Method and device for recognizing low-grade fault of deep tight sandstone gas reservoir

Abstract

The invention provides a method and a device for recognizing a low-grade fault of a deep tight sandstone gas reservoir. The method comprises steps: frequency division processing is carried out on post stack seismic data of a to-be-recognized low-grade fault, and dominant frequency band seismic data capable of highlighting the low-grade fault can be acquired; directional filtering processing is carried out on the dominant frequency band seismic data to acquire seismic data in four main directions; according to the seismic data in the main directions, an ant swarm algorithm is adopted to calculate and acquire a tracing attribute volume in each main direction; and fault traces of the fault in each main direction are extracted, and the tracing attribute volume in each direction is combined to acquire a system diagram. Through carrying out frequency division processing and filtering processing on the post stack seismic data with a relatively poor quality and adopting the ant swarm algorithm again for recalculation on the basis of the original ant swarm, accurate fault traces are extracted, the tracing attribute volume in each direction is combined to acquire the system diagram, the method and the device of the invention are applied to seismic data with various mechanical properties and frequencies, and recognition reliability on the low-grade fault can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of petroleum exploration, in particular to a method and device for identifying low-order sequence faults in deep tight sandstone gas reservoirs. Background technique [0002] Tight sandstone gas reservoirs have unconventional geological features, such as strong reservoir diagenetic compaction, low porosity and low permeability, high content of clay minerals, low water saturation, abnormal formation pressure, etc., but few people mention the key role of the fault system. Due to the characteristics of bottom water or edge water in deep gas reservoirs, after the formation pressure changes, the fluid is easy to coning along the fault and cause water intrusion in the gas reservoir. Both will directly or indirectly lead to large differences in single well productivity and the risk of water breakthrough in production wells, which will affect the development benefits of gas reservoirs. [0003] With the continuous ...

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Problems solved by technology

[0006] The present invention provides a method and device for identifying low-order faults in deep tight sandstone gas reservoirs, which are used to solve the difficulty of comprehensively analyzing the distribution of low-order faults in deep tight sandstone gas reservoirs in various existing technologies. Problems with detection and identification

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