Anisotropic formation dip angle determination method based on transient multi-component induction logging

Abstract

The invention discloses an anisotropic formation dip angle determination method based on transient multi-component induction logging. The method comprises the steps of (1) building a transverse isotropic formation model, and designing a multi-component transmitting and receiving antenna combination mode; (2) selecting a lower step signal source as an excitation source for transient multi-componentelectromagnetic wave logging, and measuring a pure secondary field in a formation after the excitation source is cut off; (3) adopting an inverse laplace transformation method for transforming a frequency domain multi-component induction logging tensor into a time domain, and obtaining an induced electromotive force for transient multi-component induction logging; (4) building an algebraic relation between a transient multi-component induction logging measurement signal and a formation dip angle; and (5) according to a change characteristic of an anisotropic formation dip angle in the time domain, determining a formation dip angle determination method. The anisotropic formation dip angle determination method based on transient multi-component induction logging provided by the invention can solve the problems of cumbersome operation, time consumption and solution multiplicity of current anisotropic formation dip angle inversion, and can quickly and accurately provide dip angle information for anisotropic formation evaluation and geological orientation.

Description

Technical field [0001] The invention relates to the field of oil and gas exploration and development, in particular to a method for determining anisotropic stratum dip based on transient multi-component induction logging. Background technique [0002] Electrical anisotropy has always been an important problem that plagues the exploration and development of unconventional oil and gas reservoirs such as thin interbedded sandstones and shale reservoirs. Affected by anisotropy, the spatial distribution of formation resistivity is related to the direction, and the specific expression is The resistivity in the stratigraphic direction is much smaller than the vertical resistivity. Traditional induction logging can only measure the horizontal resistivity in vertical wells, and the water saturation evaluated by Archie’s formula is too high, which easily leads to the loss of effective reservoirs. Therefore, major oil companies have successively introduced multi-component induction logging...

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Problems solved by technology

[0003] Aiming at the problem that the existing technology needs to extract the formation dip angle through complex inversion, the present invention proposes a method for determining the anisotropic formation dip angle based on transient multi-component induction logging, which is reasonable in design, simple in application, and has good prospects

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