Comprehensive identification method for polygonal fault system

Abstract

The invention discloses a comprehensive identification method for a polygonal fault system, and a concrete embodiment is based on the Sanzhao depression of the Songliao Basin. The main characteristics of the polygonal fault system are that faults on a plane are mutually interlaced to form a polygon; the fault distribution in a vertical direction has obvious top and bottom interfaces and has a 'stratabound characteristic'; and the geometric characteristic is a characteristic with a small extension length and a small distance. Based on this, the key characteristics of the polygonal fault system are induced, an identification model of the polygonal fault system is established, the fault plane characteristics, vertical characteristics and geometric features are integrated, a weight coefficient is determined and a mathematical model is constructed, an integrated identification index is obtained, and the polygonal fault system is identified. According to the method, multiple geometric features are considered, the accurate requirements of polygon fault identification can be satisfied, and the method can be widely applied to the field of oil and gas resource geological exploration.

Description

technical field [0001] The invention belongs to the field of geological exploration and development evaluation of oil and gas resources, and in particular relates to a comprehensive identification method of a polygonal fault system. Background technique [0002] A polygonal fault system refers to a small-scale extensional fault system developed in fine-grained sediments. A large number of small faults interweave each other on the plane to form a polygonal shape, and are confined to specific strata vertically, generally of non-structural origin. At present, polygonal fault systems have been discovered in many regions abroad, such as the New Jersey Basin, the Shetland Islands, the North Sea Basin, the Côte d’Ivoire Basin, and the Viking Basin. A polygonal fault system has been discovered in the basin, and it is controversial. [0003] At present, the identification methods of polygonal fault systems mainly focus on the qualitative description stage. It is generally believed t...

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Problems solved by technology

[0003] At present, the identification methods of polygonal fault systems mainly focus on the qualitative description stage. It is generally believed that the planar shape, stratigraphic control and fault distance of the main faults are used to judge whether they belong to polygonal fault systems. It can be considered as a polygonal fault system, but the qualitative identification method is greatly affected by human factors. The plane shapes of faults at different scales are obviously different, and it is difficult to accurately identify a polygonal fault system.

[0004] Although the research on the polygonal fault system has made many important progress through the efforts of scholars at home and abroad, its identification is still at a relatively early stage, and there is still no mature and accurate evaluation method

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