Optimization and Application of Under-balance Drilling Program for Nanpu Oilfield

The drilling problems,such as the loss,blowout,borehole collapse and sticking are normal with the perpetual exploration and development of Nanpu oilfield in over-balance drilling. It not only makes drilling cost and period increase,but also damages the reservoir. With the formation condition of Well 128 Dong3 in Nanpu oilfield,it evaluates and optimizes aerated under-balance drilling is the best under-balance drilling program for the well.