Application and Research of Friction Coefficient Variation Law of the Extended Reach Well in the Bohai Sea

In order to meet the requirements of accuracy and timeliness of on-site engineering calculation, this paper establishes a friction factor database by inverting the friction factors of tripping in/out BHA and tripping in casing/liner,which can provide the basis for the selection of friction factor. By analyzing the data of the database,we found the changing law of the friction coefficient under the condition of tripping in casing and liner. In practical application, the inversion friction factor of the tripping in 7-in liner in A5H1 is applied to A7H3, which is in the same field with similar inclination and same drilling fluid system. The predicted results are in good agreement with the actual results. The establishment of the friction factor database is of great significance to improve the accuracy of on-site engineering calculations.