is the permeability of the target mottled carbonate core sample; A is the area ratio of the reservoir on the cross section in the target mottled carbonate core sample.
确定得到的各岩心样品中储层的孔隙度、渗透率参见图10。The porosity and permeability of the reservoir in each core sample determined are shown in FIG10 .
由图9、图10可以看出，利用实验室测定的岩心样品孔隙度、渗透率校正后的数据 建立的孔隙度-渗透率关系图相较于利用实验室测定的岩心样品孔隙度、渗透率校正前的数据建立的孔隙度-渗透率关系图，孔隙度-渗透率关系明显改善，由此可知，利用本发明提供的方法确定的花斑状碳酸盐岩的储层孔隙度和储层渗透率能够更好的用于孔隙度-渗透率关系解释，为后期储层渗透率测井解释奠定基础。As can be seen from Figures 9 and 10, the porosity-permeability relationship diagram established using the porosity and permeability correction data of the core samples measured in the laboratory shows a significantly improved porosity-permeability relationship compared to the porosity-permeability relationship diagram established using the porosity and permeability correction data of the core samples measured in the laboratory. It can be seen that the reservoir porosity and reservoir permeability of the piebald carbonate rock determined by the method provided by the present invention can be better used for the porosity-permeability relationship interpretation, laying the foundation for the later reservoir permeability logging interpretation.

Claims (10)

  1. 一种花斑状碳酸盐岩的储层孔隙度和/或储层渗透率确定方法，其中，该方法包括：A method for determining reservoir porosity and/or reservoir permeability of a piebald carbonate rock, wherein the method comprises:
    获取目标花斑状碳酸盐岩岩心样品的孔隙度和/或渗透率；Obtaining the porosity and/or permeability of a target piebald carbonate core sample;
    获取所述目标花斑状碳酸盐岩岩心样品中储层的占比；Obtaining the proportion of reservoir in the target piebald carbonate rock core sample;
    基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的孔隙度和/或渗透率进行校正，确定所述目标花斑状碳酸盐岩岩心样品中储层的孔隙度和/或渗透率即为目标花斑状碳酸盐岩的储层孔隙度和/或储层渗透率。Based on the proportion of the reservoir in the target piebald carbonate rock core sample, the porosity and/or permeability of the target piebald carbonate rock core sample is corrected to determine that the porosity and/or permeability of the reservoir in the target piebald carbonate rock core sample is the reservoir porosity and/or reservoir permeability of the target piebald carbonate rock.
  2. 根据权利要求1所述的方法，其中，基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的孔隙度进行校正的步骤包括：The method according to claim 1, wherein the step of correcting the porosity of the target piebald carbonate core sample based on the proportion of the reservoir in the target piebald carbonate core sample comprises:
    基于所述目标花斑状碳酸盐岩岩心样品中储层的体积占比，利用如下公式对所述目标花斑状碳酸盐岩岩心样品的孔隙度进行校正：Based on the volume proportion of the reservoir in the target piebald carbonate rock core sample, the porosity of the target piebald carbonate rock core sample is corrected using the following formula:
    Figure PCTCN2022138976-appb-100001
    Figure PCTCN2022138976-appb-100001
    式中，φ为目标花斑状碳酸盐岩岩心样品中储层的孔隙度；φ 0为目标花斑状碳酸盐岩岩心样品的孔隙度；m为目标花斑状碳酸盐岩岩心样品中储层的体积占比。 Wherein, φ is the porosity of the reservoir in the target mottled carbonate rock core sample; φ0 is the porosity of the target mottled carbonate rock core sample; and m is the volume proportion of the reservoir in the target mottled carbonate rock core sample.
  3. 根据权利要求1所述的方法，其中，基于所述目标花斑状碳酸盐岩岩心样品中储层的占比，对所述目标花斑状碳酸盐岩岩心样品的渗透率进行校正的步骤包括：The method according to claim 1, wherein the step of correcting the permeability of the target piebald carbonate core sample based on the proportion of the reservoir in the target piebald carbonate core sample comprises:
    基于所述目标花斑状碳酸盐岩岩心样品中横截面上储层的面积占比，利用如下公式对所述目标花斑状碳酸盐岩岩心样品的渗透率进行校正：Based on the area ratio of the reservoir on the cross section of the target piebald carbonate rock core sample, the permeability of the target piebald carbonate rock core sample is corrected using the following formula:
    Figure PCTCN2022138976-appb-100002
    Figure PCTCN2022138976-appb-100002
    式中，k为目标花斑状碳酸盐岩岩心样品中储层的渗透率；k 0为目标花斑状碳酸盐岩岩心样品的渗透率；A为目标花斑状碳酸盐岩岩心样品中横截面上储层的面积占比。 Wherein, k is the permeability of the reservoir in the target mottled carbonate core sample; k0 is the permeability of the target mottled carbonate core sample; A is the area ratio of the reservoir on the cross section in the target mottled carbonate core sample.
  4. 根据权利要求1所述的方法，其中，获取所述目标花斑状碳酸盐岩岩心样品中储层的占比的步骤包括：According to the method of claim 1, the step of obtaining the proportion of the reservoir in the target piebald carbonate core sample comprises:
    获取所述岩心样品的不同截面CT扫描图；Obtaining CT scan images of different cross sections of the core sample;
    获取CT扫描图的储层灰度阈值；Obtaining reservoir grayscale threshold of CT scan image;
    利用CT扫描图的储层灰度阈值，分别对岩心样品的各截面CT扫描图进行储层识别，并基于储层识别结果确定所述岩心样品中储层的占比。Reservoir identification is performed on each cross-sectional CT scan image of the core sample using the reservoir grayscale threshold of the CT scan image, and the proportion of the reservoir in the core sample is determined based on the reservoir identification result.
  5. 根据权利要求4所述的方法，其中，获取CT扫描图的储层灰度阈值的步骤包括：The method according to claim 4, wherein the step of obtaining the reservoir grayscale threshold of the CT scan image comprises:
    获取岩心样品某一截面的显微薄片图像；基于所述岩心样品某一截面的显微薄片图 像与岩心样品该截面的CT扫描图，确定CT扫描图的储层灰度阈值。A microscopic thin-section image of a certain cross section of the core sample is obtained; based on the microscopic thin-section image of the certain cross section of the core sample and a CT scan image of the cross section of the core sample, a reservoir grayscale threshold of the CT scan image is determined.
  6. 根据权利要求4所述的方法，其中，对岩心样品的截面CT扫描图进行储层识别包括：The method according to claim 4, wherein performing reservoir identification on a cross-sectional CT scan of a core sample comprises:
    获取岩心样品的截面CT扫描图中各像素点的灰度值；Obtain the gray value of each pixel in the cross-sectional CT scan of the core sample;
    利用CT扫描图的储层灰度阈值，判断岩心样品的截面CT扫描图中各像素点是否为储层。The reservoir grayscale threshold of the CT scan image is used to determine whether each pixel point in the cross-sectional CT scan image of the core sample is a reservoir.
  7. 根据权利要求4所述的方法，其中，获取所述岩心样品的不同截面CT扫描图的步骤包括：获取所述岩心样品中至少两个横截面的CT扫描图。The method according to claim 4, wherein the step of obtaining CT scan images of different cross sections of the core sample comprises: obtaining CT scan images of at least two cross sections of the core sample.
  8. 根据权利要求7所述的方法，其中，基于储层识别结果确定所述岩心样品中储层的占比的步骤包括：The method according to claim 7, wherein the step of determining the proportion of the reservoir in the core sample based on the reservoir identification result comprises:
    基于岩心样品的各横截面CT扫描图的储层识别结果，确定岩心样品各横截面上储层的面积占比，进而基于岩心样品各横截面上储层的面积占比确定岩心样品中储层的体积占比即岩心样品中储层的占比。Based on the reservoir identification results of the CT scan images of each cross section of the core sample, the area proportion of the reservoir on each cross section of the core sample is determined, and then the volume proportion of the reservoir in the core sample, that is, the proportion of the reservoir in the core sample, is determined based on the area proportion of the reservoir on each cross section of the core sample.
  9. 根据权利要求1所述的方法，其中，获取目标花斑状碳酸盐岩岩心样品的孔隙度的步骤包括：The method according to claim 1, wherein the step of obtaining the porosity of the target piebald carbonate core sample comprises:
    获取目标花斑状碳酸盐岩岩心样品的外表体积；Obtain the apparent volume of the target piebald carbonate core sample;
    获取目标花斑状碳酸盐岩岩心样品的岩石骨架体积；Obtain the rock skeleton volume of the target piebald carbonate core sample;
    基于目标花斑状碳酸盐岩岩心样品的外表体积和目标花斑状碳酸盐岩岩心样品的岩石骨架体积，确定目标花斑状碳酸盐岩岩心样品的孔隙度。The porosity of the target piebald carbonate rock core sample is determined based on the surface volume of the target piebald carbonate rock core sample and the rock skeleton volume of the target piebald carbonate rock core sample.
  10. 根据权利要求1所述的方法，其中，所述目标花斑状碳酸盐岩岩心样品的渗透率为气测法测定的目标花斑状碳酸盐岩岩心样品的渗透率。The method according to claim 1, wherein the permeability of the target piebald carbonate rock core sample is the permeability of the target piebald carbonate rock core sample measured by gas logging.
PCT/CN2022/138976 2022-11-21 2022-12-14 Method for determining reservoir porosity and/or reservoir permeability of graniphyric carbonate rock WO2024108689A1 (en)

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