Exploration Well Structure Optimization and Risk Study in Shengli Offshore Area

With the development of drilling technology, well structure has been changed repeatedly in Shengli offshore area. From 660.4 mm×444.5 mm×311.2 mm×215.9 mm×152.4 mm to the recent use of mature 914.4 mm×444.5 mm×311.2 mm×215.9 mm×152.4 mm well structure, they have been widely used in middle-deep wells and deep wells, the multiply casing has been used to protect the weak formation and avoid the drilling risk. But in the year of 2006, a new well structure of 914.4 mm×444.5 mm×241.3 mm×152.4 mm had been used in H9 well and got success. From then on, it gradually applied to other wells. With the long open hole design been used, it can shorten the drilling period, improve the company's benefit, meanwhile, it also increases the drilling risk.