A Method of Quantitative Porosity Inversion Using Seismic Wave Impedance

Abstract

The invention provides a method for quantitatively inverting porosity by using seismic wave impedance and belongs to the field of exploration and development of oil and gas. The method comprises the following steps: taking the seismic wave impedance as input data, constructing an error function inverting the porosity by using a rock physical equation and a seismic wave propagation velocity equation, constructing a feasible domain space of solutions in the value range of the porosity, and performing iterative inversion in the feasible domain space by adopting a non-linear global optimization algorithm to obtain the final porosity. The method provided by the invention is based on the rock physical equation and an elastic parameter to invert the seismic porosity, so that the physical significance is clear and the applicability is strong; the value range of the porosity is added into the inversion process as a constraint, so that the stability and the prevision in inversion are improved, and the advantage of prestack elastic parameter inversion can be kept; moreover, the method has the advantage of directly forecasting an oil and gas distribution favorable zone and can be directly used for inverting the porosity of actual seismic data.

Description

technical field [0001] The invention belongs to the field of petroleum and natural gas exploration and development, and in particular relates to a method for quantitative inversion of porosity by seismic wave impedance. Background technique [0002] Seismic exploration technology is the most widely used geophysical method in oil and gas exploration. Seismic waves are artificially excited on the surface or in wells, and the changes in the parameters such as the velocity, amplitude, frequency, phase, and waveform of seismic waves propagating in different media are used to analyze, Predict the distribution range and physical characteristics of oil and gas reservoirs. With the deepening of exploration and development, seismic exploration has gradually developed from the structural exploration of understanding the underground structure to the lithology exploration of directly using seismic information to judge lithology, analyze lithofacies, and quantitatively calculate the physi...

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Problems solved by technology

[0007] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art, and provide a method for quantitative inversion of porosity using seismic wave impedance, aiming at the difficulty in obtaining porosity profiles in seismic data interpretation and the inversion existing in conventional seismic porosity inversion methods. Due to low precision, complex input data, difficulty in applying complex geological conditions, and limited application, the present invention performs seismic porosity inversion based on rock physics equations and elastic parameters, with clear physical meaning and strong adaptability. The value of porosity The scope is added to the inversion process as a constraint, which improves the stability and accuracy of the inversion, can maintain the advantages of pre-stack elastic parameter inversion, and at the same time has the advantage of direct prediction of favorable oil and gas distribution zones, which can be directly used in actual seismic data The porosity inversion of

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