Seismic Wavelet Low-Frequency Enhancement for Deep Carbonate Reservoirs

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Solution Overview

Problem

Conventional seismic data acquisition methods lack low-frequency components, leading to poor characterization and imaging of deep carbonate reservoirs due to absorption attenuation and low signal-to-noise ratios, making it difficult to trace stratum distribution and fracture systems effectively.

Innovation Solution

A method involving seismic data inversion using statistical information and optimized sparse regularization to enhance low-frequency seismic data by constructing a seismic wavelet with rich low-frequency information through specific Fourier transformations and convolution operations, controlled by parameters Pa and Pb to optimize low-frequency component enhancement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional seismic data acquisition methods are used, then the seismic data can be obtained, but the low-frequency components are lacking due to hardware constraints

Engineering Contradiction:

Improvelow-frequency componentsVSAvoidhardware constraints

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent performs preliminary action by estimating the wavelet and constructing a low-frequency enhancement operator before the main seismic data processing. This allows the low-frequency components to be restored in advance through spectral shaping operations, compensating for the hardware-induced frequency limitations without requiring complex hardware modifications.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If seismic waves propagate through deep carbonate reservoirs, then the seismic reflection signal can be obtained, but the signal suffers from absorption attenuation and low signal-to-noise ratio

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidabsorption attenuation

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent converts the harmful effect of absorption attenuation into a benefit by using the spectral characteristics of the attenuated signal to guide the wavelet estimation and low-frequency enhancement process. The attenuation effects are incorporated into the spectral shaping operator construction, allowing the enhancement method to specifically compensate for the expected losses and improve the signal-to-noise ratio in the restored low-frequency components.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Quantity of substance

If compensation operators are constructed based on existing seismic data with multiple control parameters, then low-frequency information can be enhanced, but the process becomes complicated and difficult to optimize

Engineering Contradiction:

Improvelow-frequency informationVSAvoidparameter adjustment complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent implements self-service by using the seismic data itself to automatically estimate the wavelet and construct the enhancement operator through sparse regularization inversion. The method eliminates the need for manual parameter adjustment by allowing the data to self-determine the optimal wavelet characteristics and spectral shaping parameters, thereby reducing operational complexity while maintaining enhancement effectiveness.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly improves the imaging quality of deep carbonate reservoirs by enhancing low-frequency energy, reducing side lobes, and improving resolution, allowing for clearer geological feature identification and fracture system characterization.

Implementation Method 1

performing an N-point Fourier transform on the average seismic wavelet wa, and obtaining a normalized amplitude spectrum Sa of the average seismic wavelet wa

Methodology Applied

Scientific EffectFourier transformation:

Implementation Method 2

calculating a temporary seismic wavelet w according to the following formula: w=real(ift(ft(wa)∘C))

Methodology Applied

Scientific EffectInverse Fourier transformation:

Implementation Method 3

convoluting the seismic wavelet wb with the reflection coefficients obtained by the inversion in step (1), so as to finally obtain a seismic data set with rich low-frequency information and enhanced low-frequency energy

Methodology Applied

Scientific EffectConvolution:

Data Source

PatentUS11262470B2Method of low-frequency seismic data enhancement for improving characterization precision of deep carbonate reservoir

Publication Date: 2022.03.01 CHENGDU UNIVERSITY OF TECHNOLOGY

AI summary

A method of low-frequency seismic data enhancement for improving the characterization precision of a deep carbonate reservoir includes: first performing inversions on an input seismic data set to obtain the corresponding reflection coefficients and average seismic wavelet; then constructing a seismic wavelet with rich low-frequency information; and finally, performing convolution on the seismic wavelet with rich low-frequency information and the reflection coefficients to obtain seismic data with rich low-frequency information and enhanced low-frequency energy. In the present invention, changes of the seismic data in a work area in transverse and longitudinal directions are taken into consideration, and processing parameters can be quickly determined according to actual conditions of the work area to obtain an optimal processing effect. In this way, the characterization quality of geological anomalies, such as a fault, a fracture system, or the like, in a deep carbonate reservoir can be improved significantly.