TITLE:
The Method and Practice of Constructing 3D Geological Model from Coalfield Exploration 2D Maps
AUTHORS:
Hui Su, Qingyuan Li, Duohu Hao, Ke Xiong, Wei Hu, Xinyong Wei, Xuan Zhang
KEYWORDS:
Coalfield Exploration, 3D Geological Modeling, Semi-Automatic Partition, Partition Triangulation, Reverse Fault Duplicate Area Triangulation
JOURNAL NAME:
International Journal of Geosciences,
Vol.14 No.7,
July
28,
2023
ABSTRACT: 3D geological modeling is an
inevitable choice for coal exploration to adapt to the transformation of coal
mining for green, fine, transparent and Intelligent mining. In the traditional Coalfield
exploration geological reports, the spatial expression form for the coal seams
and their surrounding rocks are 2D maps. These 2D maps are excellent data sources
for constructing 3D geological models of coal field exploration areas. How to
construct 3D models from these 2D maps has been studying in coal
exploration industry for a long time, and still no breakthrough has been
achieved so far. This paper discusses the principle, method and software design
idea of constructing 3D geological model of an exploration area with 2D maps
made by AutoCAD/MapGIS. At first, the paper analyzes 3D geological surface
expression mode in 3D geological modeling software. It is pointed out that
although contour method has unique advantages in coal field
exploration, TIN (Triangular
Irregular Network) is still the standard configuration of 3D modeling software
for coal field. Then, the paper discusses the method of 2D line features
obtaining elevation and upgrading 2D curve to 3D curve. Next, the method of
semi-automatic partition is introduced to build the boundary ring of the
surface patch, that is, the user clicks and selects the line feature to build
the outer boundary ring of the surface patch. Then, Auto-process method for
fault line inside of the outer boundary ring is discussed, it including
construction of fault ring, determining
fault ring being normal fault ring or reverse fault ring and an algorithm of
dealing with normal fault ring. An algorithm of dealing with reverse
fault ring is discussed detailly, the method of expanding reverse fault ring
and dividing the duplicate area in reverse fault into two portions is introduced. The paper also discusses the method of extraction ridge
line/valley line, the construction of fault plane, the
construction of stratum and coal body. The above ideas and methods have been
initially implemented in the “3D modeling platform for coal field exploration”
software, and applied to the 3D modeling practice of data from several coal
field exploration areas in Ningxia, Shanxi, Qinghai, etc.