CN-122016591-A - Method and device for predicting rock face porosity of shale oil reservoir, electronic equipment and medium

CN122016591ACN 122016591 ACN122016591 ACN 122016591ACN-122016591-A

Abstract

The invention relates to the technical field of unconventional oil and gas exploration, and discloses a method, a device, electronic equipment and a medium for predicting the rock face porosity of a shale oil reservoir. The method comprises the steps of processing shale oil samples into at least two parallel samples, observing longitudinal wave spectrum characteristics of the first parallel samples by an acoustic emission system, extracting waveforms and signals of longitudinal wave spectrums in corresponding time windows, converting longitudinal waves from a time domain to a frequency domain based on discrete Fourier transform to obtain a rock sample longitudinal wave frequency spectrum characteristic curve, quantitatively representing the whole distribution range of longitudinal wave frequencies by using rock sample longitudinal wave centroid frequency F z based on frequency distribution characteristics in the longitudinal wave frequency spectrum, fitting the relation between the rock sample longitudinal wave centroid frequency F z and corresponding rock face aperture rate phi S , and constructing a face porosity prediction model. The technical scheme enriches the shale oil reservoir pore structure evaluation method, has good application effect on shale oil reservoirs, and has strong practicability, universality and operability and good evaluation precision.

Inventors

LU JING
LIU KUN
ZOU YOULONG
LIU MI
ZHANG GUOCAN

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司石油勘探开发研究院

Dates

Publication Date: 20260512
Application Date: 20241112

Claims (11)

1. A method of predicting the rock face porosity of a shale oil reservoir, comprising: Processing the shale oil sample to include at least two parallel samples; the acoustic emission system observes the longitudinal wave spectrum characteristics of the first parallel sample and extracts waveforms and signals of the longitudinal wave spectrums in the corresponding time window; Converting the longitudinal wave from a time domain to a frequency domain based on discrete Fourier transformation to obtain a rock sample longitudinal wave frequency spectrum characteristic curve; based on the frequency distribution characteristics in the longitudinal wave frequency spectrum, quantitatively representing the overall distribution range of the longitudinal wave frequency by utilizing the rock sample longitudinal wave centroid frequency F z ; Fitting the relation between the rock sample longitudinal wave centroid frequency F z and the corresponding rock face rate phi S , and constructing a face porosity prediction model, wherein a scanning electron microscope observes a second parallel sample and obtains the rock face rate phi S through image processing software.
2. The method for predicting the shale oil reservoir rock face porosity of claim 1, wherein said at least two parallel samples are processed and then baked.
3. The method for predicting rock face porosity of a shale oil reservoir of claim 1, wherein for said first parallel sample, waveforms and signals of longitudinal wave spectra within a time window of 0-300 μs are extracted as a whole.
4. The method for predicting the rock face porosity of a shale oil reservoir according to claim 1, wherein the discrete sampling value x (nT) of the continuous signal x (t) is obtained in the characteristic curve of the longitudinal wave frequency spectrum of the rock sample, and the specific formula is as follows: Wherein X is a frequency domain signal discrete sequence, X (k) is a frequency domain parameter, k=0, 1,.., Omega is the angular frequency, rad/s, X is the discrete sequence of the time domain signal, X (n) is the data of the nth sampling point in the discrete signal x, J is an imaginary number and is represented by the imaginary number, N is the discrete signal length.
5. The method of predicting shale oil reservoir rock face porosity as recited in claim 1, wherein said rock sample longitudinal wave centroid frequency F z is defined as: Wherein, F z is the discretized frequency value, KHz, A (Fi) is the amplitude of the frequency wave, mV, ΔF is the difference between adjacent frequencies, kHz.
6. The method for predicting the rock face porosity of a shale oil reservoir according to claim 1, wherein the calculation formula of the rock face porosity Φ S is: Wherein, phi S is the areal ratio,%; A pi is the area of the ith aperture, μm 2 or pixel; a is the area of the entire field of view, μm 2 or pixel.
7. The method of predicting shale oil reservoir rock face porosity of claim 1, wherein the face rate prediction model is: Ф S ＝AF z +B Wherein F z is a transverse wave centroid frequency value, KHz; Phi S is the porosity of the rock sample surface,%; A. B is a fitting parameter, and is dimensionless.
8. The method of predicting shale oil reservoir rock face porosity as claimed in any of claims 1-7, wherein said method of predicting shale oil reservoir rock face porosity comprises: Analyzing the correlation between the longitudinal wave centroid frequency F z of the rock sample and the corresponding rock face rate phi S , wherein the face rate prediction model is applied based on high correlation, or the rock core is collected again and the face rate prediction model is built again based on low correlation.
9. A device for predicting the rock face porosity of a shale oil reservoir, comprising: The core processing module is used for processing the shale oil sample into at least two parallel samples; the longitudinal wave time window inner wave spectrum extraction module is used for observing longitudinal wave spectrum characteristics of the first parallel sample by the acoustic emission system and extracting waveforms and signals of the longitudinal wave spectrums in the corresponding time window; The frequency spectrum conversion module is used for converting the longitudinal wave from a time domain to a frequency domain based on discrete Fourier transform to obtain a rock sample longitudinal wave frequency spectrum characteristic curve; The longitudinal wave centroid frequency extraction module is used for quantitatively representing the whole distribution range of the longitudinal wave frequency by utilizing the rock sample longitudinal wave centroid frequency F z based on the frequency distribution characteristics in the longitudinal wave frequency spectrum; The scanning electron microscope image processing module is used for observing the second parallel sample by a scanning electron microscope and obtaining the rock face porosity phi S through image processing software; A fitting analysis module for fitting the relation between the rock sample longitudinal wave centroid frequency F z and the corresponding rock face hole rate phi S , and And the prediction model construction module is used for constructing a face rate prediction model.
10. An electronic device, comprising: Memory, and A processor; wherein the memory is for storing one or more computer instructions for execution by the processor to implement the method of any one of claims 1 to 8.
11. A readable storage medium having stored thereon computer instructions, wherein the computer instructions, when executed by a processor, implement the method of any of claims 1 to 8.

Description

Method and device for predicting rock face porosity of shale oil reservoir, electronic equipment and medium Technical Field The invention relates to the technical field of unconventional oil and gas exploration, in particular to a method, a device, electronic equipment and a medium for predicting the rock face porosity of a shale oil reservoir. Background The pore structure system is an overall description of the geometry, size, spatial distribution and combinations of the complex disordered pores and throats within the porous medium. In the field of oil and gas exploration and development, pore structure systems control reservoir properties and seepage characteristics, so that it is particularly critical to achieve fine characterization of pore structures by using petrophysical experiment technology (Li et al, 2017;Salahshoor et al, 2017). Rock flake analysis is one of the most basic research methods in the field of petrology, and rock sample flakes are ground to be extremely thin (0.03 mm) using a cutting mill, and the type, combination, granularity, microstructure, etc. of minerals inside the rock can be observed and analyzed by using a polarization microscope. The cast sheet is one of rock sheets, and is mainly used for observing the internal pore space, throat and two-dimensional space structure matched with each other of rock by injecting colored liquid glue (blue or red) into the rock pore space under vacuum pressurization and grinding the rock pore space into sheets, and can be used for determining a series of rock under-lens characteristic parameters (Zhao Ming and the like, 2009, chen Gengxin and the like, 2016, du Xiangyi and the like, 2021) such as rock lithology, pore structure type, surface porosity, gap filler type, contact relation and the like. The observation of multi-scale rock slices is the most basic, visual and quick analysis method in scientific research and production in the oil and gas geology field, and particularly has the effect that other research means cannot replace in the aspects of rock morphology and organization (Saif et al, 2017; shao et al, 2017). The traditional optical microscope has been used for many years as a main technical means for observing the rock structure, and has the advantages of intuitiveness and rapidness, but is limited by resolution and magnification, so that finer pore structure information can not be provided, and the rock scanning electron microscope method can compensate the short plate. The scanning electron microscope analysis method is an observation means between a transmission electron microscope and an optical microscope, is widely applied to observing the surface ultrastructure and composition of various solid matters, utilizes a focused high-energy electron beam to scan a rock sample, excites various physical information through the interaction between the light beam and the matters, amplifies and re-images the collected information to achieve the aim of representing the microscopic morphology of the matters, and has the characteristics of high resolution, large depth of field, strong third dimension and the like (Du Gu and the like, 2014, zhang Qiyan and the like, 2022, li Wenhao and the like, 2022). The technology is widely applied in the field of geological research, particularly the field of oil and gas exploration and development, can clearly observe the surface morphology features and component differences of minerals and the pore structure and distribution of the minerals on a micro-nano scale, and provides information such as the micro morphology, the structure and the like of the minerals (Xiao et al, 2018; huang et al, 2021). Researchers can visually observe the type and the form of the rock pore structure by using a scanning electron microscope and a cast sheet, but the two types of test methods cannot realize the integral quantitative characterization of the pore throat radius. Meanwhile, due to the difficulty in coring, a sufficient amount of core physical data cannot be obtained for cast sheet or scanning electron microscope observation in a part of the area (Hemes et al, 2015; li et al, 2015; xiao et al, 2018; huang et al, 2020). In conclusion, the shale oil reservoir has the characteristics of complex lithology, rapid lithofacies change and the like, so that the shale oil reservoir has unique micro-pore structure characteristics. The rock scanning electron microscope has stronger intuitiveness and convenience, but the utilization of the scanning electron microscope in the past research is mostly qualitative research, and meanwhile, partial rock physical samples can be cut by the scanning electron microscope for observation, and the core physical data of a sufficient quantity cannot be obtained in partial areas due to difficult coring. Disclosure of Invention The invention provides a method, a device, electronic equipment and a medium for predicting the porosity of a rock face of a shale oil reservoir, which are used for solv