New fluid detection method based on well logging curve wavelet analysis and Hilbert Transform
Zhao Jun-long1, Li Xin-sheng2, Zhang Bin3
1. College of Petroleum Resources, Xi'an University of Petroleum, Xi'an City, Shannxi Province, 710065, China;
2. Geophysical&Geochemical Exploration Team, Shannxi Geological Prospecting Bureau, Xi'an City, Shannxi Province, 710043, China;
3. Dingbian Production Plant, Yanchang Oilfield Company Ltd, Dingbian City, Shannxi Province, 718600, China
Abstract：The well logging response characteristics for fluid property in reservoirs with low and extra low permeability are extremely complicated, as a result it is very difficult to conduct fluid detection and evaluation for those reservoir and ambiguity is always a big problem. Based on available data (core data, geology data and dynamic data) and principles of wavelet analysis and Hilbert Transform, forward model was established, wavelet deposition and reconstruction were conducted, for trend information which could better reflect fluid property change, Hilbert transform was applied, then amplitude spectrum and phase spectrum for the trend signals were calculated and then were analyzed, then based on wavelet deposition and reconstruction, as well as Hilbert transform the relationship between spectrum characteristics and fluid property was obtained. The study results show that the wavelet reconstructed signal for the routine well logging curve could better reflect vertical distribution characteristics of the fluid properties, while the amplitude spectrum and phase spectrum of the wavelet reconstructed well logging curves for which Hilbert Transform was conducted could clearly disclose vertical change and difference for the fluid properties, the new method was applied in Erodes Basin, and excellent results ware achieved there.
