Method for distinguishing calcareous mudstone from sandstone

Abstract

The present invention provides a method for distinguishing calcareous mudstone from sandstone. The method includes the steps as follows: S1, establishing an isochronous stratigraphic framework; S2, performing sparse impulse wave impedance inversion on the basis of the isochronous stratigraphic framework establishment so as to acquire a wave impedance data volume with high lateral continuity; S3, performing sensitivity curve optimization and correction; S4, performing variation function analysis by utilizing the optimized sensitivity curve so as to acquire a parameter probabilistic model with high longitudinal resolution. The method for distinguishing calcareous mudstone from sandstone can increase reservoir prediction precision by utilizing macro-view cognition such as geology and well drilling as a guide, utilizing well log curve as a starting point, and utilizing the corresponding reservoir prediction method as a tool.

Description

technical field [0001] The invention relates to the technical field of oilfield exploration, in particular to a method for distinguishing calcareous mudstone and sandstone. Background technique [0002] Reservoir prediction mainly involves amplitude and frequency attributes. Conventional reservoir prediction methods include root mean square amplitude, total amplitude, arc length, frequency division interpretation, average reflection intensity, and energy half-life time. Through the comparison and analysis of a series of reservoir prediction methods, it is found that none of them can effectively distinguish calcareous mudstone and sandstone, mainly because calcareous mudstone has similar AC, DEN and GR values ​​to sandstone (pebble-containing sandstone, fine sandstone, siltstone) . The inaccuracy of reservoir prediction greatly reduces the success rate of exploration and affects the progress of exploration. [0003] Lime mudstone affects reservoir prediction accuracy in all...

AI Technical Summary

Problems solved by technology

Through the comparison and analysis of a series of reservoir prediction methods, it is found that none of them can effectively distinguish calcareous mudstone and sandstone, mainly because calcareous mudstone has similar AC, DEN and GR values ​​to sandstone (pebble-containing sandstone, fine sandstone, siltstone)

The inaccuracy of reservoir prediction greatly reduces the success rate of exploration and affects the progress of exploration

[0003] Lime mudstone affects reservoir prediction accuracy in all sags of the Jiyang Depression. Lin Zhongkai and others from the Institute of Geophysical Prospecting of Shengli Oilfield calculated the main frequency of seismic data in the development section of lime mudstone, extracted the frequency-divided data volume of the corresponding frequency, and then used the data The body uses the amplitude attribute to predict the distribution range of the lime mudstone within a certain time window, so as to achieve the purpose of removing the influence of the lime mudstone. However, the limitation of this method is that it can only predict the development range of the lime mudstone. At the same time, the sandstone as an effective reservoir is also removed, which is a semi-quantitative reservoir prediction method and cannot accurately reflect the distribution of reservoirs.

Images