Method for continuously quantitative evaluation of pore structures of reservoir strata by utilizing nuclear magnetic resonance well logging data

Abstract

The invention relates to a method for continuously quantitative evaluation of pore structures of reservoir strata by utilizing nuclear magnetic resonance well logging data, so as to divide types of the reservoir strata. The method comprises the following steps of: classifying T2 spectrums according to parameters reflecting differences of reservoir strata, and carrying out a nonlinear calibration method on different T2 spectrums to obtain a continuously distributed capillary pressure curve of the reservoir strata; obtaining continuous reservoir stratum pore throat radius distribution and pore structure parameters by utilizing the nuclear magnetic capillary pressure curve; and evaluating the pore structure of each reservoir stratum on the basis of the nuclear magnetic capillary pressure curve, the features of the reservoir stratum pore throat radius distribution and the pore structure parameters, and dividing types of the reservoir strata. Through the adoption of the method, the nuclear magnetic capillary pressure curve on each depth point can be continuously obtained by utilizing the nuclear magnetic resonance well logging data, the pore structure of each reservoir stratum can be quantitatively evaluated according to the reservoir stratum pore throat radius distribution and the pore structure parameters of the reservoir stratum, and the types of the reservoir strata are classified, therefore, the exploitation and development efficiency of complicated oil-gas reservoir is improved.

Description

technical field [0001] The invention relates to petroleum geological measurement and analysis technology, and is a method for continuously and quantitatively evaluating reservoir pore structure by using nuclear magnetic resonance logging data to improve the exploration and development efficiency of oil reservoirs. Background technique [0002] Quantitative evaluation of reservoir pore structure and accurate division of reservoir types are widely concerned by geologists, especially in complex oil reservoirs, continuous quantitative evaluation of pore structure and division of oil and gas potential Particularly important. If the characteristics of reservoir pore structure can be continuously and quantitatively characterized and the reservoirs can be classified, the exploration and development efficiency of oil and gas reservoirs will be greatly improved. [0003] At present, the most direct and effective data for quantitative evaluation of reservoir pore structure and classif...

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Problems solved by technology

These methods do not have a strict petrophysical basis, and the accuracy of the calculation results will be affected by the selected core samples, and the application conditions are relatively strict, so they are not suitable for large-scale applications

[0033] It is difficult to accurately determine the conversion scale factor in the process of obtaining NMR capillary pressure curves by using NMR logging data in existing methods, and the research method only stays at the stage of exploratory core experiment research, and cannot reach the goal of using actual NMR logging data. For the purpose of continuous and quantitative evaluation of reservoir pore structure, direct use of NMR logging T 2 The relationship between geometric mean and reservoir pore structure parameters Calculation of reservoir pore structure parameters also has limitations and difficulties in practical application

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