Yi 187 well was an appraisal well, and it was located on the fifth fault block of Ji Yang Downwarp in Bohai Bay Basin. The total depth is 3980m. The borehole wall was very instable in the second interval because of the length of open well and crack. Complex accident of stight hole sticking occurred frequently in the third interval because of gypsolyte and argillaceous, and theological property became bad because drilling fluid was contaminated. Bottomhole temperature was high and the drilling fluid density was heavy, so exploratory drilling difficulty was great. After sulphonated polymer and anti-caving drilling fluid and polyamine and high inhibition drilling fluid were applicated and the corresponding maintenance and handling technics were asisted, the well was finished successfully. Testing oil showed that crude oil production was 185.2t a day and gas production was 13400m3 a day, with a good prospect of exploration and development.