Method for quickly recognizing carbonate formation lithologies while drilling

Abstract

The invention provides a method for quickly recognizing carbonate formation lithologies while drilling. The method includes the first step that the different lithologies are judged; the second step that rock debris of the different lithologies are sampled and are analyzed through the X-ray fluorescence element logging technology, and the Ca element pulse content and the Mg element pulse content are counted; the third step that rock debris of the different lithology centers are sampled, the Mg pulse content and the Ca pulse content of the different lithology centers are counted, and the average interval between the Mg pulse content and the Mg pulse content at the lithology center and the average interval between the Ca pulse content and the Ca pulse content at the lithology center are calculated; the fourth step that the Ca pulse content average value and the Mg pulse content average value of different lithologies are calculated respectively, then logging lithology recognition standards are obtained, and a lithology interpretation chart is established. The method achieves accurate recognition of the lithologies while drilling, judges that whether a horizontal well track passes through dolomite or not in time, and then provides a scientific basis for the necessity of adjustment of a track of an undrilled well segment and for predicament of the track of the undrilled well segment.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a method for quickly identifying lithology while drilling in carbonate formations. Background technique [0002] The lithology of the Yuanba gas field is complex, and most of the wells drilled are ultra-deep wells, and PDC bits are generally used for construction. At present, most wells use horizontal well drilling technology, resulting in fine and mixed cuttings. The traditional cuttings logging technology is difficult to accurately identify lithology. The emerging gamma-ray cuttings analysis technology has very limited identification effect on marine strata. The debris imaging technology has a very good effect on clastic rocks with large particles, but in marine strata, limestone and dolomite are very similar in appearance, and the application effect is not good. In order to improve the accuracy of lithology identification and deal with the problem of fin...

AI Technical Summary

Problems solved by technology

[0003] The technical problem solved by the present invention is to provide a chart interpretation method for rapid identification of lithology while drilling in carbonate formations in view of the lack of a method for rapid identification of lithology while drilling in carbonate formations in Yuanba complex

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