Inadequate wellbore cleaning is the main cause of more than 60％of the downhole accidents in extend-ed-reach wells.Since the 1970 s,scholars have been committed to the experimental research on cuttings migration in extended-reach wells and the theoretical research on cuttings migration,aiming to provide reliable experimental data and theoretical technology for accurate prediction and diagnosis of the whole borehole cleaning state in ex-tended-reach wells.In this paper,the cuttings transport experiments at home and abroad are comprehensively re-viewed and analyzed from the aspects of experimental equipment,experimental purposes,experimental methods,and sensitivity analysis of the borehole cleaning state obtained based on experimental data.The cuttings transport theory is sorted out into three categories:statistical regression model,particle dynamics model,and stratification model.The model's characteristics,practicability,and applicability are compared and analyzed.It is an important development direction of the cuttings migration experiment to build a Ø311 mm large-size cuttings experimental loop with the function of accurate measurement of annulus accumulation cuttings quality and visual measurement of cuttings concentration in cross-sectional annulus.At the same time,a large amount of experimental data is mined to establish an artificial neural network prediction method based on big data,which can map the complex nonlinear relationship between engineering factors and borehole cleaning state,and is expected to obtain more ac-curate and reliable prediction results than the traditional theoretical model.
关键词
岩屑运移/井眼清洁/大位移井井筒/实验/理论模型
Key words
cuttings transport/hole cleaning/extended-reach wellbore/experiment/theoretical model
维普
万方数据