Please note this is a comparison between Version 1 by Yuyang LIU and Version 2 by Peter Tang.

Three-dimensional (3D) geological property modeling is used to quantitatively characterize various geological attributes in 3D space based on geostatistics with the help of computer visualization technology, and the results are often stored in grid data. The 3D geological property modeling includes two main components, grid model generation and property interpolation.

- 3D model
- property modeling
- grid generation
- property interpolation
- geostatistics

Three-dimensional (3D) geological property modeling refers to the quantitative characterization of various geological features in 3D space in digital form based on geostatistics using computer visualization technology. It serves as the basis for evaluating mineral resource assessments, reservoir physical property simulations, and reservoir numerical simulations ^{[1][2]}[1,2].

The main application of 3D property modeling in the petroleum field is to establish a geological model of the reservoir; this type of modeling is therefore also called reservoir modeling. The characterization of 3D reservoir models provides an in-depth understanding of the macroscopic distribution, internal structure, physical parameters, and variation characteristics of oil and gas reservoirs, and this understanding is of great importance for oil and gas exploration and development [3]. Geostatistics, which is the core method of 3D property modeling, was proposed by Journel in the 1970s for application in petroleum exploration and development ^{[4][5]}[4,5] and has been widely used and developed since then. The advantage of geostatistics is its ability to integrate data according to the source and reliability of the data and to integrate various information, such as core, log, and seismic data, into the model while ensuring data consistency. In addition, geostatistics can also provide uncertainty assessment as a basis for risk evaluation. In China, research on the theory, methods, and applications of geostatistics started around the 1980s [6], and the application of geostatistics in reservoir descriptions for reservoir geological modeling began in the early 1990s. Since Qiu [7] introduced the related work on reservoir modeling, Zhang and Wang [8], Yu and Li [9], and Zhang et al. [10] successively carried out research on reservoir modeling methods for actual reservoirs in China; this research laid the foundation for applying reservoir modeling technology in oilfield development. Since then, with the development of computer technology and the research of numerous studies in petroleum science and technology, the methods and techniques of reservoir modeling and its application to various reservoir types have developed rapidly.

The oil and gas reservoirs in China are mainly terrestrial oil reservoirs with very complex subsurface conditions; consequently, establishing a 3D property model for reservoir characterization is difficult. At present, most oilfields have entered the middle and late stages of development and are in a state of high water content. The balance between injection and production poses an increasingly prominent problem, so it is especially important to determine the amount and distribution of the remaining oil in the reservoir. In addition, today’s petroleum exploration and development focus on unconventional oil and gas reservoirs, such as shale gas and tight sandstone gas. Although such oil and gas reservoirs are abundant in China, they are characterized by low porosity, low permeability, and high water saturation. Therefore, compared with that of conventional oil and gas reservoirs, the development of unconventional oil and gas reservoirs is bound to pose new requirements for reservoir modeling. To solve these problems, there is an urgent need to establish a more refined reservoir model. Therefore, it is necessary to study grid framework models and geostatistical theories and methods in depth so that they can accurately characterize the reservoir at various levels and describe the heterogeneity of the reservoir while quantitatively evaluating the uncertainty of the model and reducing the risk of exploration and development. Therefore, studying 3D property modeling methods can provide a powerful tool for improving the recovery of oil reservoirs in China and offer theoretical guidance for effectively recovering the remaining oil and developing unconventional oil and gas reservoirs.

3D property modeling represents the heterogeneity of properties in the geological body, thereby reflecting the distribution of the characteristic values of a certain class of physical and chemical properties of the geological body in 3D space, and the results are stored in raster data ^{[11][12]}[11,12]. Based on this definition, 3D property modeling includes two main components: 3D grid model generation and property interpolation. In petroleum exploration and development, the 3D raster model is also referred to as the reservoir grid, and due to the complexity of the physical structure of the reservoir, geostatistics are applied to the model’s property interpolation.