A New Method of Evaluation Shale Brittleness Using X-ray Fluorescence Element Logging Data

In order to evaluate the fracability of shale gas reservoir and provide recommendation for fracturing,this paper made a study on evaluation method of shale brittleness.Based on relationship between mineral composition and rock mechanics properties,the way of using mineral composition to characterize its brittleness was considered.After measuring chemical elements composition of rock,making correlation analysis,selecting the elements which could respectively represent sandy,argillaceous and calcareous,using appropriate method to calculate the content of different minerals.Subsequently,the evaluation method of shale brittleness was established based on mineral composition.Applying this method to three wells of shale gas and performing element logging,comparing with ECS logging,a better linear relationship was presented.Compared with X-ray diffraction tests,the same trend was shown.It is able to meet the demands of realtime evaluation of shale brittleness.This indicated that the way of using element data to model minerals and thus characterizing shale brittleness was feasible,which provided a new means of technology for selecting favorable shale intervals to fracture.