Research and Application of Synthetic Borehole Diameter Characterization Method
Drilling diameter information can assist in identifying abnormal conditions such as rock cuttings beds and falling blocks underground.Based on the shape of the wellbore,the quality of cementing,casing damage,and the degree and direction of fracture can be analyzed.At present,the form of characterizing well diameter graph is simple and the intuitionistic is poor.The average wellbore diameter change rate calculated using simple mathemat-ical averaging hides the engineering impact caused by serious expansion and contraction points and other abnormal situations.Moreover,a quantitative method for determining the qualification rate of continuous wellbore diameter changes has not yet been established.This article is based on wellbore logging data and adopts comprehensive methods such as mathematical representation and theoretical derivation to establish a flat wellbore graphical repre-sentation method.The equivalent circumference average wellbore change rate and the quantification method of continuous wellbore qualification rate are derived to finely characterize the wellbore information of continuous drilling sections.Taking A oilfield as an example,a comprehensive characterization of 74 drilled well diameters from 2020 to 2021 was conducted.The analysis showed that drilling in B formation is prone to collapse and block falling,and the qualified rate of well diameter changes in drilled wells is mostly over 90％.The comprehensive characterization method of wellbore diameter can better characterize the information of oilfield wellbore diameter,and the planar graphical representation of wellbore diameter can deeply reflect the inherent meaning of wellbore diameter changes.The calculation method of equivalent circumference average wellbore diameter change rate has expanded the sensitivity of average wellbore diameter change rate to outlier points,increased engineering safety,and quantified the wellbore qualification rate for the first time.This provides a theoretical basis for the evaluation of drilling operation quality and wellbore quality.
wellbore diametersynthetic characterization methodgraphical representationaverage change rate of wellbore diameterqualified rate of wellbore diameter change
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