Research and application of drilling fluid suitable for new well bore structure in the Shunbei oil field

In the Shunbei oil field, leakage often took place in Permian, well bores are instable in Silurian, collapse stress is high in the Sangtamu Formation, and it is difficult to carry debris directionally in deep and slim holes. A new well bore structure with special intrusion for sealing is proposed. Through laboratory experiments, we choose polyethylene amine, high softening point asphalt, sulphonate copolymer treating agent such as methy-lamine, and introduce methylamino drilling fluid and filming technique, to deal with longitudinal cracks in Permian. Field applications were made in 5 wells, and proved successful. A set of suitable drilling fluid technology has been developed to meet the needs of new well structure.