Well X92 is a prospecting well set by Shengli Oilfield. In order to save investment, long open well drilling has been adopted in the 215.90mm hole, which is 3771m long. With complex geological conditions, there are not only general drilling difficulties, but also the coexisted various pressure strata with uncertain formation pressure coefficients, which is easy to cause drilling accident. These difficulties were overcome by reasonably controlling the performance of drilling fluid and adopting corresponding technologies of drilling fluid maintenance and treatment. The experience of this engineering case could be the reference for the long open well drilling design and construction in the same area.