CN111291497A

CN111291497A - Improved digital core modeling method

Info

Publication number: CN111291497A
Application number: CN202010128527.8A
Authority: CN
Inventors: 杨莎莎; 傅少君; 谢明; 权娟娟; 习羽; 刘恺德
Original assignee: Xijing University
Current assignee: Xijing University
Priority date: 2020-02-28
Filing date: 2020-02-28
Publication date: 2020-06-16

Abstract

The invention discloses an improved digital core modeling method, which comprises the following steps: A. obtaining rock particle characteristics; B. simulating rock particles; C. simulating the deposition, compaction and diagenesis; D. and constructing a digital core model. The invention can simulate the changes of translation, deformation, rotation, rearrangement, crushing and the like of particles in the compaction action by applying the EDEM, can also combine the simulation of early deposition action and later diagenesis action to visualize the forming process of the whole rock, and can monitor and analyze the change of the particles and the pores at any time. The digital core is more accurately constructed by the whole process method.

Description

Improved digital core modeling method

Technical Field

The invention relates to the technical field of rock and soil, in particular to an improved digital core modeling method.

Background

The digital core technology is an effective method for core analysis which is started in recent years, is widely applied in the fields of geoscience, geotechnical engineering, environmental engineering and the like, and has achieved great success. The basic principle is that based on two-dimensional or three-dimensional core scanning images, a computer image processing technology is applied, and digital core reconstruction is completed through a certain algorithm.

The core is formed by the sedimentation, compaction and diagenesis of rock particles in nature. The process method is a technology for constructing a digital core by simulating the above rock formation process. Because the constraint condition of the process method is rock particle information data obtained from rock slices or other ways, the modeling flexibility is stronger, and because geological factors are added in the simulation of the process method, the formation process and the anisotropy of the rock are considered, and the constructed digital core is more accurate. Has received wide attention of scholars at home and abroad.

The formation of rock in nature comprises three stages of deposition, compaction and diagenesis, and the process is complex. Particularly, when the compaction action occurs, the rock particles are subjected to the pressure of rocks above and around, the friction force generated by water flow, the static pressure in water and other friction forces, so that the particles are changed in translation, deformation, rotation, rearrangement, even crushing and the like, and the original pores among the rock particles are greatly reduced. For example, compaction in tight sandstone can result in raw porosity losses as high as around 60%. Since the compaction effect exists all the time in the rock diagenesis process, the influence on the rock property is huge, and the accurate simulation of the compaction effect is particularly important when a digital rock core is simulated by using a process method.

To solve this problem, scholars at home and abroad set assumed conditions when performing compaction simulation. Bakke and Φ ren (1997) in the course of simulating compaction, the compaction of the rock was achieved by changing only the vertical coordinates of the individual particles, assuming no change in the geometry of the particles, no lateral displacement, no rotation of the particles and no elastic deformation of the particles. Zhu (2012) assumed that the particles only translated during compaction, and that the compaction of the particles was considered to include both vertical (Z-axis) and horizontal (X-axis, Y-axis) compaction, which was simulated in both directions. Droole (2014) to achieve the effect of particle rearrangement and porosity reduction after compaction, the Z-axis coordinate of all deposit particles or globules is reduced (moved down) and the degree of compaction and particle alignment is controlled throughout by a compaction factor (typically [0,1 ]) and a particle rearrangement factor (typically [ -0.02,0.02 ]).

In summary, the prior art has assumed that the translation of the particles is used to simulate the compaction process without deformation, rotation, and breakage of the particles. In order to ensure the accuracy of the digital core, the compaction factor and the particle rearrangement factor are required to be changed for carrying out simulation for multiple times, so that a satisfactory effect can be achieved. The trial process is slow, the randomness of the simulation result is too strong, and the efficiency of digital core modeling is greatly reduced.

Disclosure of Invention

The invention aims to provide an improved digital core modeling method to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

an improved digital core modeling method, comprising the steps of:

A. obtaining rock particle characteristics;

B. simulating rock particles;

C. simulating the deposition, compaction and diagenesis;

D. and constructing a digital core model.

As a further technical scheme of the invention: the step A is specifically as follows: and acquiring rock particle characteristics. Selecting a rock core to prepare a sample, and acquiring the size, shape, components and distribution characteristics of rock particles in the sample by using a casting body slice, granularity analysis and CT scanning mode.

As a further technical scheme of the invention: the step B is carried out in two steps: firstly, simulating the shape of real rock particles by using three-dimensional software; and secondly, guiding the particle geometric shape simulated by the three-dimensional software into the EDEM by using a Creator, and adding particle components and size information to complete the establishment of the particle model.

As a further technical scheme of the invention: in the deposition process of the step C, the rock particles are descended and rolled until the rock particles reach an initial stable state, the rock particles enter a compaction stage, the rock particles are changed in translation, deformation, rotation, rearrangement, crushing and the like, and then enter a diagenesis stage, the particles are cemented, corroded or enlarged by themselves, so that the rock particle morphology is further changed, and the current rock is finally formed.

As a further technical scheme of the invention: and C, simulating a series of changes of the particles in the processes of deposition, compaction and diagenesis by using a Simulator.

As a further technical scheme of the invention: the step D is specifically as follows: after a series of rock formation process simulations were completed, a digital core model was generated using Analyst.

As a further technical scheme of the invention: the three-dimensional software is CAD.

Compared with the prior art, the invention has the beneficial effects that: the invention can simulate the changes of translation, deformation, rotation, rearrangement, crushing and the like of particles in the compaction action by applying the EDEM, can also combine the simulation of early deposition action and later diagenesis action to visualize the forming process of the whole rock, and can monitor and analyze the change of the particles and the pores at any time. The digital core is more accurately constructed by the whole process method.

Drawings

FIG. 1 is an identification flow diagram of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: referring to fig. 1, an improved digital core modeling method includes the following steps:

a: and acquiring rock particle characteristics. Selecting a rock core to prepare a sample, and acquiring the size, shape, components and distribution characteristics of rock particles in the sample by using a casting body slice, granularity analysis and CT scanning mode.

B: simulating rock particles. The method comprises the following two steps:

1. the shape of the real rock particles is simulated by CAD (computer Aided design) software.

2. And (3) introducing the geometry of the particles simulated by the CAD into the EDEM by using a Creator, and adding particle components and size information to complete the establishment of a particle model.

C: and (4) simulating deposition, compaction and diagenesis. In the deposition process, rock particles can descend and roll until the rock particles reach an initial stable state, then the rock particles enter a compaction stage, the particles are subjected to changes such as translation, deformation, rotation, rearrangement, crushing and the like, and then enter a diagenesis stage, the particles are subjected to cementation, corrosion or self-generation increasing action, so that the rock particle morphology can be further changed, and finally the current rock is formed. Simulation of a series of changes in the particles during deposition, compaction, diagenesis was performed with a Simulator.

D: and constructing a digital core model. After a series of rock formation process simulations were completed, a digital core model was generated using Analyst.

Example 2: on the basis of embodiment 1, the CAD used in step B may be replaced with other three-dimensional software.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. An improved digital core modeling method is characterized by comprising the following steps:

A. obtaining rock particle characteristics;

B. simulating rock particles;

C. simulating the deposition, compaction and diagenesis;

D. and constructing a digital core model.

2. The improved digital core modeling method as claimed in claim 1, wherein said step a is specifically: and acquiring rock particle characteristics. Selecting a rock core to prepare a sample, and acquiring the size, shape, components and distribution characteristics of rock particles in the sample by using a casting body slice, granularity analysis and CT scanning mode.

3. The improved digital core modeling method as claimed in claim 1, wherein said step B is performed in two steps: firstly, simulating the shape of real rock particles by using three-dimensional software; and secondly, guiding the particle geometric shape simulated by the three-dimensional software into the EDEM by using a Creator, and adding particle components and size information to complete the establishment of the particle model.

4. The improved digital core modeling method as claimed in claim 1, wherein during the sedimentation process of step C, rock particles undergo descending and rolling until an initial steady state is reached, and then the rock particles enter a compaction stage, and undergo changes such as translation, deformation, rotation, rearrangement and crushing, and then enter a diagenesis stage, and the particles undergo cementation, erosion or autogenous enlargement, so that rock particle morphology can be further changed, and finally the current rock is formed.

5. The method as claimed in claim 1, wherein step C is performed by simulation of a series of changes in the particles during deposition, compaction, diagenesis using a Simulator.

6. The improved digital core modeling method as claimed in claim 1, wherein said step D is specifically: after a series of rock formation process simulations were completed, a digital core model was generated using Analyst.

7. The improved digital core modeling method as claimed in claim 3, wherein said three dimensional software is CAD.