Method for automatic calculation of lithological curve by employing logging curve in geophysical exploration

Abstract

The invention provides a method for automatic calculation of a lithological curve by employing a logging curve in geophysical exploration, and belongs to the field of petroleum geophysical exploration. The method includes: (1) loading the logging curve, comprising curves of gamma, spontaneous potential, resistivity, neutron, and neutron lifetime; (2) respectively correcting the five curves, and obtaining corrected curves; (3) respectively reading the maximum GMAXi and the minimum GMINi of the five curves from the corrected curves; (4) calculating the curve shale content relative value Shi; (5) calculating the shale content; (6) calculating the final shale content Vsh; (7) calculating the lithological curve with the combination of the final shale content Vsh obtained by the step (6) and a measured density curve Density; and (8) outputting the lithological curve.

Description

technical field [0001] The invention belongs to the field of petroleum geophysical exploration, and in particular relates to a method for automatically obtaining lithology curves by using well logging curves in geophysical exploration. Aiming at the problem of logging-constrained seismic inversion, it involves the application of well logging data for lithology analysis and identification technology. It can be applied to lithological inversion in petroleum geophysical exploration. Background technique [0002] With the deepening of oilfield exploration and development and the development of reservoir description technology, it is difficult to find large and integrated structural oil and gas reservoirs. At present, the focus of research is on complex and subtle lithologic oil and gas reservoirs. played a major role in the discovery. With the development of subtle lithologic reservoirs, the demand for seismic inversion is getting higher and higher. Conventional wave impedance ...

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Problems solved by technology

[0010] This method mainly uses gamma and density curves to obtain the shale content curve, and then uses the shale content curve to obtain the lithology curve. After comparing and analyzing with the actual lithology logging data, it is found that there are some errors, including these pure mudstone The determination of natural gamma values ​​of pure sandstone and pure sandstone is also very artificial, so the obtained shale content curve is not very accurate, so it is necessary to carry out research on the accurate calculation of shale content curve, which needs to be combined with other Calculation of lithology curves

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