A Method for Extracting Viscoelastic Parameters of Fractured Reservoirs

Abstract

The invention belongs to the field of exploration geophysics, and relates to a viscoelasticity parameter extraction method of a carbonatite fractured reservoir. The viscoelasticity of a rock matrix of the carbonatite fractured reservoir and the anisotropy induced by fractures are introduced into the method, and an equivalent medium model of the viscoelasticity of the fractured reservoir is established, wherein a quality factor, the fracture density, the fracture opening degree and the fracture occurrence are used as the parameters. A rotating staggered mesh high-order finite difference method is used for conducting seismic wave field simulation, and forward modeling records of various fracture combinations in different buried depths and at different construction positions are obtained. On the basis of seismic wave field transmission mechanism analysis, a fracture sensitivity parameter is obtained. Optimizing processing is conducted on high precision prestack earthquake location angle set extracted through a sticky sound wave reverse time migration method according to the fracture sensitivity parameter. The prestack earthquake location angle set after optimizing processing is used for extracting the viscoelasticity parameter of the carbonatite fractured reservoir. The viscoelasticity parameter extraction method of the carbonatite fractured reservoir is suitable for fracture detection of the carbonatite fractured reservoir.

Description

technical field [0001] The invention belongs to the field of geophysical exploration, and in particular relates to a method for extracting viscoelastic parameters of fractured reservoirs. Background technique [0002] Carbonate fractured reservoirs refer to reservoirs in which the oil and gas storage spaces and seepage channels are mainly fractures, which occupy a very important position in several carbonate oil and gas fields discovered in my country in recent years. continue to show its importance. Seismic technology plays an irreplaceable role in the petroleum industry because of its comprehensive advantages in exploration cost and coverage area. However, due to the limitation of resolution and other factors, it is almost impossible to directly find fractures on seismic data, so the fracture detection method for seismic data has always been a major problem in the petroleum industry. [0003] A large number of experimental results and production data show that seismic wav...

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Problems solved by technology

[0004] At present, the viscoelastic parameter extraction method usually used in industrial production is based on post-stack seismic data. The stacking of seismic data can be approximately considered as a low-pass filtering process, that is, the stacked seismic data loses part of the middle and high frequency. Regrettably, the weak reflection seismic signals caused by fractures are just in the high-frequency information; in addition, most of the commonly used imaging methods are acoustic migration methods, which cannot fully reflect the characteristics of the viscoacoustic earth medium , the effect of seismic imaging in work areas with medium absorption characteristics is not good

[0005] For the above reasons, the existing viscoelastic parameter extraction methods are not suitable for the viscoelastic parameter extraction of carbonate rock salt fractured reservoirs.

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