By analysis of its difficulties,matching tools and technology of the YD301 well are introduced,and successful experience of drill stem testing in long open hole well is summarized.

To solve the problems resulted from the damages of parkers and parking during drill stem test in open holes,the composition and mechanical properties of commonly used for compressible parking and parking holder are examined in laboratory.

Considering the characteristics of technology of drill stem test in the first deep horizontal gas well in Jilin oilfield,from technology analysis,the technical difficulties are comprehensively analyzed and studied during testing,and the basic principle of test operation is proposed,appropriate and necessary measures are taken to solve these problems.

To the fact of sampled well structure,long bore hole zone and irregular hole radius,taking example of bore hole test of JN1-1 well,the operation of collar location,adjusting mud and measuring actual bottom has been done to make sure test successful.

By comparing and analyzing for testing data, it is found that the polluti on to formation of open hole testing is little, production is high and formation productivity and physical information are gained which have irreplaceable role to work of knowing reservoir and latter testing operation.