Method and device for predicting reservoir in weak-amplitude karst layer controlled by sequence interface

Abstract

The invention provides a method and a device for predicting a reservoir in a weak-amplitude karst layer controlled by a sequence interface. The method comprises the following steps: acquiring a time domain seismic data volume comprising seismic data of the weak-amplitude karst layer and an adjacent surrounding rock layer; leveling the time domain seismic data volume by taking the sequence interface data in the time domain seismic data volume as a constraint to obtain a stratigraphic domain seismic data volume; obtaining principal component seismic data according to the stratigraphic domain seismic data volume; obtaining a stratigraphic domain weak amplitude seismic data volume according to the stratigraphic domain seismic data volume and the principal component seismic data; and predicting a reservoir in the weak-amplitude karst layer according to the stratum domain weak-amplitude seismic data volume. According to the method, the weak-amplitude seismic data volume of the weak-amplitude karst layer is determined through a leveling and principal component analysis method.

Description

technical field [0001] This specification relates to the technical field of petroleum geophysical exploration, and specifically relates to a method and device for predicting reservoirs in weak-amplitude karst layers controlled by sequence boundaries. Background technique [0002] During the generation of carbonate rock oil and gas, the formation boundary is an important factor controlling the development of carbonate rock reservoirs. However, because the carbonatite karst pores and caves developed in the formation have a large impedance difference with the surrounding rock, the aforementioned carbonatite karst pore layer and surrounding rock form strong reflections on the seismic section at the formation interface, and the reservoirs adjacent to the formation interface are affected by the formation interface. Due to the influence of strong reflection, the seismic signal is weak and prediction is difficult. [0003] For example, the karst reservoirs in the Tazhong area of ​​...

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Problems solved by technology

However, because the carbonatite karst pores and caves developed in the formation have a large impedance difference with the surrounding rock, the aforementioned carbonatite karst pore layer and surrounding rock form strong reflections on the seismic section at the formation interface, and the reservoirs adjacent to the formation interface are affected by the formation interface. Due to the influence of strong reflection, the seismic signal is weak and prediction is difficult

[0003] For example, the karst reservoirs in the Tazhong area of ​​the Tarim Basin are mainly developed in the Ordovician Lianglitage Formation, and the Lianglitage Formation karst fracture-vuggy reservoirs are relatively well developed, showing strong reflection characteristics of "beads" and small fractures -The cave-type reservoir shows a weak amplitude seismic response, and the frequency domain is mainly medium-high frequency; while the top reservoir of the Lianglitage Formation is close to the overlying mudstone formation of the Sangtamu Formation, so the seismic wave reflected by the top of the reservoir is affected by the upper mudstone The influence of strong reflection at the interface with carbonate rocks is often shielded by the strong-amplitude seismic response characteristics of the formation interface, making it difficult to predict such storage

[0004] At present, some engineers have eliminated strong reflections by extracting and processing seismic data, but the effect is not satisfactory

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