CN-122024865-A - Modeling method and saturation prediction method for petrophysical model containing unevenly distributed hydrate sediments

CN122024865ACN 122024865 ACN122024865 ACN 122024865ACN-122024865-A

Abstract

The invention provides a petrophysical model modeling method and a saturation prediction method containing unevenly distributed hydrate sediment, which comprise the steps of obtaining model parameters and calculating the porosity of a mineral framework based on the model parameters Calculation of bulk modulus of dry hydrate skeleton Shear modulus Calculation of bulk modulus of dry mineral frameworks Shear modulus Calculating the bulk modulus of a dry composite framework consisting of a dry mineral framework and a dry hydrate framework Shear modulus Calculating the bulk modulus of rock at fluid saturation Shear modulus Calculating rock density value at fluid saturation Calculating the formation longitudinal wave velocity And transverse wave velocity . Based on the formation mechanism and the distribution characteristics of the non-uniformly distributed hydrate, the non-uniformity of the hydrate and the mineral particles is considered in the modeling process, the hydrate and the mineral particles are regarded as two independent rock frameworks, and the isotropic rock physical model suitable for the non-uniformly distributed hydrate is constructed.

Inventors

ZHU XIANGYU
PANG WEIXIN
ZHU ZHENYU
LI LIXIA
GE YANG
FAN QI
LIU DINGYUAN

Assignees

中海石油(中国)有限公司
中海石油（中国）有限公司北京研究中心

Dates

Publication Date: 20260512
Application Date: 20251009

Claims (10)

1. A method of modeling a petrophysical model containing unevenly distributed hydrate deposits, comprising: obtaining model parameters including total porosity of the deposit Mineral components is the percentage of (2) Bulk modulus of each mineral component Shear modulus of mineral components Coefficient of friction Critical porosity Saturation of hydrate Density of hydrate Hydrate volume modulus Shear modulus of hydrate Density of mineral particles And sea water density ; Based on the total porosity of the deposit And the hydrate saturation Calculating the porosity of the mineral framework ; Determination of bulk modulus of dry hydrate framework Shear modulus Respectively equal to the bulk modulus of the hydrate Shear modulus ; Based on the percentage of each mineral component Bulk modulus of the mineral components Shear modulus of the mineral components Said coefficient of friction Porosity of the mineral framework And the critical porosity Calculation of bulk modulus of dried mineral frameworks Using Voigt-Reuss-Hill mean equation and Hertz-Mindlin model Shear modulus ; Bulk modulus based on the dry hydrate backbone Shear modulus Bulk modulus of the dry mineral framework Shear modulus Calculating the bulk modulus of a dry composite framework consisting of the dry mineral framework and the dry hydrate framework using the Hashin-SHTRIKMAN lower limit Shear modulus ; Bulk modulus based on the dry composite backbone Shear modulus Bulk modulus of the dry mineral framework Shear modulus Bulk modulus of the dry hydrate skeleton Shear modulus Calculation of the rock bulk modulus at fluid saturation Shear modulus ; Based on the total porosity of the deposit Saturation of the hydrate Density of the hydrate Density of the mineral particles And the sea water density Calculating rock density value at fluid saturation ; Based on the bulk modulus of the rock at saturation of the fluid Shear modulus Rock density value at saturation of the fluid Calculating the formation longitudinal wave velocity And transverse wave velocity 。
2. The method of modeling a petrophysical model comprising non-uniformly distributed hydrate deposits according to claim 1, wherein the mineral framework porosity The calculation formula of (2) is as follows: 。
3. a petrophysical model modeling method comprising non-uniformly distributed hydrate deposits according to claim 1 or 2, wherein the percentage content of each mineral component is based on Bulk modulus of the mineral components Shear modulus of the mineral components Said coefficient of friction Porosity of the mineral framework And the critical porosity Calculation of bulk modulus of dried mineral frameworks Using Voigt-Reuss-Hill mean equation and Hertz-Mindlin model Shear modulus Comprising the following steps: the percentage of each mineral component based on the mineral components Bulk modulus of the mineral components Shear modulus of the mineral components Calculation of the bulk modulus of mineral particles using the Voigt-Reuss-Hill average equation Shear modulus Wherein: When the mineral framework porosity is Equal to the critical porosity Based on the bulk modulus of the mineral particles Shear modulus Said coefficient of friction And the Hertz-Mindlin model, calculating the bulk modulus of the dried mineral framework Shear modulus Wherein: In the middle of 、 The coordination number and poisson ratio are respectively, And Bulk modulus and shear modulus in the extended Hertz-Mindlin effective media model, Represents a friction coefficient with a value ranging from 0 to 1, Is an effective pressure; When the mineral framework porosity is Not equal to the critical porosity Based on the mineral framework porosity Said critical porosity Bulk modulus in the extended Hertz-Mindlin effective Medium model Sum and shear modulus Calculation of the bulk modulus of the dried mineral framework at non-critical pores Shear modulus Wherein: When (when) The calculation formula is as follows: When (when) The calculation formula is as follows: 。
4. a petrophysical model modeling method comprising non-uniformly distributed hydrate deposits according to claim 3, characterized in that the bulk modulus of the dry composite framework Shear modulus The calculation formula of (2) is as follows: In the formula, And Respectively represents the volume percentage of minerals and hydrates in the composite rock framework, And The values of (2) are respectively the bulk modulus of the hydrate Shear modulus 。
5. The method of modeling a petrophysical model containing non-uniformly distributed hydrate deposits according to claim 4, characterized by a bulk modulus based on the dry composite framework Shear modulus Bulk modulus of the dry mineral framework Shear modulus Bulk modulus of the dry hydrate skeleton Shear modulus Calculation of the rock bulk modulus at fluid saturation Shear modulus Comprising the following steps: Bulk modulus based on the dry composite backbone Bulk modulus of the dry mineral framework And bulk modulus of the dry hydrate skeleton Calculating the equivalent bulk modulus of the composite solid particles Wherein: In the formula, , ; Equivalent bulk modulus based on the composite solid particles Calculating equivalent bulk modulus of the pore space of the composite solid particles Wherein: ; Equivalent bulk modulus based on the composite solid particles And equivalent bulk modulus of the void space of the composite solid particles Calculation of the rock bulk modulus at fluid saturation Shear modulus Wherein: 。
6. the method of modeling a petrophysical model comprising non-uniformly distributed hydrate deposits according to claim 5, wherein the rock density values at fluid saturation The calculation formula of (2) is as follows: 。
7. The method of modeling a petrophysical model comprising non-uniformly distributed hydrate deposits according to claim 6, The formation longitudinal wave velocity The calculation formula of (2) is as follows: The formation shear wave velocity The calculation formula of (2) is as follows: 。
8. A method for predicting saturation of unevenly distributed hydrates, characterized in that a petrophysical model containing unevenly distributed hydrate deposits obtained by the method for modeling a petrophysical model containing unevenly distributed hydrate deposits according to any one of claims 3 to 7 is used for establishing a flow for accurately estimating saturation based on a longitudinal wave velocity, a transverse wave velocity and a porosity log at a well location, the flow comprising: logging longitudinal wave speed based on water saturation stratum And transverse wave velocity Gridding value coordination number Coefficient of friction Iteratively calculating longitudinal wave velocities corresponding to different grid points by using the petrophysical model containing the unevenly distributed hydrate sediments And transverse wave velocity Finally, the objective function value is made Minimum, at this time And I.e. model fixed parameters, wherein the objective function values The method comprises the following steps: ; acquiring logging parameters, wherein the logging parameters at least comprise a porosity logging curve and the percentage content of each mineral component; logging longitudinal wave velocity based on the hydrate-containing formation And transverse wave velocity Inputting the model fixed parameters and the logging parameters point by point according to logging data based on the petrophysical model containing the unevenly distributed hydrate sediment, and gridding the valued hydrate saturation Iterative computation of longitudinal wave velocities corresponding to different grid points using a petrophysical model containing unevenly distributed hydrate deposits And transverse wave velocity Until the objective function value is made Minimum, at this time I.e. the predicted hydrate saturation value, wherein the objective function value The method comprises the following steps: 。
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the steps of the petrophysical model modeling method comprising non-uniformly distributed hydrate deposits according to any one of claims 1 to 7 or the non-uniformly distributed hydrate saturation prediction method according to claim 8 when the program is executed.
10. A non-transitory computer readable storage medium having stored thereon a computer program, which when executed by a processor, implements the steps of the method for modeling a petrophysical model comprising non-uniformly distributed hydrate deposits according to any one of claims 1 to 7 or implements the method for predicting non-uniformly distributed hydrate saturation according to claim 8.

Description

Modeling method and saturation prediction method for petrophysical model containing unevenly distributed hydrate sediments Technical Field The invention relates to the technical field of natural gas hydrate exploration, in particular to a petrophysical model modeling method and a saturation prediction method containing non-uniformly distributed hydrate sediments. Background Natural gas hydrate is an icelike crystalline compound formed by natural gas and water in a high-pressure low-temperature environment, and is mainly distributed in a permafrost region and a large Liu Bianyuan submarine sediment. The global reserves of natural gas hydrates are huge and are considered as a future energy source with great development potential. At the same time, natural gas hydrates are also closely related to global geological disasters and climate change. For example, sea level changes or elevated ground temperatures may cause hydrate decomposition, release of strong greenhouse gases such as methane, and further exacerbate global warming processes. In the sediment, natural gas hydrates occur in a variety of forms. In isotropic media, the morphology of occurrence can be broadly divided into two categories, uniform distribution and non-uniform distribution. The uniform distribution mainly comprises a 'fluid floating' (hydrate particles uniformly suspended in pore fluid) and a 'framework supporting' (hydrate and sediment particles are uniformly mixed to form a rock framework). While non-uniform distribution is manifested by non-uniform mixing of the hydrate with the mineral particles in the form of nodules, lumps, etc. The morphology of the hydrate presence has a significant effect on the physical properties such as the acoustic velocity of the deposit. Therefore, petrophysical models based on different occurrence morphology assumptions are widely used to invert hydrate saturation from acoustic or seismic wave velocities. However, the existing model generally ignores the non-uniform distribution form of the hydrate, so that significant errors are introduced in practical application if the saturation estimation is still performed on the non-uniform hydrate by using the uniform model. Such errors not only affect the accuracy of the energy reserve assessment, but may also lead to deviations in the climate effect prediction. Therefore, constructing a reliable petrophysical model for unevenly distributed hydrates and developing a corresponding accurate saturation prediction method have become key technical problems to be solved in the field. Disclosure of Invention The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a petrophysical model modeling method and a saturation prediction method containing non-uniformly distributed hydrate sediment, and aims to solve the problem that a conventional petrophysical model generally ignores non-uniformly distributed hydrate, and in practical application, a uniform model is still adopted to perform saturation estimation on the non-uniformly distributed hydrate, so that a significant error is introduced. The invention provides a petrophysical model modeling method containing unevenly distributed hydrate sediments, which comprises the following steps: obtaining model parameters including total porosity of the deposit Mineral components is the percentage of (2)Bulk modulus of each mineral componentShear modulus of mineral componentsCoefficient of frictionCritical porositySaturation of hydrateDensity of hydrateHydrate volume modulusShear modulus of hydrateDensity of mineral particlesAnd sea water density; Based on the total porosity of the depositAnd the hydrate saturationCalculating the porosity of the mineral framework Determination of bulk modulus of dry hydrate frameworkShear modulusRespectively equal to the bulk modulus of the hydrateShear modulus; Based on the percentage of each mineral componentBulk modulus of the mineral componentsShear modulus of the mineral componentsSaid coefficient of frictionPorosity of the mineral frameworkAnd the critical porosityCalculation of bulk modulus of dried mineral frameworks Using Voigt-Reuss-Hill mean equation and Hertz-Mindlin modelShear modulus; Bulk modulus based on the dry hydrate backboneShear modulusBulk modulus of the dry mineral frameworkShear modulusCalculating the bulk modulus of a dry composite framework consisting of the dry mineral framework and the dry hydrate framework using the Hashin-SHTRIKMAN lower limitShear modulus; Bulk modulus based on the dry composite backboneShear modulusBulk modulus of the dry mineral frameworkShear modulusBulk modulus of the dry hydrate skeletonShear modulusCalculation of the rock bulk modulus at fluid saturationShear modulus; Based on the total porosity of the depositSaturation of the hydrateDensity of the hydrateDensity of the mineral particlesAnd the sea water densityCalculating rock density value at fluid saturation; Based on