Study On Wellbore Purification Technology Of Large Displacement Well In JZ25-1 Oilfield

The large displacement well has become the most widely used well in Bohai oilfie ld.However,welhead cleaning has become one of the major problems in the effic ie nt drilling of Jinzhou 25-1 oilfield.Based on the domestic and foreign research,this paper analyzes the main reasons that affect the effect of rock carrying in the high gradient.By analyzing the data of Jinzhou 25-1 oilfield,this paper summarizes the block from three aspects: geological factors,physical and chemical factors and engineering factors The main reason for difficulties in carrying rock.Aiming at the difficulty of carrying the rock,based on the indoor simulation experiment and the numerical simulation,the optimiza tio n of the drilling process is carried out.In this paper,the wellbore structure is optimized for the geological characteristics of the oilfield,and the reasonable casing level is reduced to reduce the difficulty of rock formation.The influence of different drilling fluid parameters on the rock carrying effect is analyzed,and reasonable dril ing fluid parameters and system formula are given.The drilling fluid performance was optimized.Combined with the construction characteristics of the oilfield,the cutting bed was removed and a mechanical rock formation method was formed.In this paper,the application of highefficiency rock drilling process in the second phase of drilling engineering application of 12 wells,down the eye speed increased 69.72%,from the drilling speed increased 12.24%,single well drilling cycle shortened 18.39%,and achieved good application effect.