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CN-121859597-B - Construction method of resistivity model for evaluating oil adsorption content of shale oil reservoir

CN121859597BCN 121859597 BCN121859597 BCN 121859597BCN-121859597-B

Abstract

The invention relates to the technical field of oil and gas geology evaluation, in particular to a construction method of a resistivity model for evaluating the oil adsorption content of a shale oil reservoir. The method comprises the steps of establishing a shale oil adsorption resistivity model composed of five components of a rock framework, adsorbed oil, free water and clay bound water based on an effective medium symmetrical conduction theory, determining mineral framework content, clay content and porosity in the model according to logging data, determining geometric parameters of the model by using all-rock XRD (X-ray diffraction), porosity measurement and rock pyrolysis experimental data of a core sample and using a Powell optimization algorithm, and finally solving the content of the oil adsorption component according to a bipartite iterative algorithm and converting the content of the oil adsorption component into the quality of the adsorbed oil. The method solves the problem that the traditional step-by-step pyrolysis experiment is limited by the core sample and is difficult to realize continuous evaluation of the whole well section, realizes continuous and quantitative evaluation of the adsorbed oil content of the shale oil reservoir, and provides technical support for evaluation of the adsorbed oil content of the shale oil reservoir.

Inventors

  • FU JIAN
  • XU YIFAN
  • YU BOWEN
  • YU MIAO
  • FENG XIAOKUN
  • LIU YUCHEN

Assignees

  • 东北石油大学三亚海洋油气研究院

Dates

Publication Date
20260508
Application Date
20260317

Claims (8)

  1. 1. The construction method of the resistivity model for evaluating the adsorption oil content of the shale oil reservoir is characterized by comprising the following steps of: Based on the effective medium symmetrical conduction theory, a shale adsorption oil resistivity model formed by five components of a rock framework, adsorption oil, free water and clay bound water is established, and a shale model formed by five components of the rock framework, adsorption oil, free water and clay bound water is established, wherein the mass balance equation is as follows: ; Wherein, the 、 、 、 、 、 、 The volume content, the total porosity, the effective porosity, the adsorbed oil, the free water and the clay bound water content of the shale are respectively in decimal; the symmetrical conductive model of the effective medium of the five-component shale adsorption oil is as follows: ; Wherein, the 、 、 、 、 、 The conductivity of shale, non-conductive framework particles, adsorbed oil, free water and clay bound water are respectively S/m; 、 、 、 、 、 、 The relative contents of non-conductive framework particles, adsorbed oil, free water and clay bound water are in decimal; Is the conductivity of the virtual medium, S/m; Determining mineral skeleton content, clay content and porosity in the shale adsorption oil resistivity model according to logging data information, and calculating clay content Wherein Based on natural gamma argillaceous index And formation age coefficient Determining and calculating the clay content The formula of (2) is: ; Wherein, the For stratum of the third system as stratum chronology coefficient Has a value of 3.7, and is suitable for old stratum The value is 2; is natural gamma argillaceous index, SI = , wherein, The natural gamma well logging value of the argillaceous rock, the natural gamma well logging value of the pure sand rock and the natural gamma well logging value of the pure argillaceous rock are respectively; Selecting a core sample with a representative shale section according to the core and logging data, and performing full rock XRD, porosity measurement and rock pyrolysis experiments on the core sample; And determining the geometric parameters of the shale adsorption oil resistivity model by using a Powell optimization algorithm based on the results of the all-rock XRD, the porosity measurement and the rock pyrolysis experiment.
  2. 2. The method of constructing a resistivity model for evaluating the adsorbed oil content of a shale oil reservoir of claim 1, wherein said determining of porosity comprises calculating a total porosity And effective porosity 。
  3. 3. The method for constructing a resistivity model for evaluating the adsorbed oil content of a shale oil reservoir of claim 2, wherein the total porosity is calculated The formula of (2) is: ; Wherein, the For the acoustic time difference log readings, Is the time difference of the skeleton sound wave, Is a fluid acoustic wave time difference.
  4. 4. The method for constructing a resistivity model for evaluating the adsorbed oil content of a shale oil reservoir of claim 2, wherein the effective porosity is calculated The formula of (2) is: ; Wherein, the For shale acoustic apparent porosity, The porosity is corrected for the acoustic wave of the clay mineral, Is organic matter porosity.
  5. 5. The method for constructing a resistivity model for evaluating an adsorbed oil content of a shale oil reservoir of claim 4, wherein said shale acoustic apparent porosity Calculated by the following formula: ; acoustic apparent porosity of the clay mineral Calculated by the following formula: ; acoustic wave corrected porosity of the clay mineral Calculated by the following formula: ; Porosity of the organic matter Calculated by the following formula: ; Wherein, the For the density of the skeleton, In order to be a volume density of the rock, In order to achieve a fluid density, Is the clay density, the clay is used for the preparation of the high-density ceramic, For the content of the mud material, the mud material is prepared, Is the total organic carbon content.
  6. 6. The method for constructing a resistivity model for evaluating an adsorbed oil content of a shale oil reservoir of claim 1, wherein said geometric parameters include 、 、 、 The percolation rates of skeleton particles, adsorbed oil, free water and clay bound water in the rock are respectively dimensionless; 、 、 、 、 The percolation indexes of skeleton particles, adsorbed oil, free water and clay bound water in the rock are respectively, and the method is dimensionless.
  7. 7. The method of constructing a resistivity model for evaluating an adsorbed oil content of a shale oil reservoir of claim 1, wherein said determining a mineral framework content comprises calculating a mineral framework content The calculation formula is as follows: ; Wherein, the Is the total porosity.
  8. 8. The method for constructing a resistivity model for evaluating an adsorbed oil content of a shale oil reservoir as defined in claim 1, further comprising solving the adsorbed oil component content by a binary iterative algorithm 。

Description

Construction method of resistivity model for evaluating oil adsorption content of shale oil reservoir Technical Field The invention relates to the technical field of oil and gas geology evaluation, in particular to a construction method of a resistivity model for evaluating the oil adsorption content of a shale oil reservoir. Background The oil gas in shale oil reservoirs exists mainly in two forms of free oil and adsorbed oil. The adsorption oil is mainly endowed on the surfaces of kerogen and clay minerals and is a key component of shale oil. Traditionally, adsorbed oil content can be determined by laboratory multi-stage temperature pyrolysis analysis (e.g., step pyrolysis experiments), but this method is limited by the number of core samples and longitudinal continuity, making it difficult to achieve continuous evaluation of the entire wellbore interval. In terms of theoretical models, effective medium theory (e.g., maxwell-Garnett model, bruggeman model) can describe the conductive behavior of complex pore structures through the coupling mechanism of multi-component medium conductivity. However, this theory has not been applied in the quantitative evaluation of oil adsorption in shale oil reservoirs. Therefore, there is a need in the art to build a quantitative evaluation model of adsorbed oil based on conventional resistivity logging data to overcome the dependence on a large number of core samples and achieve continuous and accurate calculation of the adsorbed oil content of shale oil reservoirs in full well sections. Disclosure of Invention In view of the above, the invention provides a construction method of a resistivity model for evaluating the adsorbed oil content of a shale oil reservoir, which aims to solve the problem that the traditional step-by-step pyrolysis experimental method is limited by the number of core samples and the longitudinal continuity, so that the continuous evaluation of the adsorbed oil content of the whole well section of the shale oil reservoir is difficult to realize, and a quantitative evaluation model of the adsorbed oil based on the resistivity is established. In order to achieve the above purpose, the present invention adopts the following technical scheme: in a first aspect, the invention provides a construction method of a resistivity model for evaluating the adsorption oil content of a shale oil reservoir, which comprises the following steps: based on an effective medium symmetrical conduction theory, establishing a shale adsorption oil resistivity model consisting of five components of a rock framework, adsorption oil, free water and clay bound water; According to logging data, determining mineral skeleton content, clay content and porosity in the shale adsorption oil resistivity model; Selecting a core sample with a representative shale section according to the core and logging data, and performing full rock XRD, porosity measurement and rock pyrolysis experiments on the core sample; And determining the geometric parameters of the shale adsorption oil resistivity model by using a Powell optimization algorithm based on the results of the all-rock XRD, the porosity measurement and the rock pyrolysis experiment. In a specific embodiment, the determination of the argillaceous content comprises calculating argillaceous contentWhereinBased on natural gamma argillaceous indexAnd formation age coefficientAnd (5) determining. In a specific embodiment, the argillaceous content is calculatedThe formula of (2) is: ; Wherein, the For stratum of the third system as stratum chronology coefficientHas a value of 3.7, and is suitable for old stratumThe value is 2; is natural gamma argillaceous index, SI = , wherein,The natural gamma well logging value of the argillaceous rock, the natural gamma well logging value of the pure sand rock and the natural gamma well logging value of the pure argillaceous rock are respectively obtained. In a specific embodiment, the determination of the porosity includes calculating a total porosityAnd effective porosity。 In a specific embodiment, the total porosity is calculatedThe formula of (2) is: ; Wherein, the For the acoustic time difference log readings,Is the time difference of the skeleton sound wave,Is a fluid acoustic wave time difference. In a specific embodiment, the effective porosity is calculatedThe formula of (2) is: ; Wherein, the For shale acoustic apparent porosity,The porosity is corrected for the acoustic wave of the clay mineral,Is organic matter porosity. In a specific embodiment, the shale acoustic apparent porosityCalculated by the following formula: ; acoustic apparent porosity of the clay mineral Calculated by the following formula: ; acoustic wave corrected porosity of the clay mineral Calculated by the following formula: ; Porosity of the organic matter Calculated by the following formula: ; Wherein, the For the density of the skeleton,In order to be a volume density of the rock,In order to achieve a fluid density,Is