Fn指标法在建立保靖复式构造裂缝分布模式中的应用

复式构造裂缝分布模式和裂缝密集带的预测是油气勘探中的难点和关键技术，本文在地质模型、数学模型和力学模型的基础上，提出了Fn指标法，建立了模拟复式构造裂缝分布模式的方法，直接预测了复式构造裂缝密集带，并对保靖复式构造横剖面的裂缝分布模式进行Fn指标法的实际应用，得出本区最有利的油气圈闭构造为腾家湾背斜裂缝带，解决了最大剪应力法难以解决的问题。

The application of Fn index method in fracture distribution pattern of complex structure

It is a difficult and critical technology in oil and gas exploration to predict fracture distribution and fracture concentration area in a complex structure. Traditional finite element method is mainly used to investigate the development of fracture by structure stress field simulation. Based on geologic, mechanical and mathematics models, the \%F\-n\% Index method was brought forward in this article to simulate the pattern of tectonic fracture distribution, and it is well used in prediction of fracture concentrated area. As an example, Baojing complex structure profile was selected to investigate fracture distribution. It showed that there are four concentrated fracture zones in Baojing complex structure, and they are controlled both by rock properties and by structural locations. Structural fracture is well developed in the hard and sub\|hard blocks, small synclinal cores and small anticlinal upheave, fault blocks between two faults and the vicinity of fault surface. Combined with other conditions of reservoir, the author concluded that Tengjiawang anticlinal fracture zone is the most favorable oil and gas trap. Fracture zone of Upper Sinian Series in the core of Xinzai box\|anticline ranks secondary oil and gas trap. The author also found that fracture zone of Upper Sinian Series in small anticlinal upheave and fault block between two faults is the most possible part of oil reservoir.