A method and device for determining Poisson's ratio of shale gas reservoir based on element logging

Abstract

The application discloses a method and device for determining Poisson's ratio of a shale gas reservoir based on element logging. The method comprises the following steps: based on the mineral content, rock porosity, TOC content, water saturation, rock skeleton density and rock density of the shale gas reservoir rock determined according to element logging data, the rock skeleton P-wave and S-wave velocity and the rock P-wave and S-wave velocity of the shale gas reservoir are determined in sequence by using a volume model method; the rock skeleton Poisson's ratio is determined according to the rock skeleton P-wave and S-wave velocity, and the rock Poisson's ratio is determined according to the rock P-wave and S-wave velocity. The method can quickly and accurately determine the dynamic Poisson's ratio of the rock skeleton and the rock by using the element logging data.

Description

Technical Field

[0001] This invention relates to the field of comprehensive application of elemental logging data and calculation of logging rock mechanical parameters in the field of oil and gas exploration and development, and particularly to a method and apparatus for determining the Poisson's ratio of shale gas reservoirs based on elemental logging. Background Technology

[0002] The Poisson's ratio used in the logging industry mainly comes from two sources: core laboratory analysis and well logging Poisson's ratio. The Poisson's ratio obtained through laboratory physical experiments is called the static Poisson's ratio, while the Poisson's ratio calculated through the P-wave (S-wave) transit time is called the dynamic Poisson's ratio. Generally, the static Poisson's ratio and the dynamic Poisson's ratio are basically equivalent.

[0003] Currently published patents related to elemental logging (XRF) and Poisson's ratio calculation include:

[0004] The invention patent title is: "A Method for Obtaining Poisson's Ratio in Rocks Based on XRF Elemental Logging During Drilling," invention patent application number: 202011041897.4, application date: September 28, 2020, inventors: Liang Bo, Wang Chongjing, Tang Cheng, et al. This invention patent mainly utilizes correlation analysis between elemental logging parameters and well logging Poisson's ratio to obtain key parameters with good correlation and corresponding fitting coefficients, establishing a Poisson's ratio fitting formula related to well logging Poisson's ratio and elemental logging parameters. The advantage of this method is that it does not need to consider the physical meaning and theoretical calculation formula of Poisson's ratio, directly obtaining the Poisson's ratio based on data fitting. The disadvantage of this method is that the key parameters and fitting coefficients in the Poisson's ratio fitting formula vary depending on the region and the elemental logging instrument, resulting in poor universality.

[0005] In addition, Luo Faqiang, Wang Zhizhan, and others published a paper titled "Real-time Calculation Method of Rock Mechanical Parameters in Complex Strata—Taking Bachu Uplift in Tarim Basin as an Example" in Science Technology and Engineering in June 2020. This article proposed two methods for calculating Poisson's ratio and Young's modulus. One method is the forward modeling method, which calculates minerals based on element logging and then calculates the P-wave and S-wave velocities based on the minerals. However, this method does not consider reservoir fluids and porosity, resulting in low accuracy in calculating Poisson's ratio and Young's modulus. The other method is the direct method, which establishes a fitting formula for Poisson's ratio and Young's modulus by using the correlation between single elements obtained from element logging and the logging Poisson's ratio and Young's modulus, and directly calculates Poisson's ratio and Young's modulus. This method is basically consistent with the method mentioned in the invention patent "A Method for Obtaining Rock Poisson's Ratio Based on XRF Element Logging While Drilling" filed by Liang Bo et al. Meanwhile, because shale gas horizontal wells lack coring data, and due to cost-saving or engineering factors, some horizontal wells are not logged, making it impossible to obtain rock mechanical parameters such as Poisson's ratio and Young's modulus. Therefore, logging cannot accurately evaluate the rock mechanical parameters of shale gas reservoirs, such as Poisson's ratio and Young's modulus.

[0006] In summary, existing methods for calculating dynamic Poisson's ratio suffer from poor versatility and limited accuracy. Summary of the Invention

[0007] In view of the above problems, the present invention is proposed to provide a method and apparatus for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, which overcomes or at least partially solves the above problems. It can quickly and accurately determine the rock skeleton and dynamic Poisson's ratio of the rock using elemental logging data, and has a wide range of applications.

[0008] In a first aspect, embodiments of the present invention provide a method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, including:

[0009] Based on the mineral content, porosity, TOC content, water saturation, rock skeleton density, and rock density of the shale gas reservoir rocks determined by elemental logging data, the volumetric model method was used to sequentially determine the P- and S-wave velocities of the shale gas reservoir rock skeleton and the P- and S-wave velocities of the rocks.

[0010] The Poisson's ratio of the rock skeleton is determined based on the longitudinal and transverse wave velocities of the rock skeleton.

[0011] Secondly, embodiments of the present invention provide a device for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, comprising:

[0012] The P-wave and S-wave velocity determination module is used to determine the P-wave and S-wave velocities of the shale gas reservoir rock skeleton and the P-wave and S-wave velocities of the rock skeleton sequentially using the volume model method, based on the mineral content, rock porosity, TOC content, water saturation, rock skeleton density and rock density determined from the elemental logging data.

[0013] The Poisson's ratio determination module is used to determine the Poisson's ratio of the rock skeleton based on the longitudinal and transverse wave velocities, and to determine the Poisson's ratio of the rock based on the longitudinal and transverse wave velocities.

[0014] Thirdly, embodiments of the present invention provide a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-mentioned method for determining the Poisson's ratio of shale gas reservoirs based on element logging.

[0015] Fourthly, this disclosure provides a server, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described method for determining the Poisson's ratio of shale gas reservoirs based on element logging.

[0016] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0017] (1) The method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging provided in this embodiment of the invention, based on the mineral content, porosity, TOC content, water saturation, rock skeleton density, and rock density of the shale gas reservoir rock determined by elemental logging data, sequentially determines the P-wave and S-wave velocities of the rock skeleton and the rock P-wave and S-wave velocities using the volumetric model method; then, the Poisson's ratio of the rock skeleton is determined based on the P-wave and S-wave velocities of the rock skeleton, and the Poisson's ratio of the rock is determined based on the P-wave and S-wave velocities of the rock. Utilizing elemental logging data, considering the properties of pores and fluids, the dynamic Poisson's ratio of the rock skeleton and the rock is determined quickly and accurately, providing data support for calculating parameters such as pore pressure, minimum horizontal principal stress, maximum horizontal principal stress, and fracture pressure of the shale gas reservoir through elemental logging, laying a solid foundation for logging rock mechanics evaluation.

[0018] (2) The method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging provided in this embodiment of the invention uses only elemental logging data as the basis for calculation, without the need for core data and related logging data, so it has a wide range of applications.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0022] Figure 1 This is a flowchart of the method for determining the Poisson's modulus of shale gas based on elemental logging in Embodiment 1 of the present invention;

[0023] Figure 2 for Figure 1 The detailed implementation flowchart of step S11 is shown below;

[0024] Figure 3 This is a flowchart illustrating the specific implementation of the method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging in Embodiment 2 of the present invention.

[0025] Figure 4 This is a comparison chart of Poisson's ratio calculated by element logging and Poisson's ratio in Embodiment 3 of the present invention;

[0026] Figure 5This is a schematic diagram of the device for determining the Poisson's ratio of shale gas reservoirs based on elemental logging in an embodiment of the present invention. Detailed Implementation

[0027] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] This invention provides a method and apparatus for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, which can quickly and accurately determine the rock skeleton and dynamic Poisson's ratio of the rock using elemental logging data.

[0031] Example 1

[0032] Embodiment 1 of this invention provides a method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, the process of which is as follows: Figure 1 As shown, it includes the following steps:

[0033] Step S11: Based on the mineral content, rock porosity, TOC content, water saturation, rock skeleton density, and rock density determined from the elemental logging data, the P- and S-wave velocities of the shale gas reservoir rock skeleton and the P- and S-wave velocities of the rock are determined sequentially using the volumetric model method.

[0034] Shale gas reservoirs consist of a rock framework, total organic carbon (TOC), shale gas, and formation water. Assuming the shale gas reservoir is a homogeneous body, see [link to relevant documentation]. Figure 2As shown, the rock skeleton and P- and S-wave velocities of the shale gas reservoir are determined through the following steps:

[0035] Step S111: Obtain the mineral content, rock porosity, TOC content, water saturation, rock skeleton density, and rock density of the shale gas reservoir rocks determined based on elemental logging data.

[0036] Specifically, the above parameters are obtained in the following way:

[0037] (1) Calculate the mineral content in shale gas reservoir rocks according to the method of inverting sedimentary rock minerals by element logging, including the content of at least one mineral among quartz, potassium feldspar, sodium feldspar, analcime, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum and pyrite.

[0038] Furthermore, the content here refers to the percentage of minerals by mass relative to the rock skeleton.

[0039] Mineral content can be a decimal, that is, a number less than 1, and the sum of the contents of all minerals equals 1 (the unit of mineral content can also be %, and the sum of the contents of all minerals equals 100). However, in actual calculations, it is almost impossible to calculate all the mineral components in the rock. Therefore, minerals with extremely low content and less important content do not need to be calculated. This makes the calculated sum of the contents of all minerals equal to 1 an approximation.

[0040] (2) Calculate rock porosity using the method of calculating shale gas reservoir porosity based on element logging.

[0041] (3) Calculate the total organic carbon (TOC) content, water saturation, rock skeleton density and rock density based on the method of calculating shale gas reservoir density using element logging.

[0042] The methods for calculating various parameters based on element logging described above can all be implemented using existing technologies, so they will not be described in detail here.

[0043] Step S112: Based on the mineral content, rock skeleton density, and predetermined mineral P and S wave velocities, determine the P and S wave velocities of the rock skeleton using the volumetric model method.

[0044] Based on the mineral content, rock skeleton density, and predetermined mineral P-wave velocities, the following formula (1) is used to determine the rock skeleton P-wave velocity V. ps-el :

[0045]

[0046] Based on the mineral content, rock skeleton density, and predetermined mineral transverse wave velocities, the rock skeleton transverse wave velocity V is determined using the following formula (2). ss-el :

[0047]

[0048] In formulas (1) and (2), ρ s-el For the density of the rock skeleton, ω i-el ρ i-el V ps-i-el and V ss-i-el These represent the content, density, P-wave velocity, and S-wave velocity of the i-th mineral, respectively, where i is the index of the mineral type (i = 1, 2, ..., n), and n is the number of mineral types, with a mineral content less than 1. Furthermore, the units for the rock skeleton density and mineral density are not specifically limited, as long as they are consistent; the units for the P-wave and S-wave velocities of the minerals are also not specifically limited, as long as the units for the P-wave and S-wave velocities of various minerals are consistent, and the units of the calculated rock skeleton P-wave and S-wave velocities are consistent with the units of the mineral P-wave and S-wave velocities; optionally, the unit for mineral content can also be %, which can be converted to a decimal by dividing by 100 during the calculation.

[0049] Step S113: Based on the P and S wave velocities of the rock skeleton, rock porosity, rock density, TOC content and water saturation, as well as the pre-determined P and S wave velocities and TOC density of shale gas, TOC and formation water, the volumetric model method is used to determine the P and S wave velocities of the shale gas reservoir rocks.

[0050] Specifically, the longitudinal wave velocity V of the shale gas reservoir rock is determined using the following formula (3). pb-el The shear wave velocity V of shale gas reservoir rocks is determined using the following formula (4). sb-el :

[0051]

[0052]

[0053] In formulas (3) and (4), V ps-el and V ss-el These represent the longitudinal and transverse wave velocities of the rock skeleton, V. p-fw and V s-fw These are the longitudinal wave velocity and transverse wave velocity of formation water, respectively, V pg-el and V sg-el These are the P-wave velocity and S-wave velocity of shale gas, respectively, V pb-TOC-ef and V sb-TOC-ef These are the TOC longitudinal wave velocity and transverse wave velocity, respectively, ρ b-el and ρ TOC These are rock density and TOC density, respectively. el φ el and S w-el These are TOC content, rock porosity, and water saturation, respectively; TOC el φel and S w-el All values ​​are less than 1. This is optional, and the unit can also be %. In the calculation process, simply divide by 100 to convert it to a decimal.

[0054] Furthermore, the units for rock density and TOC density are not specifically limited, as long as they are consistent; V p-fw V s-fw V pg-el V sg-el V pb-TOC-ef and V sb-TOC-ef The units are not specifically limited, as long as they are consistent. The units of the calculated rock longitudinal and transverse wave velocities are consistent with those of the former.

[0055] Step S12: Determine the Poisson's ratio of the rock skeleton based on the longitudinal and transverse wave velocities.

[0056] The P and S wave transit times of the rock skeleton are determined based on the P and S wave velocities; the Poisson's ratio of the rock skeleton is determined based on the P and S wave transit times using the following formula (5):

[0057]

[0058] The rock P-wave and S-wave transit times are determined based on the rock P-wave and S-wave velocities; the rock Poisson's ratio is then determined based on the rock P-wave and S-wave transit times using the following formula (6):

[0059]

[0060] In formulas (5) and (6), σ s-el and σ b-el These are Poisson's ratio of the rock skeleton and Poisson's ratio of the rock, respectively, dimensionless parameters; DT ps-el DT ss-el DT pb-el and DT sb-el These are the P-wave and S-wave transit times of the rock skeleton, and the P-wave and S-wave transit times of the rock itself. The units for these transit times are not specified.

[0061] The method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging provided in Embodiment 1 of this invention utilizes elemental logging data, considering the properties of pores and fluids, to quickly and accurately determine the rock skeleton and the dynamic Poisson's ratio of the rock. This provides data support for calculating parameters such as pore pressure, minimum horizontal principal stress, maximum horizontal principal stress, and fracture pressure of shale gas reservoirs using elemental logging, laying a solid foundation for logging rock mechanics evaluation. This method uses only elemental logging data as the calculation basis and does not require core data or related logging data, thus having a wide range of applications.

[0062] Example 2

[0063] Embodiment 2 of the present invention provides a specific implementation flow of a method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, as follows: Figure 3 As shown, it includes the following steps:

[0064] Step S31: Obtain the mineral content, rock porosity, TOC content, water saturation, rock skeleton density, and rock density of the shale gas reservoir rocks based on the elemental logging data.

[0065] The mineral content includes the content of quartz, potassium feldspar, sodium feldspar, analcime, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum, and pyrite, specifically the mass percentage of the corresponding mineral in the rock framework, in percentages (%).

[0066] Step S32: Determine the P and S wave velocities of the rock skeleton using the volumetric model method based on the mineral content, density, rock skeleton density, and predetermined P and S wave velocities of the minerals.

[0067] V ps-el =(ω quartz-el ×ρ s-el / ρ quartz-el ×V ps-quartz-el +ω pf-el ×ρ s-el / ρ pf-el ×V ps-pf-el +ω albite-el ×ρ s-el / ρ albite-el ×V ps-albite-el +ω analcite-el ×ρ s-el / ρ analcite-el ×V ps-analcite-el +ω kaolinite-el ×ρ s-el / ρ kaolinite-el ×V ps-kaolinite-el +ω montmorillonite-el ×ρ s-el / ρ montmorillonite-el ×V ps-montmorillonite-el +ω illite-el ×ρ s-el / ρ illite-el ×V ps-illite-el +ω mica-el ×ρ s-el / ρ mica-el ×V ps-mica-el +ω calcite-el ×ρ s-el / ρ calcite-el ×V ps-calcite-el +ω dolomite-el ×ρ s-el / ρ dolomite-el ×V ps-dolomite-el +ω plaster-el ×ρs-el / ρ plaster-el ×V ps-plaster-el +ω pyrite-el ×ρ s-el / ρ pyrite-el ×V ps-pyrite-el ) / 100(7)

[0068] V ss-el =(ω quartz-el ×ρ s-el / ρ quartz-el ×V ss-quartz-el +ω pf-el ×ρ s-el / ρ pf-el ×V ss-pf-el +ω albite-el ×ρ s-el / ρ albite-el ×V ss-albite-el +ω analcite-el ×ρ s-el / ρ analcite-el ×V ss-analcite-el +ω kaolinite-el ×ρ s-el / ρ kaolinite-el ×V ss-kaolinite-el +ω montmorillonite-el ×ρ s-el / ρ montmorillonite-el ×V ss-montmorillonite-el +ω illite-el ×ρ s-el / ρ illite-el ×V ss-illite-el +ω mica-el ×ρ s-el / ρ mica-el ×V ss-mica-el +ω calcite-el ×ρ s-el / ρ calcite-el ×V ss-calcite-el +ω dolomite-el ×ρ s-el / ρ dolomite-el ×V ss-dolomite-el +ω plaster-el ×ρ s-el / ρ plaster-el ×V ss-plaster-el +ω pyrite-el ×ρ s-el / ρ pyrite-el ×V ss-pyrite-el ) / 100(8)

[0069] In formulas (7) and (8), V ps-el V represents the longitudinal wave velocity of the rock skeleton. ss-el For the transverse wave velocity of the rock skeleton, ρ s-el ρ is the density of the rock skeleton. quartz-elρ is the density of quartz. pf-el The density of potassium feldspar is ρ. albite-el The density of albite is ρ. analcite-el ρ is the density of anabolic zeolite. kaolinite-el ρ is the density of kaolinite. montmorillonite-el ρ is the density of montmorillonite. illite-el The density of illite, ρ mica-el ρ is the density of mica. calcite-el ρ is the density of calcite. dolomite-el ρ is the density of dolomite. plaster-el ρ is the density of gypsum. pyrite-el The density of pyrite is 2.5, the density of potassium feldspar is 2.57, the density of sodium feldspar is 2.62, the density of analcime is 2.6, the density of kaolinite is 2.63, the density of montmorillonite is 2.6, the density of illite is 2.8, the density of mica is 3.05, the density of calcite is 2.71, the density of dolomite is 2.87, the density of gypsum is 2.4, and the density of pyrite is 5.2; ω quartz-el ω represents the percentage of quartz mass. pf-el ω represents the mass percentage of potassium feldspar. albite-el ω represents the mass percentage of albite. analcite-el ω represents the mass percentage of anabolic zeolite. kaolinite-el ω represents the percentage of kaolinite by mass. montmorillonite-el ω represents the percentage of montmorillonite by mass. illite-el ω represents the percentage of illite by mass. mica-el ω represents the percentage of mica mass. calcite-el Let be the mass percentage of calcite, and be ω. dolomite-el Dolomite mass percentage, ω plaster-el ω represents the percentage of gypsum by mass. pyrite-el V represents the percentage of pyrite by mass. ps-quartz-el V is the longitudinal wave velocity of the quartz skeleton. ps-pf-el V represents the longitudinal wave velocity of the potassium feldspar framework. ps-albite-el V represents the longitudinal wave velocity of the albite framework. ps-analcite-el V represents the longitudinal wave velocity of the anabolic zeolite framework. ps-kaolinite-el V represents the longitudinal wave velocity of the kaolinite skeleton. ps-montmorillonite-el V represents the longitudinal wave velocity of the montmorillonite skeleton. ps-illite-el V represents the longitudinal wave velocity of the illite framework. ps-mica-el V is the longitudinal wave velocity of the mica skeleton. ps-calcite-el Let V be the longitudinal wave velocity of the calcite framework. ps-dolomite-el Longitudinal wave velocity of dolomite skeleton, V ps-plaster-el V represents the longitudinal wave velocity of the plaster skeleton. ps-pyrite-el V represents the longitudinal wave velocity of the pyrite skeleton. ss-quartz-el V is the transverse wave velocity of the quartz skeleton. ss-pf-elV represents the transverse wave velocity of the potassium feldspar framework. ss-albite-el V represents the transverse wave velocity of the albite framework. ss-analcite-el V represents the transverse wave velocity of the anabolic zeolite framework. ss-kaolinite-el V represents the transverse wave velocity of the kaolinite skeleton. ss-montmorillonite-el V represents the transverse wave velocity of the montmorillonite skeleton. ss-illite-el V is the transverse wave velocity of the illite framework. ss-mica-el V is the shear wave velocity of the mica skeleton. ss-calcite-el Let V be the transverse wave velocity of the calcite framework. ss-dolomite-el Transverse wave velocity of dolomite skeleton, V ss-plaster-el V is the transverse wave velocity of the plaster skeleton. ss-pyrite-el The transverse wave velocity is the pyrite skeleton velocity; the longitudinal (transverse) wave velocity is in m / s, the mineral content is in %, and the density is in g / cm³. 3 .

[0070] Step S33: Based on the P and S wave velocities of the rock skeleton, rock porosity, rock density, TOC content and water saturation, as well as the pre-determined P and S wave velocities and TOC density of shale gas, TOC and formation water, the P and S wave velocities of the shale gas reservoir are determined using the volumetric model method.

[0071] V pb-el =V ps-el ×(1-ρ b-el ×TOC el / ρ TOC / 100-φ el / 100)+S w-el ×φ el / 10000×V p-fw +

[0072] (1-S w-el / 100)×φ el / 100×V pg-el +ρ b-el ×TOC el / ρ TOC / 100×V pb-TOC-ef (9)

[0073] V sb-el =V ss-el ×(1-ρ b-el ×TOC el / ρ TOC / 100-φ el / 100)+S w-el ×φ el / 10000×V s-fw +

[0074] (1-S w-el / 100)×φ el / 100×V sg-el +ρ b-el ×TOC el / ρ TOC / 100×V sb-TOC-ef (10)

[0075] Longitudinal (transverse) wave velocity is expressed in m / s; porosity, TOC, and water saturation are expressed in %, and density is expressed in g / cm³. 3 , where V pb-el V is the longitudinal wave velocity of the rock. sb-el TOC represents the transverse wave velocity of the rock. el The TOC content of shale gas reservoirs calculated from elemental logging, ρ TOC For TOC density, φ el V is the porosity of shale gas reservoir rocks calculated using elemental logging. p-fw S represents the longitudinal wave velocity of formation water. w-el V is the water saturation of the shale gas reservoir calculated from elemental logging. pg-el V represents the longitudinal wave velocity of shale gas. pb-TOC-ef V represents the TOC P-wave velocity of the shale gas reservoir. s-fw V is the shear wave velocity of the formation water. sg-el V represents the shear wave velocity of shale gas. sb-TOC-ef The TOC shear wave velocity is the velocity of the shale gas reservoir.

[0076] Step S34: Calculate the P-wave (S-wave) transit time of the shale gas reservoir rock skeleton and the P-wave (S-wave) transit time of the rock skeleton based on the P-wave (S-wave) velocity and the P-wave (S-wave) velocity of the rock.

[0077] DT ps-el =1000000 / V ps-el (11)

[0078] DT ss-el =1000000 / V ss-el (12)

[0079] DT pb-el =1000000 / V pb-el (13)

[0080] DT sb-el =1000000 / V sb-el (14)

[0081] The unit for P-wave (S-wave) velocity is m / s, and the unit for P-wave (S-wave) time difference is μs / m, where DT ps-el P-wave transit time of shale gas reservoir rock skeleton calculated for elemental logging, DT ss-el Shear wave time difference of shale gas reservoir rock skeleton calculated for elemental logging, DT pb-elP-wave transit time of shale gas reservoir rocks calculated for elemental logging, DT sb-el Shear wave time difference of shale gas reservoir rock calculated for elemental logging.

[0082] Step S35: Based on the P-wave (S-wave) transit time of the rock skeleton and the P-wave (S-wave) transit time of the rock calculated by element logging, calculate the Poisson's ratio of the shale gas reservoir rock skeleton and the Poisson's ratio of the rock using the Poisson's ratio acoustic calculation formula.

[0083]

[0084]

[0085] Example 3

[0086] This invention provides a specific application of a method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging. Taking a horizontal shale gas well B in the xx area of ​​the xx basin as an example, the mineral contents of quartz, calcite, dolomite, feldspar, illite, kaolinite, montmorillonite, pyrite, etc., obtained from elemental logging inversion, along with the TOC content, water saturation, and porosity calculated from elemental logging, are substituted into the aforementioned elemental logging rock Poisson's ratio calculation formula for calculation. Within the well section from 4000m to 5840m, 773 elemental analysis samples were analyzed. The minimum calculated Poisson's ratio was 0.143, the maximum was 0.287, and the average was 0.191. The minimum logging Poisson's ratio corresponding to the elemental analysis well depth was 0.116, the maximum was 0.311, and the average was 0.203. Comparing the Poisson's ratio calculated from elemental logging with the actual logging Poisson's ratio, the maximum positive error was 34.21%, with an average of 13.7%, while the maximum negative error was -29.96%, with an average of -14.81%. Overall, the errors remained largely within ±15% (see...). Figure 4 (See Table 1). It can be seen that the Poisson's ratio calculated through the embodiments of the present invention and the logging Poisson's ratio error meet the production requirements, and the overall trend is consistent.

[0087] Table 1B: Poisson's ratio calculated from well logging and statistics of Poisson's ratio from well logging.

[0088] 588 5412 0.242 0.192 -20.66 589 5414 0.253 0.192 -24.11 590 5416 0.248 0.192 -22.58 591 5418 0.238 0.198 -16.81 592 5420 0.234 0.198 -15.38 593 5422 0.252 0.198 -21.43 594 5424 0.254 0.204 -19.69 595 5426 0.247 0.204 -17.41 596 5428 0.244 0.198 -18.85 597 5430 0.247 0.192 -22.27 598 5432 0.233 0.198 -15.02 599 5434 0.199 0.192 -3.52 600 5436 0.201 0.204 1.49 601 5438 0.174 0.198 13.79 602 5444 0.147 0.186 26.53 603 5446 0.157 0.186 18.47 604 5448 0.159 0.186 16.98 605 5450 0.166 0.186 12.05 606 5452 0.173 0.186 7.51 607 5454 0.246 0.179 -27.24 608 5456 0.237 0.186 -21.52 609 5458 0.144 0.186 29.17 610 5460 0.140 0.186 32.86 611 5462 0.152 0.186 22.37 612 5464 0.167 0.179 7.19 613 5466 0.200 0.179 -10.50 614 5468 0.188 0.173 -7.98 615 5470 0.227 0.173 -23.79 616 5472 0.229 0.166 -27.51 617 5474 0.232 0.166 -28.45 618 5478 0.174 0.166 -4.60 619 5480 0.224 0.166 -25.89 620 5492 0.219 0.198 -9.59 621 5494 0.247 0.198 -19.84 622 5496 0.285 0.210 -26.32 623 5500 0.197 0.245 24.37 624 5508 0.210 0.266 26.67 625 5512 0.195 0.235 20.51 …… …… …… …… …… 768 5830 0.241 0.249 3.32 769 5832 0.242 0.262 8.26 770 5834 0.270 0.245 -9.26 771 5836 0.244 0.253 3.69 772 5838 0.207 0.269 29.95 773 5840 0.240 0.266 10.83

[0089] Note: Table 1 is only an illustration and does not fully show the specific details of the 773 sample points.

[0090] Example 4

[0091] Embodiment 4 of this invention provides a method for calculating the Poisson's ratio of shale gas reservoirs based on elemental logging. Taking a horizontal shale gas well in the xx area of ​​the xx basin as an example, the method includes the following steps:

[0092] (1) Calculate the content of minerals such as quartz, potassium feldspar, sodium feldspar, analcime, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum, and pyrite based on the method of inverting sedimentary rock minerals by element logging;

[0093] Within the well section with a depth of 4000–5840 m, elemental logging measurements and analysis were performed on the samples. Taking the well depth of 4168 m as an example, based on the inversion calculation of the content of each element, the mass fractions of the above minerals are as follows: quartz 55.27%, calcite 22.16%, dolomite 7.45%, clay 9.59%, pyrite 3.73%, and albite 1.80%. The clay is further divided into illite 0.00%, montmorillonite 0.69%, kaolinite 0.00%, and mica 8.90%.

[0094] (2) The porosity of the shale gas reservoir was calculated using the method of calculating the porosity of the shale gas reservoir based on element logging. The porosity of the well at a depth of 4168m was 5.57%.

[0095] (3) The total organic carbon (TOC) content, water saturation, framework density, and rock density of the shale gas reservoir were calculated using the method of calculating shale gas reservoir density by element logging. The TOC content of the well at a depth of 4168m was 4.78%, the water saturation was 15.62%, the framework density was 2.67 g / cm3, and the rock density was 2.51 g / cm3.

[0096] (4) Based on the mineral content, framework density, rock density and P (S) wave velocity corresponding to single minerals such as quartz, potassium feldspar, sodium feldspar, zeolite, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum, and pyrite calculated by element logging, the P (S) wave velocity of the shale gas reservoir framework was calculated using a volumetric model. The P (S) wave velocity of the framework at a well depth of 4168m was 5882.35m / s and the S (S) wave velocity of the framework was 3412.39m / s.

[0097] (5) Based on the longitudinal (transverse) wave velocity, porosity, TOC content, water saturation, and the corresponding densities of TOC, shale gas, and formation water, the longitudinal (transverse) wave velocity of the shale gas reservoir rock was determined. At a well depth of 4168m, the longitudinal wave velocity of the rock was 4511.82m / s and the transverse wave velocity was 2769.09m / s.

[0098] (6) Based on the longitudinal (transverse) wave velocity of the shale gas reservoir skeleton and the longitudinal (transverse) wave velocity of the rock, the longitudinal (transverse) wave transit time of the shale gas reservoir skeleton and the longitudinal (transverse) wave transit time of the rock were calculated. At a well depth of 4168m, the longitudinal wave transit time of the skeleton was 170.00μs / m, the transverse wave transit time of the skeleton was 293.05μs / m, the longitudinal wave transit time of the rock was 221.64μs / m, and the transverse wave transit time of the rock was 361.13μs / m.

[0099] (7) Based on the sonic calculation formulas for the longitudinal (horizontal) transit time of the shale gas reservoir framework, the longitudinal (horizontal) transit time of the rock, and the Poisson's ratio of the shale gas reservoir (Well Logging Principles and Comprehensive Interpretation / Hong Youmi, ed. — Dongying: China University of Petroleum Press, 1998 (reprinted in February 2007)), calculate the Poisson's ratio of the shale gas reservoir framework and the Poisson's ratio of the rock. According to the calculation formulas, the Poisson's ratio σ of the framework at a well depth of 4168m is... s-el =1 / 2×(293.05×293.05-2×170.00×170.00) / (293.05×293.05-170.00×170.00)=0.246、Rock Poisson's ratio σ s-el =1 / 2×(361.13×361.13-2×221.64×221.64) / (361.13×361.13-221.64×221.64)=0.198.

[0100] In this embodiment, at the same depth and location of the shale gas well, the logging Poisson's ratio is 0.198, and the error between the elemental logging-calculated Poisson's ratio and the logging Poisson's ratio is 0.0%.

[0101] Example 5

[0102] Embodiment 5 of this invention provides a method for calculating the Poisson's ratio of shale gas reservoirs based on elemental logging. Taking a horizontal shale gas well in the xx area of ​​the xx basin as an example, the method includes the following steps:

[0103] (1) Calculate the content of minerals such as quartz, potassium feldspar, sodium feldspar, analcime, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum, and pyrite based on the method of inverting sedimentary rock minerals by element logging;

[0104] Within the well section with a depth of 4000–5840 m, elemental logging measurements and analysis were performed on the samples. Taking the well depth of 4388 m as an example, based on the inversion calculation of the content of each element, the mass fractions of the above minerals are as follows: quartz 55.31%, calcite 19.76%, dolomite 6.99%, clay 12.13%, pyrite 4.09%, and albite 1.72%. Among them, the clay is divided into illite 1.80%, montmorillonite 0.75%, kaolinite 0.00%, and mica 9.58%.

[0105] (2) The porosity of the shale gas reservoir was calculated using the method of calculating the porosity of the shale gas reservoir based on element logging. The porosity of the well at a depth of 4388m was 5.60%.

[0106] (3) The total organic carbon (TOC) content, water saturation, framework density, and rock density of the shale gas reservoir were calculated using the method of calculating shale gas reservoir density by element logging. The TOC content of the well at a depth of 4388m was 5.30%, the water saturation was 28.62%, the framework density was 2.68 g / cm3, and the rock density was 2.50 g / cm3.

[0107] (4) Based on the mineral content, framework density, rock density and P (S) wave velocity corresponding to single minerals such as quartz, potassium feldspar, sodium feldspar, zeolite, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum, and pyrite calculated by element logging, the P (S) wave velocity of the shale gas reservoir framework was calculated using a volumetric model. The P (S) wave velocity of the framework at a well depth of 4388m was 5765.35m / s and the S (S) wave velocity of the framework was 3301.2m / s.

[0108] (5) Based on the longitudinal (transverse) wave velocity, porosity, TOC, water saturation and TOC content of the shale gas reservoir skeleton, the corresponding densities of shale gas and formation water, and the longitudinal (transverse) wave velocity, the longitudinal (transverse) wave velocity of the shale gas reservoir rock was determined. At a well depth of 4388m, the longitudinal wave velocity of the rock was 4494.18m / s and the transverse wave velocity of the rock was 2775.08m / s.

[0109] (6) Based on the longitudinal (transverse) wave velocity of the shale gas reservoir skeleton and the longitudinal (transverse) wave velocity of the rock, the longitudinal (transverse) wave transit time of the shale gas reservoir skeleton and the longitudinal (transverse) wave transit time of the rock were calculated. At a well depth of 4388m, the longitudinal wave transit time of the skeleton was 173.45μs / m, the transverse wave transit time of the skeleton was 302.92μs / m, the longitudinal wave transit time of the rock was 222.51μs / m, and the transverse wave transit time of the rock was 360.35μs / m.

[0110] (7) Based on the sonic calculation formulas for the longitudinal (horizontal) transit time of the shale gas reservoir framework, the longitudinal (horizontal) transit time of the rock, and the Poisson's ratio of the shale gas reservoir (Well Logging Principles and Comprehensive Interpretation / Hong Youmi, ed. — Dongying: China University of Petroleum Press, 1998 (reprinted in February 2007)), calculate the Poisson's ratio of the shale gas reservoir framework and the Poisson's ratio of the rock. According to the calculation formulas, the Poisson's ratio σ of the framework at a well depth of 4388m is... s-el =1 / 2×(302.92×302.92-2×173.45×173.45) / (302.92×302.92-173.45×173.45)=0.256、Rock Poisson's ratio σ s-el =1 / 2×(360.35×360.35-2×222.51×222.51) / (360.35×360.35-222.51×222.51)=0.192.

[0111] In this embodiment, at the same depth and location of the shale gas well, the logging Poisson's ratio is 0.235, and the error between the elemental logging-calculated Poisson's ratio and the logging Poisson's ratio is -18.3%.

[0112] Based on the inventive concept of this invention, embodiments of this invention also provide a device for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, the structure of which is as follows: Figure 5 As shown, it includes:

[0113] The P-wave and S-wave velocity determination module 51 is used to determine the P-wave and S-wave velocities of the shale gas reservoir rock skeleton and the P-wave and S-wave velocities of the rock skeleton in sequence using the volume model method based on the mineral content, rock porosity, TOC content, water saturation, rock skeleton density and rock density in the shale gas reservoir rock determined by elemental logging data.

[0114] The Poisson's ratio determination module 52 is used to determine the Poisson's ratio of the rock skeleton based on the longitudinal and transverse wave velocities of the rock skeleton, and to determine the Poisson's ratio of the rock based on the longitudinal and transverse wave velocities of the rock.

[0115] In some embodiments, the P-wave and S-wave velocity determination module 51 is specifically used for:

[0116] Obtain the mineral content, porosity, TOC content, water saturation, rock skeleton density, and rock density of the shale gas reservoir rocks based on elemental logging data; determine the P- and S-wave velocities of the rock skeleton using a volumetric model method based on the mineral content, rock skeleton density, and pre-determined P- and S-wave velocities of the minerals; determine the P- and S-wave velocities of the shale gas reservoir rocks using a volumetric model method based on the P- and S-wave velocities of the rock skeleton, rock porosity, rock density, TOC content, water saturation, and pre-determined P- and S-wave velocities and TOC density of shale gas, TOC, and formation water.

[0117] In some embodiments, the P-wave and S-wave velocity determination module 51 is specifically used for:

[0118] Based on the mineral content, rock skeleton density, and predetermined mineral P-wave velocities, the rock skeleton P-wave velocity V is determined using the following formula (1). ps-el :

[0119]

[0120] Based on the mineral content, rock skeleton density, and predetermined mineral transverse wave velocities, the rock skeleton transverse wave velocity V is determined using the following formula (2). ss-el :

[0121]

[0122] In formulas (1) and (2), ρ s-el For the density of the rock skeleton, ωi-el ρ i-el V ps-i-el and V ss-i-el These are the content, density, P-wave velocity, and S-wave velocity of the i-th mineral, respectively, where i is the index of the mineral type, i = 1, 2, ..., n, and n is the number of mineral types, with a mineral content less than 1.

[0123] In some embodiments, the P-wave and S-wave velocity determination module 51 is specifically used for:

[0124] Based on the P and S wave velocities of the rock skeleton, rock porosity, rock density, TOC content, and water saturation, and the pre-determined P and S wave velocities and TOC density of shale gas, TOC, and formation water, the P wave velocity V of the shale gas reservoir rock is determined using the following formula (3). pb-el The shear wave velocity V of shale gas reservoir rocks is determined using the following formula (4). sb-el :

[0125]

[0126]

[0127] In formulas (3) and (4), V ps-el and V ss-el These represent the longitudinal and transverse wave velocities of the rock skeleton, V. p-fw and V s-fw These are the longitudinal wave velocity and transverse wave velocity of formation water, respectively, V pg-el and V sg-el These are the P-wave velocity and S-wave velocity of shale gas, respectively, V pb-TOC-ef and V sb-TOC-ef These are the TOC longitudinal wave velocity and transverse wave velocity, respectively, ρ b-el and ρ TOC These are rock density and TOC density, respectively. el φ el and S w-el These are TOC content, rock porosity, and water saturation, respectively. el φ el and S w-el All are less than 1.

[0128] In some embodiments, the Poisson ratio determination module 52 is specifically used for:

[0129] The P and S wave transit times of the rock skeleton are determined based on the P and S wave velocities; the Poisson's ratio of the rock skeleton is determined based on the P and S wave transit times using the following formula (5):

[0130]

[0131] In formula (5), σs-el For the rock framework Poisson's ratio, DT ps-el For the P-wave time difference of the rock skeleton, DT ss-el The transverse wave time difference of the rock skeleton.

[0132] In some embodiments, the Poisson ratio determination module 52 is specifically used for:

[0133] The rock P-wave and S-wave transit times are determined based on the rock P-wave and S-wave velocities; the rock Poisson's ratio is then determined based on the rock P-wave and S-wave transit times using the following formula (6):

[0134]

[0135] In formula (6), σ b-el For the Poisson's ratio of rocks, DT pb-el For the P-wave transit time of rocks, DT sb-el The transverse wave time difference of the rock.

[0136] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0137] Based on the inventive concept of this invention, this embodiment of the invention also provides a computer storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-mentioned method for determining the Poisson's ratio of shale gas reservoirs based on element logging.

[0138] Based on the inventive concept of this invention, this embodiment of the invention also provides a server, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned method for determining the Poisson's ratio of shale gas reservoirs based on element logging.

[0139] Unless otherwise specifically stated, terms such as processing, calculation, operation, determination, display, etc., may refer to the actions and / or processes of one or more processing or computing systems or similar devices that represent the manipulation and conversion of data representing physical (e.g., electronic) quantities within the registers or memory of the processing system into other data similarly representing physical quantities within the memory, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals can be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0140] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0141] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0142] Those skilled in the art will also understand that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps described above are generally described in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art can implement the described functionality in alternative ways for each specific application; however, such implementation decisions should not be construed as departing from the scope of this disclosure.

[0143] The steps of the methods or algorithms described in conjunction with the embodiments herein can be directly embodied in hardware, software modules executed by a processor, or a combination thereof. The software modules can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. The ASIC can reside in a user terminal. Alternatively, the processor and storage medium can exist as discrete components in the user terminal.

[0144] For software implementation, the techniques described in this application can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described in this application. This software code can be stored in memory units and executed by a processor. The memory units can be implemented within the processor or outside the processor; in the latter case, they are communicatively coupled to the processor via various means, as is well known in the art.

[0145] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

Claims

1. A method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, characterized in that, include: Obtain mineral content, rock porosity, TOC content, water saturation, rock skeleton density, and rock density in shale gas reservoir rocks based on elemental logging data; Based on the mineral content, rock skeleton density, and predetermined mineral P-wave velocity, the rock skeleton P-wave velocity V is determined using the following formula (1). ps-el : （1）； Based on the mineral content, rock skeleton density, and predetermined mineral transverse wave velocity, the rock skeleton transverse wave velocity V is determined using the following formula (2). ss-el : （2）； In formulas (1) and (2), Density of the rock skeleton , , and These are the content, density, P-wave velocity, and S-wave velocity of the i-th mineral, respectively, where i is the index of the mineral type, i=1,2……n, n is the number of mineral types, and the mineral content is less than 1. Based on the P and S wave velocities of the rock skeleton, rock porosity, rock density, TOC content, and water saturation, and the pre-determined P and S wave velocities and TOC density of shale gas, TOC, and formation water, the P wave velocity of the shale gas reservoir rock is determined using the following formula (3). The shear wave velocity of shale gas reservoir rocks is determined using the following formula (4). : （3）； （4）； In formulas (3) and (4), and These are the longitudinal wave velocity and transverse wave velocity of the rock skeleton, respectively. and These are the longitudinal wave velocity and transverse wave velocity of formation water, respectively. and These are the P-wave velocity and S-wave velocity of shale gas, respectively. and These are the TOC longitudinal wave velocity and transverse wave velocity, respectively. and These are rock density and TOC density, respectively. , and These are TOC content, rock porosity, and water saturation, respectively. , and All less than 1; The Poisson's ratio of the rock skeleton is determined based on the longitudinal and transverse wave velocities of the rock skeleton.

2. The method as described in claim 1, characterized in that, The mineral content refers to the percentage of minerals by mass relative to the rock skeleton.

3. The method as described in claim 1, characterized in that, The determination of the Poisson's ratio of the rock skeleton based on the longitudinal and transverse wave velocities specifically includes: Determine the P- and S-wave transit times of the rock skeleton based on the P- and S-wave velocities of the rock skeleton. Based on the P-wave and S-wave transit times of the rock skeleton, the Poisson's ratio of the rock skeleton is determined using the following formula (5): （5）； In formula (5), Poisson's ratio for the rock framework For the P-wave time difference of the rock skeleton, The transverse wave time difference of the rock skeleton.

4. The method as described in claim 1, characterized in that, The determination of Poisson's ratio of a rock based on its longitudinal and transverse wave velocities specifically includes: Determine the rock P- and S-wave transit time based on the rock P- and S-wave velocities; Based on the P-wave and S-wave transit times of the rock, the Poisson's ratio of the rock is determined using the following formula (6): （6）； In formula (6), For the Poisson's ratio of rocks, For the P-wave time difference of the rock, The transverse wave time difference of the rock.

5. The method according to any one of claims 1 to 4, characterized in that, The minerals include at least one of quartz, potassium feldspar, sodium feldspar, analcime, kaolinite, montmorillonite, illite, mica, calcite, dolomite, gypsum, and pyrite.

6. A device for determining the Poisson's ratio of shale gas reservoirs based on elemental logging, characterized in that, The apparatus is used to perform the method for determining the Poisson's ratio of shale gas reservoirs based on elemental logging as described in claim 1. The apparatus comprises: The P-wave and S-wave velocity determination module is used to determine the P-wave and S-wave velocities of the shale gas reservoir rock skeleton and the P-wave and S-wave velocities of the rock skeleton sequentially using the volume model method, based on the mineral content, rock porosity, TOC content, water saturation, rock skeleton density and rock density determined from the elemental logging data. The Poisson's ratio determination module is used to determine the Poisson's ratio of the rock skeleton based on the longitudinal and transverse wave velocities, and to determine the Poisson's ratio of the rock based on the longitudinal and transverse wave velocities.

7. A computer storage medium, characterized in that, The computer storage medium stores computer-executable instructions, which, when executed by a processor, implement the method for determining the Poisson's ratio of shale gas reservoirs based on element logging as described in any one of claims 1 to 5.

8. A server, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the method for determining the Poisson's ratio of shale gas reservoirs based on element logging as described in any one of claims 1 to 5.

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