Research On Fault Identification Method Using Coherent Information Of 3-D Seismic Data

The increasing stratigraphic complexity as a result of progress of oil and gas exploration work imposes restrictions on original seismic data interpretation. The emergence of 3-D seismic technology brings about a new situation for geophysical exploration. 3-D coherence technology is a significant fault identification method. The main idea of it is to get coherent data by coherent calculation of original data. Location of fault is confirmed using coherent section and coherence slice at the end.First of all, the research background and significance of 3-D seismic data based fault identification technique is described. Research status of fault identification technique at home and abroad is introduced. Developments and applications of coherent cube techniques are mainly introduced. Problems and defects of common fault identification technique are analyzed and then the research content of this topic are put forward.Then fundamental of coherent algorithm is narrated, and impact of parameter on coherent algorithm result is analyzed combined with real 3-D seismic data. A detailed comparation of display results between original seismic data slice map and coherent data slice map. As common coherent algorithm failed to clearly reflect situation of the small fault in original section this paper proposed a coherent enhancement method to make coherent enhancement process on original seismic data. Simulation result shows that profile map highlights the location and towards of tiny faults. At the same time, frequency-domain analysis method is put forward to make up the defect of long computing cycle in common coherent, and its validity and feasibility is verified through real data. Merits and demerits between frequency-domain coherent algorithm and common coherent algorithm are compared. Loads of simulation results show that this method improves computational efficiency and shortens the interpretation cycle of seismic data. As slice map from frequency-domain analysis has certain breadth and burr which makes it difficult to determine boundary of the fault, image filtering and thinning technique is studied in this paper to enhance and optimize fault image so as to determine the location of axle wire.Finally ant colony algorithm is applied to track fault location in vertical section and horizontal slice of Coherence Cube. It will determine fault region and noise region furthermore based on thinning technique. Simulation results show that fault line from ant colony algorithm has well continuity, and avoid the burr phenomenon. It provide an effective technical support for fast and accurate fault identification.