Abstract:

The technique of balanced section is a combination of geological thought and computer technique, which improves the research for fault structure up to quantitative stage. The theory is that the length, area(2D) or volume(3D) of the strata are balanced in the inline section. According to the principle of the balanced geological cross-section and theory of structural geology,this paper discusses some problems that may affect the reconstruction of  paleotectonics when using the “back stripping” method in constructing evolution sections.Four balanced sections are inversed using 2DMOVE software and the structural evolution characteristics of Guojuzi Sag are analyzed and the quantitative conclusion is drawn. It is indicated that the lower part of Shasi member, middle and lower part of Shasan member, Shayi member and Dongying formation are formed in rapid tectonic descent stages, and the extend ratio in southnorth orientation section is 2.5 times of that in eastwest section. Structural quantification research can provide foundation for analysis of sedimentary filling history, reservoir distribution, migration pathway and accumulation pattern.

Key words: Chezhen depression, balanced section, fault throw remove, structural evolution, extend quantity