The Application of MEG Drilling Fluid in Well Bin26X1.

Dagang Oilfield planned to drill deviated wells in year 2007 in the medium shallow formations of the Qikou sag,and underbalanced drilling were to be used in the target zones.Requirements for drilling fluids used were fo- cused on the lubricity,cutting-carrying capacity,borehole stability,and reservoir protection.MEG mud was se- lected for use in these wells.An MEG mud containing BST-Ⅱwas studied in laboratory experiments,and the re- suits showed that the MEG mud had good cutting-carrying and inhibitive capacity.The properties of the MEG mud was stable at elevated temperatures(up to 150℃),and high concentration of contaminants(20% drilled cuttings powders).The MEG mud had satisfactory lubricity without using any other lubricants.The recovery rate of per- meability of cores was greater than 90% using this MEG mud.This MEG mud had little,if any,negative influ- ence on mud logging because of its low fluorescence levels.